Simple Symetrical Amplifier

[Jay]

Anybody know how to test the usefulness of the R-D strings in the supply rail with simulation?

[keantoken]

Depends on the reason you have for using R-D strings. You need to test it's usefulness for that goal.

That goal could be supply filtering, supply impedance, supply sag reduction... So your question is very vague.

[Jay]

Originally Posted by keantoken

Depends on the reason you have for using R-D strings.

I wanted to know one good reason.

Originally Posted by keantoken

You need to test it's usefulness for that goal.

That's the question. Except that my goal is the best overall performance.

Originally Posted by keantoken

That goal could be supply filtering, supply impedance, supply sag reduction... So your question is very vague.

For supply filtering and impedance I don't need the diode... There is another goal... but anyway, the question is... to make it simpler, will you use it in Shaan schematic?

I was afraid that rough simulation will not be precise enough to predict it's behavior...

[keantoken]

Simulation could tell you performance specs, but those specs on't tell you if you ill like the result or not if your goal is to enjoy the sound. Simulation ill help you understand hy something changes the sound, provided you already have empirical observations to begin ith. So the process in this sense is backards: test first simulate after to understand.

As for filtering, I think it is orth a try on the current sources and/or the VAS, since there are still unprotected Early junction effects, but I think the difference ill be small. I think there may be a bigger improvement if you filter the rails ith my poer K-multipliers, so the FETs get a regulated rail. Hoever my Kmultipliers seem to ork much better on BJT output amps. I don't have a lot of experience here but the small signal area of the amp seems ell protected from the rails.

Another factor is rectifier spikes on the rails, if your supply isn't ell filtered.

[naf]

Originally Posted by Esperado

Congratulation.
If your amp does not heat too much, and once burned out a little, you can try to reduce the bias of each power unit to 150ma. Not sure for yours, but most of the power Fet/Mostfets i know seems to sound the best around this value in class Ab amps.

Now, if somebody ask-you if you can build an amp with no servo, you can just answer:
"Yes, I can".

Thank you, Esperado.
Yes, I can build this SSA without servo .
My heatsink only warm... i can touch with my hand as long as i want.

[naf]

Originally Posted by Lazy Cat

Super, so also newbie can do it hehehe

Without support and help from you, shaan and esperado a newbie like me maybe wouldn't hear the beatiful sound of SSA..

Originally Posted by Lazy Cat

What's the loudspeakers you have to connect to SSA?

I'm using Bookshelf Speaker build by an expereinced DIY'er from my country.

[Jay]

Originally Posted by keantoken

Simulation could tell you performance specs, but those specs won't tell you if you will like the result or not if your goal is to enjoy the sound. Simulation will help you understand why something changes the sound, provided you already have empirical observations to begin with. So the process in this sense is backwards: test first simulate after to understand.

So far I believe in simulations (coupled with good engineering judgements). I can build circuits and compare by ears, and my ears is very good enough to rely on, but I want a quick and precise approach by knowing what to look for in simulation. Then I will know how to get the best.

Originally Posted by keantoken

However my Kmultipliers seem to work much better on BJT output amps.

I don't use BJT regulators in FET amps. Sometimes I use FET regulators in BJT amps (class-A). But I prefer BJT regulators for BJT amps. I use the simplest BJT multiplier for my SSA_BJT. Might try your K-multiplier, but I'm skeptical.

Power supply should be part of amplifier design. I started with transformers I have on hand. Lowering and (often) raising rail voltage of a finished amp will reduce performance

[Esperado]

Sorry to ask a stupid question , due to my poor English: What is R-D strings ?

[naf]

Today, i connect my SSA to my speaker,
and for the first time i hear a beatiful sound of this Amp. Natural Vocal, nice bass and crisp treble and more important it stable..

[naf]

Originally Posted by Esperado

Sorry to ask a stupid question , due to my poor English: What is R-D strings ?

maybe Resistor -Diode string sir, just guess.