Double EL84 Push-Pull supply

[analog_sa]

A truly enjoyable post Frank.
I still, however, prefer thinking that your turntable (and possibly the speakers) were responsible for the incredible sound. Just had a look at the curcuit of a more recent Jadis: paralled ECC83 driving 3x6550 per side. I am much more impressed with similar amps by Audio Research, at least their circuits are not so trivial. Maybe Jadis use very nice iron?

cheers
peter

[fdegrove]

Hi,

Thanks Cobato and Peter,

I still, however, prefer thinking that your turntable (and possibly the speakers) were responsible for the incredible sound.

While both the frontend and speakers were good and top notch at the time, the continuous popping of the KT88s finally forced Jadis to pull out their gear.

Patrick Wetli, the importer for Switzerland was forced to try some other big stuff he had (solid state and top of the bill in those days ) and I can guarantee you that it didn't come close, the magic was gone, perceived dynamic range was pancake flat and so on.

Just had a look at the curcuit of a more recent Jadis: paralled ECC83 driving 3x6550 per side

That's precisely my point, I too looked at the circuit and just couldn't believe what I heard....trust me, the JA200 is even worse technically.
It doesn't measure all that well, the top is rolling of gently but: it did make music in a magical way, go figure.
The phone preamp, also an Jadis was nothing more than a PAS circuit taken to it's limits and also had reliability problems as it turned out.

Maybe Jadis use very nice iron?

True, the xformers Jadis uses are indeed exceptional. feed the amps rubbish and you're still left with rubbish though.
While the ARC amps are much more complex in design they sound (well, at least some of them) impressive at first. They do wear of in the long run for I feel they're not musically correct...something's just not quite kosher as far as PRAT goes.

Just my POV, YMMV.
Let's just say that is just a case where old and trusted circuit topology was pulling it off against all odds.

Cheers,

[PTSOUNDLAB]

Hello Boys,

The DPP EL84 is a schematic wich have been published in a French magazine called "Led". I have build this amp (it was my first tube amplifier). The sound is very good. If you want some informations, contact me (ptsoundlab@aol.com).
You can see pictures or schematic on my site
http://ptsoundlab.free.fr
http://ptsoundlab.free.fr/secinfos/infos/infos.html

"Cordialement" (in french)

Pascal.

[PTSOUNDLAB]

Hi,

you can adapt the original schematic for having a class A 20W amplifier. You have the schematic on my site at:
http://ptsoundlab.free.fr/sectubes/s...indexschem.htm
the file is in jpeg or pdf, see "Double Push Pull EL84 Classe A 20W"

All transformers can be found in France at Magnetic store. I don't know the price for delivering in others countries but transformers are very very good and price is cheap.

http://ptsoundlab.free.fr/secinfos/adresses/adrmaga.htm

Cordialement.

Pascal.

[battradio]

You don't need new transformers ,look for used pa amps to find the power transformers or tube stereo receiver chassis to find power and output transformers .Look at junk stores or even ebay , I recently purchaced a 22 tube mono receiver with a power tranformer and one audio out that would be good 4 6BQ5'S for $30.00 US on Ebay