Rev Blue and Twin Jet Plate Voltage and Bias

Simon Dorn

Active member
Hi! Here's some info regarding the plate voltage, bias and tube brands used by Bogner in the Rev Blue and Twin Jet. I couldn't find it anywhere, so i asked them directly. This is what they replied:

"We use a signal generator with a scope and set for min crossover as you have all the factors at once and each set is usually a bit different, varies, even if it's the same brand.
Also depends how exact the innput AC voltage is set, aassuming it's exactly what your amp is built for, then at about 485-500VDC something like 34-36 mA.
Twin Jet with KT88 runs at 550VDC something like 44-46mA
Some tube brands might not withstand this, we use the Ruby KT88's and EL34's as well as JJ EL34's with no problems."


I think this might be useful for some, so i thought i share.

Regards and keep on rockin'!
Simon
 
EHX branded tubes are also heavy-weights to high pV. I've used them happily and successfully in the TJ and Rev.2

Peace.
Mo
 
Just re-tubed a TwinJet with a matched quad of JJ KT-88s from thetubestore.com (great place!!)

pV was kissing 550 at idle
Biased the tubes at 42mA-45mA range
Sounded brilliant.

The new JJ tubes are actually beautifully made - definitely a step up from the older ones - they're way beefier, heavier, apparently more lead in the glass, and overall, their tone is exquisite. They can take a shit kicking too. I'd not bias any tube past 40mA on an amp unless under strict parameters given by the manufacturer. The tolerances would be pushed hard at those levels, and furthermore, the KT88s tend not to sound too great when they're highly charged - they're better bottles working within their "comfort zone". Unlike EL34s, KT88s don't sound very lovely when they're pushed to saturation. So - IMHO - always best to give them *some* heat - but not lighting bolt jolts.

YMMV.

But the TJ sounded fucking glorious once the glass was installed and set. Period.

EDIT: Note the table below (handy bit of intel for Folks in general....)

 

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+1 here ;)
I just ordered 8 JJ ECC83S (six for the amp and two spares) to compliment the JJ KT88 in the power amp of my Twin Jet.
The China 12ax7B are simply not reliable enough...at the least the ones i have...
Which preamp tubes do you run with your JJ KT88s?
Btw. I do like my Twin better than my Rev Blue...

Regards,
Simon
 
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