Subjectively, adding the power amp made a shocking shocking improvement.

Speakers: Wharfedale Vangaurd...95db Sensitive, 8ohm, 40hz-23khz(horn tweeter) - basically a flea can drive these speakers. 10" fibre-woven woofers

Totally different sound...bass response incredibly tight with bryston - incredibly flabby with Pioneer.

Was I under a placabo? At that time I had never heard of Bryston(so no name bias), Pionner Elite was gorgeous looking(no looks Bias as Bryston is ugly - no offense Bryston owners).

The improvement was laugh out loud better.

Everyone is arguing about cables...but lets get to the amps FIRST.

Why is there an improvement? Power supplies? Spec Sheets not telling me something.

Ohh and I didn't have to crank it to notice...at every volume level the Bryston was superior.

Has there been a DBT done on this kind of equipment?

 ABX with a cheap Pioneer receiver - Atexanathome 17:06:43 11/19/02 (1)
 Re: ABX with a cheap Pioneer receiver - RGA 22:46:14 11/19/02 (0)
 Bryston 3b damping factor > 500... - Gepetto 16:50:12 11/17/02 (0)

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 ABX with a cheap Pioneer receiver - Atexanathome 17:06:43 11/19/02 (1)
 Re: ABX with a cheap Pioneer receiver - RGA 22:46:14 11/19/02 (0)
 Bryston 3b damping factor > 500... - Gepetto 16:50:12 11/17/02 (0)
 Re: Never a straight answer... - JOEY. 14:39:28 11/17/02 (3)
 Re: Never a straight answer... - john curl 16:53:16 11/17/02 (2)
 Re: Never a straight answer... - Tom N. 08:38:57 11/18/02 (0)
 Re: Never a straight answer... - JOEY. 17:48:19 11/17/02 (0)

It is not easy to say EXACTLY why one amp was better than the other, but from an intuitive point of view I agree, that perhaps we should be looking at amplifiers before we look at cables, since given their complexity compared to a cable, they are likely to have a greater effect on the sound than a cable.

In an attempt to guess why one amp was better than the other I would say that knowing Bryston, it was more than likely a better voltage source than the receiver. In other words it can more easily cope impedance variations in the speakers. All speakers exhibit impedance variations, some subtle and some extreme. These impedance variations in the speaker (as a function of frequency and possibly other variables) require the amplifier to respond. If the amplifier can't respond, for power supply, device type/effect or amplifier toplogy reasons then lack of dynamics or a tonal shift is often the perceived outcome. This of course will depend on the extent of the impedance change.

The Stereohile magazine partly tests for this sort of effect by using a more realistic test load when testing its amplifier frequency response. Rather than using only a purely resistive load it aslo uses a more 'realistic' test load. It would be even better to extend this testing to different power levels and also use an impulse type signal, to see the true dynamic behaviour as a function of frequency and power of the amplifier. Then maybe we could start to understand why one amp sounds better than the other.

HAVE FUN,

JOEY.

Thanks for your response and reference. I will try to obtain the CD rom. I agree that many tests are already well established thanks to the AES and various socities around the world. But, I will go out on a not so long limb and suggest that despite this, we have yet to see these tests developed further and used in the commercial realm to explain the dynamic performance of amplifiers TO CONSUMERS. Perhaps, (as you say) the lack of progress is due to DBT issues. There could also be competing scientific egos or commercial interests at play. Who knows...people are far more difficult to predict than electrons.

HAVE FUN,

JOEY.

Tom N.

They also did an ABX test with a Pioneer SX-205 against a high-end amp and couldn't tell the difference reliably. Aczel said, "To me the outcome was predictable, but the test had to be performed because until then we had never ABX-ed really cheap electronics against the multi-kilobuck high-end stuff. Sound taps for the tweako belief system..."