Good tube DIY for EL34's?

Rino odorico · 20th November 2002, 02:51 PM

Hey all, well I have been in the basement reading all about how tubes work...still need to learn more :>) Currently I'm restoring a console type amp with EL84's. But I think I'm almost at the point of building one...or two :>)

My question is, I have a box full of Luxman EL34's (never used and still in boxes) as well as a box full of ECC83's (never used). I feel I should be doing something with these. Anyone know of a good design to build? Nothing large, just a simple but awsome sounding amp to drive a pair of 2-way bookshielfs, DIY of corse.

Man are tubes fun!

Rino Odorico

SY · 20th November 2002, 04:22 PM

It's not the tubes which will determine the direction of a design, it's the iron. What kind of OP transformers do you have access to?

Joel · 20th November 2002, 04:44 PM

EL34's? You could build some version of a Dynaco ST-70.

Rino odorico · 20th November 2002, 05:45 PM

As far as what trans. I would use, well I don't own any at the moment. But...I live in South Western Ontario so Hamond Trans. would be very easy to get. Actually, my parents live in the same town they are produced.

How about a OTL type of amp...good/bad?

Rino Odorico

fdegrove · 20th November 2002, 05:56 PM

Hi,

In case you want to put your tubes to good use:

The CR syblos are there to indicate NFB loops of which there 3 local ones and 1 global.

As far as the PSU goes you could use a tubed or one using silicon diodes.

I'll mail the daigrams with examples to Dave since I can't seem to attach a file.

Cheers,

SY · 20th November 2002, 06:02 PM

OTL with EL34s? Naah. Bad choice.

Keep it simple. Get a 6600 ohm p-p OP anchor, use a simple input circuit (like a triode voltage amp direct coupled to a long-tail inverter- the Eico HF87 circuit is a classic), use a simple power supply. I'd avoid the silicone that Frank suggests- it's too jiggly. But silicon rectifiers will work.

Joe Curcio's ST-70 circuit is a good one, too. I used his input stage and regulator to drive '34s wired as triodes with good success.

dhaen · 20th November 2002, 06:04 PM

Quote:

How about a OTL type of amp...good/bad?

Not with EL34's. Even in triode mode, they're quite high impedance.
Buy some nice Iron, and enjoy.

fdegrove · 20th November 2002, 06:10 PM

Sy,

Quote:

I'd avoid the silicone that Frank suggests- it's too jiggly. But silicon rectifiers will work.

That was your typical example of a Freudian slip.

Rino:

The two diagrams are sent off to Dave.
You'll need UL OPT for these to work as per the diagram but that shouldn't be a problem.

Cheers,

planet10 · 20th November 2002, 06:42 PM

Quote:

Originally posted by fdegrove
I'll mail the daigrams with examples to Dave since I can't seem to attach a file.

Frank, as requested -- being an IT guy i'd have thot not being able to attach pics would have frustrated you enuff to figure out what's wrong with your Windoz box (hey that might be the diagnosis right there -- sorry couldn't resist

)

dave

planet10 · 20th November 2002, 06:47 PM

Guess it would help if i actually attached the pic.

dave

20th November 2002, 02:51 PM	#1
Rino odorico diyAudio Member Join Date: Aug 2002 Location: Toronto, Canada	Good tube DIY for EL34's? Hey all, well I have been in the basement reading all about how tubes work...still need to learn more :>) Currently I'm restoring a console type amp with EL84's. But I think I'm almost at the point of building one...or two :>) My question is, I have a box full of Luxman EL34's (never used and still in boxes) as well as a box full of ECC83's (never used). I feel I should be doing something with these. Anyone know of a good design to build? Nothing large, just a simple but awsome sounding amp to drive a pair of 2-way bookshielfs, DIY of corse. Man are tubes fun! Rino Odorico

20th November 2002, 05:45 PM	#4
Rino odorico diyAudio Member Join Date: Aug 2002 Location: Toronto, Canada	What kind of trans. As far as what trans. I would use, well I don't own any at the moment. But...I live in South Western Ontario so Hamond Trans. would be very easy to get. Actually, my parents live in the same town they are produced. How about a OTL type of amp...good/bad? Rino Odorico

20th November 2002, 05:56 PM	#5
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	SHOEBOXES Hi, In case you want to put your tubes to good use: The CR syblos are there to indicate NFB loops of which there 3 local ones and 1 global. As far as the PSU goes you could use a tubed or one using silicon diodes. I'll mail the daigrams with examples to Dave since I can't seem to attach a file. Cheers, __________________ Frank

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20th November 2002, 04:22 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	It's not the tubes which will determine the direction of a design, it's the iron. What kind of OP transformers do you have access to?

20th November 2002, 04:44 PM	#3
Joel diyAudio Member Join Date: Oct 2002 Location: Brooklyn, NY	EL34's? You could build some version of a Dynaco ST-70.

20th November 2002, 06:02 PM	#6
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	OTL with EL34s? Naah. Bad choice. Keep it simple. Get a 6600 ohm p-p OP anchor, use a simple input circuit (like a triode voltage amp direct coupled to a long-tail inverter- the Eico HF87 circuit is a classic), use a simple power supply. I'd avoid the silicone that Frank suggests- it's too jiggly. But silicon rectifiers will work. Joe Curcio's ST-70 circuit is a good one, too. I used his input stage and regulator to drive '34s wired as triodes with good success.

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