Some have asked what I use for a vocal pre amp.

I use a 1950's vintage RCA BC-2b which has been modified by me with a different front end and outputs. It still uses the 12AY7 tube, but the critical feature of the pre amp is the transformers.

You MUST use the transfomers listed for this pre amp to sound right... I've tried using others, but it doesn't sound worth a damm without them.

Here is the schematic:

NOTE:

DO NOT CONTACT ME ABOUT THIS PRE AMP!

I WILL NOT RESPOND TO ANY EMAIL OR PHONE CALLS ABOUT IT...

This schematic is simply provided for your information... don't bother me with questions about it.

                                     470K     22MFD
                      *------------/\/\/\/\---| (----*
                      |                              |
                      |                              |
                      |        *------*              *-----*
       600/Grid       |        |      |              |     |       Plate/600
      Input Xfrmr     |      __|__    |            __|__   |      Output Xfrmr
                      |               | .047               |
 *------) || (--------|----* - - -    *--| (-----* - - -   *--------) || (---*
       (  ||  )       |               |  MFD     |                 (  ||  )
        ) || (   3.8V-*--&# ~~~~~    |          | ~~~~~*---        ) || (
       (  ||  )          |            |          |         |       (  ||  )
        ) || (           |     /\     |          |   /\    *---*    ) || (
       (  ||  )          |    |  |    |          |  |  |   |   |   (  ||  )
        ) || (           \    |  |    \          \  |  |   \   |    ) || (
   *---(  ||  )          /    |  |    /          /  |  |   /  3.5V (  ||  )
   |    ) || (       8K2 \   Heaters  \ 220K     \ Heaters \        ) || (
   |   (  ||  )          /            /          /         /       (  ||  )
   |    ) || (           \            \     680K \       1K\        ) || (
   |   (  ||  )          /            /          /         /       (  ||  )
   |    ) || (           |            |          |         |        ) || (
   |   (  ||  )          |     20MFD  |          |         |       (  ||  )
 *-|----) || (--*        *-----) |----*----------|---------|------*-) || (---*
   |            |        |   -     +             |         |      |
   |            |        |                       |         |      |   2K7
   |            |        |                       |         |      *--/\/\/\--B+
   |            |        |                       |         |
   |            |        |                       |         |               |.
   *------------*--------*-----------------------*---------*---------------|||:
                                                                           |'

Parts:

1. Input transformer NEEDS to be UTC LS-10 (RCA # 1234)
2. Output transformer NEEDS to be UTC LS-27 (RCA # 1233)
3. C1 .047 MFD @ 400V (High Quality Signal Cap)
4. C2 .22 MFD @ 400V (High Quality Signal Cap)
5. C3 20 MFD @ 400V (Bypass cap for power supply... electro)
6. V1 12AY7 (select for low noise)
7. R1 8K2 1/2 Watt Carbon Composition (NOT Carbon/Metal Film)
8. R2 220K 1/2 Watt Carbon Composition (NOT Carbon/Metal Film)
9. R3 470K 1/2 Watt Carbon Composition (NOT Carbon/Metal Film)
10. R4 680K 1/2 Watt Carbon Composition (NOT Carbon/Metal Film)
11. R5 1K 1/2 Watt Carbon Composition (NOT Carbon/Metal Film)
12. R6 2K7 1/2 Watt Carbon Composition (NOT Carbon/Metal Film)

Or if you can't read the text schem, here is a .GIF image: