Finished! Kegger-designed SE EL84 monoblocks

That would be a good question..

As I never got to hear the amp, Redboy built it.. ;)
(I've built similar, but not this exact amp setup)

If I had to wager a guess, it would be quite similar,
(just different in output transformers that he used)

It is the same basic design, which I've used on even
larger tubes up to an KT88/KT90 just different drivers.
(KT88 I used a 6EJ7 in the same fashion as the 6AU6)

The KT88 amp I like quite a bit, I'll eventually build an
all out version with quality caps an output transformers.
(more then likely get the large Edcor outputs for that 1)

Single ended ultra linear is defiantly one of my favorite setups.. :music:
(I've built at least a dozen different tube lineups like this circuit)
 
Kegger,

That is one clean design. You do "get" SE as that is simple and elegant as it should be. And finding a use for 6AU6's .. awesome .. I have enough 6AU6's to make 10000 of these amps.

However I am not worthy enough to do the cosmetics as well as Redboy. I figure I am at sturdy cardboard box stage as far as a chassis. :)

Good work both of you!!

Frannie
 
Thanks Frannie, ..

I like finding uses for tubes that don't get much, especially if there cheap an plentiful! ;)
(do try out the 6EJ7's sometime as well, and this "basic" circuit scales pretty well there)
 
buglegirl said:
Kegger,

That is one clean design. You do "get" SE as that is simple and elegant as it should be. And finding a use for 6AU6's .. awesome .. I have enough 6AU6's to make 10000 of these amps.

However I am not worthy enough to do the cosmetics as well as Redboy. I figure I am at sturdy cardboard box stage as far as a chassis. :)

Good work both of you!!

Frannie
Click to expand...

Hey Frannie, don't fret to much about cosmetics. Ask Kegger to post pix of the amp he made in a signal generator chassis. It is wicked cool.
 
Hiya,

I saw that and that is more what I was getting at. I was more talking about the fact living in a Baltimore Row house that I don't have the ability to do much fabrication even if I could convince myself that I could. So its creative reuse of what I have on hand which in its own way is awesome. And I am sure a lotta people could fret about that RedBoy chassis build as that is pretty damm creative and sophisticated at the same time.

Kegger I also have a pile of 6EJ7's .. looks like fun times await.

Frannie
 
Interesting thread here.....I'm thinking of maybe a SETriode-strapped 6BQ5/EL84 project design for my 6112HS James outputs I bought last year!

Regards, Ron
 
It appears the planning stage is complete on a 6JB5 PP scratch built amp. This is a compactron tube used in the vertical deflection circuits of tv's. These will be fed by a 6BL8 and powered with a 5AR4.

Hopefully this is finalized in the next week. The Kegmiester is a busy man.
 
These amps were on long-term loan to member ejfud, and I just brought them home again a couple days ago. Man, it's good to have some single-ended sound in the house again!

I know Gary put quite a few hours on them. He rolled a few different tubes through them, and used them with a couple different preamps, and several different speakers behind them. I'm hoping he might drop in to share his thoughts... :scratch2:
 
I'm here.

These amps saw lots of play in my system.

Preamps used were tube based, a buffer and a LDR based attenuator. All sounded great, but in the end I felt like the LDR let the sound of the amps shine through the most.

Speakers were many single driver baed from the collection, a RayW design and the Saba Resonating cabs. The more efficient the speakers the better these amps sounded. Incredible detail, wide and smooth across the audio spectrum.

Thanks for the loan of these superb amps it was appreciated.

Have you tried any of the el84's I sent home yet?
 
Thanks, Gary!

I haven't tried the tubes you sent back, aside from the ones that were in the amp when they came home. Were those yours or mine? I honestly don't recall what I had in the amps when they went to your place.

Hey, did these get any play time on the 604s?
 
Great amps - they're my daily mains. I've got plenty of plans for other amps, but these are perfectly satisfying in the meantime.

I sometimes wonder what an "all out" build of this circuit would sound like.
 
Still one of the nicest looking SE EL84 amps I've ever seen.:thmbsp:

Redboy said:
I sometimes wonder what an "all out" build of this circuit would sound like.
Click to expand...

Not that there's anything wrong with UL, but most of the SE EL84 variants I've heard here are running triode strapped. They sound pretty darn good, given the modest components and power.

jeff
 
I have a question about this circuit...The output cathode resistor bypass cap shows a value of 330uf, is this correct? Also why are there two resistors on the cathode and only one is bypassed?

thanks...

attachment.php
 
The 330uf is correct, anything from say 180-470uf is what I would use.

And the 2 cathode resistors are so you can can calculate current across
the 10ohm resistor and no bypass on it so you get a smidgen of feedback.
 
OK, thanks for that...I have an RH84 that sounds OK but I now have a pair of 5K Edcor UL OPT's and plan to rebuilt to your circuit using the 6BK7 as mentioned your eariler post. Is this still your recommendation or is there something different I should be looking. I like the EL84's but I'm looking for the best sound I can get. My speakers are 96db and are ok with my current setup.

thanks
 
Yep that's just fine, the 51k plate load can be lowered for using the 6BK7, down
to say 39k, and take the cathode resistor with it down to 390ohm, anything say
39k to 51k and keep that cathode resistor matching it, like if went 43k make the
cathode 430ohm then. (the lower you make them the more current, experiment)

The nice thing about wiring it for an 6BK7 is there is a whole host of other tubes
you can roll in like 6DJ8 and 6AQ8 plus many in between with all the same pinout.

Anyway, best to experiment a little and find your favorite sound. (very flexible) ;)
(I'd drop the FBK resistor if dropping the plate load as well, like say 200k there)

--
Something along the lines of this...
attachment.php
 

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OK, thanks for the information, I'm just to the point now where I know enought to really be dangerous...:thmbsp:...I'll start a new thread when I get the rest of my parts and start to make some noise.

thanks...
 
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