Where can I order a pea-sized mic like goes in the set

[Ike Milligan]

The set of mics for a full size accordion are smaller than a pea, (the
mics, not the set) and I'm missing the bass mic because I installed a
set in a guy's accordion and eventually one of the 3 wires on the bass
mic broke off and I had to take the mic out of my unused set and put it
in his. What are these mics called?
There are 4 treble mics on the circuit board and usually one or two that
go in the bass side. There is a 9 volt battery on the patch cord.

[Ike Milligan]

Note: The microphone I need is 6 mm in diameter and has 3 bare leads
where it mounts on the circuit board. I am missing one because I had to
replace one for a customer where the lead broke off on the bass side and
the place I bought the set doesn't carry it any more.

[ciao_accordion]

> Note: The microphone I need is 6 mm in diameter and has 3 bare leads
> where it mounts on the circuit board.

hi Ike

a 3 lead Mic Capsule simply has the divider circuit inside, it is
easy to make a replacement using a typical 2 wire electret Mic for replacement

basically, you need a white wire to connect to the Mixer
a red wire to connect to the Battery
a black wire for Ground

now, a Capacitor (1 or 2 microfarad is fine)
and a resistor (about 1000 ohms is typical)
BOTH connect to the Positive leg of the 2 leg Mic capsule
then the Resistor goes to red
and the capacitor gooes to white

the Cap blocks the DC voltage ,while passing through the (ac type) signal
the Resistor resists the Signal while allowing the DC to reach the capsule
the capsule needs the bias voltage to come "alive"
(vs a Dynamic Mic that comes alive from pressure on the diaphram)

this is why i personally typically use a dynamic on the Bass side
(i think they work better there because the pressure is pretty intense
from those big Bass reeds)
the element from the Shure Green Bullet (harmonic mic) is my favourite

i usually make an envelope for them out of old innertube so they
mount without picking up vibration

they only need the white and black connections, of course, and often
i mount a Jack on the bass side below the 120 on a clear spot to
plug in a wire ot wireless transmitter

again, just my preference, but when i really want the Bass amplified
cleanly and separately, i do it that way... stereo translitters for audio are
really hard to find... 2 mono units on different channels is easier and cheaper

g-30 have been selling on CList for like 100 bucks lately and work for reeds just fine

ciao

Ventura

ps: i might have a spare out in the shop ready to go, at least i can
give you the parts sometime ths weekend or next week

[Ike Milligan]

Thanks Phil this as really useful and extremely interesting, but I am
not ready to use the set yet, and don't know when I shall, so all I was
trying to do was get a duplicate mic to complete the set, ao I can use
it whenever.

[Ike Milligan]

On 11/13/2020 10:17 AM, ciao_accordion wrote:
>

'm reading where youe say it is easy to use a 2-lead mic, but I ordered
some of those, for under $2 each but they have only 2 leads and are 6 mm
diameter. Haven't got them in the mail yet. But then you go on to
describe how to use a 3 lead unit. Haven't even got the data sheet yet.
Any thoughts on how to use a 2 lead unit? it uses a 10v. bias I'm told.

[Ike Milligan]

I now have the Mallory Sonalert mics with the 2 leads but unsure how to
connect. the vendor did not send a spec sheet. The following url looks
like the spec sheet
https://www.mspindy.com/Specifications/PMO-6022PN-48KDQ.pdf

[Ike Milligan]

On 11/16/2020 4:18 PM, Ike Milligan wrote:

It looks like w/ the 2-lead configuration. you would ground the one
labeled negative, and then put a 1k or 2K ohm in series with the power
like 2 to 10 dc volts and then get the feed from a cap in parallel with
the resistor.

[Ike Milligan]

[Ike Milligan]

Testing my server settings

[Excelsior960]

> >> It looks like w/ the 2-lead configuration. you would ground the one
> >> labeled negative, and then put a 1k or 2K ohm in series with the power
> >> like 2 to 10 dc volts and then get the feed from a cap in parallel
> >> with the resistor.

correct

caveats are as follows, the common conection for the Cap and Resistor are on
the bare leg (+) mic lead

use a small scissors type heat sink as it IS possible to desolder the leg from the Mic

using 9 volt is better for these because that increases the "rail" and gives more room
for the signal without distortion
(a sound wave can generate a large voltage swing at times)

Tantalum capacitors are very small and stable, i prefer the commonly
available 2.2 microfarad but most circuits will show a 1 Mf as sufficient

i used to take those small perforated and coppered empty circuit boards and cut them
into small squares to mount this type of Mic, and the resistor and capacitor, then attach
leads up to 10" lengths (red for the Resistor, and a co-ax Mic type thin cable for the
Signal cap and Ground for shielding from hum and interference

then you can just use a square of Foam tape to mount each mic under the grille
(automotive double sided tape from Harbor Freight is like 10 times better than
normal white foam tape) foam tape helps insulate the Mics from physical vibration

if you are using a hidden Battery that is a pain to change, then adding a small off/on switch
is easy to do (i typically put a switch in) or use one leg of a 3 way Switchcraft jack to
enable power (like they do on an FX pedal)

[Excelsior960]

PS: if the grille is aluminum, and you carefully route the signal wires,
then you don't need co-ax cable and just ground the grille to the circuit for shelding

[Ike Milligan]

Wow. Just wow.