On Oct 22, 2:33 pm, mick wrote:
On Mon, 22 Oct 2007 13:50:47 -0700, Multi-grid wrote:

snip

So then Andre, you mention an AB amp having A power, you reference an
80W SE amp, claim an off the rack Vellman kit is brilliant, and then
attack anybody who'd have the guts to say you've over reached. Even with
poor S/N ratio there is still signal. Let's see some from you. cheers,

Who is this fellow "Multi-grid", and why is he addressing me?

Surely though, a class AB amp such as the Vellman *is* running in class A
up to the point where one output device starts to turn off isn't it? The
changeover to class B happens at that point and is dependent on the
quiescent current in the outputs.

I would have thought anyone with a handle like "Multi-grid" would have
taken that sort of basic tube knowledge from the teat. Mind you, I
remember when Ron Bales wanted us here on RAT to give everyone who
claimed a "tubie-handle" a test of tube knowledge to ensure they don't
give a respectable hobby a bad name by wielding their ignorance like
clubs. That was about 1998. Looks like this "Multi-grid" fellow is a
prime candidate for the Bales Test.

A true class A amp is only a special case of the normal AB class. It's
just that it clips symmetrically instead of moving smoothly into class
B. ;-)

It is beneath my dignity to rise to such provocation -- sniff. A Class
AB amp is a compromised Class A amp, and it probably requires negative
feedback too to work even acceptably. A properly designed Class A amp
never clips because the operating parameters were so chosen that it
runs out of signal from the intended source before it can clip (that
is one reason why the design instructions on my netsite feature the
*design center* process so heavily). It is only "engineers" who
"design" amps to hog the maximum power from each tube who even need a
concept like clipping; for sane tubies it is obsolete terminology.

--
Mick (Working in a M$-free zone!)
Web:http://www.nascom.infohttp://mixpix.batcave.net

Andre Jute
Our legislators managed to criminalize fox-hunting and smoking; when
will they get off their collective fat backside and criminalize
negative feedback? It is clearly consumed only by thickoes.