Accordion Microphone Systems

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~Dream~

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Dec 23, 2002, 12:16:16 AM12/23/02
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part 1

Before we get into comparisons between Mic systems and pre-amps,
let me go over the basics as I've found them.

First of all, the microphone elements themselves are the most important
part of the equation... as with computers "garbage in = garbage out".
You want a Mic that will pick up sound evenly across a broad frequency
spectrum.
It should also accept a wide range of acoustic pressure without
distorting.
This is in contrast to Vocal microphones, for instance, or Guitar
pickups,
which by design "color" the sound (acting as tone controls in a sense)
but is
similar to Studio microphones which are often prized for their
transparent quality.

In the old days, Dynamic (moving coil) microphone elements tended to be
rather
expensive, and somewhat large. They do take sound pressure well,
especially
the type with big diaphrams, and though they "color" the sound a bit,
were a huge improvment over Crystal, or Carbon elements, which give a
"tinny" sound, and are very prone to feedback.

Technology has reduced the size of Dynamic microphones dramatically...
to the point where there are now headset style vocal mics which are
nearly indistinguishable from the far more commonly found electronic
(powered) type.
There are situations where dynamic elements still are useful for the
Accordionist... perhaps you simply have an installation where using a
battery or other power source would be a problem... or wish to go with
the
old-style "one mic inside the bellows" setup for simplicity.

Personally, regarding the Bass, since there is usually ample room
inside,
and as I feel the Bass does not need the higher frequencies amplified
strongly,
I often use a Dynamic on the left side. Of course, crystal Mics would
be
considered totally unacceptable today... and though PZM Mics are also
viable,
they are not easily or widely used, so I will not be discussing them. If
someone
would like to detail the usage of Pressure Zone elements for accordion
installation,
that would be welcome... as I recall some of our English friends have
rigged these.

Even the commonest Electret Microphone element available at Radio Shack
for
a few dollars is far superior to any crystal element, and most of the
dynamic elements, ever available for Accordion. The electret microphone
was a technological marvel at it's introduction, and quickly became a
tiny
wonder as semiconductor technology rapidly advanced. The electret
microphone
itself is basically a film capacitor connected directly to a tiny, FET
type
transistor which is contained in the body of the microphone itself.
These
microphones have near flat frequency response over a wide dynamic range.
In addition, miniaturization of components has allowed designers to
reduce
the size from the tiny "mini-marshmallow" to less than a pencil eraser
while
improving the pressure handling, and most importantly the directional
characteristics.

This is the difference, for example, between the Master Sennheiser
system and
a less expensive model which uses the identical electronics and
circuit-board,
but substitutes "standard" quality elements (for about $100 less/street
price)
The difference in tone is not that great to the untrained ear, but the
resistance
to feedback and noise makes the less expensive system unsuitable for pro
use.

end part 1

Ciao Ventura

~Dream~

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Dec 23, 2002, 12:16:27 AM12/23/02
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part 2

Another consideration regarding Mic elements has to do with their
mass (weight). Medium to large Dynamic elements are often sheathed
in rubber or even spring mounted before installation inside Accordions,
so as to somewhat isolate them from the vibrations (noise) which comes
through the body of our instruments. Gravity can be a factor also...
so my typical Bass chamber installation is a rubber enveloped Dynamic
Mic,
mounted on the low side (near the base of the strap, where it's firmly
but
flexibly fastened. In the old days, for many Dynamic and Crystal
installations (particularly on the treble side) the elements were often
glued directly
to the inside of the grille - a secure mount, but very, very noisy and
even more prone to feedback. For comparison, take apart the handset of
any cheap telephone, and you'll find an electret Mic mounted rigidly.
Take apart an AT&T handset and you will find the same type Mic element
mounted intelligently with a large rubber surround The difference is
a designer and a company that just want your money, vs one that wants
you for a lifelong-repeat customer.

Electret mics are, of course, so small and lightweight that one
of their great benefits is they allow us many methods of "soft"
but still very secure mounting techniques. Even a slim circuit
board with several elements and related parts is still so lightweight
that simple foam mounting tape gives a completely secure, but cushioned,
installation. The Radio shack Mics come with a rather strong shielded
wire + 3rd hot wire pre-attached, and you can actually just dab a
spot of Silicon glue/rubber about an inch down from the element and
they'll hang there in free space happily isolated from vibration
forever.
(my red Serenellini has the elements mounted this way, and they are
still
in place 25+ years and thousands of gigs later) When using electrets on
the Bass side, I always use a matched pair... one in each and of the
chamber.
You wrap them in foam tape and find plastic "P" wire guides the right
size for a great, vibration resistant mount. Actually, one would have
to try pretty hard to screw up mounting electret elements!
(though there IS one major brand that does just that by hard mounting
their electret element inside a large, heavy metal finger which is
designed to be flat-stuck directly to the metal surface inside your
grille,
or screwed down through a hole in the body - incredibly stupid - it's a
system which completely compromizes one of the best features of
electrets...)
Firm mounting results in every noise vibration transmitted through the
body
of the accordion being picked up as noise by the Microphones
(and then amplified along with your reed sound)

While even the cheapest electrets will give good results, there are
several reasons to go with the more expensive models... Panasonic
(used by several accordion factories) has a nice line of shallow/wide
elements, which I rather like. They have models which are highly
directional
(cardiod) which helps resist feedback. (Regular elements, like used
in a Cell phone or a Lapel Mic pick up sound from ALL directions,
even from the rear, which is why they tend to feed-back far more
quickly.)
I use a model rated 20-18,000 Htz that works well on battery power (3 -
9 Volt). Overall, the best Mic element available to the Accordion
community is the
Sennheiser. The same element used in their headset-vocal mic is
available
as a loose part to OEM's. These are expensive elements, and in a kit
like
Master's you get 4 of them - which is a bargain in a way, as a single
element,
if ordered from Sennheiser's parts dept. by someone like you or me for a
repair job is @ $85 plus shipping.

Placement also is a factor... with good omni-directional mics you want
one to start where the other one leaves off. With Sennheisers, my
preference
is 4 on the treble side... slightly staggered. With Panasonic, I have
one
8 element install which is amazingly smoothe and even. With the less
desirable
and cheaper Omni-directional Mics, you can get away with as few as 2 on
the
treble and one in the bass. You have to experiment a bit to get the best
results (Velcro is your friend) before you lock everything into place.
Mic spacing on pre-built circuit boards is pretty much set, however,
to produce good results in the widest variety of installations...
but a solder gun and a bit of intelligence can improve these quite a
bit.

Under the grille, you can achieve great tonal results with even the
cheapest electret Mics, but controlling feedback requires use of the
premium elements. Mounting lesser quality Mics in a chamber that narrows
their directional pickup pattern will give you better results than
mounting premium Mics in a stupid and compromising fashion.

end part 2

Ciao Ventura

~Dream~

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Dec 23, 2002, 12:16:38 AM12/23/02
to
part 3

Now that we have a nice, rich signal coming from our Mic(s),
we need to process it. This can include some tone control,
but mostly has to do with "mixing" multiple elements
(so they work evenly together) and boosting the signal,
so a nice, hot feed is sent to be amplified. This is critical
to a good system, and is a factor in the signal to noise ratio.
That 20 foot long wire you use, even if you've bought the best
$40.00 braided shield Belden cable you could find, can't
completely protect your audio signal from noise. If the audio
signal is good and "hot", then the amplification stage doesn't
need to boost it's input so much, and the noise in the signal
is not a factor. If the audio signal is weak, the amplifier
input stage must be cranked up... which boosts the NOISE as
well as your sound... then it IS a problem (and ruins the
sound for recording, subjects you to sudden taxicab broadcasts
on stage, and makes your system more prone to feedback)

So the pre-amp needs to (mainly) mix the mics and boost
the signal. It also needs to NOT compromise the signal from
the Mic(s). A poorly constructed pre-amp can actually
contribute noise to your audio signal.

Master's pre-amp is the smallest, simplest I've seen, and
works quite well. It's about one inch square, and consists
of a good single sided Op-amp and a few discrete parts
(for bias, ground reference, isolation, and noise reduction)
I have copied it a few times, and tried to expand on it, but
it is simple, tried and true, and hard to beat for something
you can fit under the grille that won't eat batteries.
The Sennheisers are first summed, so they each are contributing
about the same level of energy to the signal to be amplified,
and then boosted slightly. I suggest turning your grille volume
control to it's maximum, set the volume at the amplifier to the
absolute loudest level you want to use for the gig, then back off
the grille volume control to the loudness you want to start with.
This leaves the least amount of resistance in the chain, allows the
strongest signal out, and still gives you decent control/headroom.

The next type of pre-amp - a "belt-pack" style unit - has gained
some popularity of late among accordionists, and is the impetus for
my current curiosity. An outboard pre-amp has some obvious advantages...
the Volume control doesn't need to be mounted on the accordion grille
(you didn't really want to drill a hole in that $5000 box) size
constraints are relaxed (you can use hefty caps again instead of
tiny Tantalum's) you can use more complex circuits (
active tone controls, for instance), the battery is easier to change,
(can even have an LED power indicator) and it's easy to fully shield
(in a little metal box). As a point of reference, I noticed that the
Barcus-Berry line has several professional electret mic based models
available which use a Belt-pack pre-amp. (Harmonica, Flute, Sax,
Clarinette, etc) Their belt-pack became available as a separate
item this year from the manufacturer/distributor (the model 3000Ae)
Pretty much any music store or repair shop can get them, as the
distributor is a major player. Wholesale cost is $40 bucks, so
you can expect to pay $70-80 from a stocking retailer
(covers their shipping, stocking, and profit) or $60 or so if
someplace just orders it for you (a phone call, a shipping fee,
and $10 bucks profit) and you pre-pay.

The Barcus-Berry is a class act. Fiberglass circuit board (strong)...
gold flashed contact-points on the jacks (better connection)...
socketed IC (easy to repair, less chance of a DOA) solid metal box
(could probably run over it with a Datsun) dipped mylar caps
(the green kind) and a full metal battery holder (vibration proof)
I estimate the parts alone would cost over $20 bucks at Active or
Digi-key, and take a day to built with a generic board. The tone
control circuit uses half the dual j-fet OpAmp, is a clean
symmetrical design and achieves it's goals with minimum resistance
placed in the audio path. The other half of the OpAmp provides the
boost.
You could use this pre-amp with any type or combination of electret
Mic(s)

K&K markets an Accordion mic system with an outboard active pre-amp.
By way of comparison, the K&K is slightly superior in manufacture...
being a wave-soldered device (smaller footprint) with machine-placed
discrete components... but slightly weaker in some areas (the Barcus
having socketed the IC and battery, for example) K&K also is configured
to be usable in mono or stereo modes. This is achieved, unfortunately,
through the use of multiple mini-jacks and sockets (they have to stuff
a whole row of 'em along the end). These connectors are by nature prone
to movement (you move, the wire moves, the jack swivels, noise is
generated - and repeat). Metal case on the Pre-Amp, of course. Also,
the K&K system comes with pretty run-of-the-mill Mics. but is an
inexpensive system, so you get what you pay for. But I would not
recommend it for professional use. You could take it, install their
Mics into a rail, hard-wire a lead through a jack-hole directly to
the input and put a good 1/4" switchcraft plug on the end to connect
to the Rail and actually end up with a pretty decent Mic system.

end part 3

Ciao Ventura

~Dream~

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Dec 23, 2002, 12:16:49 AM12/23/02
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part 4

The next comparison would be to a standard "Stomp-box" type pre-amp
or graphic EQ from DOD, BOSS, NOBELs or other decent brand. I picked up
a new NOBELs pre-1 to play around with, and it works fine with electret
Mics.
Pedals are a bit larger, heavier, and not suitable for hanging off your
belt,
but if you are just playing at home, or jamming, and you stay seated
pretty
much all the time, you could certainly build yourself a Mic rail from
surplus
electret elements, run a cable from your Accordion to a pre-amp pedal on
the
floor or table next to you, the run the pedal to your Amp. Graphic or
notch
filter pedal EQ's can give you a lot of control over tone and feedback.

For the do-it-yourselfers out there, these are.all affordable solutions.
(both
the Sennheiser and the generic kit's are readily available (from E.
Deffner,
for example) from @$300-@$400, and the K&K is @$250 (direct) but the
Barcus Berry
is a highly flexibly, easily configurable professional quality active
pre-amp,
and ideal for people who, like me, prefer to customize their Mic
systems, and
who always run Treble and Bass independantly. (the BB's are mono only)
They
can be used in any number of ways - for instance, you could install 3 or
4 mics
under the treble grille of an accordion, run a short shielded cable to
the pre-amp,
and you're ready to go. Or, since the circuit board is laid out in a
friendly
fashion, the board can be divided at the battery mount, the small
potentiometers
removed, and the jacks re-mounted so that the resulting pre-amp section
is small
enough to build into a "Rail", or under the grille. Then you could use
larger,
better potentiometers (10K with indents) for the Bass, Treble and Volume
controls.

It is worth noting here, that anyone who commits to using Wireless 100%
of the time
for acoustic accordion, has an active pre-amp and bias circuit in the
transmitter
which you can use. In other words, you buy a Wireless system, and you
get the
transmitter that comes with a headset mic or lavalier mic. Well, you can
velcro
the transmitter to your Bass strap, take the Mic it came with and
install it inside
the Bass chamber, mount a volume control on the plate below your Bass
buttons, rig
a way to plug the transmitter in and you're done! Conversley, build a
treble Rail
with 4 surplus elements , a volume control, and a battery mount, and
plug it into
any Guitar type wireless transmitter for the "pre-amp" and you're good
to go.

Follows a basic explanation of how electret type (powered) Mics are
wired:

Electret mics have a tiny transistor integrated inside their shell - a
transistor
which requires a small amount of DC (direct) current to operate.
Electret's can work effectively on a little as 2 button cells (3 volts
total)
as often found in Lapel style use, and they work quite well on a 9 volt
battery
too, which is the common power source we use for small musical devices.

There is a trick to "Bias"ing an electret element. Both the audio
signal, and
the positive plate, are essentially the same. Electret Mics that come
from the
manufacturer (both the Radio Shack and Sennheiser happen to be this way)
internally biased have 3 leads/wires (or legs) sticking out the bottom.
The hot wire is the red one, the Audio signal comes through the middle
wire
of the small co-axial cable, and the ground is the shield on the cable.

(note: shielded cables are used to protect the audio from
interference... the
audio is carried on a wire which is insulated then completely wrapped in
another
wire. Interference hits the wrapped, outer wire first and is trapped to
ground)

Or look closely on the base and you'll see a small minus sign (ground)
small plus
sign (hot) and small squiggly line (audio signal). Internally
compensated elements
are the easiest to connect, but most electret Mics you'll encounter have
only 2
leads/legs/wires sticking out of them.

You wire these by first determining which leg is ground (if it's not
marked, just
use an ohm-meter. Place one lead on the metal shell of the mic... the
ground leg
will show 0 (zero) ohms on the meter) Then you solder a small capacitor
and
small resistor in parallel on the other leg. The other end of the
resistor is
now your "hot" lead, and the capacitor gives you the audio signal.

This works because a Capacitor will block Direct current (the battery)
and pass
AC current (the audio signal) the audio signal prefers to go through the
"path
of least resistance" so it avoids the resistor and drains through the
capacitor.

You can connect 3 or 4 electret elements easily in parallel without any
problem.

An added safety feature is to connect all the bias resistors through a
common Diode
to the battery (power source) another added protection is one final
capacitor on the
last output position to help "isolate" your amplifier circuits from your
mics/pre-amp stuff.

end part 4

Ciao Ventura

~Dream~

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Dec 23, 2002, 12:16:56 AM12/23/02
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part 5

Now there is a huge difference between "Active" and "Passive" audio
electronics systems. Passive circuits are what you study in basic
electronics 101 (for the principles) and you go from there. In the
old days you used a 12AX7 in your pre-amps (whether a Fischer Hi-Fi
or in an old Cordovox...(remember the 2 upright tubes on that little
metal box sticking out ) Then we started using Transistors, which
were OK, then J-Fet's came along (transistors which exhibit the
characteristics of Tubes) and we've been using them ever since.

Why do we go to all this trouble? NOISE

Take a standard Vocal Microphone and cable. Plug it into your PA system,
turn it up to normal levels, then bring the Mic into the proximity of a
plugged in "Wall wart" transformer. Hum... Noise. Move the Mic away,
and now place the cable close to the wall-wart... unless it's a cable
with really high quality shielding, it too will pick up some hum...
noise.
Fluorescent lights give off electronic noise... all the radio
frequencies
passing through the room have energy levels... every type of Compressor
and electric motor generate interference.

Passive audio devices have a signal to noise ratio typically in the
vicinity of -40 decibels. That's why the only "passive" audio devices
on the market are what we call "emergency" items for the "toolkit"...
those tiny little resistor matrix mini-mixers from Rolls ($29.99) and
Switchcraft ($19.99)you have in the wheelwell for dire emergencies.
Passive audio devices operate ALWAYS by sacrificing part of your
signal to ground. Passive circuits ALWAYS give you less power at
their output than you gave them at their input. Passive devices MUST
use resistance to mix audio (introducing more noise through heat
dissipation)
and MUST use RC networks for tone control (which sets up resonant
frequencies
that are susceptible to external noise elements co-incidentally
transmitting
those frequencies). About the only Passive audio device legitimately
used
in Pro Audio today is the Direct-Box - which is basically a high quality
transformer that isolates a high-level audio signal and bleeds off a
mirror
image from a secondary winding. All of these little tool-kit devices
come,
of course, in a small metal aluminum or steel box to shield them from
noise.
Passive devices are more susceptible to noise than active devices - this
is key.

end part 5

Ciao Ventura

part 6

Let's take a real world example of a passive audio system. The tone
control
circuit is not symmetrical. The reactance/resonance of stage one is
affected
by stage two (in other words, set your treble, then set your bass, and
the
treble changes because the RC values of the second stage force some of
the
signal back up the audio stream. Change your Volume control and
everything
changes again (because now, the frequencies being impeded at the tone
stages
may find an easier path to ground back at the top) Mix this with a
second
identical channel that has it's tone controls set to emphasize low
frequencies
(from a Bass mic, perhaps) and it can actually bleed off some of the
treble
frequencies you wanted to keep from the first channel.

This example circuit board uses all tiny electrolytic cap's for audio
coupling,
and can introduce over 100,000 Ohms resistance into the direct path of
the
Audio depending on where the tiny little carbon trace pc-mount variable
resistors are set. The board is designed to accept better
potentiometers,
as the center-tap has an extended trace curliqued to a different hole .
This curlique is almost an inch long, and actually acts as a tiny
antenna
for stray noise... you can seriously improve the properties of this
circuit
just by scratching these traces out. Kind of wonder why they didnt do
that,
as the board itself was designed for a different use, and it has to have
a
copper trace cut by hand in order to provide power switching through the
barrel of the output jack. To compensate for this "adjustment" a tiny
little
wire is surface soldered across the circuitboard to send the Mic bias to
the
other side. Power is only used to bias the Microphones, of course. So
why the
guy with the moto-tool doesn't take half a second to trim out these
little
noise antennas is beyond me.

Of course, it wouldn't matter anyway, as the belt-pack housing of this
"fake-pre-amp" is actually made out of simple Plastic. That's right...
the entire circuit has zip, zero, nada, nothing shielding it from
interference.
The plastic is not even carbon-impregnated You gotta' wonder who would
have
the nerve to try to pass something like this off as a legitimate
Pro-Audio tool.

Now the designers of this device actually DO know the difference between
Passive and Active electronics (a typical Active pre-amp has an SN ratio
above 90) and they also know which one is better... that's why they lie
and mark right on the outside of their belt-pack the words "Active" and
"Pre-Amp"... because as old PT Barnum is reported to have said,
"there's one born every minute" But I'm sorry... if you actually look
inside one of these things, see $5.00 worth of parts, 3 weird
microphones
mounted in heavy metal sheaths, and you're out $400 bucks or more,
you're
going to feel like what? a sucker?

Personally, I wouldn't have a system like this if you GAVE it to me
(which it was... it's going back) or even if you PAID me. The K&K
was also given to me free by a Pro musician who found it too prone
to feedback and noise for professional use... but the K&K by contrast
can be salvaged, so I'll eventually send it back to the former owner
in an improved state.

end part 5

Ciao Ventura

~Dream~

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Dec 23, 2002, 12:17:02 AM12/23/02
to
part 6

that, as the board itself was originally designed for a different use,
and it has to have another copper trace cut by hand in order to provide
power switching capability through the barrel of the output jack.

To compensate for this "adjustment" a tiny little wire is surface
soldered across the circuitboard to send the Mic bias to the
other side. Power is only used to bias the Microphones, of course.
So why the guy with the moto-tool doesn't take half a second to
trim out these little noise antennas is beyond me.

Of course, it wouldn't matter anyway, as the belt-pack housing of this
"fake-pre-amp" is actually made out of simple Plastic. That's right...
the entire circuit has zip, zero, nada, nothing shielding it from
interference.

The plastic is not even impregnated. You gotta' wonder who would have


the
nerve to try to pass something like this off as a legitimate Pro-Audio
tool.

Now the designers of this device actually DO know the difference between
Passive and Active electronics (a typical Active pre-amp has an SN ratio
above 90) and they also know which one is better... that's why they lie
and mark right on the outside of their belt-pack the words "Active" and
"Pre-Amp"... because as old PT Barnum is reported to have said,
"there's one born every minute" But I'm sorry... if you actually look
inside one of these things, see $5.00 worth of parts, 3 weird
microphones
mounted in heavy metal sheaths, and you're out $400 bucks or more,
you're
going to feel like what? a sucker?

Well, the Microphone is active... all electret microphones are active.
Though the whole WORLD considers the term "Pre-amp" to mean a
device that does actually boost the signal - I guess you could pretend
you meant pre (as in before) and amp (as in amp) so you and me
would be pre-amps too, then, as we come before the amplifier too.

That's a little like the money back guarantee... we
guarantee if we don't like your Money we'll send it back.

Personally, I wouldn't have a system like this if you GAVE it to me
(which it was... it's going back) or even if you PAID me. The K&K
was also given to me free by a Pro musician who found it too prone
to feedback and noise for professional use... but the K&K by contrast
can be salvaged, so I'll eventually send it back to the former owner
in an improved state.

end part 6

Ciao Ventura

~Dream~

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Dec 23, 2002, 12:17:07 AM12/23/02
to
part 7

I hope this series is useful to some of you,
explains some things and gives you ideas.

new surplus Parts for do-it-yourselfers? allelectronics.com
(in California)

cat# MIKE-49 ($ 0.75) surplus electret mic from a cell phone kit.
These are German, I used a set for a friend... great tone.

NMH-9 ($3.50) decent NIMH re-chargable 9 volt shape battery.
Good for Mic biasing... holds a charge for a long time.
Only 7.2 volts though, so not good for transmitters and such
(Sears has a great 9Volt NIMH)

NATP-10K (2 for $1.00) 10,000 Ohm Audio taper 6mm Potentiometer with
detents. nice quality, nice size. get a bunch... you'll use 'em
eventually

Ct-8 (10feet for $6.50) Copper strip almost 1" wide for shielding

DT-3325 (3 for $1.00) 3.3 Microfarad 25 Volt dipped Tantalum capacitors
good, small, useful for audio coupling.
or if you have room
RMC-220 (10 for $1.50) 2 Uf. 200 Volt metalized poly caps (kinda big)

resistors... 10 for 50cents any value...
you need 1000 Ohm for DC bias, and some 10,000 Ohm for summing

they also have round steel speaker grilles cheap... needle file set
$4.00

end part 7

Ciao Ventura

PS:

Some of you may be wondering why the AMT system was not included
in this comparison... after all, it's among the most expensive
systems on the market, it's touted as a premium system for professional
use, and even says "active microphone pre-amp" right on the belt-pack.

In short, the Advanced Microphone Technology system was NOT included in
this
comparison as this eval was limited to actual ACTIVE electronics
pre-amps,
and the AMT belt pack is an entirely PASSIVE audio device.

Joe Kesselman (yclept Keshlam)

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Dec 23, 2002, 12:41:54 PM12/23/02
to
Strong suggestion: Put this on a website somewhere. I'd like to be able
to find it again without having to search newsgroup archives.

--
Joe Kesselman, http://www.lovesong.com/people/keshlam/
{} ASCII Ribbon Campaign
/\ Stamp out HTML mail!

Theodore Kloba

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Dec 23, 2002, 2:09:31 PM12/23/02
to
If Ventura will approve, I'll put it up on my site. It will take about
2 minutes to get it formatted and indexed.

Joe Kesselman (yclept Keshlam) wrote:
> Strong suggestion: Put this on a website somewhere. I'd like to be able
> to find it again without having to search newsgroup archives.
>


--
Theodore M. Kloba * hey...@yahoo.com
http://www.geocities.com/heytud/
http://www.mp3.com/boxman/

Richard Cunningham

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Dec 24, 2002, 1:00:52 PM12/24/02
to
Most interesting!

I built small contact mics with Panasonic electret elements, and use them
on my bouzouki, my wife's bodhran,
and the bass side of my box. I just eq at the board, and they have all
given me good results in clubs and at festivals.

I built the power supply for the box mics with an omp amp mixer (can't
recall now which chip I used-- NOT a 741),
and had planned to use three elements summed on the treble side in
conjunction with the single mic on the bass. With
these mic elements however, I just could not get what I considered to be a
good, clear sound even after experimenting
with different caps. It probably could be done if I wanted to put more time
into it, but I prefer to just use a Shure Beta-57
on the treble side and use the one mic on the basses.

Even though these are omni capsules I haven't had many problems with
feedback-- only once in a pub gig, but there
were several sound-related problems that night. These particular mic
elements are rated at 2-10 VDC bias, but
for this application you don't want to hit them with more than about 3.5V.
On the first one I built I had just fed
it with a 9V cell through a 10K resistor and I believe that gave it about 6
volts which made it WAY too hot for
mic level. For the treble box arrangement I had to get it down to around
2.5 to keep it from distorting. Even at
3 volts are so, these little mics are plenty hot. At the last festival
where this mic was used on bodhran (a hairy
Albert Aphonso bodhran), it was the only drum at the fest that didn't sound
like mush. I saw D-212s, ATM-25s,
The usual SM-57/58s, depending on which stage-- and this little cheap mic
with just a bit of low boost beat them
all hands down-- I was really surprised. I've never heard the box's basses
or the bouzouki in the house since I'm always
playing them, but friends who are players (and know who's using Fishman,
McIntyre, etc. pickups) tell me my Fylde sounds better than the pickups--
'course there's that old saw about even a crappy mic sounding better
than a pickup, so there you go.

Very interesting, Ventura-- I look forward to reading that on the website
when I'm not distracted by Christmas perparations!


Rick
"~Dream~" <acco...@worldnet.att.net> wrote in message
news:3E069CC9...@worldnet.att.net...

Theodore Kloba

unread,
Dec 26, 2002, 4:20:34 PM12/26/02
to
~Dream~ wrote:
> There are situations where dynamic elements still are useful for the
> Accordionist... perhaps you simply have an installation where using a
> battery or other power source would be a problem... or wish to go with
> the
> old-style "one mic inside the bellows" setup for simplicity.

Have you tried using a single omnidirectional electret inside the
bellows? I'm thinking about replacing the cheap mic inside my
Chemnitzer belllows with something more useful.

Theodore Kloba

unread,
Dec 27, 2002, 12:02:26 PM12/27/02
to
I found a website with circuits for powering an electret microphone from
phantom power:

http://www.jdbsound.com/art/art520.html

Phantom power is not the same as bias power, and that's why we need a
circuit to get bias power from phantom power.

Ralph Stricker

unread,
Dec 29, 2002, 12:06:59 PM12/29/02
to
I would like to thank and compliment you for an interesting and informative
series of articles. These are what the news group needs more of.
Regards
Ralph Stricker

"~Dream~" <acco...@worldnet.att.net> wrote in message
news:3E069CFD...@worldnet.att.net...

~Dream~

unread,
Dec 29, 2002, 1:29:40 PM12/29/02
to
Hello Richard,

Nice project...

I'm pretty certain, however, that you somehow got the
Op-amp gain tied to the voltage... the capsules themselves
should not have been affected by the difference in Voltage.

try this... take those 3 elements, wire them up again,
just 1000 ohms to V+ and 1UF to signal,
temporarily hook up a 9 volt battery - and feed the
output directly to your PA system. Now you should have
them working cleanly, and can hear how they sound
naturally. Their output is enough to drive
the PA input for testing purposes, but of course they
will need a small boost from a pre-amp in practical use.

This test will show you that you were on the right
track with the Mics, but need to mess around with your
Pre-amp/op-amp circuit as a "separate equation"

Ciao Ventura

Richard Cunningham wrote:
>
> I built small contact mics with Panasonic electret elements,
> and use them on my bouzouki, my wife's bodhran,

> and the bass side of my box. .................................
> built the power supply for the box mics with an omp amp mixer.......


> and had planned to use three elements summed on the treble side in
> conjunction with the single mic on the bass. With
> these mic elements however, I just could not get what I considered to be a
> good, clear sound even after experimenting
> with different caps.

.............................

~Dream~

unread,
Dec 29, 2002, 1:32:49 PM12/29/02
to
Hi Joe,

Glad you think this is good enough to keep around,
but lets get more feedback first so any errors are caught -
and maybe a section with a few questions and answers
that came out of this appended

Ciao Ventura

Joe Kesselman (yclept Keshlam) wrote:
>

~Dream~

unread,
Dec 29, 2002, 1:34:26 PM12/29/02
to
Hello T,

sure, but we'll clean it up first and I'll send you
an ascii txt or Word file directly for you
to crunch... could we have a small .jpg or 2
for wiring purposes?

Ciao Ventura

~Dream~

unread,
Dec 29, 2002, 1:42:42 PM12/29/02
to
"T" wrote:
> Have you tried using a single omnidirectional electret inside
> the bellows?

Inside the bellows, I think a Dynamic that is designed to
handle high air pressure would be the better choice,
Mike O' , I believe, used a
Shure R65 element on an inside install recently...
succesfully... perhaps he can give us more details
as to how much space it takes, how it handles,
approx price and a source of supply?

Other than experimenting, of course, the boys
at FisItalia have a decent inside the bellows
Mic system they install for those who want one...
I havn't tried it, however, but imagine they'd
sell one if asked. There's a small picture of it
in their brocure.

Ciao Ventura

Richard Cunningham

unread,
Dec 30, 2002, 9:04:31 AM12/30/02
to
Hey Ventura,

Been away for the holidays..

Actually, on the mic for the bodhran and the 'zook I don't use an op amp,
just a resistor to Vcc and 1uF to signal as you mention. With the three
mics on the treble side, the experimentation I did was the same setup, only
summed through resistors, no op amp mixer.

I'd have to pull them apart and measure it, but I ended up using a simple
pot voltage divider to get the bias to where the output was workable. So
with these Panasonic capsules at least (can't recall the model#, I got it
off the acoustic guitar list 2 or 3 years ago) the applied voltage does make
a huge impact on the output level. Ha, with a 9v cell I'm wasting power
with this arrangement, but I had a few cells sitting around and some 9V
battery clips I bought years ago that never were used. A couple of AA cells
would work just at well (maybe even a single one), but I'm cheap and wanted
to build it out of my junkbox as much as possible!

I still use the op amp mixer power supply when I use the mic on the bass
side of the box, no particular reason than I already have that built and I
made an inverter in the output to reverse the phase. As it turns out, I've
not had any feedback problems with that mic so I never use that feature.
But the op amp is just the usual single-ended power supply/inverting amp
arrangement, unity gain.


Rick


"~Dream~" <acco...@worldnet.att.net> wrote in message

news:3E0F3FC6...@worldnet.att.net...

Theodore Kloba

unread,
Dec 30, 2002, 9:22:41 AM12/30/02
to
~Dream~ wrote:
> could we have a small .jpg or 2
> for wiring purposes?

That would be no problem.

Theodore Kloba

unread,
Dec 30, 2002, 9:42:49 AM12/30/02
to
The reason I ask is that many Chemnitzers are provided with a mic inside
the bellows, and I find them to have just a horrible tone. I'm not sure
how much of it has to do with the mic itself, and how much has to do
with its location. When I asked John Bernhardt (owner of Star
Concertina and builder of my best 'box), he really didn't know much
about the mics he was installing in the instruments, so I assumed they
were just cheap. They're prone to feedback and have an annoying peak
around 4kHz.

Over the weekend, I swapped out one of these for a miniature condenser
from Radio Shack. Since Chemnitzers don't have the kind of spare
internal space that a PA has, I put the bias power supply on the outside
of the box, integrated into a patch cord. Overall it seemed better, but
the bass end was really "boomy." I was using a 3V supply from 2 AA cells.

DoN. Nichols

unread,
Dec 30, 2002, 10:26:14 AM12/30/02
to
In article <PnYP9.20199$p_6.1...@bgtnsc04-news.ops.worldnet.att.net>,

Richard Cunningham <csha...@worldnet.att.net> wrote:
>Hey Ventura,
>
> Been away for the holidays..
>
> Actually, on the mic for the bodhran and the 'zook I don't use an op amp,
>just a resistor to Vcc and 1uF to signal as you mention. With the three
>mics on the treble side, the experimentation I did was the same setup, only
>summed through resistors, no op amp mixer.
>
> I'd have to pull them apart and measure it, but I ended up using a simple
>pot voltage divider to get the bias to where the output was workable. So
>with these Panasonic capsules at least (can't recall the model#, I got it
>off the acoustic guitar list 2 or 3 years ago) the applied voltage does make
>a huge impact on the output level. Ha, with a 9v cell I'm wasting power
>with this arrangement, but I had a few cells sitting around and some 9V
>battery clips I bought years ago that never were used. A couple of AA cells
>would work just at well (maybe even a single one), but I'm cheap and wanted
>to build it out of my junkbox as much as possible!

Just some thoughts here:

1) Condenser microphone elements tend to distort (clip) at a level
determined by the bias voltage. The more voltage present, the
more volume before you get distortion. Since this distortion is
clipping -- limiting the swing of the output signal, microphones
placed in a high level sound environment can indeed produce a
(distorted) signal proportional to the bias voltage. I would
consider under the grille of an accordion to be a high level
sound environment. You should try increasing the voltage
(within the limits of the microphone elements) until the volume
stops increasing to minimize distortion. Then you can add a
voltage divider to throw away excess gain. *Don't* reduce the
voltage to reduce the signal level -- that asks for distortion.

2) If you're summing the signals with resistors, and *no* coupling
capacitors, it may be possible that the DC level of the output
is summing in those resistors, driving the preamp to one side of
its swing, and causing distortion there, too. Obviously, the
coupling capacitors need to be of sufficient value relative to
the impedance so they don't roll off the low end notes, and they
need to be properly oriented so the capacitors are not reverse
biased.

Squeeze On,
DoN.
--
Email: <dnic...@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Richard Cunningham

unread,
Dec 30, 2002, 1:07:19 PM12/30/02
to
Hey DoN,

Too bad I can't just sketch out the simple circuit I was testing the
treble side mics with, I was using a cap
on each mic element. These were just taped to the outside edge of the
grille with masking tape. If I decided to
get serious about this arrangement I could probaby mess around with it more
and make it work-- but at one
pub gig I had a homebrew mini condenser on mandolin, bouzouki, and the left
side of the box, and found myself
drowning in mini coax when I swapped back and forth. After that night I
decided a stand mic with a submixer
was a better route to take.

With the 'zook, bodhran, and box basses, distortion has not been a
problem-- even with the Mengascini which
has pretty loud basses.

How I started down this path in the first place is a friend had a Microvox
that went belly-up and I was asked if
I could fix it. So I contacted Microvox for a schematic, stating clearly
that I had no interest in manufacturing mics
and explaining the situation. Never heard from them-- but I did get a terse
reply a couple of years ago (maybe even on this list, can't remember) from
somebody there on a thread similar to this. So I just said, "Screw it, I'll
just build one from scratch if I can't fix the broken one". I was surprised
when I opened the box and saw how little there was to the circuit. Turned
out
all it needed was to have one wire resoldered and so far as I know that
Microvox is still alive and kicking. After that I decided to experiment
with my own version, which ended up being slightly more complicated but not
by much. What surprised me the most was what Micorvox charges for those
things-- and I don't care if I raise the ire of Microvox, they
ignored a simple, honest request to try to help someone who'd spent money
with them.


Rick


"DoN. Nichols" <dnic...@d-and-d.com> wrote in message
news:aupoim$a5q$1...@izalco.d-and-d.com...

dennisgu

unread,
Dec 30, 2002, 1:59:26 AM12/30/02
to
I use R65's in all my accordions, single row, triple row and PA. For
Zydeco, IMO, that setup gets the best sound. I've tried condensors, but
they are often "too clean" sounding. Also, they tend to feed back more at
the high volume levels I need to play at when playing in a band with
electric guitar, bass and drums. The R65's just seem to handle all that
better. They still cut through in the mix without feeding back so easily.


"~Dream~" <acco...@worldnet.att.net> wrote in message

news:3E0F42D3...@worldnet.att.net...

Theodore Kloba

unread,
Dec 31, 2002, 11:15:53 AM12/31/02
to
How do you suspend the mic inside the bellows? The old mic (And the
condenser I tried) was suspended with rubber bands. The R65 is a bit
heavier, I think.

Here's a photo (from Ken Yagelski's site) of an installation that's
almost idetntical to mine. Certainly it looks like the same mic element:

http://www.polishfireball.com/sbox/images/bellows2.jpg

dennisgu wrote:
> I use R65's in all my accordions, single row, triple row and PA. For
> Zydeco, IMO, that setup gets the best sound. I've tried condensors, but
> they are often "too clean" sounding. Also, they tend to feed back more at
> the high volume levels I need to play at when playing in a band with
> electric guitar, bass and drums. The R65's just seem to handle all that
> better. They still cut through in the mix without feeding back so easily.

dennisgu

unread,
Dec 31, 2002, 2:13:16 PM12/31/02
to
I use a piece of coat-hanger wire which holds the mike in place on one of
the reed blocks. Marc Savoy did this to the first accordion I bought from
him, so I just copied his method for my other boxes, including my PA. Larry
Miller of Bon Tee Cajun Accordions actually makes a special little bracket
for mounting an R65 in his boxes. I'm sure it would work in a PA also.

"Theodore Kloba" <hey...@yahoo.com> wrote in message
news:3E11C3B8...@yahoo.com...

Theodore Kloba

unread,
Dec 31, 2002, 3:35:22 PM12/31/02
to
Interesting... I wouldn't think you'd want anything solidly attaching
the mic. Doesn't it pick up noise from the keys, etc?

Also, if you have it anchored to a reedblock, would it pick up
vibrations transmitted directly from the reeds through the block? If
so, the sound could have significant components an octave below the
pitch of the "air puffs" that make up the main sound of the instrument.
Maybe this could be exploited to some useful effect.

BTW, I'm talking about Chemnitzers, not PAs.

dennisgu wrote:
> I use a piece of coat-hanger wire which holds the mike in place on one of
> the reed blocks. Marc Savoy did this to the first accordion I bought from
> him, so I just copied his method for my other boxes, including my PA. Larry
> Miller of Bon Tee Cajun Accordions actually makes a special little bracket
> for mounting an R65 in his boxes. I'm sure it would work in a PA also.

--

Helen P.

unread,
Jan 1, 2003, 6:46:56 AM1/1/03
to
Note that most of Part 6 is duplicated at the end of Part 5. It looks like
two paragraphs were added in the "real" Part 6 post.

-- Helen

"~Dream~" <acco...@worldnet.att.net> wrote

Dan Lavry

unread,
Jan 1, 2003, 3:16:20 PM1/1/03
to
"Richard Cunningham" <csha...@worldnet.att.net> wrote in message
news:PnYP9.20199$p_6.1...@bgtnsc04-news.ops.worldnet.att.net...

> Hey Ventura,
>
> Been away for the holidays..
>
> Actually, on the mic for the bodhran and the 'zook I don't use an op
amp,
> just a resistor to Vcc and 1uF to signal as you mention. With the three
> mics on the treble side, the experimentation I did was the same setup,
only
> summed through resistors, no op amp mixer.

No Op amp? No transistor amp? no active device powered by some battery or
similar source?
A lot of folks are missing the point. Yes, one can take a signal level of a
given power, and trade off voltage against current (or vica versa). Hor
example, you can use a transformer to get say 100 times voltage
amplification, but the signal is not stronger. The capability to drive athe
impeadance has just droped bt 100. Igf such was not the case, we would
replace our power amplifiers with transformers :-)

The proper view is always about energy (or power which is energy per unit
time). The mic membrane picks up some tiny amount of air vibrations. Lets
face it, it is very small indeed! Think of say 100 watt sound "near point
source", say a speaker at some distance. Now figure that the sound energy
has to "spread" over the whole space. How much area does the membrane hace
compare to the whole space? You think it is milliwatt? Try microwatts!

There are lots of way to do things, but there is no magic! You want to
overcome the problems associated with sending a tiny signal over even a tiny
distance. There are many reasons for it. The most fimiliar one is noise
pickup, be it power line hum, or a radio station or a next door neigbor with
an electric drill... While you can not avoide the pickup, nor can you tell
your neigbor what to do, you can significantly reduce the problem if you
amplify the signals a lot BEFORE you send it on the wire. Amplifying after
you pick up noise is bad news because the amplifier will also amplify the
noise.

There are many other more subtle but equaly importent reasons to so things a
certain way. I can not write a whole EE thing here. Other EE's and techs may
recall that there is such a thing as impeadance matching. The efficieny of
sending power from source to load is best when the source and load
impeadances are conjugate (the resistive part is the same and so on...). You
deviate from that optimum point, and you may be "in bad teritory". It is
often desirable to work away from that point, but you must have a large
enough signal to noise ratio... Sorry, I better stop it. Take my word for
it...

So passive stuff sucks! It sucks really bad. The advantage is that you need
not supply power. The disadvantage is every thing else, and big times so!
Condendser mics with phantom power are not passive devices. The pro devices
often require 48VDC and use uo a few milliampers od that energy source, such
as say 4mA thus .2 watt. Some more and some less than that, yet the external
power supplied is huge compare to the air power vibrating the membrane. The
condenser mics do have a built in amplifier. Think of it as an internal op
amp. It is an internal amplifier.

Another importent thing with microphones and small signals is the issue of
balance vs. unbalanced transmision. The balanced lines are SHIELDED. Even
those 48V Phanton devices with built in amps, use balanced lines for almost
any distance at all. That is because the signals are still pretty small.
With say .25watt in, you do not get enough "omph". The point here is that
for longer distances the practice is: phantom and amplified, and balanced
and shilded. A less desirable is non pahntom, but than you really relay on
good balance and shiled. That one will not be as effective, but work shorter
distances.

Some amaturish stuff discussed here is not balanced, not phantom and the
wires are long, no thought regarding impeadance matching... There are a lot
of things that can be done really badly. Do not do them all at the same
time! You want to have those terrible circuits, with no regard to so many
importent aspects? At least have some power there, use short interconects or
some shielding (or both).

This are just a few of my very proffesional coments. These are NOT OPINIONS.
You do not get to call me a snob this time.

BR

Dan Lavry

squeezer

unread,
Jan 1, 2003, 6:14:04 PM1/1/03
to
Hi Squeezers,
I have used many homebrew mic setups in my PAs over the years. I have
had crystal mics and dynamics and also electret condenser mics.I built small
op amp mixers and used them with my mics in numerous ways. I have tried many
different phsyical set ups such as under the grill and a whole slew of
places inside.Radio Shack condensers inside were moderatly successful for me
for a long time in a loud Zydeco band but had a noticable thump with bellows
change that I had to EQ out as much as possible.I only want to play now and
fool around with micing as little as possible.
Now I am using a K&K system. The quality is good enough for me but the
feedback is not. I think it was Ventura who had suggested there was a way to
improve this set up. I would like some further discussion of this if
possible.I like to run the output into a Boss digitalsound processor (it is
a 1/2 rack unit that I use for pitch shift as well as reverb, Leslie effect
and echo). The input to the Boss is stereo 1/4" unbalanced phone jacks. The
out put of that goes to a JBL G2 15.I mention the Boss because it may not be
the right impedence for the output of the K&K.
Any help would be greatly appreciated,
LooseBruce


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~Dream~

unread,
Jan 1, 2003, 9:54:29 PM1/1/03
to
Hello LB,

squeezer wrote:
>
> Now I am using a K&K system. The quality is good enough for me but the
> feedback is not. I think it was Ventura who had suggested there was a way to
> improve this set up. I would like some further discussion of this if
> possible.

What I will try with the test K&K system here, is to
install the Mics into an outboard rail, and then improve the
connection mechanism between their Mics and pre-amp belt-pack.

A Mic rail, which rests on the outside of the treble grille,
is by it's nature resistant to some of the elements which
contribute to feedback. First of all, the edges of the rail
which are in contact with the accordion are well padded,
adding an extra layer of physical vibration resistance.
The rail itself presents an unbroken plane of grounded Aluminum
which negates most electronic interference. Sound is carried
on air, of course, and air cannot penetrate the aluminum, so
sound must resonate against it or go around it to interfere
with the accordion sound we are intent on capturing with the
buisness side of the rail. Since the outside surface of
the rail is to be covered in a dampening material
(felt, suede, cloth, naugahyde, etc.) we eliminate
feedback from external rear resonance.

Now, sound from outside the accordion must first re-enter
the accordion grille and bounce back up to get into the
rail (pretty much) - so as you can see many of the elements
of feedback are really well controlled when using a nice
padded external Microphone system.

Feedback is more than just the "endless loop" we create
between the mics and the speakers... it is tones and
pitches and sounds that are "prone" to looping as well.
Treble pitches can be radiated through bodies and grilles
and get back into poorly padded microphones, for example,
and body parts may have resonance at a certain pitch
which apmlifies that pitch into feedback.

For the K&K system, I'd just use the pre-amp in MONO
mode, and simply run a shielded wire through one
of the jack-holes and solder it in place directly.
I'll strap/velcro it to the outside of the Mic-rail and
plug them in to each other. All 3 Mic elements will
be installed in the mic rail.

next post has specifics.

Ciao Ventura

~Dream~

unread,
Jan 1, 2003, 9:54:36 PM1/1/03
to
How do you build a mic rail? Well, you might run across
the shell from an old crystal SANO or PRINCE Mic rail from
the 60's, gut it, and re-use the shell. Otherwise,
go to your Home Depot store and look at the extruded
Aluminum stock. They carry 2" x 2" angle stock in both
thick and thin guages. Thin is strong enough for our work.

a 2" x 2" angle actually gives you almost a 3" open side
to work with (the side that will face the grille) and
is roomy enough to easily accomodate your 9 volt battery,
and assortment of sockets (for jacks), potentiometers
(for volume and/or tone controls) and switches (on-off)
and of course your Microphones.

Look at the angle stuff as a long pyramid... what
we're making here, in a sense, is an external tone chamber.
You'll need 2 good, strong, standard Switchcraft 1/4" jacks
with metal threaded bushings

You whack off a piece about 3" longer than the grille of the
accordion you want to use it with. Then you cut back 2"
along the seam from each end. Carefully fold over the
2 flaps, clamp them with Vise grips.
You have closed one end of the "Pyramid"
Ping a starting point slightly less than 3/4" down from the
tip of the "Pyramid" on the end you have clamped. You'll see
that if you drill a good hole carefully, you will be able
to install the 1/4" jack in the end, it will be fully
protected by the pyrimid, and will not short out.

Do so. When you tighten the nut on the jack, note there are
2 connection points on the jack. Try and position the
lug for Ground on the open side (that might ever accidentally
touch metal or something) and tighten the nut good.
Now you can release the vise grips. Cut the excess parts
of the flaps to be even with the rest of the rail edges.

Repeat on the other end.

Now you have the basic rail, the Switchcraft jacks are
strong enough to both hold the ends together forever,
and give you your output connection.

take some material and measure a piece that will cover the
outside of the pyramid, with enough excess
so you can fold it over the long edges and up inside
the tone chamber to glue it in/on.
Take mirror mounting foam tape. Along the long edges
of the pyramid "base" apply a solid line of the foam
tape, folding it over so half is inside and half outside.
Now take whatever material you cut and glue it on the outside,
fold it over the cushion of foam tape, and glue it up into
the inside of the tone chamber.

Your rail is now covered and looks good.

Find some mini-bungee cord in Black, or the color
of your accordion grille. Outfitters shops carry it,
so do many fabric stores. Wal-Marts bucket of bungees
has some skinny pieces too. Drill 2 small holes
on the end caps close to the far edges where it
won't interfere with the 1/4" jacks just big
enough to push the ends of the cord through and
tie knots is them, leaving a loop of 4" - 6" depending
on your accordion. You will loop these cords around the
hardware of your bellows straps typically, and the
tension is enough to hold your Rail in place gently
yet firmly against the accordion.

So far so good...

Depending on your needs and desires, you might wish to
install one of those 10,000 ohm detent potentiometers
as a volume control. (detents are good because they
resist shifting and I move around a lot when I play)
A nice on-off power switch is always a part of my rails,
and an LED battery indicator. You may prefer a barrel jack
switch set-up.

Now the Velcro comes into play. You will use Velcro to
softly mount the Microphones in place. you will put a
velcro dot on the Battery and velcro a good space for it
to stick to in the chamber.

Over the years, I have experimented with facing the mics upward,
into the inverted "V" of the chamber, from ends inward,
and simply facing down. Old rails here have from 2 to 10
mic elements... the more directional the elements,
the more you can use.

Wire the Mics with excess wire length, so you can play with
the placement (velcro let's you do that) until you
figure out the best set-up, then you can shorten the
wire lengths.

I have also played with different internal material.
Copper lining gives a warm tone... mahogany veneer
gives a darker tone... felt reduces the treble...naugahyde
seems to be pretty neutral... aluminum is not musical
so don't leave much exposed.

will take some .jpg photo's of my rails and try to learn
how to post them this winter if that would help...

Ciao Ventura

~Dream~

unread,
Jan 1, 2003, 10:02:55 PM1/1/03
to
Theodore Kloba wrote:
>
> Over the weekend, I swapped out one of these for a miniature condenser
> from Radio Shack. Since Chemnitzers don't have the kind of spare
> internal space that a PA has, I put the bias power supply on the outside
> of the box, integrated into a patch cord. Overall it seemed better, but
> the bass end was really "boomy." I was using a 3V supply from 2 AA cells.

cool... nice and easy and inexpensive too.

I'm assuming the old Mic was not "boomy"

Here are a couple of things to try... you can deliberately
use a coupling capacitor that will slightly impede the low
frequencies, which might be just enough to smooth things out.

I'll guess you used a 1 Microfarad cap...
so try .58 .47 .33 .2 .1 values (green drop mylars
are easy to find in these values or similar)
in turn and see if it "sures" the problem.

If the boominess comes from placement, you might try
getting a soft piece of leather and creating a small
"shell" of sorts inside the bellows for the Mic to
kind of hide in... object is just to shelter it from
exsess reflections? assuming it's a real cacophony
in there, and certain Bass frequencies are rampant.

Ciao Ventura

~Dream~

unread,
Jan 1, 2003, 10:05:23 PM1/1/03
to
hi Dennis,

dennisgu wrote:
>
> I use R65's in all my accordions, single row, triple row and PA.

Do you have a good source of supply you can
share with the Newsgroup? and what is a reasonable
price to pay for this element?

Ciao Ventura

~Dream~

unread,
Jan 1, 2003, 10:15:39 PM1/1/03
to
hi DoN

DoN. Nichols wrote:

> 1) Condenser microphone elements tend to distort (clip) at a level
> determined by the bias voltage. The more voltage present, the
> more volume before you get distortion. Since this distortion is
> clipping -- limiting the swing of the output signal, microphones
> placed in a high level sound environment can indeed produce a
> (distorted) signal proportional to the bias voltage. I would
> consider under the grille of an accordion to be a high level
> sound environment. You should try increasing the voltage
> (within the limits of the microphone elements) until the volume
> stops increasing to minimize distortion. Then you can add a
> voltage divider to throw away excess gain. *Don't* reduce the
> voltage to reduce the signal level -- that asks for distortion.

theoretical, with a 9 volt DC supply you can have
a signal output (AC waveform) up to (+9 -9) an 18 volt
swing with reference to ground?

I have pretty much always used some 9volt form factor
battery... which range from between 5 - 9 volts actual...
(one old ni-cad has a dead cell, but it is fine for bias)
and in practice I've never particularly noticed a difference in
output on any of my powered mic setups
>
> 2) .....................and they


> need to be properly oriented so the capacitors are not reverse
> biased.

it's easy to forget one end of the Volume control
is connected to ground, and so can make a DC circuit
through the leg... it always helps to draw it out
as you figure it out.

Ciao Ventura

~Dream~

unread,
Jan 1, 2003, 10:27:35 PM1/1/03
to
I've used sheet rubber, and made envelopes for different
Mic elements. It looks like leather was used to
make a pouch in that picture.

http://www.polishfireball.com/sbox/images/bellows1.jpg
shows the other side

John suggests using old Mouse pads, which are a good
vibration resistant foamy rubbery material.

Cut one disk to hold the element, and a larger disk
as backing for the first disk. Cut a hole in the
first disk that will allow sound to get to the Mic,
but is too small for the Mic to slip through.
Sandwich the mic between the 2 disks and glue the
edges all around. (after you solder the wire to the Mic)

For electrets, a small hole sized just right to squeeze
the electret into and a dab of glue, plus the backing disk.

You leave enough "flap" from the backing disk for a
screw or glue to hold the whole thing in place.

Ciao Ventura

Richard Cunningham

unread,
Jan 1, 2003, 11:52:08 PM1/1/03
to
Easy Dan,

I'm not sure what sparked that, but as I said, if I could sketch the
circuit out you'd see what I did.

On the three mics it was just a breadboard temporary thing to see how the
freq response would be using the inexpensive
elements.

BTW, I'm a wireless RF engineer by trade, have been in cellular, PCS, and
broadcasting for years-- so I'm not entirely dim.
Did you see "Vcc" mentioned there? You may also have read "mini coax"-- so
there's your power and shielding. What I did not mention is that I use an
active op-amp unbalanced-to-balanced output, I saw no reason to confuse the
discussion and besides, I've found using an unbalanced output into a passive
D/I box to be entirely adequate for typical PA applications.

I really don't understand your statements about "terrible circuits". I
think I have a pretty fair understanding of such things as
impedance matching. But I also know that in practice in a live sound
situation a lower impedance can drive a higher impedance with often no
discernable difference in the results-- but usually not the other way
around.

Look, what I'm talking about are experiments I've done with cheap mic
battery-powered mic elements-- the results of which have been suprisingly
good when compared to commercial mics. Would I record with them? No. But
I do know from years of gigs in different environments that the PA and the
room make more difference than all the other factors combined. I never
heard that mentioned at any IEEE meeting I ever attended. I'm not calling
you a snob, now or at any other time-- but what the Hell do your comments
have to do with what I was talking about?


Rick


"Dan Lavry" <danl...@mindspring.com> wrote in message
news:auviau$qqr$1...@slb6.atl.mindspring.net...

Dan Lavry

unread,
Jan 2, 2003, 12:55:24 AM1/2/03
to
> Easy Dan,
>
> I'm not sure what sparked that, but as I said, if I could sketch the
> circuit out you'd see what I did.
>
> On the three mics it was just a breadboard temporary thing to see how the
> freq response would be using the inexpensive
> elements.
>
> BTW, I'm a wireless RF engineer by trade, have been in cellular, PCS,
and
> broadcasting for years-- so I'm not entirely dim.

I do not know much about cellular, PCS or broadcasting. Not even with some
training and a couple of years in communications. I am an audio engineer. I
do know audio. Not saying anyone is dim.

> What I did not mention is that I use an
> active op-amp unbalanced-to-balanced output, I saw no reason to confuse
the
> discussion and besides, I've found using an unbalanced output into a
passive
> D/I box to be entirely adequate for typical PA applications.

I may have missed somthing. I thought I saw some comments regarding passive
circuits.

> I really don't understand your statements about "terrible circuits". I
> think I have a pretty fair understanding of such things as
> impedance matching. But I also know that in practice in a live sound
> situation a lower impedance can drive a higher impedance with often no
> discernable difference in the results-- but usually not the other way
> around.

So you know that with small signals, either way is no good. As an RF guy you
are surly sensitive to impeadance matching, though it is about reflections
and standing waves. But you surly recall that conjugate stuff from sirst
year EE courses.. Having low impeadance drive (into higer impeadance load)
is desirble so to have the line less suceptible to pickup (one side is near
AC ground or a few tenth of ohms...). One can do it
when there is enough signal....


>
> Look, what I'm talking about are experiments I've done with cheap mic
> battery-powered mic elements-- the results of which have been suprisingly
> good when compared to commercial mics.

I do not know what the commercial low end is like. I do know what the mid
and upper end is.

Would I record with them? No. But
> I do know from years of gigs in different environments that the PA and the
> room make more difference than all the other factors combined. I never
> heard that mentioned at any IEEE meeting I ever attended.

Yes, I belong to IEEE and they do not talk about it. But I also belong to
the AES and they talk abouit it to great detail - tons of papers!

> I'm not calling
> you a snob, now or at any other time-- but what the Hell do your comments
> have to do with what I was talking about?

The comment snob was due to what some other thread eneded with. It was
implied, and I felt was out of place. I thought my comments are very much to
the subject of microphone amplification, and shed some light on how to
approach things better. If you do not know what the hell I am talking about,
try reading it again. If you do not understand it, it is not my fault, and
it tells me somthing about your leve of audio knowladge. I am sure ant EE
knows more than the common accordion player, but how much more? I thought I
was contributing.

BR

Dan L.

DoN. Nichols

unread,
Jan 2, 2003, 1:34:52 AM1/2/03
to
In article <3E13AF90...@worldnet.att.net>,

~Dream~ <acco...@worldnet.att.net> wrote:
>hi DoN
>
>DoN. Nichols wrote:
>
>> 1) Condenser microphone elements tend to distort (clip) at a level
>> determined by the bias voltage. The more voltage present, the
>> more volume before you get distortion. Since this distortion is
>> clipping -- limiting the swing of the output signal, microphones
>> placed in a high level sound environment can indeed produce a
>> (distorted) signal proportional to the bias voltage. I would
>> consider under the grille of an accordion to be a high level
>> sound environment. You should try increasing the voltage
>> (within the limits of the microphone elements) until the volume
>> stops increasing to minimize distortion. Then you can add a
>> voltage divider to throw away excess gain. *Don't* reduce the
>> voltage to reduce the signal level -- that asks for distortion.
>
>theoretical, with a 9 volt DC supply you can have
>a signal output (AC waveform) up to (+9 -9) an 18 volt
>swing with reference to ground?

No. With a *single* 9v battery, you can have only a swing of
from 0V to 9V (or depending on wiring -9V to 0V), unless you go through
a capacitor to decouple the average DC value, in which case you will get
an effective swing from +4.5V to -4.5V, or a RMS voltage of 3.18V.

An exception to this is if you have a DC-DC converter which will
produce an additional -9V from the +9V -- at the cost of additional
drain from the battery which will cause more rapid discharge.

Of course -- if you use that 0V to 9V swing as the input to a
transformer, you can get pretty much whatever you want on the output by
careful choice of turns ratio. (But, of course, you have to consider
the changes in impedance which this produces, to match your input
impedance of the preamp or mixer. This has already been covered in
other branches of the thread, but if I neglect to mention it, someone
will probably pounce on it. :-)

>I have pretty much always used some 9volt form factor
>battery... which range from between 5 - 9 volts actual...
>(one old ni-cad has a dead cell, but it is fine for bias)
>and in practice I've never particularly noticed a difference in
>output on any of my powered mic setups

Hmm ... depends on the sensitivity of the mics, and the SPL
(Sound Pressure Level) where they are mounted. The closer to the
source, the louder, and the greater chance of a low bias leading to
clipping. (Of course -- the waveform from a low pitched reed is weird
enough so it is sometimes difficult to tell that is happening. :-)

>> 2) .....................and they
>> need to be properly oriented so the capacitors are not reverse
>> biased.
>
>it's easy to forget one end of the Volume control
>is connected to ground, and so can make a DC circuit
>through the leg... it always helps to draw it out
>as you figure it out.

Agreed.

Squeeze On,
DoN.

P.S. I find myself thinking of the description of making the mic
rail you gave, and considering how I would do it differently
with a full machine shop. (And I find myself wanting one tool
which I don't yet have to complete the ends properly -- a TIG
welder. :-)

I'm also now starting to think of a horseshoe shaped version for
a concertina -- perhaps with angled scoops to pick up the bass
area under the player's palms without interfering with the hand.
:-)

Theodore Kloba

unread,
Jan 2, 2003, 10:46:18 AM1/2/03
to

~Dream~ wrote:
> I'm assuming the old Mic was not "boomy"

Actually, no... That's why I was surprised. I would have described the
old mic as "tinny" or even "nasal."


> I'll guess you used a 1 Microfarad cap...
> so try .58 .47 .33 .2 .1 values (green drop mylars
> are easy to find in these values or similar)
> in turn and see if it "sures" the problem.

The data sheet that came with the mic element suggested a value of
1-10uF, so I used a 4.7uf electrolytic in parallel with a 0.1 uF film.

Theodore Kloba

unread,
Jan 2, 2003, 10:50:11 AM1/2/03
to
~Dream~ wrote:
> I've used sheet rubber, and made envelopes for different
> Mic elements. It looks like leather was used to
> make a pouch in that picture.
>
> http://www.polishfireball.com/sbox/images/bellows1.jpg
> shows the other side

I'm not sure where you see leather in the photo. The square item
surrounding the mic element is actually a piece of hardboard, and the
element is tightly-fitted and glued. With tight rubber bands suspending
the assembly, it does an excellent job of transmitting bellows noise
into the mic!

When I mounted the condenser mic, I made a new square piece from soft
sheet plastic, and let the element support itself by the leads.

> John suggests using old Mouse pads, which are a good
> vibration resistant foamy rubbery material.

That's a great idea!

Theodore Kloba

unread,
Jan 2, 2003, 12:16:26 PM1/2/03
to
~Dream~ wrote:
> Do you have a good source of supply you can
> share with the Newsgroup? and what is a reasonable
> price to pay for this element?

MSRP is about $83.

Richard Cunningham

unread,
Jan 2, 2003, 12:48:20 PM1/2/03
to
Well look,

I'm not interested in arguing via the internet over a $5 circuit. Just
do what you do and leave me alone.


Rick


"Dan Lavry" <danl...@mindspring.com> wrote in message

news:av0k8o$21e$1...@slb9.atl.mindspring.net...

dennisgu

unread,
Jan 2, 2003, 8:34:47 PM1/2/03
to
I usually get the the R65 elements from Marc Savoy in Eunice, Louisiana. I
can't remember what the price is. If you ask him, he will usually include
the coat-hanger wire bracket, the requisite "grille snaps", the transformer,
and the long-neck jack along with a rudimentary wiring diagram for hooking
it all up. The R65 is a dual impedance mic element which can be wired for
either high or low impedance. Some players prefer the low impedance setup.
It requires the use of a stereo 1/4" jack and a cable with a 1'4" stereo
plug on one end and an XLR 3-prong plaug on the other end to go into the
mixer.
Marc has a web site. Just do a search under Mar Savoy or Acadian Accordions.
You can also contact Larry Miller in Iota, LA. He also has a web listed
under Bon Cajun or Bon Tee accordions.

Good luck.

"~Dream~" <acco...@worldnet.att.net> wrote in message

news:3E13AD29...@worldnet.att.net...

~Dream~

unread,
Jan 2, 2003, 11:05:07 PM1/2/03
to
Hi DoN

DoN. Nichols wrote:
>
> P.S. I find myself thinking of the description of making the mic
> rail you gave, and considering how I would do it differently
> with a full machine shop. (And I find myself wanting one tool
> which I don't yet have to complete the ends properly -- a TIG
> welder. :-)
>
> I'm also now starting to think of a horseshoe shaped version for
> a concertina -- perhaps with angled scoops to pick up the bass
> area under the player's palms without interfering with the hand.
> :-)

Mainly, my shapes have been determined by luck, circumstance,
and available materials. I'd like to build one out of
Copper in a half moon shape, actually. but havn't found a
leftover piece of old Copper downspout to saw in half yet.

By the way... I just picked up one of those
little Oxy pellet welder thingies at a yard sale...
supposedly it can braze different materials with various rods.

On your types of concertinas and such, is there a vast difference
in the octave range from the left side VS the right typically?
(as in PA's)

Anyhow, I've lot's of scattered elements of various types in
sundry plastic compartmented cases, so if you get the
"Horeshoe" made I'll supply the innards and a pre-amp
for you to test it with.

Ciao Ventura

~Dream~

unread,
Jan 2, 2003, 11:15:24 PM1/2/03
to
hi T,

Theodore Kloba wrote:

> The data sheet that came with the mic element suggested a value of
> 1-10uF, so I used a 4.7uf electrolytic in parallel with a 0.1 uF film.

OK... capacitors in parallel are simply added to determine the
capacitance in a circuit. So your working value is 4.8

Try a single 1 MFD instead of these 2 parallel caps. See
how that works. try an 0.68 next.

Why the parallel capacitor at all? Maybe they meant a 100 picofarad
to ground? (which is commonly seen in audio circuits)
though I see 68 pf more often... sometimes even hidden inside
a 1/4" plug.

Ciao Ventura

~Dream~

unread,
Jan 2, 2003, 11:21:50 PM1/2/03
to
Theodore Kloba wrote:
>
> I'm not sure where you see leather in the photo. The square item
> surrounding the mic element is actually a piece of hardboard,

oh... on my monitor it looked the color of leather,
and I just would not guess someone would use hardboard
of their own volition <Grin> plus leather is easily
found around an Accordion shop... I'd have used
leather if I was trying to make one from this picture.


> and the element is tightly-fitted and glued. With tight rubber bands suspending
> the assembly, it does an excellent job of transmitting bellows noise
> into the mic!

I'll bet it does... the taut cat-gut may even have
a harmonic resonance!

Ciao Ventura

Theodore Kloba

unread,
Jan 3, 2003, 10:21:28 AM1/3/03
to

~Dream~ wrote:
> Try a single 1 MFD instead of these 2 parallel caps. See
> how that works. try an 0.68 next.

I'm going to put together "Version 2" with a 1uF tantalum capacitor, and
also try increasing to a 9V supply.

I also have a couple different condenser elements to try as well, and I
want to try out the mouse pad material.

> Why the parallel capacitor at all? Maybe they meant a 100 picofarad
> to ground? (which is commonly seen in audio circuits)
> though I see 68 pf more often... sometimes even hidden inside
> a 1/4" plug.

The parallel capacitors are because I didn't have anything on hand in
the 4.7uF size except an electrolytic. The 0.1uF film bypass is to
counteract parasitic inductances in the electrolytic [FWIW in this cheap
little circuit]. In "Version 2" I won't do this, since I don't need to
use an electrolytic for 1uF value.

Theodore Kloba

unread,
Jan 3, 2003, 12:24:37 PM1/3/03
to

DoN. Nichols

unread,
Jan 4, 2003, 12:39:47 AM1/4/03
to
In article <3E150CA6...@worldnet.att.net>,

~Dream~ <acco...@worldnet.att.net> wrote:
>Hi DoN
>
>DoN. Nichols wrote:
>>
>> P.S. I find myself thinking of the description of making the mic
>> rail you gave, and considering how I would do it differently
>> with a full machine shop. (And I find myself wanting one tool
>> which I don't yet have to complete the ends properly -- a TIG
>> welder. :-)
>>
>> I'm also now starting to think of a horseshoe shaped version for
>> a concertina -- perhaps with angled scoops to pick up the bass
>> area under the player's palms without interfering with the hand.
>> :-)
>
>Mainly, my shapes have been determined by luck, circumstance,
>and available materials. I'd like to build one out of
>Copper in a half moon shape, actually. but havn't found a
>leftover piece of old Copper downspout to saw in half yet.

*Now* you tell me! When our house was being rebuilt, one of the
things which went was a copper downspout. Copper is a real pain on most
machine tools, with an unusual cutting lubricant supposed to be the
best. *Milk*, of all things. (But you have to clean it up a lot
quicker than most cutting fluids, or it starts to stink. :-)

>By the way... I just picked up one of those
>little Oxy pellet welder thingies at a yard sale...
>supposedly it can braze different materials with various rods.

Hmm ... word that I have from the metalworking newsgroup is that
they are rather limited -- and have a fairly short running time for each
recharge. (And you don't want oxy when working aluminum. TIG (and MIG)
work Aluminum under a flow of inert gas, so it doesn't burn up as you're
welding it.

>On your types of concertinas and such, is there a vast difference
>in the octave range from the left side VS the right typically?
>(as in PA's)

Depends on the type of concertina. The Anglos, and the Duets
have a similar major shift. (No overlap in an Anglo, about an octave
overlap in most duets, only a half octave in the smallest ones.)

But the English system, which is what I play the most, has at
most a whole-tone difference in range between the sides. (And often
just a half-tone.) The scale alternates between hands, with all notes
on a line on the left-hand end, and all on a space on the right-hand
end. Makes fast runs possible, since one hand can be setting up for the
next note while the other is playing its note. Chords (within one
octave) stay in a triangular pattern in a single hand, though if you
want to add another octave, both hands come into play.

>Anyhow, I've lot's of scattered elements of various types in
>sundry plastic compartmented cases, so if you get the
>"Horeshoe" made I'll supply the innards and a pre-amp
>for you to test it with.

Hmm ... thanks, but not quite yet. I don't play with
amplification, so it is just something to try someday.

I've just thought of the proper thing to use as a basis. A pair
of the cake pans which are designed to make a cake layer with a hollow
center. Or one of the gelatin moulds for making Jello rings.

Enjoy,
DoN.

John C.

unread,
Jan 4, 2003, 11:24:57 AM1/4/03
to
Don,

Not sure if you are aware of it or not but there is a company
that makes welding/brazing/soldering rods for aluminum
that are relatively low temperature and can be used with a plain
old propane torch. They have a web site - http://divescoinc.com/
The stuff is a bit tricky to use and takes a bit of practice but
it works well. The metal has to be clean, all anodization sanded
off and the heat has to be applied quickly and evenly to both
sides of the joint. I have used a propane torch to braze small
antenna parts together numerous times and it works well. An
acetelene torch works even better but you have to be really
careful not to melt the aluminum if your using a soft alloy.
(most antenna parts are T6-6061 which is hard stuff).
PS: I was over at Ventura's place yesterday and saw and heard
several of the "Rails" that he built - very impressive! And his
midi set-up just blew my socks off. He has done some SERIOUS
experimentation with accordion sound and amplification. I saw
several different midi kits, preamps in various stages of
construction & deconstruction and played several different
accordions. I went over for what I thought would be an hour or
so and five hours later left with my head swimming. I'm sold on
midi and just got to get into it.

John C.

"DoN. Nichols" <dnic...@d-and-d.com> wrote in message
news:av5s33$bs0$1...@izalco.d-and-d.com...

DoN. Nichols

unread,
Jan 4, 2003, 3:04:58 PM1/4/03
to
In article <v1e2moi...@corp.supernews.com>,

John C. <(delete_this)ca...@cablespeed.com> wrote:
>Don,
>
>Not sure if you are aware of it or not but there is a company
>that makes welding/brazing/soldering rods for aluminum
>that are relatively low temperature and can be used with a plain
>old propane torch. They have a web site - http://divescoinc.com/

I've got some. It would probably do for this -- except that it
can corrode in the presence of water. It is really mostly zinc, with
just a little bit of other metals in there.

>The stuff is a bit tricky to use and takes a bit of practice but
>it works well. The metal has to be clean, all anodization sanded
>off and the heat has to be applied quickly and evenly to both
>sides of the joint. I have used a propane torch to braze small
>antenna parts together numerous times and it works well. An
>acetelene torch works even better but you have to be really
>careful not to melt the aluminum if your using a soft alloy.

You also need to be really careful not to breathe the fumes if
you get it too hot. You'll wind up with "metal fume fever", and live
with a couple of days of nasty headaches among other problems.

A nice compromise for this is the MAAP torch. Hotter than
propane, enough cooler than oxy-acetylene to make life easier. Depending
on the size of the workpiece, you may want a propane torch playing on a
nearby area to pre-heat the metal, since aluminum conducts heat quite
well.

>(most antenna parts are T6-6061 which is hard stuff).

Nice machining stuff, too. But after that torch treatment, at
least part of it is no longer T6 hardness.

If you're putting the stuff out in the weather, you probably want
a good heavy-duty paint (epoxy, or powder coat), to keep the junction
between the zinc and the aluminum from acting as a battery when wet, and
rapidly eating itself away.

At least TIG welding leave nothing but aluminum, so that problem
doesn't come into play.

>PS: I was over at Ventura's place yesterday and saw and heard
>several of the "Rails" that he built - very impressive! And his
>midi set-up just blew my socks off. He has done some SERIOUS
>experimentation with accordion sound and amplification. I saw
>several different midi kits, preamps in various stages of
>construction & deconstruction and played several different
>accordions. I went over for what I thought would be an hour or
>so and five hours later left with my head swimming. I'm sold on
>midi and just got to get into it.

I've not seen his place, yet, though he has seen mine, including
my shop.

I've considered making a MIDI controller for the English system,
just so I can practice quietly into headphones. (And maybe set up one
for the Hayden Duet system as well.

Squeeze On,

Theodore Kloba

unread,
Jan 6, 2003, 11:57:17 AM1/6/03
to
It turns out that Shure Bros. sells all their replacement parts
(including dynamic cartridges) direct by phone, with free UPS ground
shipping. Just call 1-800-25-SHURE (or 847-257-4873 outside US) to
order. I'm going to experiment with their model RPM152 dynamic
cartridge inside the bellows of my chemnitzer to replace the crappy one
it came with. Retail customers pay MSRP, but if you're a dealer, you'll
get a better price.

Incidentally for those who were following the "mic inside the bellows"
thread, I partially disassembled the mic that came with the instrument,
and it appears to be a carbon ot crystal element... At least it looks
like no dynamic element I've ever seen. All I can figure is that Star
must have had a stockpile of these left over from the 1950s and
continued to install them until 2000 (when I bought the instrument).

Mike Otterbine

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Jan 6, 2003, 12:26:47 PM1/6/03
to
I have a Shure R65 in the bellows, mounted with an aluminum hose
bracket I got at home depot.

I get good volume before feedback from the R65, but it picks up more
of the bass side than the treble side. It also distorts a little,
which I like. This element obviously isn't for everyone. You need
about an inch and a half of clearance between the bass and treble
reedblocks to be able to fully close the bellows once the element is
mounted. I got my R65 from Savoy Music Center. You can get them from
any Shure dealer, though.

I'm currently experimenting with other dynamic elements on the treble
side. My goal is to determine whether the sound of an accordion can be
transformed by amplification in somewhat the same way a harmonica can.
Obviously not many amplifers are voiced with the accordion in mind.
I'll post my findings when I come up with something interesting.

-Mike

Theodore Kloba <hey...@yahoo.com> wrote in message news:<3E15C85E...@yahoo.com>...

dennisgu

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Jan 6, 2003, 7:20:08 PM1/6/03
to
Mike-

I've found that my boxes sound great going through my Fender Vibro-King amp.
Of course, that is not a cheap amp, but it has that warm tube sound. It has
its own distortion. When you combine it with the saturated sound of the
R65, it's quite pleasing to my ears.

Dennis

"Mike Otterbine" <skweezb...@yahoo.com> wrote in message
news:3d98073c.03010...@posting.google.com...

Mike Otterbine

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Jan 7, 2003, 10:17:24 AM1/7/03
to
Dennis,

The Vibro-King is an amazing amp; Buttery smooth. I'd love to hear an
accordion through it. Maybe Elderly Instruments has one in stock I
could play through. Not that I can afford it right now.
I've been playing with settings on the Line6 Pod. Current favorite
settings are 'Small Tweed' and 'British Class A'.

-Mike

"dennisgu" <denn...@mindspring.com> wrote in message news:<avd79q$d39$1...@slb5.atl.mindspring.net>...

~Dream~

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Jan 13, 2003, 12:02:42 AM1/13/03
to
Dennis wrote:
>
> I've found that my boxes sound great going through my Fender Vibro-King amp.
> Of course, that is not a cheap amp, but it has that warm tube sound.
> ..........When you combine it with the saturated sound of the

> R65, it's quite pleasing to my ears.

This is probably a good spot to inject a small re-hash
of amplification basics...

While Carl likes his sound through the Polytone, and
Dennis likes his sound through the Fender, it should be
remembered that amplifiers like this impart their
personality on your sound - for a number of reasons -
Box amps like this are not designed to be full range,
nor are they capable of it in the framework of the cabinets
design or speakers loaded in amps like these.

So if you try different amps out, find something that pleases
your ear, and would be useful to you fine... enjoy.
Particularly with Guitar players, the concept of the Amp
being an integral part of tone control... to the point of tuned
Birch cabinets housing the speakers... this is a legitimate idea.

Hence the immense popularity of "Modeling" amps and signal
processors. In other words, you can take any full range
Audio system, pre-amp it using a "Modeling" processor, and
re-create the tone of any "guitar" amp ever built.

While this doesn't give you the tactile sensations of
a real Vibro-King (like shocking ground loops) <grin>
and the 12AX7 pre-amp tube(s) can alter tone coloration as
they age in place, it does allow a guitarist to have
a dozen "legendary" amplifiers (or so) on tap virtually.

ANY Full Range audio system with a "Modeling" stage can emulate
imitate ANY packaged amplifier - however - NO packaged amplifier can
possibly hope to emulate a full range audio sound system.

Obviously, a full range Pro audio sound system has more
useful potential for a Musician than any "box amp" ever could.

I do understand the needs of many of you to have small,
portable systems... but "newbies" need to understand in their
search for appropriate amplification solutions that anything
short of a full range high fidelity system is frankly a compromise...
you must give something up... if you accept less.

It's as simple as this... many rooms you will play in are big.
Big rooms have a lot of cubic space. If you want to move your
sound through a large area of cubic space evenly and cleanly
you must use big speakers, and amplifiers capable of driving
them. By speakers, I mean the actual drivers (the round
things... the horns...) not the cabinets they come in.

The only way to co-ordinate the two opposing concepts is to
use the small Box amp as your STAGE MONITOR primarily... and
send the output of that amplifier to the main PA system
for further amplification (where necessary) Very
few box type amps have a line/signal out that comes after
the final internal pre-amp stage, so the way to amplify
these is generally with a Shure SM-57 laid in the back
of the cabinet, or on a small tripod pointed at the speaker.

Of course, if you intend to incorporate MIDI or Karaoke CD's
or anything like that into your performance life then the
simple Box Amplifier is no longer an appropriate choice.

Fortunately, for those of you desiring simplicity and reasonable
size/weight - there are single packaged PA systems from
JBL (the Eon), Mackie, Sampson, and other big names which
are almost as good as a full fledged PA system. You must
sacrifice something to go smaller - remember - so these
all-in-one devices may give up a bit of variety in
control, FX loops, inputs, etc. and perhaps a bit on the
sound. (the moulded in horn is perhaps not as good as a fully
independant bi-radial at dispertion, or throw)

Some of these systems, however, pack an amazing amount
of useful things into their packages... the Sampson
has a gel-battery option, as well as a built in wireless
if you want one, for instance.

But again, you can do more things, more flexibly, more
consistently, in more unfriendly environments, with a
full blown PA system than any of these options discussed
above. Bottom line is analyze your potential needs well,
and try to get the best solution you can possibly
afford both in the cost of ownership ($$$$$$$.99)
and the cost of usership (the shlepping around, the
slipping and falling, the stairs, the aching back)

Part of the reason I am able to put up with all the roadie work,
admittedly, is because I have designed my entire life
around being able to handle the maximum amount of quality
equipment possible for any given situation. It took
decades, but everything from the Vehicles I use to the
building that houses my studio/shop is geared to support
and was selected/customised by my desire to deliver quality music.

Your personal level of fanaticism may differ from mine, but do
try to be as fanatic as you can about your sound not only in
the quality of Accordion you keep, and the quality of skill
with which you play, but the quality of Sound systems as well.

Ciao Ventura

Theodore Kloba

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Jan 13, 2003, 10:01:52 AM1/13/03