karatestu wrote: ↑Fri Dec 04, 2020 7:37 am
Yeah, probably best not to think about it. I do wonder sometimes what level of kit I could have bought with all that money...
Me too, and it gets very depressing, very quickly if one dwells on it too long.
I’ve been at it for longer than I can remember and have come to the unfortunate conclusion that except for speakers (and you have to be damned lucky in that respect to be honest) the average bodger as RD called us, doesn’t have a hope in hell of making anything as good as a commercial piece of hi-end amplification.
In the case of valve amplification, I’ve been hung up for far too long on single ended triodes. To get a SET amp to sound as it should, you need to spend thousands and thousands of pounds on high quality PSU chokes, even higher quality output transformers, very high spec (read very expensive) power supply and coupling caps, because they are directly in the signal path. The output valves ideally need to be NOS 845, 833A, 211 at four-figure voltages, in order to get decent power levels, and if you go the low power high efficiency speaker route, you are looking at expensive 300Bs or even more expensive PX4 or PX25 British triodes.
I’ve been banging my head on a brick wall, trying for 15 years to do single ended triodes or ultralinear with cheap iron and it simply doesn’t work. It cannot work period. Now you might well ask, how do I know this? Simple. Don’t get me wrong, my latest amp sounds great, with it’s twin power supplies, British small signal valves on the inputs and modern production pentodes in ultralinear configuration as outputs. But here’s the thing. It weighs a ton, pulls 150W out of the wall, for 10WPC and the mains transformers and chokes are mechanically noisy in operation and are irritatingly audible in quiet passages.
My NVA, A20 on the other hand is basically a class B (horrors!) transistor amplifier. It pulls 10W out of the wall when idling, makes 25WPC. AND (now I’ve sorted the dry joints on the LS5 speaker cables) when it is fed from a BTE passive pre with high quality stepped attenuator, it sounds just as good in the mids and treble as the single ended, valve setup, images just as well, and frankly pisses all over it in the bass dept. And all this lovely music for £300. It cost me more than that for my noisy bastard mains transformers.
The major take away from all this, is that for you to be a successful DIY’er in the valve amplification department, and to be able to play with the big boys....wait for it.....excuse the caps - YOU NEED A GREAT DEAL OF MONEY. You can design as much technically superb gear as you want, of that there is no doubt, and you can learn a lot on the way and have a lot of fun. However the inescapable fact remains, that if you don’t have the cash required to pay for the iron, don’t try to kid yourself that you will EVER make anything other than a
good amplifier. The chance of making a GREAT one is completely non-existent - not with single-ended amplification at any rate.
The irony in all this, is that the best sounding valve amps I have made, have been the three push-pull setups, using first, EL84s, then EL34s, then KT66s, with a phase splitting input transformer, followed by differential pre and driver stages. The input transformers cost me £70 the pair from Sowter, and the output transformers sounded better than any cheap-ass single ended OPT I’ve ever heard. And yet I abandoned push-pull. Go figure.
Anyway despite all this. DIY audio is a good hobby, but I think one does have to keep one’s feet on the ground and accept, that people like Richard, Lurcher, Tim De Paravicini, and Colin W to name a few, know exactly what they’re doing, can blow you away any day of the week and you can’t compete with them. DIY does not save you money.
