On Sat, 12 May 2007 18:37:05 GMT, "James Sweet"
wrote:


wrote in message
.. .
I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

Is this a joke? 1KW from a tube amp? What do you plan on using for output
transformers? Hope you have a forklift to move them around and a very large
electrical service to power it all. It would eliminate the need for central
heating in your house as well.


No, not a joke. I have wanted all my life to build a stereo that
handles the same power levels as a live concert. I'm now retired and
want to finally do it. Back when I was in my 20's I built my rather
crude system which consisted of 3 separate amplifiers, each putting
out 120Watts RMS, with 4 6L6 tubes in PPP. (The 3rd amp was a
"center" or combined channel that drove a bank of woofers). My huge
speaker towers that I built with one inch thick plywood, held guitar
amp speakers and horns. The power was amazing, but not quite as clean
as I wanted it, and that feedback thru the tubes was always a problem.
Once, when I was rather messed up (I'll skip the details), I cranked
it wide open and blew all the windows out of my apartment (the
landlord was NOT pleased). I attribute the window shattering to low
end distortion, (in a much too small apartment).

Now, I live on a farm and I want to fill the whole farm with
"live-like" sound. I guess you could call it my personal "Woodstock"
(ya, I'm showing my age). Actually handling hundred (or more) pound
transformers/amps would not be a problem, since I actually DO have
tractors and such to move them. but getting the xformers probably is.
I have 400AMP service at my panel, so I got enough power too.

However, I will consider using solid state amps if I can achieve the
right sound. I would imagine I could get some ready made PA system
amps. I used to know a guy that worked for a sound company that did
all the sound for major rock concerts. I know for fact that they had
the capability to run 10,000 watts total, and in most places used the
full amount at outdoor concerts. So, myself wanting to run at least
2000watts total is not too much to ask.

I'm curious why you think this is a joke? I'm asking because there
was a time when everything was tube. What did they use back then for
large concerts and auditoriums for the main system? Ya, I know that
the concerts back in those days were not as large as they have been
since the late 60's. I'm curious what they used at Woodstock, since
that was more or less the first concert of it's size, and that was
during the transition from tube to semi-conductors, and I know that
semi-con... power amps back in those days were prone to failure.

There seems to be a lot of historical information about Woodstock and
other major concerts back in the 60's and 70's, but finding details
such as the type of power amps used to supply the main system just is
not documented.

Mark