VH4 biasing - DIY video tutorial

  • Thread starter Thread starter duesentrieb
  • Start date Start date
Thank you very very much for this cool tutorial, Olaf!! Really appreciated!! :thumbsup: :thumbsup: :thumbsup:

Best regards!!!!
Raul.
 
Thanks for the video! I'm doing everything exactly the same... maybe my Multi-Meter is on the fritz yea? Maybe I'll pick up another one this weekend....
 
Olaf.... I noticed in your video... you have your red "Positive" lead hooked up to the middle wire of the transformer... and your other one is ran to either side... the pictures in the "tech corner" of Diezel's website show to do the opposite... correct? Is that why I may be getting the reading I am?
 
duesentrieb":3es0k76d said:
When reading the current it doesn't matter ;)
Click to expand...

Well don't you think reversing the leads could give you a "negative" reading perhaps? I 'm just trying to troubleshoot here, my VH-4 has always worked fine and I've put several different tubes in it, all with the negative readout, was just curious, thanks again for the video!!
 
duesentrieb, thanks for taking the time to record and post this!

I have biased my VH4 successfully before with a bias meter (with help of guys from this forum), but now this video makes me and others get how to do it this way too... very cool!

jan
 
Hello, i'm french, i ve got the VH4 amplifier.
and i have two questions....importants questions

The DMM it does not short circuit, connected like this?? (amperemeter have not electric resistance, isnt it?)

The same trimmer bias is used for both settings of bias?
 
pirloutt":ypunhg8e said:
Hello, i'm french, i ve got the VH4 amplifier.
and i have two questions....importants questions
Click to expand...
Bienvenue !


pirloutt":ypunhg8e said:
The DMM it does not short circuit, connected like this?? (amperemeter have not electric resistance, isnt it?)
Click to expand...
No, it should be a "good" though to have a low resistance.


pirloutt":ypunhg8e said:
The same trimmer bias is used for both settings of bias?
Click to expand...
The VH4 has just one bias trimmer for all powertubes - so you need a matched quartett when you replace them.
 
thanks for your quickly answer.

I've got a new question.

On the vidéo, what is the last measure, between the chassis-screw and the middle wire of OT(?) (=77Volt DC, isn't it?)
 
Thats the plate voltage - should be (depends on the age of your amp) between 450 and 480V.
 
hey guys,

bias is done, on my VH4.
The news powertubes are TubeAmpDoctor EL34. (TAD RT164 RÖHRE EL34B-STR QUARTETT)
The clean chanel is better, more clean.
Thanks for your answers.
 
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