I have a 20 year old ahuja push pull amplifier. The problem with that is distortion.I dont know how to eliminate the distortion. I am linking a model of my amplifier but it is not the exact circuit diagram of it but it resembles my amplifier.the same problem exist for another amplifier which is also 15 years old. but there is no other problem. i want to make it as a distortion free amp. i will try to give every details of that amplifier if you ask what you need like parts present in it Thank you for your help
http://www.diyaudio.com/forums/atta...01d1305291115-ahuja-amplifier-scan0002-1-.jpg
http://www.diyaudio.com/forums/atta...01d1305291115-ahuja-amplifier-scan0002-1-.jpg
With the way you describe the problem expect no one to bother to answer your post .
You need first to define the problem distortion between failure and sound .
Is your amplifier in short of failure and produces audible distortion ?
Is your approach to reduce the distortion next to some other known amplifier in order to make your amplifier better >
Make this clear first and you will get plenty of answers
Kind regards
Sakis
You need first to define the problem distortion between failure and sound .
Is your amplifier in short of failure and produces audible distortion ?
Is your approach to reduce the distortion next to some other known amplifier in order to make your amplifier better >
Make this clear first and you will get plenty of answers
Kind regards
Sakis
That's a late 50's to mid 60's style of tranny circuit but LEDs mean it's somewhat younger.
The 22k pot is adjusted to get the DC voltage shown at the collector of Q401 (8v). The right-most 470R pot adjusts the output bias and will be critical for low distortion, you probably want something like 20mA Q503 collector current so adjust the pot for 5mV across R506. It will never be top end hi-fi but you should be able to get a clean sound.
The 22k pot is adjusted to get the DC voltage shown at the collector of Q401 (8v). The right-most 470R pot adjusts the output bias and will be critical for low distortion, you probably want something like 20mA Q503 collector current so adjust the pot for 5mV across R506. It will never be top end hi-fi but you should be able to get a clean sound.
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As a Tube Amp lover, no it definitely isn't.
Not everything has to be complementary etc. This amp will never have a problem with DC at the output, for example.
That amplifier was probably designed in the early 60's. Too many stages which have no voltage gain. It's a very old and bad design. It may very well work forever. That does not mean that it's a good design. The best that you can do is minimize the distortion by correctly biasing the output stage.
One bad thing I've just noticed is the multiple RC supply decoupling stages, all fed off each other. I made the same mistake in my first 60's home design, you get massive LF phase shifts and likely motorboating (an LF oscillation) or terribly loose bass as there's little supply rejection in the input stages and the output stage sends low pass filtered audio straight back to the input and with the phase shifts anything can happen!
Came across this old thread, I have fixed a few of these in the past. I have noticed distortion cropping up because of the following issues:
1) faulty transistors and capacitors (especially the output transistors and filter caps)
2) those presets that you've marked in the schematic, those are very critical
3) output tranny issues
1) faulty transistors and capacitors (especially the output transistors and filter caps)
2) those presets that you've marked in the schematic, those are very critical
3) output tranny issues