Attenuation circuit. What is ideal location?

[albertNL]

Originally Posted by DF96

My first career was in IT, and the language of serious audio is not that different; both are branches of engineering. As I said, 'best' should make you think 'optimisation problem' which then leads to 'criteria?'.

In audio, performance is measured in terms of the subjective listening experience. There can therefore never be an objective "best".

There can however be a theoretical basis to decide that one topology is objectively better than another.

Nelson for instance tells us in the Aleph manuals that he believes that using few gain stages is better than using a lot of gain stages.

Most amplifiers on the market have between five and seven gain stages in series between the input and the output. The Aleph 30 has but two, and enjoys a very direct path from input to output, further enhancing the purity of the circuit and the resulting sound.

Or at least gives the impression that he feels that few is better than more.

[AndrewT]

Most amplifiers on the market have between five and seven gain stages in series between the input and the output.

If Pass said this then I think he is misleading us.

[albertNL]

Originally Posted by Jay

Are you following the digital technology/development in audio? In audio we have amplifier experts, speaker experts and may be "digital" experts. Sometimes an expert in one area doesn't understand the other areas. Cool, isn't it?

Yes, I see what you mean.

It is funny though that this is an example where there really is an "objective best". Do not throw away your bits!

[OllBoll]

Originally Posted by albertNL

At 0dB you can use all 16 (or 24 or however many you have) bits to send the signal. If you attenuate, you need some of those bits to send a lot of zeroes. You cannot use those bits for the actual signal. Information will thus be lost if you use digital attenuation.

Of course, but you don't really need 24 bits to represent the sound which is why digital attenuation works so well. 16 bits is enough and some more, the rest is just padding so in practice you are attenuating away the padding and not the signal you hear.

If you attenuate past 60-80 db then sure you will introduce high frequency noise compared to original signal, but then there won't be a lot of signal left so you probably wouldn't hear it anyway

[albertNL]

Originally Posted by AndrewT

If Pass said this then I think he is misleading us.

Aleph 30 manual attached

Dear Customer,

The Pass Aleph 30 is the first of the second generation of Aleph single-ended Class A power amplifiers. This design results from my commitment to create the best sounding product, a simple circuit having the most natural characteristic. The Pass Aleph 30 integrates power Mosfet devices and pure single ended Class A operation in a simple two-gain-stage topology with the sole purpose of recreating subjectively natural sound.
The Pass Aleph 30 is unique in a number of ways:
Most amplifiers on the market have between five and seven gain stages in series between the input and the output. The Aleph 30 has but two, and enjoys a very direct path from input to output, further enhancing the purity of the circuit and the resulting sound.
...

Sorry. Aleph 30 manual was too large and exceeded diyaudio upload limit. Aleph 60 manual uploaded instead. Same text in this one.

[Jay]

Originally Posted by albertNL

Nelson for instance tells us in the Aleph manuals that he believes that using few gain stages is better than using a lot of gain stages.

Make that a 2-stage class-B amplifier BTW, the TSSA is cool.

[albertNL]

Originally Posted by Jay

Make that a 2-stage class-B amplifier BTW, the TSSA is cool.

What do you mean by TSSA?

[Jay]

The Pass Aleph 30 is unique in a number of ways:
Most amplifiers on the market have between five and seven gain stages in series between the input and the output. The Aleph 30 has but two, and enjoys a very direct path from input to output, further enhancing the purity of the circuit and the resulting sound.

Nelson mentioned the Aleph 30 uniqueness: Most amps on the market are class-B, the Aleph 30 is class-A

Originally Posted by albertNL

What do you mean by TSSA?

It's an amplifier by Lazy Cat. Only two stages but you can get above 50W easily, and current feedback.