Originally posted by: kengreen
Maybe I am an old square but, to me, an amplifier is a device which can perform many functions but - most definitely - should not add anything to the signal as presented to its input.
I don't think many electric guitarists would agree with you there! The Fender tweed or Marshall stack is most definitely part of the instrument, and the way a good guitarist can use the non-linearities in these to make music is an art form in itself.
I assume, of course, that you wish to remain in control ?
Oh absolutely. That's the fun, controlling the exact point on the saturation curve of the valve using your fingers on the strings of the guitar.
A properly-designed Speaker-driver - no matter its complexity - MUST be independent of the speaker driving-point impedance throughout the frequency range specified.
Have you ever looked at speaker impedance curves vs. frequency? At points they go staggeringly low. I very much doubt if anyone has yet designed an amp with output impedances so low that they can be considered negligible: and even if they did not many people are going to mount monoblock amps in their cabinets to negate the speaker impedances. It doesn't really matter - the speaker and room response will have a far, far bigger influence - but if you wanted to be really pedantic you could almost certainly A-B test any two different designs of power amp and a skilled listener could hear some difference. What you probably couldn't say is which was "right".
Anyway, I'm glad you have such touching (if slightly misplaced) faith in the competence of design engineers. If you have any CDs recorded in the late 80's or early 90's there is an extremely
good chance that some of them were recorded through equipment that I designed, and trust me: it doesn't reach the heights of perfection you describe here! Partly because it wasn't technically possible, and partly because if we'd got any closer no-one could have have afforded it. And we were at the top end of the business, sadly there is not and never has been any money in high quality audio (otherwise I'd still be in it
); even with what appear to be ludicrously priced audiophile hi-fi systems the volumes are so small and hence the overheads so high that the money available for design time and component purchasing is tiny. This is why I still build equipment for myself, I can afford to spend more of my own time on it and use better quality parts - rather like home cooking vs. ready meals.
(We did design one product at the turn of the 90's which probably was as close as it was possible to get to audio perfection in a large scale mixing desk - we got to the point where no listeners could tell the difference between a channel with somewhere between 50-100 op-amps in it and a direct wire link. Sadly the Japanese economy collapsed during the design phase, and no-one else could possible have afforded it. For anyone interested, the SSL SL9000J series was the drastically cut down version of that desk - basically single ended rather than fully balanced and with FET rather than relay signal switching - not bad but nowhere near as good as it could have been.)
It's always worth remembering that the vast majority of music these days is listened to as MP3s, which messes up the sound far more than any vaguely competently designed amp will. I do like to think that for those who do care (and have better hearing than I do) that facilities exist for really good clean recording and playback of music, particularly classical music. But for most of us most of the time the sound just needs to be good enough to let the music - which I would suggest is the important bit - through.
I was going to stop there but I've just remembered something highly relevant, which is a shame because the dinner I was cooking smells like it's done, anyway here goes quickly: the SSL desks that I worked on were renowned for their clinical cleanness of sound. They swept through the market, and in the 80s / 90s any serious studio was fitted with one or several. BUT the reason they were liked was not specifically because of the sound (or lack of it), but because the layout and the automation system made them so easy to use. Many highly musical producers (including , famously, one G. Martin) much preferred the rival Neve desks with their highly distinctive sound. So there you go. Mind you, even with hindsight I still think SSL were right (cleanness and transparency were the mantra of the sadly late lamented founder, Colin Sanders), you could always add outboard equipment to get that season's sound. But I can also see the point that if you can find a piece of equipment, like my little 7W guitar amp, that gives the sound you're looking for then why not use it?
Andy Millar CEng MIET CMgr MCMIhttp://www.linkedin.com/in/millarandy
"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert