Modern Class A

[tube geek]

Sorry guys, I meant to place this on this forum instead of the 'wreck forum. Does anyone know the difference between the term "modern class A" and the classic class A ?

[Jana]

Classic class A is the operational range/mode of a tube. It refers to the conduction of the tube (it conducts for 360 degrees of the signal).

Modern class A is a sales slogan meant to sell amps with the inference that there is some magical class A voodoo elves at work in the amp.

Disclaimer: Bias may be present in my opinion. The amount of bias depends upon how much juice is present which results in a negative reference point.

[Aurora]

I think you just about got it right. There is only one class A, - be it technical or classic. There are, however, some "sub-modes" of class A, AB1 and AB2, which does not conduct for the full 360 deg of signal phase....increases efficiency somewhat, and lowers heat dissipation.
There is also a special version of class A, sometimes called "sliding bias", where the bias point is automatically adjusted to signal level ( with proper time constants, of course), also this mainly to reduce the dreaded heat dissipation of real class A.
Never heard of this for tube amps, though.....

The rest - "Modern Class-A" - "New Class A", etc etc is just nonsense.....

[d95err]

Does anyone know the difference between the term "modern class A" and the classic class A ?

Where did you hear/read the term?

My guess is that a "modern class A amplifier" would refer to an amp with a modern design (probably a channel switching clean/higain preamp) and with a "Class A" (usually marketing lingo for cathode bias) poweramp.

[tube geek]

Thanks guys, this is just as I suspected. I had read this in a couple discriptions of the "new guru" amps, and a factory tech. I did not see how the operation curves and plate dissipation numbers could have magically changed. What I have encountered in these amps is usually high B+ voltages (480v) and pushing the output tubes(EL34s) past the plate dissipation(92 ma ea.!), in some cases as much as 30% over. No headroom huh, imagine that. As usual someone is trying to make us believe their stuff has a special mojo happenin'

[VacuumVoodoo]

You guys are missing the finer points in guru MBS strategies. It's the "gurus" themselves that apply class qualifiers to their own mode of operation and how they see themselves. No self respecting guru would want to be a class B2. So now we have modern class A and classic class A gurus.
Just to make it clear, I am in a class of my own: Super Über Guru. Why? Because I need only to look at a tube, capacitor or any other component to know exactly how it will sound. I have it in writing from a well respected guitar magazine so it surely is honest to G-d truth. Happy MMXI everyone!

[Super_Reverb]

Why? Because I need only to look at a tube, capacitor or any other component to know exactly how it will sound.

So, you don't really even have to have an amp or guitar: you can simply visualize or "auralize" the sound, yes? Does this require you to maintain eye contact with sound guy in live situations?


I still have two lingering questions.:

1) Do I have to use analog(ue) guitar speakers for my amp or could I use "digital ready" speakers. Is some kind of NOS snake oil adapter needed, like an A/D?

Modern class A is a sales slogan meant to sell amps with the inference that there is some magical class A voodoo elves at work in the amp.

2) Do the voodoo elves in my 6550 SE amp have special bias requirements or require magical low-loss old school coupling caps with patent-pending chimey dielectric?


Happy New Year,

rob

p.s. It seems another desirable feature of a tricked out boutique amp would power efficiency > 1.00 If you could backfeed the power line some juice during a jam, you could probably get government grant money. Is anyone working on this?

[VacuumVoodoo]

Why? Because I need only to look at a tube, capacitor or any other component to know exactly how it will sound.

So, you don't really even have to have an amp or guitar: you can simply visualize or "auralize" the sound, yes? Does this require you to maintain eye contact with sound guy in live situations?

Re "auralizing" the sound. Yes, exactly. Guitar solos I hear in my head when I see a quartet of NOS EL156 tubes would make JH, EVH, SRV green with envy. Andres Segovia would die again if he wasn't classical acoustic only.
Re eye contact with sound guy. Need a mirror to achieve this. I am the sound guy.

I still have two lingering questions.:

1) Do I have to use analog(ue) guitar speakers for my amp or could I use "digital ready" speakers. Is some kind of NOS snake oil adapter needed, like an A/D?

All that binary crap is part of a brain washing conspiracy by secret clubs of under educated C++ and VHDL cultists who have no clue how to design even the simplest analogue circuit and have never seen a soldering iron. Stay away, put a garlic necklace round your neck.

[Structo]

I remember being at the doctor and he was saying something about digitizing.....is that the same thing?

I am my own best critic. I tell myself I am great all the time.

[David Root]

I love garlic! I'd eat the garlic necklace and then what?

Night of the Digitized Zombies! Aaaaaaarrrrgh!