looking for 12AT7 / ECC81 phase splitter

Empee · 11th November 2009, 12:27 PM

Hello all,

I'm looking for a input/phase splitting stage for a PP amplifier.

I've got both halves of an ECC81 / 12AT7 available per channel.

The complete stage does not have to have any gain,
just a phase-split of reasonable-to-good hifi standard.

The output(s) of the splitter will go through caps to both halves of an
ECC83 to drive EL34's in their turn.

I've got a B+ of 300V

Has anybody got a schematic which I could use ?

Gracias,

Empee

Allen Wright · 11th November 2009, 01:02 PM

>>The output(s) of the splitter will go through caps to both halves of an
ECC83 to drive EL34's in their turn.<<

Why would you put a low power, low current ECC83 after a much higher current higher power ECC81?

Let the ECC81 drive the EL34's, and put any ECC83 gain stages BEFORE the splitter, not after.

Regards, Allen

45 · 11th November 2009, 01:11 PM

Quote:

Originally Posted by Empee

Hello all,

I'm looking for a input/phase splitting stage for a PP amplifier.

I've got both halves of an ECC81 / 12AT7 available per channel.

The complete stage does not have to have any gain,
just a phase-split of reasonable-to-good hifi standard.

The output(s) of the splitter will go through caps to both halves of an
ECC83 to drive EL34's in their turn.

I've got a B+ of 300V

Has anybody got a schematic which I could use ?

Gracias,

Empee

Use a cathodyne splitter. This has to be RC coupled at the input. The cathode load is made of 2 resistors: the self bias resistor + an additional load. The sum of the two resistances is equal to the anode load resistance.
Here is an example: 6F6 Amps

Arnulf · 11th November 2009, 01:12 PM

What Allan said.

Check out this page (section of phase splitters, more specifically on Long-Tailed Pair splitters).

Empee · 11th November 2009, 01:20 PM

Quote:

Originally Posted by Allen Wright

Why would you put a low power, low current ECC83 after a much higher current higher power ECC81?

Let the ECC81 drive the EL34's, and put any ECC83 gain stages BEFORE the splitter, not after.

Regards, Allen

Hi !

that would be because I'd like to try two SE amps which I already build
as one mono PP. So the ECC83 is already taken

I got one PP output transformer so I thought I'd give it a try....

Thanks !

Empee

11th November 2009, 12:27 PM	#1
Empee diyAudio Member Join Date: Sep 2006	looking for 12AT7 / ECC81 phase splitter Hello all, I'm looking for a input/phase splitting stage for a PP amplifier. I've got both halves of an ECC81 / 12AT7 available per channel. The complete stage does not have to have any gain, just a phase-split of reasonable-to-good hifi standard. The output(s) of the splitter will go through caps to both halves of an ECC83 to drive EL34's in their turn. I've got a B+ of 300V Has anybody got a schematic which I could use ? Gracias, Empee

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11th November 2009, 01:02 PM	#2
Allen Wright R.I.P. Join Date: Dec 2001 Location: Schaffhausen Switzerland	>>The output(s) of the splitter will go through caps to both halves of an ECC83 to drive EL34's in their turn.<< Why would you put a low power, low current ECC83 after a much higher current higher power ECC81? Let the ECC81 drive the EL34's, and put any ECC83 gain stages BEFORE the splitter, not after. Regards, Allen

11th November 2009, 01:12 PM	#4
Arnulf diyAudio Member Join Date: Feb 2009	What Allan said. Check out this page (section of phase splitters, more specifically on Long-Tailed Pair splitters).