Looking for schematic - Xindak MT-3

[soundbrigade]

Trying to help a friend with his Xindak MT-3 (EL34-PP), but without a schematic, the job is very difficult.

Has anyone a schematic or can point me to one?

This is what I have got and I am not even sure if it is correct.

 

[duncan2]

Hope you get a schematic , I always have a hard time finding a Chinese amplifier schematic.

 

[soundbrigade]

Me too. 🙁

I have a PCB I bought from AliX for a GU50-SE amp. Was lazy had some spare trannies and tubes and decided to do it the easy way ...
There's a small shitty schematic in the Chinese shop but on crucial places this doesn't really match what's on the PCB. 😡

Backwards engineer, here we go!


I should add that for some amps I have nice and good schematics, not necessarly 100% correct. Azazello helped me once with one design where the schematic showed very odd figures.

 

[6A3sUMMER]

There is an intrinsically unbalanced phase inverter in that schematic.
And for best performance, it requires super well matched triodes, and may require some adjustment of one or the other of the plate loads.

Instead,
With a real current sink to the parallel cathodes, and matched plate loads, it would be intrinsically balanced, even if the two triodes are not super well matched.

 

[v4lve lover]

Schematic looks to be correct, i would drop a 10M45S in the tail of that LTP like 6A3 suggested but thats about it.


I'd also replace the pot of the GNFB with a fixed resistor, less to go wrong.