Transamp mic pre schematic?

[Jeff Goodman]

anybody have a legible copy?

Jeff

 

[CJ]

http://www.vacuumbrain.com/

note: the + and - signs on the 5532 are reversed.
will fix soon.
cj

 

[CJ]

crap. links down. hold on.

 

[CJ]

ok, try this:

http://www.vacuumbrain.com/docs/valley_people.html

 

[Jeff Goodman]

Thanks CJ,

I guess I should have been more clear.

I am looking for the schematic for the mic preamp circuitry surrounding the Transamp module itself.

I have an illegible copy of the schematic entitled "Transamp LZ -Transformerless Mic Preamp Model #MP-1000 (service information)"

The parts list is clear, but the schematic is very fuzzy. I have a few of the amp modules and would like to build some mic pres exactly like the Valley People model.

Thanks again and sorry to have been so unclear.

Jeff

 

[CJ]

Actually, that is the whole preamp. There are no transformers used on the input or output. The XLR's are not shown, but that should be easy to figure out.

 

[Jeff Goodman]

Oh! well it looks so much different with the opamp filleted in the schematic!

Thanks again CJ.


Jeff

 

[china_dude]

see post today from china_dude, the real schematic of the dollar bill block insides.

 

[JohnRoberts]

none of those links opened for me..

The transamp had differential inputs and outputs.. so needed to be followed by a simple diff amp to single end it.

The inputs need phantom supply DC blocking caps and other front end paraphernalia , like pads, polarity, whatever.

IIRC the Buff supplied app note uses a 10 ohm in series with one input and two CM trimpots. 

The schematics are out there so keep looking. I don't know if the insides have been officially published, but I have seen other Valley Audio preamp schematics that looked like the same basic topology as in side the potted block..

JR

 

[hodad]

some stuff here:
http://recforums.prosoundweb.com/index.php/m/472173/0/?srch=transamp#msg_472173