Why no single large power tube amps?

[tiktok]

I'm curious as to why I've never seen something like a tweed champ but with a 6L6 or an EL-34 in it (and a higher wattage speaker of course). Given all the other wacky things folks have tried, why not this? I suppose the THD Univalve can be configured to do this, but has anyone ever done a combo this way?

[RomanS]

Check out the EL34-Champ Plus from www.frenzeltubeamps.com - you'd have to build the tweed cab yourself, though...

[kludge]

Large single-ended output transformers are heavy and expensive, and Class A (all single-ended amps are Class A) means bigger power transformer requirements, too. Push-pull makes life a WHOLE lot more cost-effective. It's probably easier/cheaper to build a 15-20 watt push-pull amp with EL84 or 6V6 tubes than it is to build a 10 watt SE amp.

[JohnnyCrash]

Originally Posted by kludge

Large single-ended output transformers are heavy and expensive, and Class A (all single-ended amps are Class A) means bigger power transformer requirements, too. Push-pull makes life a WHOLE lot more cost-effective. It's probably easier/cheaper to build a 15-20 watt push-pull amp with EL84 or 6V6 tubes than it is to build a 10 watt SE amp.

Not at all.

My freak Champs have 10 or 15 watt output transformers and can run 6V6, 6L6, or EL34 tubes. Not very heavy at all.

A 10 watt single ender is just as simple as one with a "smaller" tube at 5 watts.

As far as the transformers, the output transformers really aren't that much more heavier... in fact, find a push/pull amp with any of the "big tubes" and the transformers are much heavier since they need to handle more current/etc.

And to answer your question tiktok:
Low watt single ended amps (5 or 10 watts) have not been very popular on the amp buying market "at large" for a long time as it is - it's a recent trend, in a way.

Through the 50s to the 70s headroom and volume for gigging use was the order of the day. Low watt Champs were reserved for kids and students on a budget. Of course these years AND here on TDPRI, folks are really starting to look for low watt amps for "home cranking".

So now, all of the sudden within the last few years, Gibson comes out with a new GA-5 and Epiphone comes out with their Valve Junior... even Fender's "one knob" low watt amps are push/pull EL84 driven 15 watt deals (Pro and Blues Juniors).

[TieDyedDevil]

Carr Mercury. KT-88.

[Poppatwang]

ADA Rocket. Single EL34. Uber-cool tone too.

[celeste]

I am not quite sure what you mean by "large" , I tend to think Bass amp when someone says large. This tube will get you about 140 watts while drawing about 500 watts at idle (2500V/200mA). The heater draws 18 amps for a total of 306 watts. Picture here. http://www.vt52.com/diy/myprojects/a...00/gm100_5.jpg . That is a 12AU7 next to it. Whole tube description here http://www.vt52.com/diy/myprojects/amps/gm100/gm100.htm . It will take a small power amp to drive it. It would be really " cool" , and really large and heavy. Perhaps even define impractical.

[JohnnyCrash]

Originally Posted by celeste

I am not quite sure what you mean by "large" , I tend to think Bass amp when someone says large. This tube will get you about 140 watts while drawing about 500 watts at idle (2500V/200mA). The heater draws 18 amps for a total of 306 watts. Picture here. http://www.vt52.com/diy/myprojects/a...00/gm100_5.jpg . That is a 12AU7 next to it. Whole tube description here http://www.vt52.com/diy/myprojects/amps/gm100/gm100.htm . It will take a small power amp to drive it. It would be really " cool" , and really large and heavy. Perhaps even define impractical.

HAHAHAHAHA!!

Good one.

It looks like a tube with elephantitis.

[Dacious]

The reason why is simple: a tube at spec limits will produce less power in single-ended (class A) than in a AB. More power is converted to heat in a class A power amp, and needs a bigger tranny to keep the tube/s conducting for 360 deg. Case in point: Champ uses the same power tranny to run one 6V6 in Class A@ 6watts, as a Princeton uses to put two into A/B at 12 watts.

[The Amazing Phil]

Well the Matamp C7 combo I use runs on a single octal power tube, and can run most octal power tubes in fact, no need to rebias, the speaker's a Celestion rated at 100watts, the amp is 7 watts, and the transformers are indeed impressive for the amps size.

I think the small amp is coming back because people are finally realising you just can't crank a big valve amp in a lot of situations without having the cops banging down the door. Even 7 watts can get anti-socially loud in an at home setting, and with a mic is quite giggable, and certainly great for recording.

It's a sad fact that you're not going to get the best out of a large amp in anything but a large venue, and even then, the developments in PA systems have rendered such setups not entirely necessary, although this has been touched upon and then some in another thread. Is there anything less tonally inspiring than a big amp on a tight leash?

[tiktok]

Originally Posted by Dacious

The reason why is simple: a tube at spec limits will produce less power in single-ended (class A) than in a AB. More power is converted to heat in a class A power amp, and needs a bigger tranny to keep the tube/s conducting for 360 deg. Case in point: Champ uses the same power tranny to run one 6V6 in Class A@ 6watts, as a Princeton uses to put two into A/B at 12 watts.

Right, but my point is how to get the single-ended class A sound of a Champ, but louder. Why not just use a more powerful output tube and output transformer as needed?

[TieDyedDevil]

Originally Posted by tiktok

Right, but my point is how to get the single-ended class A sound of a Champ, but louder. Why not just use a more powerful output tube and output transformer as needed?

Marketing, perhaps. You need a bigger output transformer and much heavier power-supply filtering, all of which adds cost and weight. (Kludge already addressed this...) Maybe the marketing guys feel there isn't a large enough demand for low-power amps at high price points.

Let's put it this way. You can get an 8-watt (switchable to lower outputs, down to 1/10-watt) Carr Mercury (comes with an EL-34, but you can switch power tubes; the only one I've ever played had a KT-88) for (IIRC) about $1,500 street price ($2,150 list). Is that a reasonable price? What if Fender did a similar design that you could buy for, say, $750 street?

Or approach it from the other direction... A quick look at EBay shows old Champs and Champ reproductions going in the $500 to $750 range. Are you willing to bump that up by a hundred bucks or so to eek out four more watts?

Designs work out the way they do at least partially based upon bang-for-the buck...

[Dacious]

You can have multi-tube, but single ended amps, where the tubes are in parallel on a single-ended tranformer. I think there was even an early Fender -1950's Harvard? - set up this way.

The problem is, two 6V6s parallel might get twelve watts at their maximum spec in single-ended config, with a fairly beefy power tranny. Whereas in AB1 you can get 20 watts out of a pair, with a slightly more expensive output tranny. Rightly or wrongly, put a 12 watter against a 20-watter for about the same dough, and most people will pick the twenty. There will also be a sonic difference. Small single ended-amps can get away with a little more distortion at the outer limits - bit po

[tiktok]

Originally Posted by TieDyedDevil

Or approach it from the other direction... A quick look at EBay shows old Champs and Champ reproductions going in the $500 to $750 range. Are you willing to bump that up by a hundred bucks or so to eek out four more watts?

In a world where guys will pay several hundred or even a thousand extra dollars to make a new guitar look like it's been beat to hell for thirty years, I wouldn't rule it out. People will also spend lots of money on magic tone capacitors, special tubes and whatnot.

In the end, I'd have to play it first. If it sounds better to me than the regular Champ, I don't care that another $100 buys me "only" four watts, but rather that it buys me a more desirable sound. And given that the majority of these small amps are never going to be played outside someone's home, who cares how much they weigh? If I'm willing to move an 80lb amp around for gigs once or twice a week, I'm willing to let a 30lb amp sit unmoving in my practice room for a few years.

[David Barnett]

http://www.guitar-engines.com/index.html

[Rob DiStefano]

Hmmm, now I think I need a Frenzel ....

[tiktok]

Originally Posted by David Barnett

http://www.guitar-engines.com/index.html

You definitely want to keep the tack in.

[TieDyedDevil]

Originally Posted by tiktok

In a world where guys will pay several hundred or even a thousand extra dollars to make a new guitar look like it's been beat to hell for thirty years, I wouldn't rule it out. People will also spend lots of money on magic tone capacitors, special tubes and whatnot.

In the end, I'd have to play it first. If it sounds better to me than the regular Champ, I don't care that another $100 buys me "only" four watts, but rather that it buys me a more desirable sound. And given that the majority of these small amps are never going to be played outside someone's home, who cares how much they weigh? If I'm willing to move an 80lb amp around for gigs once or twice a week, I'm willing to let a 30lb amp sit unmoving in my practice room for a few years.

I understand that. I wonder, though, how much the "cost-is-no-object" crowd contributes to the bottom line of the larger MI companies. I have to believe there's a reason that all of the larger companies cover a wide range of price points and seem to move a lot more lower-end product.

Anyhow, like I said... You can get just about anything you like, including higher-powered single-ended amps from smaller companies and boutique builders. Take a look at the Carr Mercury and the THD Uni- and Bi-Valve amps. Just don't expect it to be inexpensive: they're more costly to build and the potential market is smaller.

[RelicStrat]

Originally Posted by celeste

I am not quite sure what you mean by "large" , I tend to think Bass amp when someone says large. This tube will get you about 140 watts while drawing about 500 watts at idle (2500V/200mA). The heater draws 18 amps for a total of 306 watts. Picture here. http://www.vt52.com/diy/myprojects/a...00/gm100_5.jpg . That is a 12AU7 next to it. Whole tube description here http://www.vt52.com/diy/myprojects/amps/gm100/gm100.htm . It will take a small power amp to drive it. It would be really " cool" , and really large and heavy. Perhaps even define impractical.

That puppy could do double duty as a nice heater for those long cold Maryland nights too!

[celeste]

Originally Posted by RelicStrat

That puppy could do double duty as a nice heater for those long cold Maryland nights too!

this one does that pretty well. Can't use it in the summer.

http://i35.photobucket.com/albums/d1...CycloFront.jpg

http://i35.photobucket.com/albums/d1.../CycloBack.jpg

[RelicStrat]

Originally Posted by celeste

this one does that pretty well. Can't use it in the summer.

http://i35.photobucket.com/albums/d1...CycloFront.jpg

http://i35.photobucket.com/albums/d1.../CycloBack.jpg

Mad Scientist at work!

[OaklandA]

My Lil Dawg Champster will run an 6L6 (with a change in the rectifier tube as well)...and Jim will rig one with a larger transformer as well. So, to answer the original post...it's been done and can be obtained if you were so inclined.

[OaklandA]

Originally Posted by RomanS

Check out the EL34-Champ Plus from www.frenzeltubeamps.com - you'd have to build the tweed cab yourself, though...

Damn...that's saucy.

[David Barnett]

Originally Posted by RomanS

Check out the EL34-Champ Plus from www.frenzeltubeamps.com - you'd have to build the tweed cab yourself, though...

"This custom amp's design was "INSPIRED" by the classic Fender Deluxe 5E3, but in the end became much, much more. The sweet clean to warm overdrive tones this baby spits out are simply like nothing you've ever heard before!"

That's the caption for an amp with a bass-mid-treble tonestack and a master volume. I wonder which part was inspired by a 5E3?

[JohnnyCrash]

The Champ heads I build can run 6L6's or even EL34's.

Speaking of single ended/Class A amps...

I used my Hi-Octane Class A amp I built tonight at band practise. It runs on a single 6EZ5 power tube (with basically a JCM800 preamp section).

Through a 2x12" V30 cab stood on end, the thing was FREAKING LOUD. The othe