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Old 29th August 2003, 12:19 AM   #31
jlsem is offline jlsem  United States
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>They waste a LOT of power.

Not THAT much. Anyway, who cares?

>They give off a lot of heat.

How much more than silicone diodes? Again, insignificant issue.

>They use a lot of space.

??!! 2.5" X 2.5" max.

>They complicate the wiring.

You're really reaching here. That issue isn't going to stop anyone on this forum

>They can't (easily) be used in some rectifier configurations.

True, bridges with DHR's need two extra filament windings, but this isn't a normal implementation.

>They ruin regulation.

Well, you do have a point there, but with class A, an ordinary "brute force"-regulated power supply works well enough.

If you had written, "Tube rectifiers SUCK; they sound TERRIBLE.", I wouldn't argue with you. But, nearly everyone agrees that they sound better, so a pragmatic diatribe isn't going to wash in most DIY audio enthusiest circles. I don't wish to be flippant, but one reason I moved over to this forum from rec.audio.tubes is that it (RAT) had become dominated by types who weren't interested the sonic qualities of more esoteric designs, components and tube types. I mean, is there really an ultimate class AB push-pull EL34 amp out there worth pursuing?

John
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Old 29th August 2003, 03:59 AM   #32
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Quote:
Originally posted by jlsem
>They waste a LOT of power.

Not THAT much. Anyway, who cares?
30W is a heck of a lot more than "who cares".

Quote:
>They give off a lot of heat.

How much more than silicone diodes? Again, insignificant issue.
30W for maybe 250mA vs. what, uhm lemme see here LESS THAN A WATT?

Quote:
>They use a lot of space.

??!! 2.5" X 2.5" max.
2"x2"x6"

Quote:
>They complicate the wiring.

You're really reaching here. That issue isn't going to stop anyone on this forum
Tubes are often easier because they are their own terminal strips, rather than taking up a good 3 or 4 slots on a strip. But that's just a matter of a design consideration.

Quote:
>They ruin regulation.

Well, you do have a point there, but with class A, an ordinary "brute force"-regulated power supply works well enough.
And what if you're shooting for a little more power than a class A amp can do? Hmm?

Quote:
> I mean, is there really an ultimate class AB push-pull EL34 amp out there worth pursuing?
Though he usually uses 6550s or so - they're plentiful - EL34s can be used just as well in many of Patrick Turner's designs. Tell me those aren't "ultimate"?

Tim
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Old 29th August 2003, 07:26 PM   #33
jlsem is offline jlsem  United States
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>30W is a heck of a lot more than "who cares".

30W if you're using a pair of 81's maybe, but a GZ34 or better yet TV damper diodes waste considerably less than 30W. Besides, you missed the point: Tube amps waste a lot of power, so what's 10 or 15 more watts more gonna hurt, especially if you are looking for sonic advantages?


>Tubes are often easier because they are their own terminal strips, rather than taking up a good 3 or 4 slots on a strip. But that's just a matter of a design consideration.

That whole excuse for not using tube rectifiers was silly.

>And what if you're shooting for a little more power than a class A amp can do? Hmm?

A regulated power supply for a push-pull AB1 or AB2 power amp is really polishing a turd.

>Though he usually uses 6550s or so - they're plentiful - EL34s can be used just as well in many of Patrick Turner's designs. Tell me those aren't "ultimate"?

Never heard one. Patrick has come a long way since he began posting on RAT, and I mean no disrespect for the man, but designing amps from an RDH4 is nothing new, and admittingly he has come to dominate the forum and it now has limited interest for me.

John
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