Small Amp, Renioo Project

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Class A is not a guarantee of low distorsion wich is dependant
of the amp global linearity.

Class A eliminates (not _mitigates_ like feedback in ab) the major source of distortion
in a power amplifier: crossover distortion.

@Renioo

Have a look at Andrew C. Russells(Member Bonsai here on diyaudio.com) new amplifier:

Ovation sx-Amplifier

excellent execution and documentation. Very recommended.

He has A/B amps too.
 
Looks like this
 

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Looks like this
Something about this does not seem right... not saying it won't work, but the combination of parts does not seem to make complete sense.

If the transformer is +/-35V AC, that translates to ~45V DC rails. The VSSA boards from LC's group buy are +/-40V maximum (the breakdown voltage of the Jfet on the board is 40).

The maximum pk voltage out at 45V rail will be about 33Vpk, ~23V rms, which would be around 65 watt per channel into 8 ohms. If that is the case, the heatsinks shown in the pic seem too small.

At a guess, you would need a heatsink rated for around 0.4 degrees C/watt, or forced air cooling (a fan).

:scratch:
 
There's a way of simply unwinding the trafo, but I will have to look. There is a possibility of switching it from 110-120 to 220-230 and it also has a small 24v output. I will have a look.
I would ask in the Power Supply forum, someone else probably has an answer.

Unwinding the kind of transformer in your pic, is not as easy as it may look.

I would say,

1) find out how important the max voltage is - people who read the VSSA thread have been following that design for a long time, someone will know that answer.

2) There are pass transistor regulators that use only a few parts, and can be wired point to point. If you only need to drop a few volts, that is the simplest solution (I think).

3) Lazy Cat is recommending a switching power supply, which is expensive, but, there may be much cheaper alternatives, IF you only need a moderate amount of power, as you said.

A 75-100 watt +/- 22~25V DC output switching supply would give you plenty of power for single room listening. I seriously doubt I would ever use more, as long as my VSSA is connected to a conventional pair of speakers... ;)
 
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