Symetrix 202 pre
JKountz
I'm wondering is it primarily used/recommended for vocal recording or is it
just an all around inexpensive solution for general application? I do alot
of acoustic guitar and mandolin along with vocals and I have a couple other
preamps Im using but Im always looking for something decent until I can
afford something "real". Of course I guess I could just sell all the ones I
have and buy one good one but that wouldnt be any fun now would it! LOL
Jim
Monte P McGuire
The 202 is a basic, "attempt at colorless" preamp that works for many
situations. It doesn't have much coloration, so it's not something
that will only work well in one application or another.
There are cleaner preamps, and you can modify the 202 to make it a bit
cleaner than stock, but even as stock, it's really not bad at all,
specially considering it's around $100/channel.
Regards,
Monte McGuire
mcg...@theworld.com
JKountz
useless items in my inventory and buy one good mic pre. Focusrite makes some
interesting products. Anyone care to comment on the Voicemaster or the newer
Penta models??
Jim
JKountz <jko...@jdknet.com> wrote in message
news:u3hev0l...@corp.supernews.com...
Eric Agner
you want something decent, people around here will start suggesting
mic pre's in the $2000 and then some range.
What kind of budget do you project for something decent? No one can
help you much unless they know whether you mean $600 worth of decent
or $3000+ worth of decent.
Besides budget, what are you recording? Different pres are suggested
for classical music vs metal. What mics do you have available? How
good are your acoustic spaces? Good luck --Eric Agner
"JKountz" <jko...@jdknet.com> wrote...
JKountz
pre is best for under a certain amount of dollars" I would get flamed to
hell and back. Made that mistake a couple of years ago when I first found
this group. Folks around here hate that stuff and after reading this group
for some time now I understand why. Those types of questions are asked here
over and over. I found its best to ask about particular units and or setups
instead of the "give me the best for $300" route. I did say what I was
recording however in my original post and then posted another message with
two particular units in mind. Just wanted to see what others had to say
about them too. Maybe it hadnt been posted yet when you read the original
message.
Thanks!
Jim
Eric Agner <eag...@yahoo.com> wrote in message
news:df8183d5.02010...@posting.google.com...
David Satz
> If I dare ask "hey which mic pre is best for under a certain amount
> of dollars" I would get flamed to hell and back. Made that mistake
> a couple of years ago when I first found this group. Folks around
> here hate that stuff and after reading this group for some time now
> I understand why. Those types of questions are asked here over
> and over.
Yes, but that's part of why this newsgroup exists. The fact that so
many people have the same basic questions only shows that reliable
information is not always easy to obtain elsewhere. This includes
information that a person must have before he will know how to
narrow down his questions to readily answerable ones.
Each of us was an ignorant newbie at some point--actually not just
at one point, but for a considerable stretch of time. Do we all forget
what that felt like, and how many obnoxious questions we had to ask
before becoming the fully enlightened paragons that we are today?
JKountz
Jim
David Satz <DS...@msn.com> wrote in message
news:uGhYec4lBHA.1272@cpimsnntpa03...
Scott Dorsey
It was a good all around inexpensive solution for general work, and it
was also fairly easily upgraded, but it's been discontinued and now is
selling for more used than it sold for new.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Mike Rivers
In article <uGhYec4lBHA.1272@cpimsnntpa03> DS...@msn.com writes:
> Each of us was an ignorant newbie at some point--actually not just
> at one point, but for a considerable stretch of time. Do we all forget
> what that felt like, and how many obnoxious questions we had to ask
> before becoming the fully enlightened paragons that we are today?
It used to be so much easier to be an ignorant newbie, though. When I
started buying mics, I had an EV 654 and I had a friend with a couple
of Shure SM54's. I wanted to get something different, so I bought a
few Beyer M260's without ever hearing them, and y'know what? They
sounded pretty good for what I was doing. When it came time to get
some condenser mics, AKG C451's were what I could afford, so I got four
of them. No way I could afford Shoepps or Neumann at that point. Part
of the choice was that I was using a TASCAM Model 5 console without
phantom power, and could (and did) wire it up for 15V powering, which
the C451's would work with. They worked out too, being better than
the Beyers for some things, not as good for others. When I wanted some
more condenser mics, I trusted that the then new Shure SM81's would
work out, and I called my dealer and had him send me a couple. No
complaints there. When it was time to get a U87, I got some used
U87's.
I've picked up several other mics along the way, but none of my mic
purchases were ever based on the careful listening and comparison that
we all recommend today. When it was time to get another mic, I just
got another mic, and none of them suck. But the difference between
then and now was that there just weren't all that many choices. If I
had $300 to spend, there were really only one or two mics to choose
from. If I actually did perform any listening tests before making a
purchase back then, A/B-ing mics was just that, because you only had
an A and a B. Today there are a few dozen choices in any price range,
and in reality, the differences between any two at a given price are
likely to be pretty small - still it seems like some people agonize
over those decisions for weeks.
Just buy something, hook it up, and start recording. You're bound to
find some good way to use it.
--
I'm really Mike Rivers (mri...@d-and-d.com)
Rob Adelman
be worth checking out.
The Sytek MPX-4Aii with 2 optional Burr Brown Jfet IC's.
<http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1404108095>
You can probably end up with less than $200 Per channel into it. I was
tempted to bid on it myself, but fronting the Yamaha MD recorder with
this might be a bit of overkill ..
Rob Adelman
Bob Smith
>
> Don't remember who was actually looking fo the mic pre, but this might
> be worth checking out.
>
> The Sytek MPX-4Aii with 2 optional Burr Brown Jfet IC's.
> <http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1404108095>
>
> You can probably end up with less than $200 Per channel into it. I was
> tempted to bid on it myself, but fronting the Yamaha MD recorder with
> this might be a bit of overkill ..
No, it won't be. The Yamaha MD will be outgrown or go by the wayside in
time. The Sytek will be useful for a lifetime.
> Mike Rivers wrote:
> >
> > Just buy something, hook it up, and start recording. You're bound to
> > find some good way to use it.
More truth to this than many newbies might suspect.
--
bobs
we organize chaos
Bob Smith - BS Studios
http://www.bsstudios.com/
rsm...@bsstudios.com
Robert Angst
found on google.
Is there a link to the schematic available?
Robert
Ulysses
<jko...@jdknet.com> wrote:
> Well after some research thats exactly what Im going to do, sell all the
> useless items in my inventory and buy one good mic pre. Focusrite makes some
> interesting products. Anyone care to comment on the Voicemaster or the newer
> Penta models??
I'll comment on them:
You should buy a Great River instead.
--
Justin Ulysses Morse
Roll Music Studios
Minneapolis, MN
www.rollmusic.com War is terror.
Ulysses
robert...@ivtfg1.tu-berlin.de wrote:
I've got at least six SX202s and I've never found a legible schematic.
Some spotty references to various tweaks have been found here over the
last few years but Monte's promised "compleat guide to upgrading your
SX202" is long overdue.
George Reiswig
his/her time to do a favor for others it's up to them when they're going to
get it done. If you paid him good money up front, that'd be another story.
But...
George Reiswig
"Ulysses" <uly...@rollmusic.com> wrote in message
news:ulysses-0801...@x128-101-254-14.dialup.umn.edu...
Ulysses
<Rei...@europa.com> wrote:
> IMHO, in fairness to Monte, I think that any time a person volunteers
> his/her time to do a favor for others it's up to them when they're going to
> get it done. If you paid him good money up front, that'd be another story.
> But...
Very true. Maybe Monte should sell his recipe. Then we could complain
about it being "vaporware." As it stands, we can only politely whine,
"Hey monte, are you done yet?"
WillStG
<< I'll comment on them:
You should buy a Great River instead. >>
For $1000 or so more though...
Will Miho
NY Music & TV Audio Guy
Fox And Friends/Fox News
"The large print giveth and the small print taketh away..." Tom Waits
Willie K.Yee, M.D.
<Rei...@europa.com> wrote:
>IMHO, in fairness to Monte, I think that any time a person volunteers
>his/her time to do a favor for others it's up to them when they're going to
>get it done. If you paid him good money up front, that'd be another story.
>But...
>
In the meantime, I just might piss my pants waiting. (Just bought a
202 myself).
Willie K. Yee, M.D. http://www.bestweb.net/~wkyee
Developer of Problem Knowledge Couplers for Psychiatry http://www.pkc.com
Webmaster and Guitarist for the Big Blue Big Band http://www.bigbluebigband.org
Mike
gear they couldn't make a decent recording with whats left over.
"David Satz" <DS...@msn.com> wrote in message news:<uGhYec4lBHA.1272@cpimsnntpa03>...
Scott Dorsey
>Truth is there is a corp or regulars here that likes so few pieces of
>gear they couldn't make a decent recording with whats left over.
Maybe. But the truth is that there is an increasing amount of total
crap out there. There has always been more junk than well-designed
equipment, but it's getting worse as the consumer electronics guys
are entering the pro audio field and the demand for very-low-end gear
has increased so much.
Monte P McGuire
Ulysses <uly...@rollmusic.com> wrote:
>Very true. Maybe Monte should sell his recipe. Then we could complain
>about it being "vaporware." As it stands, we can only politely whine,
>"Hey monte, are you done yet?"
I haven't forgotten, but that "damn reality thing" keeps setting in
and stupid stuff like dying hard drives and pesky clients keep me from
stuff I'd prefer to do...
Seriously, it's all written up, but I should try to bolster the RF
proofing a bit and possibly change one coupling cap's size. I had a
Precision 8 in here for review and it was a lot more RF proof with no
apparent RF proofing components... It also had a more solid low end,
but a little brighter top, so I'm gonna figure out if I can graft that
low end onto the 202 with a cap change.
So... I'l say it again... "really soon now..."
Thanks for your patience...
Monte McGuire
mcg...@theworld.com
Bryson
Monte P McGuire wrote:
>
> I haven't forgotten, but that "damn reality thing" keeps setting in
> and stupid stuff like dying hard drives and pesky clients keep me from
> stuff I'd prefer to do...
>
> Seriously, it's all written up, but I should try to bolster the RF
> proofing a bit and possibly change one coupling cap's size. I had a
> Precision 8 in here for review and it was a lot more RF proof with no
> apparent RF proofing components... It also had a more solid low end,
> but a little brighter top, so I'm gonna figure out if I can graft that
> low end onto the 202 with a cap change.
>
> So... I'l say it again... "really soon now..."
Well HTFU. I wanna sell mine but I'm gonna wait for your mod notes to be
released, 'cause I know the price'll go up on 'em then (of course then
I'll wanna keep it).
You're too cool Monte!
Tim
George Reiswig
GR
"Monte P McGuire" <mcg...@TheWorld.com> wrote in message
news:Gpo2G...@world.std.com...
Monte P McGuire
Monte P McGuire <mcg...@TheWorld.com> wrote:
>So... I'l say it again... "really soon now..."
I just read what I have and it seems to be "good enough" to release,
with two caveats. The last paragraph of the Grounding section where I
talk about removing R80, the 10 ohm resistor from chassis to ground,
should probably be ignored. The whole issue of chassis to ground is
not dealt with very well in the 202 anyway, and especially WRT RF
sensitivity, something much better should be done. That will happen
soon, as I figure it out.
The other caveats are the size of the input coupling caps and the cap
that couples the 2015 stage to the output stage. Instead of the 22uF
phantom blocking caps I recommended, you could go with higher values
like 47uF or even 100uF. Also, the interstage cap, which mostly sets
the highpass frequency, could be made larger if you have a suitable
cap. I used .22uF with 100 to 150K ohm load, and this could be easily
raised to 1uF or even more if you can find a suitable, high quality
film cap. Some sort of metallized polypropylene would work well.
Aside from that, everything else seems to work well, so have at it!!!
Best of luck and if you run into trouble, ask questions!
Monte McGuire
mcg...@theworld.com
----------------------------------------------------------------------
Modifications to the Symetrix SX202 Microphone Amplifier
----------------------------------------------------------------------
The SX202 is a now discontinued but still very popular solid state IC
mike amp made by Symetrix. It is based upon the now obsolete and hard
to find SSM 2015 mike amp IC, and as such, it is a fundamentally good
sounding amplifier of the "clean and uncolored" variety.
Unfortunately, the circuit design and component choices made by
Symetrix greatly reduce the performance that the 2015 is capable of.
This paper outlines several methods for removing these performance
roadblocks and will allow a skilled modifier to greatly improve the
performance of this amplifier. The end result will be an amplifier
whose distortion products are low and largely benign and whose
bandwidth and output drive will be quite extended.
Of course, these modifications require some electronic rework skill,
will completely void your warranty and will change the way the SX202
sounds, so keep that in mind before you act upon what's written here.
If you feel you're not equipped well enough to do these mods, take
your SX202 and this paper to a competent technician, and they'll be
happy to do the mods for you.
The five main issues that can be addressed in the SX202 are the output
amplifier chip selection, the 2015 compensation capacitors, the
coupling between the SSM 2015 and the output stage, power supply
bypassing and the grounding scheme. I also discuss things you can do
to improve the gain pot, coupling capacitors, a mod to remove the peak
detector and finally a list of things you should not attempt to
fix...!
One issue that has to be addressed is that there are essentially two
different flavors of the SX202, each using different PC board layouts
and component choices. So, the instructions and component
designations may vary depending on which unit you have. The older
units with the rev. C circuit board have 6 output jacks on the rear of
the unit. The newer units with the rev. G circuit board have only 3
output jacks.
Output amplifier changes:
----------------------------------------------------------------------
The output circuit is a very simple one. It uses a follower and a
unity gain inverter to provide buffered in phase and out of phase
outputs from the SSM 2015 amplifier stage. While better balanced
output topologies could be used, I have decided to stick with the
stock arrangement because of its relative simplicity and good
performance into balanced inputs. Although the noise gain of the
stage is low, it contributes the bulk of the preamp's distortion.
As stock, the SX202 output stage uses some variant of the 4560 dual
bipolar op amp, usually either the Exar XR4560 on older units or the
Rohm BA4560 on later units, the Rohm version being especially
repugnant. At best, these amplifiers are somewhat slow, and this adds
excess distortion above 3KHz or thereabouts. The Rohm devices seem to
be marginally unstable in addition to being too slow to pass audio
cleanly, and this causes the HD spectrum to be littered with many high
order harmonics. The end result is an overly bright and hard sound,
solely due to the 4560.
As of this writing, the best possible replacement chip is the new
LT1469CN8 from Linear Technology. It is a dual, low noise bipolar
input op amp that is remarkable in that it has extremely low
distortion, excellent output drive and a very high gain-bandwidth
product. It is unity gain stable and it can operate from high supply
voltages, so it is a simple drop in replacement. The only drawbacks
are cost and availability.
Some varieties of NE5532 will also perform very well, but not quite as
well as the LT1469. In my tests, the JRC 5532D from New Japan Radio
seems to perform consistently better than most 5532 flavors, and the
Fairchild units were fairly close. The Philips 5532 varieties did not
do so well distortion wise. The main advantage to the 5532 is price,
so I would recommend that chip only if funds are tight and it's hard
to find the LT1469. However, it will not produce the best possible
peformance.
The LT1364CN8 is also a reasonable amplifier, and if ultrasonic
distortion is of prime importance, this might be the best choice.
However, due to its high idling dissipation, it should be heatsinked,
especially when driving low impedance loads at high levels. Its
midband performance is not quite as good as the LT1469, so it is not
my first recommendation.
I have recommended some JFET amplifiers from Burr Brown in the past,
such as the OPA2132 and OPA2604. While these amplifiers do sound very
good, they are not quite as clean at very high frequencies as the 1469
or even the 5532, and I cannot recommend them anymore if cleanliness
is your goal. My opinion about these amplifiers changed after finding
ways to clean up the SSM 2015 stage, which I will discuss in the next
section. After that modification, it became clear that the dominant
source of HF distortion was the Burr Brown chip, and the differences
between the 1469 and 5532 became more noticeable too.
There are three 4560 chips per SX202 to replace. Install high quality
machined pin low profile sockets after you remove the old chips, as
soldering the chips directly could damage them. Sockets also make it
easier to modify later on if a better chip or hybrid becomes
available.
When removing the old chips, clip the pins off near the epoxy chip
body and discard the old op amp. The PC board is far more valuable
than the old op amp - sacrifice the op amp to help minimize stress on
the PC board. Once the bodies of the 4560s are clipped out, remove
each pin of the old IC with a soldering iron and needle nose pliers
and the excess solder with a desoldering tool, solder sucker, solder
wick, braid or what have you. Again, if you don't know what you're
doing or you don't have the right equipment, have a technician do
these modifications! The PC board is fairly simple to rework since it
is only a two sided board, but it can be damaged by carelessness.
SSM 2015 Compensation:
----------------------------------------------------------------------
The next area for improvement is to change the way the SSM 2015 mike
amp stage is compensated. The SSM 2015 is the heart of the mike amp
and it provides all but 6dB of the gain of the completed circuit. The
SSM 2015 requires three small valued capacitors to set the internal
feedback structure at high frequencies. By changing these values, not
only is the stability of the circuit affected, but the high frequency
distortion and slewing behavior are also greatly affected.
The rev. C boards have less than optimal values, but the rev. G boards
have values that drastically increase HF distortion with no other
benefits. The capacitor betwen pin 1 and pin 13 of the 2015 is the
most critical capacitor, and the rev. G value of 47pF is simply too
large. Changing this to 7.5pF will move the frequency at which
distortion sharply rises up an entire octave from 3-4KHz to over
40KHz. The common mode amplifier capacitor should be increased to
56pF. I do not know why this improves HF distortion, but it does.
In both the rev. C circuit and the rev. G circuit, these components
are C16, C17, C18 for channel 1 and C7, C8 and C9 for channel 2. On
both boards, they are located at both ends of the 14 pin SSM 2015 chip
and look like little orange-ish tan discs with two leads.
For rev. C boards, change C9 and C18 from 47pF to 7.5pF, change C8 and
C17 from 10pF to 7.5pF and change C7 and C16 from 47pF to 56pF. For
rev. G boards, change C12 and C29 to from 47pF to 7.5pF, change C13
and C30 from 47pF to 7.5pF and change C16 and C32 from 47pF to 56pF.
In case I got any component legends wrong, make sure these are the
capacitors connected to the SSM 2015 chip after you do the mod: 7.5 pF
between pins 1 and 13, 7.5 pF from pin 1 and ground and 56pF between
pin 6 and pin 7.
Select a quality monolithic ceramic capacitor with .2" radial lead
spacings that uses the NP0 / COG dielectric. You could use a
polystyrene capacitor instead, but it must be noninductively wound and
be connected with short leads to the PC board or it will not function
properly. Note that the NP0 dielectric is a very linear dielectric,
far different than conventional ceramics used in bypass caps. Since
the capacitance is so small, degradation is very unlikely even if the
dielectric weren't so clean, so, in my opinion, there is little
benefit from using anything but a high quality NP0 ceramic capacitor.
In my units, I made the 7.5pF capacitor up out of two series connected
15pF NP0 surface mount (0805 size) chip caps. It takes a little
dexterity and a tiny bit of hookup wire to arrange this, but it can
work out well. Alternatively, through hole parts can easily be used
here too.
To illustrate the benefit of this mod, a stock rev. G with 5532 output
amplifiers but the stock compensation caps will produce almost 1-2%
distortion at 100KHz, whereas the same amp with the recommended
compensation caps will produce less than .01% distortion at 100KHz.
This is measured with the circuit set for 40dB of midband gain, 150
ohm source, 600 ohm load and a -20dBV input.
Coupling between the 2015 and output stage:
----------------------------------------------------------------------
The original rev. C boards simply connected the 2015 stage's output to
the output op amp circuit, and this was found to cause stability
problems. Most SX202s will have a 511 ohm resistor retrofitted in
series between the 2015 and the output amplifier to tame some
stability issues caused presumably by output to input coupling. In
the rev G board, this part was designed in and called R78 and R79.
If your unit does not have this retrofit, it should, or else it will
probably suffer from marginal stability and the resulting increase in
distortion. In all units I have seen, this resistor is installed, but
there may be a few early rev. C units that do not have the resistor.
If that's the case, you will have to cut some traces and install the
resistor yourself. I decided to use 432 ohms because it was handy.
As part of the coupling cap modifications, place a small film coupling
cap in series with the resistor to block any DC developed in the SSM
2015 gain stage. If DC is removed here, the coupling caps after the
buffer stage, which have to be much larger to handle low impedance
loads, can be removed. This coupling cap is loaded by the 10K input
resistors of the summed ch 1+2 output stage, (R37, R38 on rev G
boards, R51, R52 on rev C boards), so it must be scaled accordingly.
I decided to use a .22uF film-foil polypropylene cap, so the stock 10K
load would not be appropriate. On some units, I have removed the
summing stage entirely (by removing R37 and R38 or R51 or R52) and
placed a 150K resistor across pins 3 and 5 of the two remaining output
amplifier chips. This yields a single order 4.8Hz highpass filter,
which is only .24dB down at 20Hz.
On other units, I changed the summing stage to use 100K summing and
feedback resistors, and while this increases the noise in the summed
output, it's not an issue for my purposes. Note that if this approach
is taken, the offset voltage of the summed ch1 + ch2 output stage
amplifier determines the output DC sit point of the ch1 and ch2
outputs. A quality, low offset JFET amplifier like the OPA2132P will
do nicely there.
In addition to the series resistor and coupling cap, a small capacitor
to ground can be added across the input of the output amplifier to
further reduce transmission gain at extremely high frequencies. A
120pF capacitor added across pins 3 and 5 of the output amplifier
chips U3 and U5 will accomplish this. This capacitor should be a
small leaded NP0 ceramic capacitor added to the non component side of
the PC board, right at the pins of the IC socket. With this component
installed, the SX202 is only a fraction of a dB down at 100KHz, so no
useful bandwidth has been lost, only the potential for distortion
causing instability and slewing.
Power supply bypassing:
----------------------------------------------------------------------
This is a somewhat complex topic, but I can summarize my
recommendations quite easily. Don't add extra bypass caps or increase
the size of any exiting ones, except as I outline below!! The problem
with adding bypassing is that you're not really bypassing anything,
you're merely coupling transient currents on one supply rail to a part
of the ground network. Given that the circuit uses bipolar power
supplies and dual supply amplifiers, coupling one rail via a bypass to
ground can easily couple rectified audio current into ground, with a
variety of possible results, depending on the circuit and the ground
node chosen. Given that the ground layout of the SX202 boards is less
than ideal (especially on the newer 3 jack revision), this can be a
recipe for disaster.
The SX202 relies upon a pair of three terminal voltage regulators to
provide low impedance power to the SSM 2015 and output stages, and
this scheme actually works pretty well. The PC board is small so the
impedance at the amplifier chips is still quite low.
The caps across the outputs of the three terminal regulators should be
upgraded from the stock 10uF/50V to a 470uF/25V low impedance
electrolytic cap. The stock .01uF ceramics can be upgraded to .1uF
multilayer ceramics in parallel with a small 5-10uF surface mount
tantalum cap. The Sprague 195D106X0025Y2 SMD tantalum cap fits nicely
on the foil side across the pads for the stock .01uF ceramic and seems
to be pretty reliable. Use silver solder when installing this cap
(and any other SMD cap) to prevent damage to the terminations.
Supposedly, metals from the component's end terminations can leach
away from the SMD chip if conventional solder is used and weaken or
harm it. Why gamble...
This composite network will provide very low impedance across a wide
frequency range with few drawbacks. Note that the composite must have
less than 1000uF or else the voltage regulators may fail when the
circuit is powered down. This is because the capacitance before the
regulator is 1000uF and if the capacitance after the regulator is
equal to or greater than that, the input voltage to the regulator will
go below the output voltage of the regulator when the circuit powers
down; this reverse current will destroy the regulator. Protection
diodes could be installed to prevent this problem, but I haven't seen
the need. Increasing the size of the pre-regulator capacitors to
counteract this is also not recommended, as this increases the peak
switching currents in the rectifiers and the ground system and
therefore increases the noise of the power supply.
The output amplifier chips can have additional local bypasses only if
a new grounding scheme is added to the board with stout copper foil.
This will be discussed below. However, if you do not do the copper
mod, don't add or change any other bypasses. The SSM 2015 basically
drives only a high impedance load, so it really won't benefit from
such a reservoir of current.
Since the circuit relies on the three terminal regulators for a low
impedance supply, it would seem wise to try to upgrade the regulators
themselves. The problem is that I know of no simple drop in part that
will provide lower output impedance, so the only solution would be to
use a more complex circuit on a piggyback board. If anyone does any
work regarding this, please let me know! I know Walt Jung has done
some excellent work on ultra low impedance regulators for audio
circuits, but as far as I'm aware, the designs are too large for this
chassis. Perhaps with a good PC layout and SMD parts, they could be
adapted to fit the SX202.
Grounding:
----------------------------------------------------------------------
There are a few things you can do to improve the internal grounding of
the SX202. A strip of copper foil added to connect each 'pin 1' of
the input and output jacks at the rear of the PC board will help to
make the 202 behave better, and also ends up creating the ideal ground
for output stage supply bypasses, if you choose to add them.
I used rather thick (.25 mm) and wide (1 cm) copper strip stock, cut it
into a piece 15 cm long and soldered it over the sleeve connection of
each 1/4" jack so that the foil was nearly flush with the edge of the
PC board. I then cut a pair of 2 cm strips to reach to each of the
XLR pin 1 connections and soldered those to the main strip and to pin
1. This is actually sort of difficult to solder, since the copper
strap will expand from the heat more than the PC board. If you get
the whole thing to solder reflow temperature, the PC board can warp
when it cools as the copper contracts. So, you want to make a
connection on one end of the board, let it cool, make a connection at
the other end and then work your way into the middle.
Once this strap is in place, you can remove R80, a 10 ohm resistor
that connects chassis to signal ground. This component is near the
input XLR connectors, and is present only in rev G. units. You can
also remove C49 and R65 (on rev C units), two components located right
next to the input power jack.
Output Bypass Caps:
----------------------------------------------------------------------
If you wish to add bypass capacitors to the output buffers, then you
need to add another pair of ground straps. These 6 cm. straps are
connected between the new 'pin 1' strap at the edge of the PC board
and pin 5 of each output amplifier. It's easier to add this strap
after you've installed sockets for new output ICs and added the
tackdown resistor and 120pF shunt capacitor between pins 3 and 5 of
the output amplifier chip. The foil can rest on the leads of these
components at the pin 5 node and thus be lifted away from the other
traces and cut component leads on the PCB. You may also want to make
a pair of bends near where this strap connects to the pin 1 strap to
further elevate it away from other traces near the rear of the PC
board.
Once the straps are in place, output bypasses can be added. I used a
pair of 5uF/35V Kemet axial solid tantalum capacitors for this purpose
since they were thin enough to fit between the PC board and the
chassis, they have very good electrical performance at high
frequencies, they are quite reliable and they shouldn't need to be
changed on a regular basis.
A cap goes between pin 4 and the output strap as well as from pin 8
and the output strap. Remember that pin 8 is positive and pin 4 is
negative, so install the caps with positive towards pin 8 and positive
away from pin 4. Make sure to keep the lead lengths very short. I
found it easiest to rest the caps along either side of a ground strap
and solder that connection in place to hold the part. Then, the
connection to pin 4 or pin 8 is made once the cap is soldered to the
strap.
Coupling caps:
----------------------------------------------------------------------
All transformerless mike amps require input blocking capacitors to
keep P48 out of the front end. I had previously replaced the input
phantom blocking capacitors with 10uF/100V metallized polypropylene
capacitors, but there are problems that can result from this
modification. The physical size of the replacement capacitors forced
me to mount the caps for channel 2 above above the output stage, and
this caused some undesireable ultrasonic coupling and resultant
instability.
While film caps do sound cleaner than electrolytics, their size can
cause input - output coupling problems, especially once you have
extended the bandwidth of the amplifier, so I feel that replacing the
stock caps with new, high quality replacement electrolytic caps is a
better way to go with the SX202. I chose 22uF 63V Panasonic HFQ
radial electrolytics. If you choose a higher capacitance value,
leakage will increase, and this can upset the balance of the first
stage, so it's probably wise to stick to a cap in the 22-47uF range.
Low leakage is a very important parameter to optimize here, as well as
any other dielectric losses. In practice, very little signal voltage
will develop across these caps, so the nonlinearities of aluminum
electrolytics should not be a problem if you use a fresh, quality
capacitor. Since the SX202 is an older unit, a few of your input caps
are probably starting to leak and need to be replaced anyway.
There is a set of coupling capacitors after the output buffer
amplifiers that can be jumpered if the output amplifier and
intserstage coupling mods are done. They are 100uF 35V polarized
electrolytics located near the output jacks. The output offset of the
modified preamp should be very low, less than a millivolt, so unless
you have special requirements, these caps can be removed and jumpered.
There are also some 4.7uF nonpolar coupling caps after the polarity
switch and pad, and these too can be jumpered if you don't mind
hearing ticks or pops when the pad or polarity switches are used. I
decided to remove them just so I would not have another electrolytic
cap that would need to be replaced after some years.
Gain Pot:
----------------------------------------------------------------------
The gain pot on the SX202 can be a source of excess noise and possibly
microphonics. Ideally, it should be replaced with a switched resistor
network to eliminate these problems. I used a 12 position C & K
miniature rotary switch and some conventional RN55 style resistors to
assemble a switched gain network and I am very pleased with the
results.
While conducting distortion tests listening to the analyzer residual,
I noticed that moving the gain pot caused a lot of scratchy hash, and
in some cases, some pot positions caused somewhat high level low
frequency noise to be heard. Both of these problems are caused by
poor contact from the wiper to the irregular carbon track of the gain
pot, and this can sound nasty. A simple, high quality switch and
quality metal film gain setting resistors will have none of these
problems.
The only drawback to this mod, aside from the complexity of assembling
the network, is dealing with a stepped gain control. Some engineers
prefer them for interchannel accuracy and resettability, but note that
the gain of a switched gain preamp is almost impossible to change
gracefully while recording.
If you're interested in a switched gain knob, set up a spreadsheet to
calculate the gains given a set of resistors. While it's useful to
know the gain of each step, the difference in gain between steps is
also useful to see while choosing resistor values. I opted for steps
of 2.5 to 2.75dB, and with 12 positions, this gives me around 30db of
gain range. The maximum gain of around 50-55dB might be too low for
some uses, but you can take whatever sort of tradeoff desired if you
design your own gain network.
The Input Pad:
----------------------------------------------------------------------
I often record using high output mikes placed close to loud sources,
so the SX202's stock 15dB pad and 26dB minimum gain was a problem.
Reducing the 2015 minimum gain is possible up to a point, but this can
reduce the stability margin and honestly, I don't know if you can
lower it more than a handful of dB.
A simpler thing is to change the pad from 15dB to 20dB. This can be
done in a way that lowers the effective input noise of the preamp, so
it's not such a bad tradeoff for most situations. Finally, the SSM
2015 has less distortion if it is presented with a smaller input
signal, so using a pad and higher gain is often not such a bad idea
for medium - low gain situations.
The SX202 pad is actually a pair of unbalanced pads, one for each
input leg. This is actually a good design since it will be more
effective than a pi network for mikes that have single ended outputs.
Some modern transformerless condensers like the high output Neumann
TLM 103 have single ended outputs and if an unbalanced pad is not
used, massive, unattenuated common mode signal is presented to the
mike amp, and this can cause problems.
The trouble with this design is that the two pairs of resistors used
in the unbalanced pad must be matched carefully to preserve the input
stage's balance. I used 3K09 and 301 ohm resistors instead of the
stock 3K01 and 681 ohm resistors, yielding approximately 21dB of
padding when the next stage's 20K load is considered.
These resistors should be closely matched from a supply of quality
metal film resistors. Buy 50 or 100 of a particular value and measure
them with a quality ohm meter. These days, the HP 3490A multimeter
can be found as surplus for $25-100 and it's hard to beat for this
work. It has a 5.5 digit display, provision for 4 wire Kelvin
measurement leads and is sensitive enough to measure the effects of
your body heat and the temperature coefficient of a typical resistor.
Sorting resistors is tedious, but it can help to preserve the input
stage's balance and it's probably cheaper than specifying ultra
precision parts.
Peak detector:
----------------------------------------------------------------------
The peak detector stage is a transistor follower driven by a diode
attached to the output of the SSM 2015 stage. While the input
impedance of the follower is large and the output impedance of the SSM
2015 is low, the load on the SSM 2015 is nonlinear and it is remotely
possible that distortion could be introduced into the amplifier's
output by this arrangement.
I personally do not require a peak detector, since I almost always
have an analog to digital converter on the output of the SX202 that
clips before the SX202 will. If you wish to disable the peak
detector, remove diodes D20 and D21. This removes the nonlinear load
and also disables the peak detector function. I have no opinion as to
whether you or I could hear any benefit from this mod, but it seemed
like a prudent thing to do, so the peak detector is gone. If you
disable the peak detector in this way, it is very simple to reconnect
should you decide you need it again.
Things that don't work:
----------------------------------------------------------------------
The SSM 2015 chip uses a resistor to program the first stage bias
current, and in the SX202, this resistor is set to the maximum bias
current that the 2015 can safely handle. Do not reduce the value of
this resistor, as you will probably damage the 2015 chip. These chips
are very hard to find these days, so you will have to live with the
extra distortion from a damaged chip for some time. What's more
annoying is that increasing the bias beyond the stock arrangement does
not improve performance. I found this out the hard way, so leave the
27K bias resistor alone! There is some evidence to suggest that
distortion might be improved by increasing the value of the bias
resistor, but this increases noise, and the preamp is already on the
noisy side. Leave the bias alone, as it already seems to be optimal!
----------------------------------------------------------------------
Good luck with these modifications and enjoy your new preamp!!
Monte McGuire
mcg...@theworld.com
George Reiswig
that knowledge is pretty much worthless if it isn't shared. In this day of
"intellectual capital" and so forth, I think we owe a big thanks to the
Scott Dorseys and Monte McGuires of the world.
George Reiswig
Song of the River Music
"Monte P McGuire" <mcg...@TheWorld.com> wrote in message
news:Gpop7...@world.std.com...
George Reiswig
GR
"George Reiswig" <Rei...@europa.com> wrote in message
news:a1i5f1$p...@news.or.intel.com...
Bill Newell
> Mike Rivers wrote:
>>
>> Just buy something, hook it up, and start recording. You're bound
to
>> find some good way to use it.
>
> More truth to this than many newbies might suspect.
The collective falsehoods of the Internet have helped bring about the
notion that buying a "magic" piece of gear will make you an instant
success at recording and/or music creation. The truth is that success
comes to those who figure out how to get good sounds out of what they
have, and you can do that with tons of gear now.
Returning to topic: my very first outboard pre was a Symetrix 302, I
live near the factory and their current products are easy to find
here. It's designed to be clean and functional. It's also a bit
sensitive to RF, which gets noticed in my video/DAVW-oriented home
studio. The discontinued 202 uses a discontinued IC op-amp which many
people on here say was superior to what Symetrix uses now. And yet
there are lots of threads about mods to the 202 which involve
substituting a Burr-Brown op-amp to make it sound cleaner. Since
those mods don't apply to the 302, I haven't paid attention to them.
I do know that modding a $100/channel pre with semi-rare ICs that may
not be replaceable in a couple of years isn't my cup of tea. Plus I'm
pennies away from the GR.
(bill)
--
I am a software engineer, not a musician.
Len Moskowitz
Monte P McGuire <mcg...@TheWorld.com> wrote:
>The SX202 relies upon a pair of three terminal voltage regulators to
>provide low impedance power to the SSM 2015 and output stages...
> ...
>Since the circuit relies on the three terminal regulators for a low
>impedance supply, it would seem wise to try to upgrade the regulators
>themselves. The problem is that I know of no simple drop in part that
>will provide lower output impedance...
What regulator does the 202 use?
--
Len Moskowitz Binaural StealthMics, Cables, DPA, M-Audio
Core Sound http://www.stealthmicrophones.com
Teaneck, New Jersey USA http://www.core-sound.com
mosk...@core-sound.com Tel: 201-801-0812, FAX: 201-801-0912
Bob Smith
>
> There are some real rare gems on lists like this, people who seem to think
> that knowledge is pretty much worthless if it isn't shared. In this day of
> "intellectual capital" and so forth, I think we owe a big thanks to the
> Scott Dorseys and Monte McGuires of the world.
I second that sentiment. Thanks Monte (and Scott et all).
Ulysses
Thank you. Sorry for hassling you about this so much. But I guess my
pestering has been rewarded, so I am now conditioned to be a pest. Who
should I bother for free lessons next?
Monte P McGuire
7815 and 7915, TO220 package, pretty standard stuff. I have heard
that substituting the 317 and 337 variable regulators will give you
lower impedance, but the data sheets don't seem to bear this out.
There is enough space in there to float a tiny PC board to make a
nicer replacement, but I've never tried that.
Regards,
Monte McGuire
mcg...@theworld.com
Monte P McGuire
Ulysses <uly...@rollmusic.com> wrote:
>Thank you. Sorry for hassling you about this so much. But I guess my
>pestering has been rewarded, so I am now conditioned to be a pest. Who
>should I bother for free lessons next?
No problem, I should have sent them off months ago, but that little RF
issue still nags me. That'll get addressed soon...
Have fun folks,
Monte McGuire
mcg...@theworld.com
Scott Dorsey
>Len Moskowitz <mosk...@panix.com> wrote:
>>What regulator does the 202 use?
>
>7815 and 7915, TO220 package, pretty standard stuff. I have heard
>that substituting the 317 and 337 variable regulators will give you
>lower impedance, but the data sheets don't seem to bear this out.
Sheldon stokes says that the 317 sounds better than the 78xx due to
lower induced noise problems and that the Linear Technology drop-in
replacements are still better. I think he is crazy about the noise
thing, but I do think the LT chips have lower impedance. Then again,
I think a huge whacking bypass cap will buy you more anyway.
>There is enough space in there to float a tiny PC board to make a
>nicer replacement, but I've never tried that.
You only gotta cut two traces and put some SMT chip caps between them.
George Reiswig
suggested that it might be easier and about the same price to buy a used
Presonus MP-20 and put the new op-amps and Jensen transformers in it. Given
the level of modification that the Symetrix seems to need, he has a point:
modding the SX-202 is not for the novice, and not for people who have little
spare time.
Is there a general concensus about the relative quality of a modified SX-202
versus a modified MP-20? I know the question risks getting into the "better
than/worse than" territory despised on R.A.P., but if someone has some
comments on the relative sounds of these two, I for one would like to hear
them.
George Reiswig
Song of the River Music
"Scott Dorsey" <klu...@panix.com> wrote in message
news:a1l5e5$14h$1...@panix2.panix.com...
Willie K.Yee, M.D.
My very own 202 arrived today, bought from another member of this
group. I already know more about its innards than I ever expected or
wanted to know.
Also what I know is that although I can use a soldering pen, this
project is just beyond my capabilities. I know I would f**k something
up somewhere alond the line. And then there's getting the parts . . .
So, is there someone out there who will do the full job? How much
would it cost. seems to be it would be much more worth my while to pay
somone with skill, and maybe even experience on this particular
project, and access to parts, and be guaranteed a working pre at the
end of it all.
I would be glad to wait a few months, so I can get to know the pre as
it is. Just 'cause I have it now.
hank alrich
> Plus I'm pennies away from the GR.
Go, Bill go! <g> I predict thrills are headed your way.
--
hank alrich * secret__mountain
audio recording * music production * sound reinforcement
"If laughter is the best medicine let's take a double dose"
Ulysses
bill....@worldnet.att.net (Bill Newell) wrote:
> Returning to topic: my very first outboard pre was a Symetrix 302, I
> live near the factory and their current products are easy to find
> here. It's designed to be clean and functional. It's also a bit
> sensitive to RF, which gets noticed in my video/DAVW-oriented home
> studio. The discontinued 202 uses a discontinued IC op-amp which many
> people on here say was superior to what Symetrix uses now. And yet
> there are lots of threads about mods to the 202 which involve
> substituting a Burr-Brown op-amp to make it sound cleaner. Since
> those mods don't apply to the 302, I haven't paid attention to them.
> I do know that modding a $100/channel pre with semi-rare ICs that may
> not be replaceable in a couple of years isn't my cup of tea. Plus I'm
> pennies away from the GR.
Buy the GR so it'll be academic, but the "preferred" chip in the SX202 is
the SSM2015, which was replaced by the 2017 in the SX302. These are NOT
the chips that get replaced in the modifications. These chips are
designed to be monolithic mic preamps, and the chips that get replaced are
the output op-amps. The original chip is not so great and the
replacements, of which there are many, make a dramatic improvement and are
basically drop-in compatible. I'd be very surprised if the same weren't
true of the 302, but it's the 2017 chip being supposedly inferior to the
2015 that keeps people from bothering to try it. You might want to have a
look at your SX302 and see if it can be done. If you like the 302, you
can live with the 2017 chip and dressing it up a bit probably couldn't
hurt.
Monte P McGuire
George Reiswig <Rei...@europa.com> wrote:
>Alan Whiteside (of Scrip Productions) and I were talking about this, and he
>suggested that it might be easier and about the same price to buy a used
>Presonus MP-20 and put the new op-amps and Jensen transformers in it. Given
>the level of modification that the Symetrix seems to need, he has a point:
>modding the SX-202 is not for the novice, and not for people who have little
>spare time.
Well, I know my instructions are _way_ long and complicated, but my
point was to try to educate along the way and not just say "cut here,
snip here, replace this, replace that". I apologize for being so
verbose; my editor at Recording has to deal with my verbosity on a
regular basis, and I pity those fine folks. But, don't let that
discourage you! I hope that the length of the article doesn't make
you think that there's a ton of things that you absolutely need to fix
in the 202!
Honestly, the most important things to change on an SX202 are the
output opamps and the compensation caps, and that totals only 6
components. It's not a complicated modification. I listed those
first because they're the most important mods. Yes, the other things
I outlined will probably help out, but they can take a bit more time
with possibly less "payoff". That's why they are mentioned later in
the article. I mentioned them to be thorough, and also to document
what I did to my dozen channels of SX202 to get them into the state
that I use them in.
>Is there a general concensus about the relative quality of a modified SX-202
>versus a modified MP-20? I know the question risks getting into the "better
>than/worse than" territory despised on R.A.P., but if someone has some
>comments on the relative sounds of these two, I for one would like to hear
>them.
The question becomes: what is this modified MP20! There are lots of
ways to modify a beast, and without knowing what that means, it's sort
of hard to judge.
My problem with the MP20 is that the basic circuit concept seems very
promising, but the actual device doesn't sound very good. I don't
know why at this point because I haven't played with an MP20, but I do
know that some very unglamorous early 80s Altec mike mixers using a
similar ratio transformer and a 5543 gain stage sounded quite amazing,
whereas the MP20 does not. I don't know why...
Similarly, the SX202 sounds a good bit nicer than an MP20 as stock,
and I know that it can be improved a good bit with a few mods.
My suggestion is to read through the mods again and focus on the
"action items" and gloss over the theory. You'll find the mods to be
pretty concise at that point and maybe that'll lead you to realize
exatly how little you need (or want) to do to a 202 to make it better.
You can do a lot to it, but if you just do the output amps and
compensation caps, you'll have 90% of the benefit with little effort.
Regards,
Monte McGuire
mcg...@theworld.com
Monte P McGuire
Bill Newell <bill....@worldnet.att.net> wrote:
>The collective falsehoods of the Internet have helped bring about the
>notion that buying a "magic" piece of gear will make you an instant
>success at recording and/or music creation. The truth is that success
>comes to those who figure out how to get good sounds out of what they
>have, and you can do that with tons of gear now.
This is a very valuable statement... gear lust and the satisfaction of
that desire, both of which I succumb to on a regular basis, won't fix
my most serious problem, which is how I approach a mix. It's not to
say that just because you own the gear makes it good, but similarly,
just because you just bought new gear doesn't make it more suitable
either. The more I focus on my technique, the better my work becomes.
>Returning to topic: my very first outboard pre was a Symetrix 302, I
>live near the factory and their current products are easy to find
>here. It's designed to be clean and functional. It's also a bit
>sensitive to RF, which gets noticed in my video/DAVW-oriented home
>studio. The discontinued 202 uses a discontinued IC op-amp which many
>people on here say was superior to what Symetrix uses now. And yet
>there are lots of threads about mods to the 202 which involve
>substituting a Burr-Brown op-amp to make it sound cleaner. Since
>those mods don't apply to the 302, I haven't paid attention to them.
>I do know that modding a $100/channel pre with semi-rare ICs that may
>not be replaceable in a couple of years isn't my cup of tea. Plus I'm
>pennies away from the GR.
If you can afford it, just get a GR preamp. They are significantly
better than any sort of hacked 202, and they'll hold their resale
value quite well. But, if you like soldering, you have a low budget
and you have a need for nice, utilitarian preamps, a hacked 202 could
be a good thing for you. Yeah, the SSM2015 ICs are semi-rare, but
they don't blow up unless you torture them.
Still, "you're pennies away from a GR", so just buy the dang thing!!
It's gonna sound great and you'll happily use it for a long
time... what more could you want??!!
Happy recording,
Monte McGuire
mcg...@theworld.com
Willie K.Yee, M.D.
>Also what I know is that although I can use a soldering pen, this
>project is just beyond my capabilities. I know I would f**k something
>up somewhere alond the line. And then there's getting the parts . . .
>
On the second thought, since I am in not that great a hurry, maybe I
could do this one step at a time - a chip this week, a couple of caps
next, etc.
At least I would know what the last thing I did when the thing stopped
operating completely. Desodering a chip is still something I have not
done (learned soldering in the days before IC boards).
Your ancient friend,
Steve Morphet
> Desodering a chip is still something I have not
> done (learned soldering in the days before IC boards).
As I think Monte points out in his article, there's no
good reason to keep the original parts. This means that
you can snip the legs off the chip first, and then remove
the pins from the board one at a time. This makes the job
a lot easier. Put a good quality socket into the space,
and you can continue to swap ICs without having to worry
about desoldering again.
Steve.
Robert Angst
--
____________________Monte P McGuire schrieb:
>
> Well, I know my instructions are _way_ long and complicated, but my
> point was to try to educate along the way and not just say "cut here,
> snip here, replace this, replace that". I apologize for being so
I am realy thankful for this 'education'!
For me it makes your comments far more valuable than just a 'how to
tweak a xyz' posting.
I just tweaked an Behringer 502 micpre (no flaming here boys, it's no
longer a Behringer now) according to your hints (+..) and it worked out
quite well. I haven't compared it to my new 202 yet, since I just got
it.
Robert
Scott Dorsey
Spend $20 and get the solder sucker from Soldapulit or Paladin. Absolutely
wonderful. It turns desoldering from a painful and dangerous operation into
a merely tedious one.
Get some practice taking apart an old PC power supply board or something
before you work on critical equipment, though.
George Reiswig
did not go unnoticed!
George Reiswig
Song of the River Music
"Monte P McGuire" <mcg...@TheWorld.com> wrote in message
news:GprnI...@world.std.com...
Monte P McGuire
Scott Dorsey <klu...@panix.com> wrote:
>Sheldon stokes says that the 317 sounds better than the 78xx due to
>lower induced noise problems and that the Linear Technology drop-in
>replacements are still better. I think he is crazy about the noise
>thing, but I do think the LT chips have lower impedance. Then again,
>I think a huge whacking bypass cap will buy you more anyway.
Which LT regulators are these?
Regards,
Monte McGuire
mcg...@theworld.com
Bill Newell
> If you can afford it, just get a GR preamp. They are significantly
> better than any sort of hacked 202, and they'll hold their resale
> value quite well. But, if you like soldering, you have a low budget
> and you have a need for nice, utilitarian preamps, a hacked 202 could
> be a good thing for you. Yeah, the SSM2015 ICs are semi-rare, but
> they don't blow up unless you torture them.
Of course as soon as I made my previous post, you came up with the
long-awaited definitive SX202 upgrade guide! And I was obviously
behind the times in thinking the Burr-Brown output op-amp was the most
current recommended replacement. I'm not going to touch my SX302. I
may let someone look at my SX628 channel strip someday, but it's not a
priority. With that piece as well, my major problem is RF.
> Still, "you're pennies away from a GR", so just buy the dang thing!!
> It's gonna sound great and you'll happily use it for a long
> time... what more could you want??!!
Except that I do video first and audio second, and I just shelled out
big $ for a new DVW with audio on the side. It went something like
this:
Dell Precision 530, 450W PS, 2x1.7 GHz P4 Xeon CPU, 1 GB RDRAM,
80 GB IDE, 2.4x Sony DVD+RW, 48x CD-ROM, keybd, opt mouse, XP Pro:
$2,800
3x WD Caviar 100 GB (8 MB cache) 7200rpm IDE + PCI/66 IDE RAID: $850
Maxtor 80 GB 7200rpm IDE 1394: $300
ATI All-in-Wonder Radeon 8500DV: $300
Matrox RT2500: $750
SB Audigy Plat EX: $200
Echo Layla24: $650 (2nd unit) + $150 for PCMCIA card for 1st unit
ShuttlePro USB jog/shuttle controller: $79 (www.contourdesign.com)
spare 19" FD Trinitron monitor: $350
Netgear 8-port firewall router: $250
MSDN Universal license: $1,500
misc. Adobe upgrades: $1,000 (all upgrades for apps being moved to new
box)
3D Studio Max upgrade: $don't ask
DVDit! upgrade: $500 (includes AC-3 encoding)
Sonar XL upgrade: $200
BIAB upgrade: $49
Xbox + DVD support + DVW integration + dev kit: $400 (no games :)
Token Xmas video gear purchase: Sony HDTV $don't ask
Token Xmas music gear purchase: Yamaha AG Stomp $299 (goes with Big
Baby)
For some odd reason, I find myself still pennies away from the GR this
month. You audio-only guys have it so easy... :)
Marc Stager
I'm always looking for new ideas for upgrading my
old Neotek Series I - which, unfortunately uses
mainly quad chips, thereby limiting upgrade options.
I'm definitely going to be looking at the LT1469CN8
for some TLO72 and NJR4556 replacements.
One passage left me a little puzzled. You said:
"Changing this (47 pF) to 7.5pF will move the frequency
at which distortion sharply rises up an entire octave
from 3-4KHz to over 40KHz."
An entire octave? That would only shift the distortion
to 6-8KHz. 40 KHz is about 4.5 octaves.
________________ Marc Stager
purple M
I have two of these babies and have been dying to upgrade.
I can hardly wait!?
(Hurry please? Pretty please?)
Jer
mcg...@TheWorld.com (Monte P McGuire) wrote in message news:<Gpo2G...@world.std.com>...
> In article <ulysses-0801...@x134-84-252-200.dialup.umn.edu>,
> Ulysses <uly...@rollmusic.com> wrote:
> >Very true. Maybe Monte should sell his recipe. Then we could complain
> >about it being "vaporware." As it stands, we can only politely whine,
> >"Hey monte, are you done yet?"
>
> I haven't forgotten, but that "damn reality thing" keeps setting in
> and stupid stuff like dying hard drives and pesky clients keep me from
> stuff I'd prefer to do...
>
> Seriously, it's all written up, but I should try to bolster the RF
> proofing a bit and possibly change one coupling cap's size. I had a
> Precision 8 in here for review and it was a lot more RF proof with no
> apparent RF proofing components... It also had a more solid low end,
> but a little brighter top, so I'm gonna figure out if I can graft that
> low end onto the 202 with a cap change.
>
> So... I'l say it again... "really soon now..."
>
>
Monte P McGuire
Marc Stager <Marc....@Verizon.net> wrote:
>I'm always looking for new ideas for upgrading my
>old Neotek Series I - which, unfortunately uses
>mainly quad chips, thereby limiting upgrade options.
Yeah, I have a Series II and there aren't a lot of good replacements.
The best so far is the OPA4132P, but it may be discontinued at this
point. You may have to buy the SO-14 version and adapt it to a
DIP-14. What a royal pain... At that point, you could just about as
easily build adapters to go from a pair of dual SO-8 op amps to a
DIP-14, so maybe it isn't such a horrible fate.
If you'd like something close to the TL074 in character but a bit more
refined and cleaner, the AD713JN or KN is a great chip. It's pricey,
but the -KN part has really good DC properties, so you may be able to
ditch some coupling caps at the same time. The 713 has much of the
same colorations as a good quality TL074, but a bit less of it.
That's what's in the majority of the channels on my II right now...
>One passage left me a little puzzled. You said:
> "Changing this (47 pF) to 7.5pF will move the frequency
> at which distortion sharply rises up an entire octave
> from 3-4KHz to over 40KHz."
>
>An entire octave? That would only shift the distortion
>to 6-8KHz. 40 KHz is about 4.5 octaves.
Yep, good catch. I meant _decade_, but it didn't hit the paper that way.
The 40KHz part is right, the octave part is wrong.
Thanks for catching this...
Regards,
Monte McGuire
mcg...@theworld.com