Noisy JSX Ultra Channel V2 Recommended V2 12ax7

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fuzzylogic8250
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Noisy JSX Ultra Channel V2 Recommended V2 12ax7

Post by fuzzylogic8250 » Sun Apr 25, 2021 4:11 pm

Hey people. This is my first post. I’m happy to be here.

I got great deal on a JSX. A true pawn shop prize. The amp is in great condition and fully functional. While I’m mostly a blues and classic rock guy I cut my teeth on 80s metal and I am a huge fan of Joe Satriani. While I bought this amp on a fluke after pairing it with a decent cab with v30s it has become my main amp. The amp is very quite and tone full on the clean and crunch channel. I love the Ultra channel with its thick gain structure

The ultra channel is becoming more noisy and maybe a little hum. It’s to the point where it effects the tone. Compared to the crunch channel it produces a lot of extra noise.

I understand the V2 12ax7 position is dedicated only to the Ultra channel so I am thinking this tube is the source of the noise or at least the first place to start.

The tubes in the amp now appear to be the stock EH tubes. The amp is a 2007 model.

What’s a quite (low noise) current production tube or NOS tube that would suite the V2 position that would be nice and quite while preserving the gain structure?

I am also open to tube suggestions in general because I am looking forward to replace all the tubes because my other amps are vintage or modern vintage. I mostly use NOS tubes but any current tubes in production recommendations would be highly appreciated.

Anyway, I love the JSX and I have many questions about it so I will be posting more later.

Please chime in.

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Enzo
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Re: Noisy JSX Ultra Channel V2 Recommended V2 12ax7

Post by Enzo » Tue Apr 27, 2021 12:03 am

First, just swap positions with another tube. Does the noise change? If it does the tube was the cause but if not, the tube is innocent.

Now about "lower noise" tubes. ALL tubes vary widely A Brand X low noise tube individually can be more noisy than a particular plain old Brand Y tube.

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JamesPaul
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Re: Noisy JSX Ultra Channel V2 Recommended V2 12ax7

Post by JamesPaul » Tue Apr 27, 2021 2:07 am

I love my JSX 212 combo and I should've acquired it much sooner than I did. I just wish it didn't weigh like a battleship.

If you do determine this issue is a noisy tube, I have had good luck with the Tung Sol 12AX7 being a low noise tube.

Regarding general JSX questions, if you haven't seen it yet, the Tech Tips/Tricks/FAQ- READ THIS FIRST! Topic does have a JSX FAQ post:

viewtopic.php?f=19&t=2464#p20314

A lot of what applies to the Triple XXX Clean and Ultra channels will also apply to the JSX. The Triple XXX was the starting platform for the JSX and the goal was to replace the Triple XXX Crunch channel with the Classic 50 Lead channel. At one point, Chris Goodwin (I think) posted pictures of Joe using the prototypes which still had the Triple XXX head shells and cabinets.

Joe with the prototype JSX's
Joe with the prototype JSX's
joe&xxx2.jpg (23.9 KiB) Viewed 1382 times
Enzo wrote:I find if the amp is working, that is a good point to stop fixing it.
James Paul's Peaveys
Decade, Classics, Ecoustic, Windsors, VYPYR, Triple XXX, XXL, VKs, Bandit, JSXs, VIP, Piranha and a Penta.

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