Valve power - feel the force!

Have I got this wrong or am I right in recalling Marco's amp has 2x KT88 per channel ?[/QUOTE]

yes, two KT88's in push pull run in AB will give 100 watts.
in marcos amp they are run in the warm side of AB1.
anthony...

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Originally Posted by jcbrum

So Marco's amp is only flat at 30w, that's what I expected. I wouldn't like to guarantee how long it would deliver 60w on a warm day !

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More unsubstantiated waffle. Is that like the way you wouldn't guarantee how long the transport mech in my Sony will last? It'll outlast you, that's for sure! ;)

Marco.

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Originally Posted by Shian7

Erm... Yes. :(

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Well done, ;) so did I :lolsign:

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Originally Posted by jcbrum

I have some early transformer coupled amps in my collection. :) I bought them new in 1967 I think.

So Marco's amp is only flat at 30w, that's what I expected. I wouldn't like to guarantee how long it would deliver 60w on a warm day !

Have I got this wrong or am I right in recalling Marco's amp has 2x KT88 per channel ?

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example,
kt88's were used in for example, loss testers in the steel industry, they drove huge triode valves flat out for months at a time!:)

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Originally Posted by anthonyTD

Have I got this wrong or am I right in recalling Marco's amp has 2x KT88 per channel ?

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Quote:

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Originally Posted by anthonyTD

, two KT88's in push pull run in AB will give 100 watts.
in marcos amp they are run in the warm side of AB1.
anthony...

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100w is a "catalogue" figure, at that level the distortion would be awful and they would go bang v quickly. Don't you agree ? :)

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Originally Posted by jcbrum

[/B]



100w is a "catalogue" figure, at that level the distortion would be awful and they would go bang v quickly. Don't you agree ? :)

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no,
i dont agree, the distortion figures are relatively high [10%] at that power without feedback, but the 100 watt power output is feasible, and definitely achievable, and with sufficient cooling, sustainable!:)

off to bed now folks...
anthony...;)

Ok, matey. You've well and truly kicked JC's ass now anyway! Nighty night :smoking:

Marco.

The limiting factor with most valves is the anode dissipation of heat, which is mainly controlled by the bias setting, not the output power.

In class A, KT88's might provide 10w out, in AB 30w, in class C 60w, in class D 100w.

It is therefore misleading to talk in terms of output power and anyway 60w is only 3db louder than 30w (v small difference)

To exceed double the volume (spl) you'd probably need to go from 30w to 300w.

In an attempt to do that in a push pull design the crossover distortion would be enormous >10% and clipping would be absolutely inevitable, but some do regard this as "involving musicality" and even get to like the sound.

Marco has already set fire to his amplifier once :) I rather think this "mythical" 100w from a pair of 88's in ab push pull will provide an even bigger bang eventually. :lol:

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Originally Posted by jcbrum

To exceed double the volume (spl) you'd probably need to go from 30w to 300w.

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More like 900W :eyebrows: