The Russian 6h8C is excellent value. The FU50 is the Chinese version of the Russian GU50. Not as reliable but not bad.
Thanks ill have a look at those
Any comments on the schematic? Would it beneficial to upgrade any of the caps?
Any comments on the schematic? Would it beneficial to upgrade any of the caps?
When you put a stereo(L+R) 100k potmeter in serie with the 5.1k feedback resistor. You can adjust feedback, this has a lot of influence on the soundsignature of the amp.
Ronny
Ronny
The usual requirement with a Chinese amp it to ensure that it is safe.
What voltage it the mains tranny specified for and is it giving correct output? (Measure not guess.)
Do components like caps and rectifiers have a safe working voltage above the maximum expected?
Is the wiring and earthing up to western standards and safe?
Do these, then you can improve it.
What voltage it the mains tranny specified for and is it giving correct output? (Measure not guess.)
Do components like caps and rectifiers have a safe working voltage above the maximum expected?
Is the wiring and earthing up to western standards and safe?
Do these, then you can improve it.
Wise words Colin. I can measure mains tranny output once I recieve it. Can also post photos of wiring etc. But how do I determine if the components have a safe working voltage other than trusting the print on the components? Which components would be best to replace just in case?
Yes, but probaly you do not like the sound. With a adjustable feedback you can set the sound as you like best.
Checking what is printed on them is a start.
Power supply caps can be good one's to look at.
Then it's up to you and your budget what you change.
Disconnect the wire going from the output transformer to pin 3 on the FU50 tube. Insulate the end of the wire so that it cannot short out to anything else.
Connect a 100R resistor (value is not critical) from pin 3 (screen grid) to pin 6 (anode) of the FU50 tube.
Pin 6 of the FU50 remains connected to the output transformer anode lead.
All other connections remain the same. Adjustments may be necessary. These will vary, depending on what else is in the circuit.
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I can read schematic to save my life but isnt FU50 pin 3 already connected with a 100R resistor to pin 6?
LOL, I didn't even look at the schematic, I just answered the question. That amp has its FU50 wired in triode already.
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Sorry that was my fault. For some reason I assumed it was in UL mode.
Would it be worth converting this amp into a set of monoblocks? In terms of additional power I mean. They are cheap enough to make it worth trying potentially...