• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

EAR 859 questions

Status
Not open for further replies.
Jump to Latest
N

nonos

Member
Joined 2004
#1
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?
 
#2
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 🙂
 
#3
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
 
#4
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
 
#5
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.

An externally hosted image should be here but it was not working when we last tested it.


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 !
🙂
 
#10
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
 
#11
EAR859 schematic

Hi,

Here is the EAR schematic !

I have everything for this schematic just the power and output transformer missing. because I have to the correct Ra value for the EL509 and the value of the power transformer .

I don't know the EAR834 but I will find it on the web.
 

Attachments

  • ear859_.jpg
    ear859_.jpg
    74.6 KB · Views: 2,937
#13
:cop: I'm sorry that we've had to remove the post of the EAR859 schematic. The reason is our uncertainty of it's copyright status.
If we can ascertain that it is "public domain" material, or if Tim deParavicini gives his permission, it will be restored. :cop:

It is certainly of great technical interest, and I certainly hope this can be resolved.
 
#14
Hi,

One of the MAJOR assets of TDP is that he knows exactly how he wants his iron....

While you can try out ETM, you'll only be just that lucky to make it work the way you should...

Lest of course you have the equipment to test it in full etc., etc....

In short, if you don't have a plotter to have the new tube's curves drawn, you'd still be working blind...

Cheers, 😉
 
#18
Only one tube is best! Triodes do not work good together in parallel.

Enhanced Triode Mode was discovered and well documented in a Ham magazine for which I can't remember. Does it work... yea pretty well. But again parallel and push pull... well that does not sound good.

Thanks
Gordon


J. Gordon Rankin
Owner and Chief Scientist
====== Wavelength Audio, ltd ======
High-End Audio since 1981
SET Tube Amplifiers, DACS & Preamps
http://www.WavelengthAudio.com


Vortex wrote:

What works in your opinion ?

So REALLY.

I would also be interested in your opinion on that EAR 859 "enhanced triode mode" - good and usable or not ?
Click to expand...


Cheers 😉
 
Status
Not open for further replies.
Top Bottom