HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

Just did some sim's with a pair of 300b's



Signal Voltage, AC current (ma, p/p), DC Current (ma)
10, 3, 50
20, 13, 55
30, 32, 64
40, 59, 80
50, 80, 90
60, 120, 100
70, 150, 120

Graphing those gives curves with no obvious A->AB-B transition point, but is related to (as expected) the power into the load.

Fascinating, so in my book that is truly Class AB and not Class A at all !

Marco had an on going argument with me about his amp for weeks insisting it is class A, not agreeing to disagree again was one of his reasons for booting me. He sees people insulting him when they tell him he is wrong, and even proving it - the man will not back down. The conversation reminded me of this

https://www.youtube.com/watch?v=KOO5S4vxi0o

You could meet him at Scalford along with other members of his Klan. A program on BBC4 last night brought him and his mafia to mind, the Klu Klux Klan and the deep South. Nasty people who expected to own people....

Dave Cawley wrote:Fascinating, so in my book that is truly Class AB and not Class A at all !

Yes, anything can be in class A if the signal is small enough assuming ther eis no gap and both devices are not shutoff at idle, that would not work for a audio amp as its on the edge of C. For the classes to have meaning it must relate to full power condition. IMHO, the class A or B stigma is back ported into valves from solid state. You can say for certain, for example, that a emitter follower SS amp with +- 20v rails, can only be in class A with a 8R load if the idle current is more than 2.5A. Its can't leave A.

Lurcher300b wrote:For the classes to have meaning it must relate to full power condition.

Exactly, and hence it's Class AB and not Class A, this is fundamental and thanks for the results.

Vlad_Dracul wrote:http://sound.whsites.net/valves/classes.html

Yep, that makes it look nice and simple, but what happens if you take the class-a example



You get something that looks suspiciously like the class ab example



So it partly depends on the driver stage

Prompted by this thread I have taken the time to read the pros and cons of valve amps on AOS .

I am amused at Marco's inane interjections and his pathetic attempts to find a voice in the thread.

I am very amused at RFC providing me with an exemplar par excellence of my critique that he is a cut and paste theorist who actually understands nothing . Watch with glee as he takes on Arkwright open after 1pm only and in less than four posts is destroyed by the fact arkless does actually know something ,

Well we have chapter and verse on valve amps here with Lurcher.