Amplifier Distortion!

With time on my hands and no other humans in the vicinity. I finally settled down to test my audio Rig…people test GPU’s, CPU’s so I thought …why not my amp?… why not push it to the limit. And got some interesting results. First of all, you need some heavy metal to help digest the distortion! Try listening to something which was recorded to sound like it was played with live acoustic instruments and human voices , and you’d end up crying.
My audio system wasn’t integrated with its current shape in mind. Originally, it had bookshelf speakers as fronts, and sats all around, with 50 W for the fronts and 30 for the rest. Some last minute jockeying for the price and some floorstanders which my integrator was trying to dump let me get an 18K setup for 14!, with the catch being that I’d never be able to run it at full juice (at least for the speakers anyway).
Usually, I run it with the sub on full power and the rest on about quarter to half. even when my friends come over ‘cos the last time I tried it, I blew out a fuse:( Spades of bass is a good thing for handling Jazz and Country, but not trance or heavy Rock. So I decided to tilt the balance in favor of the fronts and turned down the sub to half. And I heard my main speakers distort for the first time .In fact, I saw the clip LED’s turn on!
Most of my friends say they like listening to trance and rock. But I’ve always had problems reconciling to that. Now I know why…DISTORTION!!
Rock especially demands a bit of distortion, and lesser systems and ALL ordinary pc speakers start distorting by the quarter mark. This adds to the sound which I had been missing .I had a hint of that when I took one of my CD’s downstairs to listen it on his Panasonic mini compo...Manson sounded way better at the minicompo pushing 70% power than in mine at the 10% I usually I run it at! I got the same sound out of mine at its three quarter mark, which was, I must add quite loud!
The answer to all this lies in distortion, and its mechanism. Tons of enthusiasts have raved about ‘valve’ sound and how much better it is when compared to transistor sound. Frankly, it’s just a measure of the distortion and more importantly, when and where it kicks in that is important. Valves (triodes, tetrodes, pentodes) etc have higher distortion levels at ordinary levels (2~5% is typical) but the thing is, distortion levels don’t increase much with greater power levels. even then, it is more due to even order harmonics (which are much more pleasant sounding than odd order harmonics).
Transistor Amps meanwhile give a slight distortion at minimum levels which decreases to almost negligible levels at the designed power level after which it rises Quite sharply. An amp which is rated at 100W RMS at .08% THD (total harmonic distortion) will manage 120 with as much as 10% distortion which is mainly due to power supply clipping and device non linearity.

And to compound their woes, most transistor amps are run in class B unlike valves which run in class A which gives better linearity
All said, I love transistor distortion! Who knows, in the future when digital amplification has taken over, there will be old timers like us vouching for how transistor sound is better than ‘Digital’ sound!

posted by kickassso, 10:18 PM