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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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In Reply to: If your amplifier is clipping, have you left the realm of high fidelity? posted by AJinFLA on October 31, 2006 at 16:11:48:
I live not too far from Denver, so I went to the RMAF. The only room I visited was this one, to check out their demos. It was pretty interesting and thought-provoking.They had a 35 WPC tube amp designed by Bob Cordell (push-pull, not SET) and a solid-state amp that put out about 240 WPC. There was a handheld switch you could use to switch between the two amps. Levels were matched. I had never done such a test before. I brought in a CD and played the solo piano version of Malachi from Andrew Hill's Time Lines CD. This is a beautifully recorded piece, and one that moves me emotionally very much. Speakers were DIY two-way monitors that appeared to have 8" woofers. These were built by Peter Smith, the main host of the demo. I was amazed at how good these small speakers sounded.
I tried to figure out which amp was which. The first thing I noticed was that I was wishing I had brought a very repetitive piece of music for this test. This would have allowed listening to a section with one amp, then switching, then listening to the repeated sounds with the other amp. As it was, each time I switched I found I had lost my frame of reference because the music itself was rather abstract and ever-changing. I was trying to detect a slightly flabby bass, which I would have attributed to the tube amp with its output transformers. The non-repetitive nature of the music I chose made this very difficult. The second thing I noticed was that my emotional attachment to this piece of music was getting in the way of trying to figure out which component was which. I found myself just wanting to leave the switch in one position and just listen to this great song on a great-sounding system. So I did.
One conclusion I drew from this is that the popular audiophile notion of attributing "involvement" to the properties of a piece of equipment is to me just hooey. For me, the emotional involvement was a big distraction from trying to figure out one piece of equipment from another. This may be particular to me as an individual though. I've often been completely baffled by audiophiles who have what they call "office systems". I wonder how they get any work done while listening. To me, this would be like trying to get work done while having sex. Not gonna happen :-). Bob Dylan said it best when he said "The geometry of innocent flesh on the bone causes Galileo's math book to get thrown".
This demo also got me thinking about some other things. Trying to assess the quality of power amplifiers in normal listening tests with speakers isn't exactly foolproof. Of course speakers produce distortion, and lots of it. Suppose you had a speaker that, when hit with a low-distortion, high-power signal sounds harsh in the midrange and treble on the peaks. Now suppose you had a tube amp with only moderate power, and an overload characteristic that is like a very soft limiter and subjectively less unpleasant than that of the speaker. Combining this amp and speaker might result in the amp preventing the harsh overload aspects of the speaker from acting up. So while the tube amp is less accurate than the high-power solid-state unit, its soft limiting might do a nice job of covering up a somewhat harsh speaker behavior at high SPLs. This is just speculation of course, but it doesn't seem totally far-fetched to me either. Now look at another extreme case. Suppose you have a subwoofer that "takes a licking and keeps on ticking". Powering such a sub with a low-power tube amp will definitely show the deficiencies of the tube amp, while a good quality, high power solid state amp is likely to sound much better in that application.
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Follow Ups
- This was a fun demo - andy_c 11:33:12 11/01/06 (0)
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