Transistors, Tubes Sound The Same, It's The Circuit Topologies That Sound Different

[Primalsea]

Just found this article online and thought it was quite interesting:

https://www.electronicdesign.com/ana...se-fire-part-2

This is part two and part one is a good read too, although I haven't got all the way through it as of yet.

The writer touches on a few other things but overall he says that it is not the actual devices that dictate the sound but the actual topology. The claim is that he has made various swap-outs, like replacing tubes for MOSFETs (as part of a sub circuit, to make it a drop-in replacement) and that the measurements and perceived sound remained pretty much constant.

Between both parts there a few other things in here worth a look, such as, capacitor distortion, tying knots in speaker cables and the limits of perceiving phase and distortion down to ppm.

Not saying it's all gospel.

Wondering what other people's thought are on this?

[anthonyTD]

I tend to agree with him to a point, you can indeed make each topology perform very similar, in sonics, and on test, however; there is undoubtably diffrences in the way each device works that dictate why one is better than the other when comparing them as far as their strengths and weaknesses etc.
A....

The writer touches on a few other things but overall he says that it is not the actual devices that dictate the sound but the actual topology, Wondering what other people's thought are on this?.

[struth]

there was a guy who used to adjust amps to sound like any amp you want.. think he had an ongoing bet he could do it. so i guess its possible to a degree anyway.

[hifi_dave]

Several years ago, Tim De Paravicini (EAR Yoshino) made two amps with very similar specs. One was transistor, the other valve and the purpose of these was to show that the two approaches could sound the same. We had them on demo for a few months and tried them on willing customers and a couple of reviewers of the time. The results were that they sounded, pretty much, the same and couldn't, reliably, be identified as valve or transistor.

[Primalsea]

there was a guy who used to adjust amps to sound like any amp you want.. think he had an ongoing bet he could do it. so i guess its possible to a degree anyway.

I guess that was Bob Carver, formally of Carver and then Sundyne I think it was called. I repaired a Carver amp once, a TFM 25 I think. It was a beast of a thing and had three sets of voltage rails. The amp would switch in the next highest rail when a peak output signal exceeded the limit of the current rail being used. I think NAD done something similar.

TFM stood for Transfer Function Modified, which I understood meant that the amp was voiced in a particular way buy modifying the output impedance and dampening factor among other things.

I thought about the Bob Carver stuff when I read this article.

[struth]

I guess that was Bob Carver, formally of Carver and then Sundyne I think it was called. I repaired a Carver amp once, a TFM 25 I think. It was a beast of a thing and had three sets of voltage rails. The amp would switch in the next highest rail when a peak output signal exceeded the limit of the current rail being used. I think NAD done something similar.

TFM stood for Transfer Function Modified, which I understood meant that the amp was voiced in a particular way buy modifying the output impedance and dampening factor among other things.

I thought about the Bob Carver stuff when I read this article.

yeah, thats the guy

[Frazeur1]

Good old Bob, yes Carver and Sunfire....I used to own a couple of Carver products back in the day, when it was modeled pretty much after his former Phase Linear stuff, the C500 power amplifier and the C4000 preamp/console. I liked the C500 amplifier better than the C4000 preamp, but it was all fun stuff at the time.

[JohnJo]

Just found this article online and thought it was quite interesting:

https://www.electronicdesign.com/ana...se-fire-part-2

This is part two and part one is a good read too, although I haven't got all the way through it as of yet.

The writer touches on a few other things but overall he says that it is not the actual devices that dictate the sound but the actual topology. The claim is that he has made various swap-outs, like replacing tubes for MOSFETs (as part of a sub circuit, to make it a drop-in replacement) and that the measurements and perceived sound remained pretty much constant.

Between both parts there a few other things in here worth a look, such as, capacitor distortion, tying knots in speaker cables and the limits of perceiving phase and distortion down to ppm.

Not saying it's all gospel.

Wondering what other people's thought are on this?

I've heard this argument before but I haven't heard the SS amplifier that genuinely sounds like valves.

Yes, they may be voiced similarly but there's a naturalness, grace, air and freedom from artifice that valves provide which SS devices can't seem to match.

Of course, SS can do other things well and arguably better (high power, bass slam) but give the same result, not that I've heard.

Here's a good comparison, same manufacturer, same preamp, and the SS amp even has output transformers so probably as good as it gets for an A-B but for me the valve amp is so much more listenable even with the mic overloading!

[Primalsea]

Personally I'm not so sure about the that particular point made in the article. If I've understood it correctly in order to get the solid state device to work in a valve based circuit you need a load of auxiliary components. Therefore the circuit topology is no longer like the original and what you have is something else (hybrid) designed to operate as a facsimile of the original. At that point the circuit with the substituted part in no longer has that same topology as the original circuit.

[JohnJo]

My point was if it's easy to make a transistor amp sound like valves why isn't it done regularly?

If it's because you can't really due to circuit limitations but in theory the devices don't matter then it's a bit of a waste of time talking about it.