• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

What *practical* SE amp design has the most output?

GuyNoir

GuyNoir

Hallowed State
Is there a DIY single ended amp that will put out in the neighborhood of 20-25wpc, while retaining the inherent sweetness of the flea powered pentode and triode configurations? A few weeks ago I did a search for an HO single ended, and came up with a few returns, but I can't seem to find anything now. I think they featured smallish RF tubes.

Thanks!
 
Register to hide this ad
Have you looked at SE 211 or 845 or GM70?

I have power transformers capable of these beasties but it will be a few years before I am building anywhere near that level..... I don't want to be crispy lol.....
 
seti said:
Have you looked at SE 211 or 845 or GM70?

I have power transformers capable of these beasties but it will be a few years before I am building anywhere near that level..... I don't want to be crispy lol.....
Click to expand...

I looked those up. Scarey stuff. I didn't make the connection that the iron would probably be prohibitively expensive. Not for novices either.

seti said:
..... I don't want to be crispy lol.....
Click to expand...

I used to change out 4cx25000 and 4cx250b's in our 100kw transmitter to save our engineer a 150 mile round trip. Even though the power was cut, it still scared the living bajeezus out of me.

Charles 1973 said:
Does SE parallel count?
This Musical Paradise MP 501 outputs 55 wpc for a reasonable $1,400 Brand New. It gets high marks from reviews I've read from the press and by owners.
Click to expand...

Nice lead, Charles, thanks!
 
Patrick Turner has designed and built several SE amps based on the 13E1, which can be operated with a relatively low plate voltage. Here is one of them.
 
6C33C, maybe?

Honestly, I don't believe (anymore) in a SET/SEP outputting 20+W of power. In my experience, they are just not worth the time and effort. But if you must burn yourself with a project like think, I think a 6C33C-based SET, or a 6C33C OTL will get you into that power range (15-18W SET, 20+W OTL)... The 6C33C is a "low" voltage (when compared to 21, 845 or GM70 based amps), but still it is a "no walk in a park" to build them: expensive (especially the OPTs due to high current requirements); produce a LOT of wasted heat (so chassis design/parts placement/mounting has to account for that); and so on... And did I mention how HEAVY the amps are?!?!

There are plenty of schematics available... Here are a few links:

http://www.bonavolta.ch/hobby/en/audio/6c33c.htm

http://www.borbelyaudio.com/adobe/15wse.pdf

http://www.mi.ru/~tube-art/6c33_amplifiers.htm


good luck!!!

PS: Another though just occurred to me: you can try building Kegger's KT88 SE/UL amp widely described here, and use KT150's instead of KT88... This will get you just under 20W...
 
Last edited:
GuyNoir said:
I looked those up. Scarey stuff. I didn't make the connection that the iron would probably be prohibitively expensive. Not for novices either.

I used to change out 4cx25000 and 4cx250b's in our 100kw transmitter to save our engineer a 150 mile round trip. Even though the power was cut, it still scared the living bajeezus out of me.
Click to expand...

100kw.... EEEeek!

That is the trade off for sure. Expensive and possibility of turning us into deep fried fair food.
 
You get more power from SE designs with higher voltage and parallelling output devices. I am not a fan of paralleling output devices, and I don't really feel the need to step up further than the octal power tube family like KT-88 in terms of voltages (500VDC would be around the max). I like my Kegger KT-88 SEUL, and for me it's the most straightforward and practical design in it's class.
 
Ah hell, thanks gentlemen. It sounds largely impractical (for me at least). I've not the money nor the skills to build one. Class A PP isn't bad at all, in light of this information. :D
 
seti said:
100kw.... EEEeek!
Click to expand...

I also "tuned" the transmitter on occasion. That was 25 years ago. To this very day, I still have nightmares of the transmitter running wildly out of control, spewing sparks and lightning like some kind of Tesla contraption. Still have dead air dreams too.
 
prelius said:
PS: Another though just occurred to me: you can try building Kegger's KT88 SE/UL amp widely described here, and use KT150's instead of KT88... This will get you just under 20W...
Click to expand...

Thanks for your work and links on this. I'll investigate the Kegger KT88 further...if just a pipe dream for now.
 
Actually I don't think a Parallel KT88 would be a bad amp, an you could build it
where you could pull the "Parallel" tubes out when you didn't need extra power.
(pretty straight forward and easy build as well)

I've built a couple Parallel SE amps and they've been quite nice here..
 
Kevin Kennedy built a good sounding SE amp some years back using paralleled 300B outputs; indeed, he even - briefly - sold them commercially (d/b/a KTA Audio, if memory serves).

Otherwise I would agree with the truism that paralleled outputs are probably better avoided.

I am no expert, though.
 
I wouldn't recommend build 845 based amp from scratch. But you can always buy one of made in China used amps and modify it. From the factory it will likely get you 10 real watts at best. But if you use Mosfet driver, you may get into 20-25W range with 845 tube. Good thing is that output transformers and high voltage supply will be already there, and you can concentrate on input and drive stages.
 
I think your approach is fundamentally flawed. If it's power you want, why torture yourself by insisting on SE? But do you really need the power? It would easier and safer to put your energy into high efficiency speakers.
Amps can sound very, very good without going above 10 watts.
 
I would agree with the previous post, FWIW.
But then, I am a 3.5 watt per channel kind of guy.

I listened to a few select tracks from the Black Crowes' debut album yesterday (the re-released CD with a couple of bonus tracks) -- and it was just superb. Plenty of cojones with SE 2A3 feedin' a pair of Duplexes.
 
Good for you, Mhardy! I get the impression that 2A3 is where it's at.

I agree with the both of you too. That realization started to dawn on me towards the end of the evening last night. I love my speakers dearly, but a pair of Tektons or Omegas would certainly be a less expensive route to more volume. And it's not like I can't keep my beloved speakers. In the meantime, I have an SMSL SA-36 Pro with a TPA3116 variant in it on the way. One fellow on diyaudio.com said he prefers it over his EL84 SE. We shall see.
 
Here's one...

Friend of mine is now working with a SE PPP 6V6 design good for 25 WPC. My initial listening session and other people's reviews have all been extremely favorable....I did plop in a couple quads of vintage smoked glass RCAs and they got even sweeter....:music:

 
analog addict said:
Friend of mine is now working with a SE PPP 6V6 design good for 25 WPC. My initial listening session and other people's reviews have all been extremely favorable....I did plop in a couple quads of vintage smoked glass RCAs and they got even sweeter....:music:
Click to expand...
I am not quite following on this Allan, you reference SE (Single-ended) and PPP (Parallel Push-Pull). Did you mean it is SE quad Parallel - or is it a combined SE (mid/high) with some PP also for Bass (Xformer underneath?) as in some console amps? :scratch2:
 
You must log in or register to reply here.
Back
Top Bottom