All the influences on a highend amplifier sound

[PMA]

As the thread
Stereophile, January 2008, pages 13 and 15
was closed, though it has brought quite interesting discoveries, I would like to continue in a constructive discussion here.

[PMA]

I am suggesting several topics to discuss:

1) PSU, line stage and power stage solutions
2) passive components - resistors, capacitors
3) PCB, materials, number of layers, starr gnd and groundplane
4) case, shielding, point of connection of case and signal gnd, if any, connection to PE - if any
5) balanced or SE interconnection
6) EMI/RF content in audio signal and its audible influence
7) EMI throughput thru power supplies

[AJinFLA]

The list of what influences the "sound" of a "high" end amplifier will be infinitely long and highly contentious: NFB, resistors (and direction), etc,etc,etc,etc, all dependent upon the depth of the disorder of the particular "listener".
Why not just greatly simplify things and just ask what doesn't influence amplifier sound?
Hex vs Philips screws? White vs Black lettering? Blue vs Red LEDs? Wire insulation color? Sun spots?
Or perhaps even those alter sound for some? As evidenced by audiophiles hearing improvements while listening *very* carefully to loose screws.

cheers,

AJ

[Bobken]

Hi,

I am pleased to see this 'resurrection', as between the noisy parts, there was a lot of interesting information.

In case anyone wishes to further the earlier comments on relays, and at the risk of accusations of self-promotion, I posted some of my own experiences here.

why does a relay attenuator sounds much worst than an alps black ?

In an earlier post on that thread I also mentioned my personal preferences for Shallco-based switched attenuators, which I still consider to be the most transparent (and least damaging to the signal) method of attenuation for pre-amps etc.

I also agree wholeheartedly with Charles' earlier comments on shunt components being every bit as significant as any signal-path parts used in circuits, even though this may not seem intuitive. Careful listening tests tell me that this is so in every area, and not merely in potential divider situations.

Regards,

[PMA]

Thanks. In case we overlook some kind of excessive attacks, I am sure we will be able to keep viable, constructive discussion.

[Jan Dupont]

Thanks PMA for bringing this alive again

[PMA]

Regarding RF level in audio signal, I found this to have considerable influence on a sound of the audio system. I show you 2 alternatives of the same system, differing in an RF content, and differing in sound considerably:

[PMA]

Now the same system, with modifications. Both measured at loudspeaker terminals, with speakers and cables connected. The RF in previous image is local AM transmitter.

[lumanauw]

There's a good information about components in Bruno's slide (http://www.hypex.nl/docs/Bruno%20Masterclass/slides.htm), #128-129. I don't know how far this will affect in analog amps, but the effect is clear in classD amps (about 500khz).

The point is, up until high frequencies, does a capacitor still a "capacitor", that ONLY do capacitance, or they have transformed into something else (like a capacitor behaves more like inductor in HF, due to (big) body construction), or have become an antenna?. Does a resistor still a "resistor" or have become inductor? Maybe this behavior in HF is audible in AF, interpreted as different sound from different component (while we cannot measure a difference, if the measurement is only in AF). We can just predict what happens if your CCT has additional red components like in slide#128.

In HF, a PCB track with groundplane on the other side transforms into "microstrip" with Mhz transmission-line properties. But how far this will be audible for AF?

[Bobken]

In post #4 I intended to say "shunt ..... being as significant as *series* signal-path parts" etc.

My apologies for any unintentional confusion, and it was too late to correct that post when I realised this.

Regards,