Solderdude, how does it perform compared to other topologies?
It's not the amp I use the most often and specs also show average results mostly because of losses in the transformers and even though I use no overall feedback in this particular design that isn't even as bad as I thought it would.
FR is kind of limited by the transformers.
The ones used in Doug's amp may very well go further up and maybe further down.
This is what RMAA had to say about it. (for what it is worth)
Frequency response (from 40 Hz to 15 kHz), dB +0.05, -0.26
Noise level, dB (A) -89.8
Dynamic range, dB (A) 89.6
THD, % 0.0072
THD + Noise, dB (A) -78.7
IMD + Noise, % 0.122
Stereo crosstalk, dB -86.1
IMD at 10 kHz, % 0.012
General performance Good
From 20 Hz to 20 kHz, dB -0.74, +0.05 (soundcard plays a role here too)
From 40 Hz to 15 kHz, dB -0.26, +0.05
My own measurements say 15Hz to 20kHz -0.5dB
5Hz to 35kHz -3dB (don't like the -3dB spec but is generally given).
I don't have golden ears but some say it sounded slightly less than 2 other designs I had brought along others said it sounded good.
In a blind AB test (that always followed) nobody could tell the apart from a tube-hybrid and all SS amp.
