mic project / low noise transistor recommendation

[barret77]

Hello all

I'm impressed with the quality and the low cost of the diy mic projects I've seen around; I'm considering trying it - and I'd like to post two questions.

1) Is there any recommendation for a good mic "body" ? I would like something that could fit a standard mic stand... any ideas?

2) I'm searching for a good pair of transistors to fill in here:

Better electret microphone phantom powering circuit

This circuit provides lower impedance output than the circuit above:

(drawing at http://www.epanorama.net/circuits/microphone_powering.html#phantom)

Component EBC is a PNP bipolar transistor (for example BC479). Ideally these should be hand-picked for low noise and matched gain. Bear in mind that VCE can be up to about 36V. The 1u0 capacitors should be high quality plastic film types. The circuit may benefit from the addition of 22pF capacitors in parallel with the two 100k resistors. For minimum hum pickup the two 2k2 capsule bias resistors should be accurately matched.

I'm not being able to find in mouser/digikey this transistor; any ideas of a really realiable one? Is it possible for be to buy it already matched?


grateful again for any help...

[Paul Perry (Frostwave)]

The only cheap (and available) PNP matched pair I can see is DMMT5401 (50cents from Mouser).
What you REALLY want is probably the (unavailable) SSM2220 or MAT03.
Or something from THAT Corp (if you can find anyone who sells single packages).

[barret77]

thanks

if anyone around has one of these to sell me... let me know

[barret77]

http://www.diodes.com/datasheets/ds30312.pdf

what about this one? It's dual and available...

[Joe Kramer]

Hi!

You can use off-the-shelf 2N5087 for those transistors and it will work just fine.  A very similar circuit was published in Recording magazine by Scott Dorsey a while back.  The capsule is a Panasonic WM-60AY and it sounds surprisingly good.  

The first version I built used the aluminum body of a Sanford "King Size" marker and some plumbing fittings.  The mic element went in the aluminum tube and a short rat tail went to a Hammond box with the output circuitry and an XLR plug.  Later I just mounted the mic element in a grommet on the face of the Hammond box and got rid of the marker body and rat tail.  The mic looks kind of weird. like a black brick clamped into one of those spring mic clips, but it sounds really nice.

Joe

[barret77]

great! thanks for your reply