Hi, I have a old amplifier Sansui A-80 with the power stages burning, I can replace the power stage with this DIY LM3886 Overture Hight-Performance Audio Power Amplifier Kit.
I would appreciate any suggestions you can give me
Thank you so much
Link
60W LM3886TF AC 20~28V Sound Audio Amplifier Mono Digital Power AMP DIY Kit | eBay
I would appreciate any suggestions you can give me
Thank you so much
Link
60W LM3886TF AC 20~28V Sound Audio Amplifier Mono Digital Power AMP DIY Kit | eBay
Nice, simple Sansui amplifier. It's a shame not to repair, or have it repaired properly. There is a problem anyway, in that the main power supplies are +/-54VDC. This is much too high for an LM3886, even the Mosfet types like TDA7294. The recommended safe maximum supply voltages are +/-35V with 8 ohm speaker loads and +/- 28V to cope with 4 ohm speaker loads. http://www.ti.com/lit/ds/symlink/lm3886.pdf
For practicality, you would need to replace the power transformer with a suitable type having 20-25VAC windings in either a 40-50V CT, old square style transformer or the equivalent in separate toroidal windings. You could still use the regulated supply for the preamplifier which is taken from the same 37VAC windings. It should work with lower AC voltages too.
http://www.hifiengine.com/manual_library/sansui/a-80.shtml
The complete replacement process can become an expensive nuisance in my view but it could suit you if the cost and the work are no problem. If you have not worked with mains power wiring and mounting heavy parts before, get the right tools, check your local power safety regulations and take due care 😉.
For practicality, you would need to replace the power transformer with a suitable type having 20-25VAC windings in either a 40-50V CT, old square style transformer or the equivalent in separate toroidal windings. You could still use the regulated supply for the preamplifier which is taken from the same 37VAC windings. It should work with lower AC voltages too.
http://www.hifiengine.com/manual_library/sansui/a-80.shtml
The complete replacement process can become an expensive nuisance in my view but it could suit you if the cost and the work are no problem. If you have not worked with mains power wiring and mounting heavy parts before, get the right tools, check your local power safety regulations and take due care 😉.
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It´s WAY simpler, cheaper and faster to repair it as is.
I guess the idea to use a chipamp is to keep it simple, fine with me, but:
1) the transformer must be custom wound (*expensive*)
No commercially available one will do, because it has an extra 14VAC winding
2) not so sure the regulator will work properly with 28 or 35V rails (what chipamps want) instead of 54V rails.
3) the original power PCB ,even if unused, still occupies a lot of space inside the chassis
4) how will you mount a chipamp shape to original heatsinks?
that said, I´m amazed at the very high power rails, for a rated 45W/ch amp ... normal would be 35 to 38V rails, a BIG difference.
I guess the idea to use a chipamp is to keep it simple, fine with me, but:
1) the transformer must be custom wound (*expensive*)
No commercially available one will do, because it has an extra 14VAC winding
2) not so sure the regulator will work properly with 28 or 35V rails (what chipamps want) instead of 54V rails.
3) the original power PCB ,even if unused, still occupies a lot of space inside the chassis
4) how will you mount a chipamp shape to original heatsinks?
that said, I´m amazed at the very high power rails, for a rated 45W/ch amp ... normal would be 35 to 38V rails, a BIG difference.
A80 is not quiet easy to repair ...most of it has to do with the way its made inside one piggy board on the top of each other
Today's original and drop in output stages are 4467 and 1695 can be found original and dirt cheap but repair can be tricky since this amplifier uses servo and regulated rails for a few stages ...meaning some of the capacitors might need to be replaced also .
Kind regards
Sakis
Today's original and drop in output stages are 4467 and 1695 can be found original and dirt cheap but repair can be tricky since this amplifier uses servo and regulated rails for a few stages ...meaning some of the capacitors might need to be replaced also .
Kind regards
Sakis
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