Axiom Home Page Forums General Discussion Advice from Axiom Owners QS series surrounds

My personal take on the psychology of separate vs. integrated electronics is, the design philosophy with over-spec'ed parts. When you look into the innards of an AV receiver vs. a separate power amp with identical (actual, third-party measured) power outputs, you always find that the separate amp has much bigger heatsinks, transformer(s) and power capacitors, etc. The question is whether, given that the measured power outputs are essentially identical, these bigger things really lead to a better sound quality. By definition, these bigger parts are over-spec’ed with respect to obtaining the given level of power output. While the little tech nerd in me would freely admit that the innards of the separate look infinitely more “beautiful” (and that may well lead to a better sound perceived by me), you can also argue that the integrated AV receiver has achieved the “art of just-enough design” at a higher level, producing the same power output and other specs within a much more demanding space (and often cost) requirements.

John, Sushi,
You guys are not making it any easier for me to convince my wife I "NEED" more gear..
If I'm note careful here, I will lose next years appropriation fundings !! She would just love to cut into MY reserves and use them for something really silly.. Like more flowers in the garden (that I would have to plant) or new drapes for the kitchen (that I would have to hang).. Well, you get the picture..
So from now on remember, everything is essential and most certainly needed.. :-)

If that's the case then you absolutely NEED to have a Rotel setup. RSP-1095 amp paired with their new RSP-1098 processor.

That preamp is a truly beautiful piece of equipment, spiff.

As far as the amp goes, however, I'm still waiting for an amp that gives me 1F of capacitance per channel.

Ok, gotta ask. What would that gain you?

BIG CAPACITORS!

Yes, thank you for explaining what I knew already. ;-) What would BIG CAPACITORS do for the sound, amplification, etc technically speaking? I know they're a good thing, I just don't know why.

Lemme try to 'splain in, then.

You know how an amplifier rated at X watts into Y ohms is not constantly delivering that wattage, right? Right. So let's say you're listening to the 1812 Overture right before the cannons start to fire. You're on the verge of a huge transient and a huge change in required power. When called upon, the caps will dump their stored energy into the amp in order to meet the needs of the cannons. The larger the capacitor, the more energy it can store and deliver when called upon.

In addition to storing the energy, capacitors also act as filters. Since they sit between your wall outlet and the output stage of the amp, any irregularites in the flow of power to and from the power supply will be smoothed out and not propagated down the line.

K, that makes sense. I'm pretty sure I knew some of that before, but I just wasn't remembering. Thanks!

To add my $0.02 to Peter’s excellent explanation, my understanding is that there are two schools of amplifier power-supply design:

(1) Use a power supply with an excellent regulation to start with, so that the power-rail voltage won’t “sag” too much even when all channels are fully driven. If the power supply maintains, say, 90% of the voltage under full load, then there will be less benefits of using a bulkier, higher-capacitance power capacitors.

(2) Don’t care too much about the power-supply regulation, and instead, supplement the power supply voltage under the full-load transients during music playback by the discharge from big power capacitors. This is so-called the “crest factor” school of amplifier design.

For example, the earlier generations of NAD amps (don’t know about the current models) and the current Sony ES receivers belong to (2) -- they can deliver a much higher transient power for a short time period (1 second or so) than what they can deliver steady-state. In contrast, according to the HiFi News (UK) measurements, the Pioneer Elite 45TX clearly belong to (1) above -- its power supply does not give in too much even when fully loaded steady-state.

Both schools of design are valid, and in reality, most practical designs belong to somewhere in-between. But my understanding is that the high-regulation power transformers have come a long way, so that today it is often easier and less costly (both in terms of money and space) to go with (1). That is why we don’t see anymore, even in the high-end separate amps, those HUGE capacitors that used to be found often in older amps.