There's the other GUANZO thread.

[Rob DeFries]

Ok, that makes sense. I was pondering what I would do to improve it and thought about putting the volume control between the stages (as a conventional potential divider) but of course the global feedback would try to maintain the same gain regardless of the pot setting, so that's not great.
Putting the pot before the gain stages would mean the circuit is operating at a much lower signal level so the distortion would be much lower, but the signal/noise ratio would be degraded. I suppose it's a toss-up which is the better trade-off.
Anyway, have fun experimenting and get back to us if you come up with anything interesting.

I don't have any intention to experiment with it, other than to try other tubes. The pre is dead quiet btw. So is the 3116.
Since there's no theory on the thing, why they made it this way, and since I seem to be the only one who made a complete schematic, I just leave it as it is and plumb it into a nice box and try to sell it.
I don't know the tube either, used to experiment with the 6P2N 20 years ago, but that's it on experience with Russian double triodes.
I think that any NOS ECC88 will outclass this Chinese clone of a Russian tube.

 

[Rob DeFries]

Ofcourse the feedback has to be altered.
Better do it my own way I guess.....

Might even step back into this, if I can find the schematic...

 

[Rob DeFries]

When I fired up the Guanzo this morning, static noise started at the left channel. Wiggling one of the tubes was enough to get rid of it.
Had been playing for 12 hrs and started to break up already. The problems stayed away for the rest of the day.
Listening to the 3116 and Guanzo gave some nice stereo placement, loads of air and detail. Impressive for this budget priced Hi-Fi.

I tried a small Denon POA-F100 with the Guanzo. The whole stereo image changed to inbetween the speakers. Good placing in the stereo, but not behind, in front or outside the speakers. I just missed the twinkle, the system had with the Guanzo driving the 3116.

 

[Morrism]

I replaced the Chinese tubes with GE JAN 5670W. They are inexpensive and seem to work fine. Someone with a better ear could give a better review.