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Posted By: thefwam Self Built Amplifiers - 06/25/08 09:42 PM
Good day everyone!

I have recently become enamored with the idea of building amplifiers. Well to take a step back I've been in school studying Electrical Engineering for a bit here, so I have LONG been enamored with playing with electronics, as I'm sure many of you have. But recently it has become wanting to build some sort of amplifier.

Maybe starting with a Headphone amp, and progressing to a monoblock or blocks. Does anyone have any experience with the difficulty in undertaking one of these projects? Also if anyone knows any good resources for schematics/tips/etc that would be great.

It's been on my mind, so I thought i'd get it out to people smarter than me!
Posted By: St_PatGuy Re: Self Built Amplifiers - 06/26/08 12:08 AM
Steve, here are some of the sites I've looked at over the years:

Transcendent Sound--tube gear. I don't have any of the kits, although I've wanted to try some. I do have a book by Bruce Rozenblit in which he shares his philosophy and knowledge about tube based designs. Schematics for projects are included.

Bottlehead--more tube gear. I bought a preamp kit years ago and it's still under construction. Very easy to follow and build. There is a headphone kit in there.

Aspen Amplifiers--here's some solid state stuff. These are from Australia and more info can be found here at the Audiocircle forum.

Hopefully some of these will help!
Posted By: JohnK Re: Self Built Amplifiers - 06/26/08 02:18 AM
Steve, in addition to do-it-yourself type audio sites and eventually more work in school, you might benefit from studying "The Audiophile's Project Sourcebook" by G. Randy Slone and "Audio Power Amplifier Design Handbook" by Douglas Self(Mr. Self also has a web site ). I've gotten quite a bit of no-nonsense info on what counts in amplifiers from these. If your local library doesn't have them, it should be possible to get them through interlibrary loan.
Posted By: thefwam Re: Self Built Amplifiers - 06/26/08 04:22 PM
Thanks for the help guys! So I'm wondering, having very (read none) little experience with tubes myself, I don't know how to interpret the difference in the wattage produced.

When I was in a band in High school our guitarist upgraded from some solid state amplifier to a Mesa Boogie 25 or 50W (I think) tube amplifier, which blew the old one away at 1/4 the power.

I'm just wondering, looking at some of these that are 1.5-3 WPC, how will these compare to the power put out by a traditional receiver, say if I was to mate that two channel amp for my fronts with the receiver for the center and surrounds. Any thoughts?
Posted By: St_PatGuy Re: Self Built Amplifiers - 06/26/08 04:31 PM
I don't know the exact ratio, but tubes will have more power than solid state of equal wattage.

I would definitely stay away from 1.5-3 WPC if you plan on incorporating it into your HT. There is not enough headroom to handle the dynamic peaks.

Generally speaking, that kind of small wattage pretty much requires highly sensitive speakers, and/or moderate listening levels.
Posted By: Ken.C Re: Self Built Amplifiers - 06/26/08 04:33 PM
Not really more power, but less susceptibility to unpleasant distortion. Because tubes have even order distortion, when they distort, they sound pleasant. Solid state has odd order distortion, so when they distort, it sounds obvious and bad. Therefore you can get away with lower wattage with tubes (and some find it desirable.)
Posted By: thefwam Re: Self Built Amplifiers - 06/26/08 05:01 PM
exactly, power is power, it just handles it in a different way than your solid state amplifier. Tubes Vs. Solid state and now Vs. Digital seems to be entering the debate. I just want something that sounds good, and if I can build something for cheaper than buying for my power needs then I'm all for it.

Where do the Axioms fall in terms of sensitivity? I'm rocking the M22's in front, VP100, and the QS8's
Posted By: jakewash Re: Self Built Amplifiers - 06/26/08 05:47 PM
 Originally Posted By: thefwam
Where do the Axioms fall in terms of sensitivity? I'm rocking the M22's in front, VP100, and the QS8's
Um..not hard to look up yourself, but they are 89db anehoic @ 1w 1m, which is reasonably sensitive, better than most bookshelfs, not as good as a few others out there.
Posted By: thefwam Re: Self Built Amplifiers - 06/26/08 06:37 PM
I should've realized I could look it up, sorry. I've heard people here talk about how they were pretty sensitive, but I hadn't ever heard numbers...and until today I didn't know there were numbers. Thanks for the info though.
Posted By: BrenR Re: Self Built Amplifiers - 06/26/08 09:34 PM
 Originally Posted By: St_PatGuy
I don't know the exact ratio, but tubes will have more power than solid state of equal wattage.
Ken got to this before I did but, yeah... they'll still distort at roughly the same levels (depending on the tube condition as well)... but with even order distortion (think tube overdrive pedals for the guitarded types out there) instead of staticy odd-order distortion (everyone knows what a clipping solid state amp sounds like).

On the plus side, by overdriving a small tube amp, you could find out what Zamfir's pan flute would sound like through a Rat stompbox.

Bren R.
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