You must understand that when Pavel talks about circuit design, he is limiting himself to old fashioned ways.
Oh I don't disagree with you. And while I didn't type it all in most of those I posted were spec'd properly across full power bandwidth etc. But those I listed were considered heavy hitters at least among audiophiles in the USA. They were good in many ways, but there were some Japanese designs that eclipsed them in performance for a better price. Also it seems the very cream of the crop in Japanese amps didn't get sent to the USA back in the 80s and 90s.
I remember some ads for the Magnetic field amps tried to explain it with illustrations of a large tank of water and a small tank of water and an adjustable outlet valve. It was basically correct, in that the Carver was shown with a big tank with lots of water level and therefore more pressure on tap for momentary peaks, vs a nearly empty tank where water flowed out as fast as it flowed in.
Yes, classic topology, but with a few twists. Is that really a 33.2 K degeneration resistor in the emitter of Q1, not 33.2 R? It reduces the gain of Q1 massively, which would result in poor noise performance. Also, since Q2 is not degenerated, the LTP would be unbalanced, maybe in an attempt to generate HD2?
That link didn't work for me, but putting Carver-M1.5-Service-Manual.pdf into google did. The copies are hard to read, but it is a very different circuit from the 555. Input Opamp (designated TLO-81 in the typed circuit description which is probably a TL081?) driving a resistive load that controls a bipolar current mirror with gain, triple EF with dual output pairs and rail switching. There's a neat optocoupler circuit that detects clipping by looking at the opamp output and will attenuate the input via an LDR type optocoupler. The TL081 (if that's what it is) is not exactly a gourmet choice, but on the whole, I don't see why the circuit should generate this much distortion.
Found the manual on vintagehifi with a much better scan of the schematic. R3 is the emitter resistor of Q1. I couldn't find an R4 on the whole schematic. Assuming it was supposed to be the emitter resitors of Q2, with both of them in the 10 - 100 R range (well, 220 R if you're Onkyo), this would fit the description. This would constitute a degenerated LTP, i.e. a sacrifice of open loop gain to attain a larger linear input range. Replacing R4 with a short would result in all kinds of interesting harmonics, so maybe this is intentional.
And there were actually a few different versions of the original 555; for example, mine (from the original product release) has an input blocking cap which is not shown on that schematic.
Yeah, it is like shitting on a Trabant for being a bad car, which was in production up until 1991. You would not want this amp hooked up to your speaker, fine and competitor products were better at the time, but come on, it is 40 years old. I wonder how some of you might feel, when you are judged by what you posted on social media 40 years from nowFor a 40-year-old amplifier, I'm having trouble understanding the opprobrium. Cancel culture appears to be alive and well at ASR.
Seriously, this thing runs circles around the silly Crimson tube amp. I doubt many people would hear much difference between this device and the Benchmark driving reasonably efficient loudspeakers.
The GFA-555 II was supposed to be a "ground up" redesign by Walt Morey. There were several other variations on the 555, as SIY noted.
