Originally Posted by eurotubes

August 2007: Here is the latest on the screen grid resister problems with the XXX and now the JSX amps.

The XXX amps can use either a quad of 6L6's or supposedly EL34's. For the first two years of XXX production my customers ( a little over three hundred of them ) were all using the JJ E34L's because they sounded so good in these amps and there were no problems of any kind. About two years into production PV started using sub par screen grid resisters and players started having problems using the E34L's and even standard EL34's. PV made a design change in late 2004 going to 700 ohm SG resisters but using the E34L's is still something we do not recommend because we have had a couple customers now that have blown SG resisters in the new XXX and JSX amps with the E34L's.

PV has of course blamed the JJ E34L saying it's the problem but I happen to see it another way. I retube hundreds of Marshall, Mesa, Laney, Ampeg, Crate, Engl, Bogner, Carvin, Gibson, Hughes & Kettner, Orange, Rivera, Traynor and VHT amps just to name a few and none of these amps have any problems what so ever using the E34L's so I think this speaks for it's self...

PV can not tell you by serial number if your amp has the upgraded SG resisters but it seems to be moot, because there are still problems with the new amps.

If all of this is too much information, the bottom line is that I do not recommend using E34L's in the XXX or JSX amps. In other words use at your own risk!! This is a shame because the XXX and JSX amps sound great using the E34L's.

These amps sound great using the JJ EL34 and Peavey has finally taken time to listen! They have swung a deal with JJ and a lot of the new JSX amps are coming straight from the factory with JJ EL34's. Another option is running the JJ KT77's in the XXX and JSX amps. These tubes do not draw any more current than EL34's do so no resistor issues and they sound great with a big chunky low end and a very harmonically rich mid and high end.

If you do want to run the E34L's and run the amp hard ( who doesn't ) then I would highly recommend having the SG resistors swapped out for good high quality 700 ohm 5 watts wire wound or sandblock resistors ( not parts supplied by PV ) which any decent tech can do for about 50.00 and then you will have piece of mind about this.

Back in August of 2000 I modified a 5150 to run a pair of KT88's and a pair of E34L's at the same. This amp was showcased at the first North West Peavey gathering ( Jam, party and Micro Brew celebration for Peavey players ) which I hosted in late 2000. The news about this amp pictured on my front page traveled fast and when Peavey heard about this they said "This can and will not work. The amp will blow up!" Well this amp has been played about every other day now for almost four years and it gets ridden VERY hard and all the components other than the bias circuit including the 100 ohm screen grid resisters and transformers are stock so this is testament that it's not so much the value of the screen grid resisters, it's whether or not they are quality parts!