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-   -   EAR 859 questions (http://www.diyaudio.com/forums/tubes-valves/27132-ear-859-questions.html)

nonos 29th January 2004 08:46 PM

EAR 859 questions
 
Hi,

I am new guy in this forum. I am from Hungary and my english is wrong, sorry.


I heard a lot the Paravichini EAR859 amplifier. I would like to build this amplifier. I found the schematic in the web, but I have some question.
What is the correct value of the output transformer?
What is the correct voltage values on the power transformer?

Can anybody help me?

analog_sa 29th January 2004 09:43 PM

Posting a link or the circuit itself will certainly help. From what i remeber though, EAR often use custom made outputs with extra FB and cathode windings so finding a replacement won't be trivial.

No need to excuse your English - very few of us speak any Magyar at all - in fact i can only think of Frank :)

contaxchen 30th January 2004 03:23 AM

Hello,
Why not EAR834? They got the schematics for this amp for sale. You can use google to search the this schematics. There is a guy selling this for $5.
I haven't find any schematics for 859. If you find one, I am interested to take a look too. I agree with the first reply that it's hard collect the parts for EAR. :whazzat:
Yeah... If you use the same quality power and output transformers, the cost will be amazing!
I just got my EAR 834 fixed. It sounds more bright and soundstage shrinked after I replace its crappy cathode caps from elyctic to medallized polyester. But, definition increases. We can discuss a little bit further if you want.
lhchen

contaxchen 30th January 2004 03:28 AM

Hello again,
One thing more, EAR uses CGW FP series resistor for output tube cathode. They erase the brand, but I still find correct series by comparing stuffs over internet.
I've tried to use dale wirewound resistors, the result is not good. It sounds very metal!
lhchen

Vortex 30th January 2004 09:01 AM

EAR 859
 
Hi nonos (szia) :)


I also have the EAR 859 schematics, not bad...

why don't you try to design some kind of 2A3 class-A ?

they are sounding according to lots of tube-interested forum reviews superior to another triodes, it even beats the classic 300B.

Directly heated triodes have an issue regarding potential difference between the heating and the cathode. Therefore it's better if the heating voltage keeps really small, with higher heating Ampers of course. The 300B needs a heating Voltage of about 5V while 2A3 only 2,5V.

(In Hungarian for you: maga a fütöfeszültség (egyenfesz.) potenciálkülönbséget okoz a fütöszál-katód két vége között. Ezért ideális, ha igen alacsony a fütöfeszültség, de magas a fütöáram. A 300B még 5V fütöfeszültséget igényelt, míg a 2A3 már csak 2,5 V-ot!!! Nézd meg az adatlapjukat, http://www.jj-electronics.sk )

Check this out, a nice Class-A with 3 smaller feedbacks designed for 2A3 tubes.

http://www.wu-wien.ac.at/usr/h00c/h0...ube/2a3sch.gif

I also have some other Class-A schematics (they don't really differ from that all) with/without any feedback, if interested, visit http://www.hificity.hu/forum.php -> Audiofil -> Csövesek ide! (by Eperkutyus, that's me) :) It's a good forum by the way, but too few resources ... so I've just registered here, too.

Output transformers of very high quality will be made in hungary by http://www.hmtrafo.hu according to your needs. They make classic EI core designs, toroid isn't very acceptable for Class-A).

Keep up the good work and let me know of anything !
:)

Vortex 30th January 2004 09:28 AM

Correction
 
oops I mis-translated something ...

WRONG:
"Directly heated triodes have an issue regarding potential difference between the heating and the cathode."

GOOD:
"... potential difference between the two ends of the heating-wire-cathode ..."

contaxchen 30th January 2004 11:10 PM

Hello,
May I have a copy of your EAR 859 schematics?
Could you send it by Email?
Thanks,
lhchen

Vortex 31st January 2004 04:15 PM

I'll put that paper onto the scanner next week and send it to you if you mail me at eperkutyus@hotmail.com !

Ciao.

Vortex 1st February 2004 09:02 PM

contaxchen!

Svetlana Project 33

This is not the EAR 859, but VERY similar to it, the same concept, same output tube... great !

contaxchen 2nd February 2004 03:46 AM

Hello,
Thanks for the message.
I just removed my ear834's cathode bypassing caps last week. To see if this can make the amp quicker and more difinition. Yes it is, but the sound stage is smaller and lost its EAR character! :whazzat:
Do you have any experience about upgrading EAR?
Thanks,
lhchen


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