Herbert plate voltage ???

Les Zombie

Les Zombie

Well-known member
I retubed my herbert earlier this week with a new sixlet of ruby EL34BHT, i used a bias rite and i noticed my plate voltage was 370 to 380. Is that normal, i was under the impression that it would be in the 450 range. I use a furman AR-15 and it says uts at 120 on the voltage meter.
I biased my tubes at 35ma per tube or 70ma for the pair.

So im thinking maybe my amp doesnt have a high plate voltage or my bias rite could be broken, the bias rite had a new battery. Overall the amp sounds great with the new tubes.
 
The plate voltage on the Herbert MK1 should
be around 470 to 480 volt. Are you sure your
volt meter is ok ?

Best,
Peter
 
update- 5/2/14
i sent my bias rite back to weber and it was broken, they either rebuilt it or gave me a new one and now it works great. im thinking its new since my old one had some scuffs and looks a little worn. really good customer service.

once i plugged in the bias rite the voltage was in the 450 range and the tubes was too hot, they was at 44ma and i had to lower to 34ma.
the amp sounds great now and im happy.
 
If your not sure the meter is working correctly you could take a reading at the wall outlet to see of it is off or correct there.
You could also borrow one from from a buddy and see if the voltage matches your meter
 
I want to cover my ass and say that I knew that hahahaha!!!
It's still worth checking, every function on the meter could be off of the DC option is incorrect.
 
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