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in article , Miles O'Neal at
wrote on 2/21/04 7:58 PM:

Patrick Turner responded to WakyAmps, who said:

Yes, how it is set up makes a huge difference, no a Vox AC-30 isn't
really class A.

The ones I have serviced were class A, with absolutely no feedback.
They had a high bias current, and each of the 4 EL84 draws about 12 watts
at least at idle.

Now this doesn't make any sense at all.
In Class A, full tilt isn't different
enough from idle to make any difference.

So, just curious - why do you say they
were Class A? What do you think that
means?
Yeah, and 12 watts on an EL84 is almost Ice cold!
My Guytron runs em at 17-18 watts static (45-50ma)!

Lloyd

...
As I see it, all the 6550 from yesteryear about which ppl rave as being
just so superior to
anything else are all actullay prone to failure from hard use, unfortunate
events with the wrong speaker impedance, etc, since all the ratings
indicate that they are what they are, mortal tubes, and like us mortal
human beings,
they are gonna die one day.

While this is true, some of the tubes made back
in the far exceeded their published specs, and
hence are worth far more than the common tubes
of today, to some people. If it'll last five
times as long when being punished, it's worth at
least five times the price - more if you calculate
the lower likelihood of failure during a gig.

I'm merely suggesting
that, while for Rich there's no other tube than the GE and no other amp
than the PS400, the OP is looking to retube a reissue SVT and the OP may
be quite satisfied with the Sovs (at half the price no less). And it is
the OP's needs we're trying to address here, right?

Sure. I agree with you here. At the same time
I understand where Rich is coming from. He's a
firm believer in the value of the old tubes over
anything built today (so far), and wants to help
others understand that.

In some case I agree with him on the state of the
art and the value; in others I don't. Most of the
time we're in different threads, because I mostly
deal with 6BQ5s and 6V6s, which he dismisses as
"radio tubes". 8^)

I assure you that other folks make big tube amps. As new old stocks of
favourite old tubes dry up, all we are gonna have is sovtek, EH, Svetlana
etc.
But asking more than 75 watts per pair of bottles is asking for trouble.

With the new tubes this may be so - I don't know.
But I have known lots of folks getting 100W or more
per pair (think SVT!) with no problem.

...
Remember, Rich claims that the GE and Sov "aren't even close" sonically
or electrically. Maybe so in his tweaked 400PS and to his ears and
playing style; there may not be as strong a case in the OP's RI-SVT and
to the OP's ears and style.

How anyone can tell much difference between the sound of tubes when the
thd is at around 25%, and IMD at around 50% is beyond me.

Just curios - are you a musician? Do you care about
tone? Do you consider your ears good? Because the
sonic differences in tubes are ell documented. My
wife and kids, none of whom play guitar (Josiah keeps
saying he wants to, but never practices much) can hear
these differences, and they aren't tube freaks by any
stretch of the imagination!

[Story of 0 ohm tube PA into 1 ohm bins snipped]

In this case, its better to err on the load value by choosing a value too
high, rather than too low!

Why not try your friend's PA head into, say, 64
ohms at full blast and let us know how that goes?

-Miles

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