Amplifier design

[canyn]

I got a couple new-to-me Adcom GFA-555s last week. First time I've seen the insides of one.

There's nothing in there!

I have been using Proton D1200s for some years...know what they look like from having to fix them once or twice.

There's a LOT of stuff inside a D1200.

Granted, the 'DPD' design of the power supply in the Proton comes with a good bit of associated layout that the Adcom doesn't have. Still, the amount of space in the Adcom was a surprise.

I've listened to Protons because I like their sound. I think the Adcoms sound MUCH better.

I'm not operating under the misconception that 'more stuff' inside necessarily means anything, and in this case it doesn't.

How is it, though, that an amplifier as minimalistic as the Adcom seems to work so well? There is no soft turn on, no relay protected outputs, not even a regulated supply.

Is the Adcom superior merely through simple design? That is what Nelson Pass is known for, I guess.

On the other hand, the complexity of the Proton D1200 doesn't make it BAD...does it?

Thanks!

[AKSA]

Yes, on both counts..... simpler is often better, but it's hard to tweak it so it's better.

[ontoaba]

NO.. Better is better and worse is worse, no matter it is simple or complex. Simple is limited, it need more complex to be expanded, and the more it complex, the more its difficulty, and if it fail then become worse.

[AKSA]

OK, how about this:

Everything should be as simple as possible, but no simpler.....

Cukup jelas, dong?

Hugh

[destroyer X]

regards,

Carlos

[djk]

The basic design of the McIntosh MC2120/2125/2200/2205 makes the Adcom GFA555 look complex. A diff pair (a dual transistor) with a resistor for the current source, a Vas transistor with a resistor for the current source, bias, and the output stage.

[lanchile]

I agreed with all the posts, Simpler is better!. But again if it is well design.
I had a few Adcom and they are really good, I had an integrated Proton too , but "there is not comparison between them". Adcom way better than Proton!!!

[wg_ski]

Originally Posted by djk

"A diff pair (a dual transistor) with a resistor for the current source, a Vas transistor with a resistor for the current source, bias, and the output stage."

Sounds just like the DX.. right, Carlos? So simple a caveman can build it (and not make an oscillator).

[canyn]

Re: 'Better is better and worse is worse...'

Well now...that is simply stated...and certainly true!

How about saying it this way: Considering the Adcom GFA-555 to be straightforward in design (and it a good amp by most folks' opinion), and the earlier referenced Macintosh amps to be even straight-ER-forward, then why does anyone bother to complicate things to an n-th degree only to end up with a product that is not as good?

Because razzle-dazzle sells a lot of product?

Maybe part of 'more design' it is due to what people want. Fer instance, I'd like a silent power on/off in the Adcom: No pops, clicks, thumps, or fizzles.

[CBS240]

Complexity is relative. Suppose you want to build a direct coupled 'modular' amp, where each circuit block performs a single function. For example, you might have a series/shunt regulator circuit that is in itself an amplifier circuit. Then you would have one for the opposite rail. A direct coupled, separate pre-amp circuit might be another circuit block and don't forget the DC servo. Each circuit would be constructed and tweaked individually. In the end as a whole, the circuitry would appear very complex but relatively it may not be as such.


However, such circuits are difficult to simulate because of the ‘complexity’.