EL34 SE, direct coupled

nesha · 14th April 2007, 12:42 AM

Hi everybody.It is obvious what schematics I m looking for.Tubemaster s el84 se direct coupled and Morrison 2a3 are both interesting , but el34 and it s 5 watts are a temptation I can not ressist... but to look for.Thanks .

Eli Duttman · 14th April 2007, 01:04 AM

You say you like the DC coupled EL84 circuit, but want more power. EL34s are harder to drive than EL84s. OTOH, 7591s are as easy to drive as EL84s, a fact that Fisher and Scott took full advantage of.

What Fisher and Scott did, you can do too. 7591s are in production at Saratov and Jamona.

nesha · 15th April 2007, 08:35 AM

Thanks, I ll try to learn obout 7591 . 813 transmiting pentode is very interesting too, representing easy job for driver tube and could give 20 w in triode mode.BUT ... a good output tranies of that power are too expensive , and I don t have directcoupled schematics for it. I m newbie , so I can t calculate desired cirquit ...yet. Thanks again.

Empee · 11th January 2008, 10:33 AM

Hi !

Sure, EL34's are harder to drive than EL84's,
but can't it be done with two halves of a ECC81 parallel ?

I'd really like a schematic for a direct coupled EL34 SE using
ECC81 driver, but is it possible ?

Cheers,

Empee

Empee · 12th January 2008, 11:18 AM

c'mon, guys ?!

nobody on a direct coupled EL34 ?

cheers,

Empee

<edit:>

Ok, so I found this....

That cap isn't in the signal pad

(or is it? someone once told me;
"anything in there affects the signal")

but it seems direct coupled, and using 12at7 & el34

will this be any good ?

Cheers again !
:-)

Empee · 12th January 2008, 11:58 AM

OK, sorry for the above post...

I looked closer and saw my mistake;
half #1 of the 12AT7 is actually driver stage, coupled via
the cap, half #2 of the 12AT7 is for distorsion purposes...
so no good for my apllication

However,
I found attached shematic !

Now this IS dc-coupled but it uses a 6H23 tube, wich would be
close to an ECC88...

can this schematic be re-worked for a 12AT7 / ECC81 ?

Cheers,

Empee

Empee · 14th January 2008, 10:26 PM

really nobody on a EL34 SE, driven by a ECC81 ?

can't it be done ?

jnb · 14th January 2008, 11:42 PM

Why do you want direct coupled, to avoid the capacitors? What about C3, C4?

Empee · 15th January 2008, 10:21 PM

Well,

not to completely avoid caps,
(I do not think it's possible)
but surely to minimize their effect by reducing their number...

So far I only found one schematic using an 12at7/ecc81,
but this one isn't DC coupled...

still a nice schematic, I think

Cheers,

Empee

jnb · 15th January 2008, 10:47 PM

I think being able to use smaller caps is good because they can be film and not electrolytic. Your latest schematic looks better in this one regard.

11th January 2008, 10:33 AM	#4
Empee diyAudio Member Join Date: Sep 2006	Hi ! Sure, EL34's are harder to drive than EL84's, but can't it be done with two halves of a ECC81 parallel ? I'd really like a schematic for a direct coupled EL34 SE using ECC81 driver, but is it possible ? Cheers, Empee __________________ In the end, all is good If it's not good, it's not the end

14th January 2008, 10:26 PM	#7
Empee diyAudio Member Join Date: Sep 2006	really nobody on a EL34 SE, driven by a ECC81 ? can't it be done ? __________________ In the end, all is good If it's not good, it's not the end

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14th April 2007, 12:42 AM	#1
nesha diyAudio Member Join Date: Jan 2007 Location: Beograd, Serbia	el34 se,direct coupled Hi everybody.It is obvious what schematics I m looking for.Tubemaster s el84 se direct coupled and Morrison 2a3 are both interesting , but el34 and it s 5 watts are a temptation I can not ressist... but to look for.Thanks .

14th April 2007, 01:04 AM	#2
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	You say you like the DC coupled EL84 circuit, but want more power. EL34s are harder to drive than EL84s. OTOH, 7591s are as easy to drive as EL84s, a fact that Fisher and Scott took full advantage of. What Fisher and Scott did, you can do too. 7591s are in production at Saratov and Jamona. __________________ Eli D.

15th April 2007, 08:35 AM	#3
nesha diyAudio Member Join Date: Jan 2007 Location: Beograd, Serbia	Thanks, I ll try to learn obout 7591 . 813 transmiting pentode is very interesting too, representing easy job for driver tube and could give 20 w in triode mode.BUT ... a good output tranies of that power are too expensive , and I don t have directcoupled schematics for it. I m newbie , so I can t calculate desired cirquit ...yet. Thanks again.

14th January 2008, 11:42 PM	#8
jnb diyAudio Member Join Date: Dec 2006	Why do you want direct coupled, to avoid the capacitors? What about C3, C4?

15th January 2008, 10:47 PM	#10
jnb diyAudio Member Join Date: Dec 2006	I think being able to use smaller caps is good because they can be film and not electrolytic. Your latest schematic looks better in this one regard.

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