heavy duty valve amps.... for PA use....?

[jc808]

Valve power amp, rackmountable, 2- channel, approx 500-800wpc

Do such units exist? and where can you get em. (ive searched all over the web)

the closest ones i can find are the marshall ones, 100wpc, 200 bridged, not sure thats enough for my uses.

Can anyone point me in the right direction? regards jc808

[Positron]

but not cheap. Special order items.

[jc808]

thanks for the reply, Steve, I suspected so.

Do you happen to know of a company in the uk that undertakes such tasks?

i reckon, looking at the 'home project photo albums' thread that a few of the users of this site could do a half-decent job ;-) at least

[mcs]

You can get 340W from a pair of 811As... And the supply voltage is only 1500V

1900W from a pair of 833As at 3000V is another option...

Or perhaps a PPP amp running at a lower voltage is a more "sane" option.

Why do you need that much power BTW?

Best regards,

Mikkel C. Simonsen

[jc808]

1900w? ouch

the reason i was thinking about such a powerful option was i was thinking about doing a few parties, and wanted something powerful, with a little 'headroom' to avoid clipping (which is not such an issue with valve amps, but...)

a custom-made 833a system would be roughly how impactive on the wallet?
and fairly large, one would presume..?

youd also need a three-phase inlet with a 3000v draw, surely :-s

cheers for all the answers so far guys (and gals?), youve been a great help

fyi the size of room i would be playing in would be no larger than 50ftx 40ft, max

[Sch3mat1c]

Or forced-air tubes like 4CX250.

But yes, typically you don't need "quality" tube audio of such power levels, especially for PA use, you might as well use SSatanic equipment.

Tim

[SHiFTY]

On eBay about a year ago there was a pair of massive PPP KT88 amps with about 16 KT88 per channel... They were used by some Sound System for jungle/rave parties in London apparently!

They looked pretty tired, but who knows? I remember they had massive transformers and the ad stated that the tubes glowed in time with the music... glowing plates perhaps?

[Colt45]

You dont need 600w for a 40x50' room.

[phase_accurate]

1900w? ouch

The largest tube-amp I have seen so far was a 3 kW one (mono only). It wasn't rack mountable - it was consisting of a whole rack!

When you talk about PA, I assume it is for FOH and not for a single instrument, is it ?
A large tube amp for that purpose was the Dynacord "Gigant" (German for giant) with 200 Watts. Maybe they can be obtained 2nd hand. But you will need two of them since they are also monaural.

Regards

Charles

[mcs]

Originally posted by jc808
1900w? ouch

a custom-made 833a system would be roughly how impactive on the wallet?
and fairly large, one would presume..?

I guess it would be very expensive. The circuit can be very simple (look at some of the old WE or Altec amps - a couple of transformers and four tubes). But all parts made for high voltages are very expensive and hard to get. I don't think anybody makes output transformers with 3000V isolation. A 1000-1200V amp. would probably be possible, but still very expensive. But I wouldn't make an amp like that - it's bloody dangerous!

You would need a lot of expertise to take on a project like that...

I would think you should look for a more sane/normal amp - perhaps 100-150W. And if that's not loud enough it's probably because your speakers are too ineffective.

Best regards,

Mikkel C. Simonsen