Guitar store experience/ tube question

SwitchfootRulz! · 09-20-2006, 07:41 AM

My best friend and I went to the local music store. There was the stereotypical guitar store kid there, playing Crazy Train and Eruption through a huge marshall half-stack...with a little squier. I equated it to the Marshall being sick.

Anyway, I got to play a Fender MIA Strat, with a mirror pickguard. Which looks really cool. Through a MESA RECT-O-VERB!

I absolutely LOVED the tone.

But the question I have is this: What exactly is the difference between Class A, A/B, and B amps?

Also...

Quote:

Originally Posted by mesaboogie.com

50 Watts, Class A/B Power / 2x6L6, 5x12AX7
Bias Select Switch (6L6/EL34)

Does this mean it's all tube? I'm pretty clueless when it comes to this.

(I played a DeVille too...eh. I would've liked to hook it up through an attenuator though.)

**thesteve** · 09-20-2006, 08:52 AM

Quote:

Originally Posted by SwitchfootRulz!

But the question I have is this: What exactly is the difference between Class A, A/B, and B amps?

Good question. I've always liked the wikipedia explanation: http://en.wikipedia.org/wiki/Class_A...lifier_classes

Quote:

Does this mean it's all tube? I'm pretty clueless when it comes to this.

It's according to who you ask. For all practical purposes, the pre-amp is all tube, and the power amp is all tube. As far as I'm concerned, it's all tube.

However, sticklers would note that the rectifier is solid state...honestly, I don't think it's that big of a deal. Some people swear by their tube rectifiers, others swear they can't hear a difference. It certainly isn't going to be a loss of tonal quality, just a change in it. If you like the tone, then there's no reason to get bent out of shape if you have one or not.

Ax · 09-20-2006, 09:07 AM

Quote:

Originally Posted by thesteve

It's according to who you ask. For all practical purposes, the pre-amp is all tube, and the power amp is all tube. As far as I'm concerned, it's all tube.

However, sticklers would note that the rectifier is solid state...honestly, I don't think it's that big of a deal. Some people swear by their tube rectifiers, others swear they can't hear a difference. It certainly isn't going to be a loss of tonal quality, just a change in it. If you like the tone, then there's no reason to get bent out of shape if you have one or not.

Don't know much about the Rect-O-Verb but i know that if he were to get a Dual or a Triple rect he could switch between SS and Tube... i think the Dual offers Class A and SS, and the Triple Offers Class A, Class A/B, and SS...

if it has Class A or Class A/B then the rectifier is tube... so yes it would be an all-tube circuitry....

nate95366 · 09-20-2006, 09:09 AM

Quote:

Originally Posted by thesteve

Some people swear by their tube rectifiers, others swear they can't hear a difference.

Some people (like me) actually prefer the solid state rectifier slightly (at least on amps where I can tell the difference, which really isn't that many).

I'm also fairly sure that the Boogie Rect-O-Verb is "all tube" by anyone's definition - in that it uses tube rectifier "technology."

Nate

Ax · 09-20-2006, 09:14 AM

i couldn't at first, but over time i've learned to pick out the difference in SS and Tube Rectifiers... it's not easy, to the end consumer who is buying your CD for the most part they're not gonna know the difference... but live you might get a few fans saying "it just doesn't sound real to me"...

**thesteve** · 09-20-2006, 09:24 AM

Quote:

Originally Posted by AXguitar

Don't know much about the Rect-O-Verb but i know that if he were to get a Dual or a Triple rect he could switch between SS and Tube... i think the Dual offers Class A and SS, and the Triple Offers Class A, Class A/B, and SS...

if it has Class A or Class A/B then the rectifier is tube... so yes it would be an all-tube circuitry....

Regardless of the rectifier, an amp is going to have a classification (A or A/B in the case of a wide majority of tube guitar amplifiers). The reason the Dual and Triple rectifier amps have their name is because of tube compliment (two tubes in the Dual, three in the Triple). They actually call their rectifier settings "Normal" (tube) and "Hi-gain" (SS). It has nothing to do with class operation. Mesa Boogie amps, unless specifically noted are all Class A/B amplifiers. I'm pretty sure any high wattage amp that has a rectifier selection switch that says "Class A, A/B" is describing a tone, not the amp's actual class of operation.

Quote:

Originally Posted by nate95366

I'm also fairly sure that the Boogie Rect-O-Verb is "all tube" by anyone's definition - in that it uses tube rectifier "technology."

Nate

I'm not sure if you're trying to allude to something here Nate that I'm missing. None of the tubes used in the Rect-O-Verb is a rectifier tube. Mesa uses 5U4GB rectifier tubes in all of their tube rectifier amps except the LoneStar Special. The Rect-O-Verb is definitely an amp with a SS rectifier.

Ax · 09-20-2006, 09:33 AM

Wow, and i thought my B52 was directly modeled after the triple rect but i guess i was wrong, mine gives an option for Tube A, Tube A/B, an SS... that's what's actually written on it it... i prefer to leave it in A/B... but that's just me...

What5647 · 09-20-2006, 09:48 AM

steve is correct, the rectifier type has nothing to do with the power amp class.

if it was me, i'd say it's an all tube amp, since it has an all-tube signal path.

**thesteve** · 09-20-2006, 10:37 AM

Quote:

Originally Posted by AXguitar

Wow, and i thought my B52 was directly modeled after the triple rect but i guess i was wrong, mine gives an option for Tube A, Tube A/B, an SS... that's what's actually written on it it... i prefer to leave it in A/B... but that's just me...

yeah. Even their website confuses the issue. On this page it says, Tube A, A/B or SS A/B, but the back of the amp is labelled as you noted.

This is what might be going on:
When running in "Class A", the amp actually cuts two of the four power tubes out of the circuit and runs the remaining two in what I can only think to describe as "hot A/B". By doing this, they might have been able to simulate Class A tone with an A/B amp. Some people say that this is the basis for people claiming that VOX AC30s are Class A, when they actually have some sort of weird in-between going on. The reason behind this speculation is that with the Dual Rectifier, when you run it on half power by removing two of the tubes, you are supposed to remove one of the rectifiers. Since your amp only has two rectifiers, this might be the case. (that was pure speculation by the way...though I'm sure somebody...in some cubicle...somewhere...knows)

I don't really know what your amp is supposed to be modeled after. If it's a modeled after a Mesa, it's definitely after the Dual Rectifier. The primary differences would be the tube count (two rectifiers vs. one), and the rectifier modes.

Ax · 09-20-2006, 11:16 AM

all i know is, that when i jam out, i gets some crazy heavy OD'd tones, that are remiscent of a triple rect, but it does have it's own flavor to it...

nate95366 · 09-20-2006, 02:20 PM

Quote:

Originally Posted by thesteve

I'm not sure if you're trying to allude to something here Nate that I'm missing. None of the tubes used in the Rect-O-Verb is a rectifier tube. Mesa uses 5U4GB rectifier tubes in all of their tube rectifier amps except the LoneStar Special. The Rect-O-Verb is definitely an amp with a SS rectifier.

You've got it then. I was just thinking from a potential marketing perspective. If you're going to draw attention to the rectifier by calling the amp a Rect-o-verb, you'd think it wouldn't have a plain-Jane (solid state) par-for-the-course rectifier. But, I guess it could indeed.

Nate

**thesteve** · 09-20-2006, 03:03 PM

Quote:

Originally Posted by nate95366

You've got it then. I was just thinking from a potential marketing perspective. If you're going to draw attention to the rectifier by calling the amp a Rect-o-verb, you'd think it wouldn't have a plain-Jane (solid state) par-for-the-course rectifier. But, I guess it could indeed.

Yeah...I never figured out Mesa's naming scheme. The Single Rectifier amps are SS only...Dual and Triple have two and three rectifier tubes respectively. The Rect-o-verb is based on the Single Rectifier, and the discontinued Trem-o-verb was based on the Dual Rectifier...HOW CONFUSING!

***BillSPrestonEsq*** · 09-26-2006, 06:58 PM

Quote:

Originally Posted by AXguitar

Don't know much about the Rect-O-Verb but i know that if he were to get a Dual or a Triple rect he could switch between SS and Tube... i think the Dual offers Class A and SS, and the Triple Offers Class A, Class A/B, and SS...

Only the rectifier, which is not actually in the audio signal path. Changing the rectifier mode would not change a class a/b amp to class a.

Quote:

if it has Class A or Class A/B then the rectifier is tube... so yes it would be an all-tube circuitry....

Nope. The valve Jr has a solid state rectifier. Supposedly, it is class a. My classic 120 has a tube rectifier, as does the power amp I am currently playing with.

I think I prefer solid state rectifiers from testing things out. I can't really tell any difference unless I am really giving the power amp a run for its money. Then, it has fallen very slightly in the solid state rectifiers favor...

Ax · 09-26-2006, 07:13 PM

Quote:

Originally Posted by BillSPrestonEsq

Only the rectifier, which is not actually in the audio signal path. Changing the rectifier mode would not change a class a/b amp to class a.

Nope. The valve Jr has a solid state rectifier. Supposedly, it is class a. My classic 120 has a tube rectifier, as does the power amp I am currently playing with.

The thing in question here was always the rectifier, i meant if the rect switch was labeled "A A/B" then that meant the rect was tube, but i was wrong... and yes i knew that switching the rect from A to A/B was only switching the rect circuit... My B52 is a Class A All Tube Circuitry amp, I learned like so much from reading the owners' manual (not the one on the website, it actually came with a slightly bigger book explaining some things about circuitry..)

**thesteve** · 09-26-2006, 07:57 PM

Quote:

Originally Posted by AXguitar

My B52 is a Class A All Tube Circuitry amp, I learned like so much from reading the owners' manual (not the one on the website, it actually came with a slightly bigger book explaining some things about circuitry..)

Uh...what exactly in the manual that you have says that? since Class A is full power all of the time, and very inefficient, you never see Class A amplifiers over 30W.