Push-pull vs. Single-ended

[DeanEVO_Dude]

I have been getting into tube amps lately... I have owned the Champion 600 (single-ended 6v6), currently own a Crate V5 (single-ended) EL84 (slightly modified), and have never owned a Push-pull (class B?).

What I am looking for is more wattage/volume, 5 or 6 watts only gets you so far... The only amps that I have owned that are more power than that are solid-state amps. As for tone, I have never plugged into a higher wattage tube amp, so I ask the question (sort of), what should I expect with a push-pull powered amp vs a single-ended amp? I hesitate to make the jump to a medium powered, tube amp (15-30 watts) because the price jumps up so drastically on the larger amps (5 watts $50-150, 20 watts $250 and up). I know that it is very subjective and hard to quantify the differences in sound and tone of these mini (and not so mini) monsters, but I'm just interested in what others on here think, i.e. pros, cons, likes, dislikes, etc. and other recommendations.

As for my usage, I don't gig, just play at home (my playing is not fit for human consumption LOL), so it has to be able to play at "bedroom" volume, as well as somewhat "cranked" volume, those E and G power chords really sound grand at higher volume with a healthy dose of dirt! LOl. I don't play metal, but if it has that much gain, all the better. And, I like pedals, overdrive and distortion pedals to get my "dirt" most of the time.

Some amps that attracted my attention are:
Bugera V22 combo
Crate Vintage Club 20
Fender Vibro Champ

So, there it is. Waddaya like, what dontcha like? I'm not looking for the "you should get X amp" or "you need to play thru as many as you can", I'm just looking for thoughts and experiences. :thankyou

[markb]

The Vibro Champ should be the first one off your list as it's a single ended 5 watt design too.

The trouble with valve amps is that to get "that" sound you've got to drive the output stage. Without an attenuator any of the amps you list will be far too loud for "bedroom levels".

If you're still looking though, add the Fender Pro Junior and Blues Junior to your list. They're both good little amps. I used both live and at practice levels to good effect.

For a real bargain that'll do just about anything but metal consider the Peavey Classic 30. Another good, solid amp with great tone at a reasonable price.

I'd also suggest looking at the Laney VC range but I think they're hard to find in the states.

[DeanEVO_Dude]

Thanks mark, that's the kind of info I was looking for...
As for the Vibro Champ, I may have made a mistake. The one that Fender makes that I am thinking of has 2 6V6 tubes and a 10" speaker... not the Vibro?

[markb]

That'll be the Super Champ. It's a hybrid with a modelling front end and a valve power amp. Sounds good.

[oldguy]

Fender Super Champ XD.
Jet City 20H 20w head.
I own these and like them (lots).

Bugera V22
Epiphone Valve Senior head.
These I don't own, but hear good things about.

[Eric]

Well...in my experience the thing about tube amps is that they're great when they're "in the zone" (correct volume for the situation, etc.), but otherwise are heavy and expensive.

Would you ever consider a solid-state amp? There are some darn nice ones out there these days, and the thing with SS is that you don't necessarily have to crank it to get the sound you're looking for. I'm not sure if I understood your actual question, but that's what I have to offer right now.

BTW, if you don't mind, could you enlighten me as to the difference between single-ended and push-pull? Is it just another set of terms for class A and class AB, respectively? I don't necessarily know the details of those either, but I have some idea.

[FrankenFretter]

I agree with Old Guy on the Jet City, and I would add the Vox Night Train (15/7½ watts). I own a Night Train, and it gets plenty loud. Great cleans and on the Thick channel, it has a great dirt sound. Of course, it's only available as a head, not a combo (unless that's changed recently).

Have you looked at an Egnater Tweaker? That's available as a combo, and they sound fantastic!

[DeanEVO_Dude]

Well...in my experience the thing about tube amps is that they're great when they're "in the zone" (correct volume for the situation, etc.), but otherwise are heavy and expensive.

Would you ever consider a solid-state amp? There are some darn nice ones out there these days, and the thing with SS is that you don't necessarily have to crank it to get the sound you're looking for. I'm not sure if I understood your actual question, but that's what I have to offer right now.

BTW, if you don't mind, could you enlighten me as to the difference between single-ended and push-pull? Is it just another set of terms for class A and class AB, respectively? I don't necessarily know the details of those either, but I have some idea.

I have a prety good solid state amp with my H&K Edition Blue, I am just lookin' for some new toys... :happy
Push-pull as I understand it, the tubes are paired up where one is on when the signal is positive (up side) and the other is on when negative (down side). Yes, Class A vs. Class AB. There are some higher wattage amp that use multiple output tubes that work in tandem as Class A (as opposed to AB) with the tubes in a parallel configuration, I think one of the old Gibson amps did it this way, about 12 watts outta a pair of 6V6s.

[DeanEVO_Dude]

That'll be the Super Champ. It's a hybrid with a modelling front end and a valve power amp. Sounds good.

Yes, that was the one I was thinking of, thanks.:applause

[marnold]

Jet City 20H 20w head.
This ^^

[guitarmadman85]

I agree with those in support of the JCA20H. I own a crate vc-508.... So I understand a little about the gear you use. Here is a quick overview of the difference between class A and class AB from Mike Soldano's viewpoint.

http://soldano.com/Soldano_Guitar_Amplifiers_Help/Soldano%20Guitar%20Amp%20Help-Class%20A%20vs.%20Class%20AB.htm

I think upgrading with give you a huge jump in the quality of your preamp. The thing I hate the most about the crate is the preamp. A great amp consists of a great preamp and a great poweramp working together to give you all the tones you desire. I prefer class AB any day.... but that's just my opinion. I really notice the differences that the soldano site points out. I hope this helps. If you want class A, I think the Marshall Class 5 would be a good choice, from what I've heard.

[hubberjub]

Jet City 20H 20w head.


As the owner of the amp that the Jet City was based on I have to agree.

[DeanEVO_Dude]

I am not too concerned with class-a/class-ab. I am not too sure (at this point) I know the difference. The link that gutarmadman85 (thank you, sir) posted from the Soldano web site was informative. I will have to do some more homework and save much more money.

I must say, it seems that Jet City Amplification has hit a grand slam with the guitar playing fans out there! Many people here really like them and I must say, the JCA2112RC looks like a sweet combo. It kinda scares me to think about changing tubes in it... 5 12AX7s and 2 EL84s! Thankfully they are not $60/tube! I will have to check them out some time.
I do notice that most here are talking about the head version, which does not sport the tube-driven reverb... anyone have the combo version?

At any rate, the two on the block to be looked at right now seem to be the Bugera V22 and the Jet City 2112 combo. Need to get in to check 'em out sometime. Thanks everyone, keep the opinions comming.

[kiteman]

I have a Blackheart Handsome Devil half stack and it makes a nice bedroom amp. The tone is pretty consistent at any volume (7.5/15 watts) and when cranked pretty sweet. Of course that's with the good tubes. The stock tubes are ok but the amp deserves better. Hard to describe the tone, sort of a mixture of American/British voices.

Hmm... I have no idea what class this amp is.

[DeanEVO_Dude]

I have been corrected in my assesment of Class A/Class AB and single-ended/push pull.

http://www.thefret.net/showthread.php?t=5088
This link to another thread that was posted many, many moons ago was very informative. Particularly the link from the Mesa Boogie web site. It went into some real layman's detail (if that is even possible!) on the differences. It seems, in a nut-shell, that Class A/AB reffers to how the power tubes are biased, and single-ended/push-pull reffers to how the tubes are configured to drive the output. This is very simplistically put, but makes the point. Any way...
I was at a local GC and saw something that really piqued my GAS! There was a used Ashdown Fallen Angel 40 DSP sitting in the used amph area, with a price tag hanging off it that said $99! Well, suffice to say, I was more than a little curious as to why there was such a low price... It seem that the damn thing makes no sound. They told me that they have changed all the tubes (Groove Tubes), but no dice on the output. Now, doing the math, 4 x EL84 and 3 x 12AX7, that is about $100 in tubes... so, it is like getting the amph for free. With my ability to use a soldering iron, and a background in electronics, it seems like it could be an interesting project.

Any thoughts on the quality and tone of this bad boy?

Thanks.

[tunghaichuan]

I have been corrected in my assesment of Class A/Class AB and single-ended/push pull.
http://www.thefret.net/showthread.php?t=5088


Basically, 99% of all push pull guitar amps are configured to run in Class AB. There are only a few exceptions, one from Allesandro comes to mind. It is a true Class A push pull amp using two EL84 tubes in the output. It puts out about 8-10 watts.

All single ended guitar amps are Class A. It is the only way to operate the amp and have it sound good. Most of these only have one output tube. The Gibson Gibsonette/Discoverer used a parallel single ended output stage with two 6V6s but it is still single ended. There is no phase inverter tube in the amp.

The main problem with Class A is that it is very inefficient. It also requires a special type of output transformer. OTOH, SE Class A circuits are very simple so in the olden days it cheaper to make low end/low cost practice amps (a la the tweed/BF/SF champs) class A amps.




I was at a local GC and saw something that really piqued my GAS! There was a used Ashdown Fallen Angel 40 DSP sitting in the used amph area, with a price tag hanging off it that said $99! Well, suffice to say, I was more than a little curious as to why there was such a low price... It seem that the damn thing makes no sound. They told me that they have changed all the tubes (Groove Tubes), but no dice on the output. Now, doing the math, 4 x EL84 and 3 x 12AX7, that is about $100 in tubes... so, it is like getting the amph for free. With my ability to use a soldering iron, and a background in electronics, it seems like it could be an interesting project.

Any thoughts on the quality and tone of this bad boy?

Thanks.

I don't know much about Ashdown amps, but the DSP would keep me from buying it. Amps like that are very complex and may require considerable troubleshooting skills. It may require parts that are no longer available. It could turn into a money pit in a hurry.

[tunghaichuan]

I have a Blackheart Handsome Devil half stack and it makes a nice bedroom amp. The tone is pretty consistent at any volume (7.5/15 watts) and when cranked pretty sweet. Of course that's with the good tubes. The stock tubes are ok but the amp deserves better. Hard to describe the tone, sort of a mixture of American/British voices.

Hmm... I have no idea what class this amp is.

It is definitely push pull, Class AB. The 7.5w setting is for a pseudo triode mode.

All the confusion comes from amp manufacturers (who should know better) marketing cathode bias amps as Class A, but biasing methods are independent of operating class. Apart from one or two exceptions, most push pull amps using two, four or six tubes are Class AB.

[guitarmadman85]

It is definitely push pull, Class AB. The 7.5w setting is for a pseudo triode mode.

All the confusion comes from amp manufacturers (who should know better) marketing cathode bias amps as Class A, but biasing methods are independent of operating class. Apart from one or two exceptions, most push pull amps using two, four or six tubes are Class AB.

The Blackheart website says the amp is pull pull class A.... I don't know that much about the difference between classs A and AB, besides the fact they sound quite different. Here's the link.
http://www.blackhearteng.com/bh15h.html

[DeanEVO_Dude]

This discussion seem like the "Never Ending Song" from Sharri Lewis show...

Anyway, as I understand class a/ab, that refers to how the tubes are biased. For example, a class a is biased in the "middle" (50%) of its operating range so that the signal can go all the way positve and negative. In the case of a push-pull pair of tubes, both tubes "conduct" both sides (neg. and pos.) of the signal (guitar note(s)) all the time. These amps can have tubes in a push-pull pair(s), single-ended, or in parallel (Gibson made an amp in the '50s with 2 6V6 tubes in this configuration, about 12 watts).
In a class ab (must be a push-pull pair), the tubes are biased anywhere from 10% to 30% of their range. One tube can amplifiy the positive side of the guitar signal 100%, the other tube is "shut off". As the signal pass to the negative side, the first tube (pos.) can only conduct between 30% to 0% (shut-off) so the second tube takes over and can amplify the negative side of the signal, that is where the Phase Inverter comes into play. This is why AB amps provide more power output (22 watts on the Bugera V22 versus 15 watts on the Blackheart).

I just love discussions like this... everyone has their take on which is best. If you want more power (watts output) with more power amp headroom, AB is the way to go, usually with a looser bottom end. If you want the tighter botom end and overdriven power tubes without the super-loud volume, class a is the way to go. These are not stone-written rules, but general guidelines.

I hope that this is clear as mud! LOL
Cheers!

[tunghaichuan]

The Blackheart website says the amp is pull pull class A.... I don't know that much about the difference between classs A and AB, besides the fact they sound quite different. Here's the link.
http://www.blackhearteng.com/bh15h.html

Many amp manufacturers call their Class AB, cathode bias amps "Class A." Mojo sells.

Here is a pretty good explanation I think:

http://www.aikenamps.com/VoxAC30classA_2.html

[DeanEVO_Dude]

Many amp manufacturers call their Class AB, cathode bias amps "Class A." Mojo sells.

Here is a pretty good explanation I think:

http://www.aikenamps.com/VoxAC30classA_2.html

Very good post and link. Prety straight forward.

Cheers!

[guitarmadman85]

Many amp manufacturers call their Class AB, cathode bias amps "Class A." Mojo sells.

Here is a pretty good explanation I think:

http://www.aikenamps.com/VoxAC30classA_2.html

That makes sense.... I just wish the way the manufacturers presented it was a little more straight forward.