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    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

SUPER budget DIY tube amp - need help

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The easiest thing to do within this budget is to buy a chinese amp then mod it to make it sound close to High end.

I have done this a number of times, and always let someone ELSE buy the amp before I mod it.

There are a few good candidates out there. The tough thing is to find one with decent enough OPT's. Some even have a choke!

Find a decent pentode PP with 6550's or kt88's or whatever, remove the global feedback loop, wire the output tubes for triode, replace the 6sl7 input tubes with some better candidate (chinese 6sn7's are good.). You need to re-calc for different input tube. Remove a lot of resistors and capacitors that muck up the sound.. use LED bias, etc. etc. etc.

These days there are Chinese amps with good build quality. Its just the circuits that sound disasterously BAD. Bad Bad bad bad bad..... just terrible... No idea why they copy such Lo-Fi designs... Ok the China Iron can be weak too if you are unlucky. Can't help you there.

Some that I have modded sound pretty darned good - usually just by removing stuff.
 
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The answer is to go with a hybrid, use SS output instead of an OT. It's all about the marketing in the end and if you can convince that it has the tube sound but power for any speaker then your customer base is broad. My next amplifier fits into this description and uses current production tubes. Mind you, I'm not crazy enough to turn it into a business so it'll likely eventually end up on this forum.

Agree with this too. The most expensive part will be the chassis.
 
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