« Reply #28 on: February 25, 2006, 01:28:09 PM »
Technically speaking (not my native tongue ), the sound pros box (12v batt box excluded) only provides ~4.5volts to each mic with the 9v battery. The 3wire setups provide a full 9v to each mic, correct? At least, that's how I understood it... (as always, someone chime in if need be)
I suspect that you're a little mixed up about how the battery boxes work
The goal is to have roughly half the supply voltage across the FET in the mic, for best overload levels.
With a 2-wire connection you should end up with the FET drain (output wire) at about 4.5V and the FET source at 0V (it's connected to the ground wire) - that gives 4.5V across the FET.
With a 3-wire connection, the FET drain (red wire) is at 9V and the FET source (yellow wire) is at about 4.5V - again that's 4.5V across the FET.
Of course it's possible that the Sound Professionals box does something weird, but it seems unlikely.
HTH
i am an unfrozen caveman layer and your words and discriptions sometimes frighten me... however, when i contacted chris at sp when i had a similar idea about only half the power going to the mics. i told him that i would rather 2 9v in the box so the mics could each have the full 9v or to have a larger cell put in (12v) if it was going to be split. he told me that the mics would still be recieving 9v each even with one battery. now i dont know if what he said and you describe in a technical way means the same, but at the end of the day, he had my specific request and an unlimited budget to achieve that and only used one battery.
I think Chris did the correct wiring for a 3-wire battery box. If you get a chance, I'd be interested in seeing a close up photo of the guts, perhaps with board/battery holder removed.
If in fact Chris has wired it correctly, we could just instruct others to ask Chris for your "special order" box. Or, we could just give Sanjay a ring...
Richard
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Mics: Sennheiser MKE2002 (dummy head), Studio Projects C4, AT825 (unmodded), AT822 franken mic (x2), AT853(hc,c,sc,o), Senn. MKE2, Senn MKE40, Shure MX183/5, CA Cards, homebrew Panasonic and Transsound capsules.
Pre/ADC: Presonus Firepod & Firebox, DMIC20(x2), UA5(poorly-modded, AD8620+AD8512opamps), VX440
Recorders: Edirol R4, R09, IBM X24 laptop, NJB3(x2), HiMD(x2), MD(1).
** This individual has moved to user "illconditioned" **