The Clones of Zen
The SE 6N1P/EL84 Amps
I'll show you the second one first because it looks and sounds much better than the first try. This amp resides with my brother in MN and I think it convinced him that tube audio gear can produce wonderful sound and doesn't have to be expensive or need constant attention. This design was taken directly from the Decware site. They really deserve thanks for providing the schematic on-line for us DIYers. There are some differences between this one and the schematic. The most obvious is that I didn't use a tube rectifier. Simple 1N4007s were used because the power transformer (a salvaged unit from an old organ amp) lacked a 5 volt tap. I omitted the selectable bias switch on the driver tube and can't remember what value I chose for the cathode resistor. If you do a little searching on the Decware forum, you might find that there is a general consensus.
This project cost nearly nothing for me to build, but I have a pretty good stock of parts and old tube type gear. The only parts that were actually purchased at retail were the 6N1P, a RS dual section pot, and the input jacks. Even the EL84 tubes were free, given to me by a local guitar tech who thought they might be microphonic. They tested and worked fine for hi-fi gear. The output transformers were pulled from an old stereo console amp that, for some reason, had 60 volts AC at chassis ground. I dismantled that one quickly after it took out the op amps in my Sonic Frontiers DAC.
We had an opportunity to listen to this amp connected to some superb Norelco dual cone drivers at a friends house. We were stunned by what we heard. No, it did not compare to his custom built 45 amp, but it sounded much better than my 2A3 mono amps. I had invested nearly 20 times the money and many more hours on the 2A3s and I realized that it was "back to the drawing board" for me. This experience spawned this ugly mess.
More to come....later