Kit Preamp for Sophia Electric Baby

[DreadPirate]

I'm not that thrilled with this amp's performance straight through and have vastly improved it using a Carver preamp (C-2). I am using <90dB efficiency speakers (Spica TC-50 and others) which is probably a factor. I do plan on getting higher efficiency speakers one day.

Anyway, I've scoured eBay for currently sold diy preamps (assembled or not, does not matter to me) and have compiled this list. I do want tone control and these all have it. Would any of these be worthy of use with this amp? It is a 10W tube amp that apparently has highly acclaimed sound. I believe the NE5532 based boards would provide up to 36dB gain, is this the key to solving my problem with higher being better (given modest distortion of course)?

NE5532

NE5532 HI-FI STEREO PREAMPLIFIER WITH TONE CONTROL! - eBay (item 380138443985 end time Feb-06-10 07:33:49 PST)

HI-FI STEREO FET INPUT PREAMPLIFIER WITH TONE CONTROL! - eBay (item 120412507582 end time Jan-22-10 04:41:58 PST)


NAD 3020 clone

Stereo tone control low noise preamplifier NAD 3020 ! - eBay (item 320471857083 end time Feb-06-10 07:34:31 PST)


FET

FET input stereo tone control low noise preamplifier ! - eBay (item 220520964215 end time Feb-01-10 08:28:02 PST)

 

[DreadPirate]

Ok, after reading a bit, it looks like what I also want is an unbalanced design. Are the Aleph and BOSOZ preamps available in that format and if so where?

 

[DreadPirate]

I found the schematic of the FET version.