Lectron JH50 Tube Bias
 

Hi, gang. This is my first visit to this site, so please be gentle. I have long had a Lectron JH50 tube amp, but when I moved recently I lost the diagram and instructions on how to set the tube bias. Does anyone have a copy of the tube bias instructions (hopefully in English!) that they can forward to me so I can set the bias without having to take the thing to a repair shop? Thanks so much!----Starsailor

(PS----When it's right, it sounds just HEAVENLY with my Magnepan speakers!)

Hi "starsailor"...

Did you ever receive the schematic regarding the bias adjustment?

I also need this information! ;-)

Sincerely
Nilau

No, I haven't had any reply but yours. A bit disappointing, even though I know this amp has not been very widely distributed in my country (the US.) I have had to guess at the the tube bias, but it STILL sounds wonderful....and that's the real goal, isn't it......? -----Starsailor

Re: Lectron JH50 Tube Bias
 

I sure wish that I did. You see, I wrote the English manual for the JH-50. :)
But my copy has long since vanished.

I was hoping to find a schematic of the JH-50 somewhere when I stumbled across this thread. Anyone seen a copy? Would it be in the Revue de l'Audiophile? Maybe #41?

The Lectron JH-50 is covered in #40 and #41.
Sounds great on ESL63s too, as does the Jean Hiraga 60.

Thanks Jacco! I'll have to get the Revue in CD.

The JH50 was amazing at its debut on the big 4-way horn system. Probably more the speakers than the amp. =)

The $65 for the Davidenko CDs are worth it, considering the many Francs transferred to France for the paper versions. I found the foreign annual subscriptions pretty expensive.

The EL34s in the JH-50 are biased at 25mA.
Either just with a DMM or sweeped with a tone generator and a scope, as preferred by the French-Japanese gent.