• 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.

Lectron JH50 Tube Bias

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Starsailor

Member
Joined 2006
#1
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!)
 
#3
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
 
#4
Starsailor said:
Does anyone have a copy of the tube bias instructions (hopefully in English!)
Click to expand...

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?
 
#7
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.
 
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