Preamp valve replacement advice needed

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Originally Posted by musicegbdf

Anything to report back ? I am looking to buy some preamp valves. MY JJ were starting to crackle and hiss so changed them to some soveks. The seem OK and are quiet .

I am just looking to get some for "stock" and curious what people find out ...

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I ordered the valves from Hotrox and they arrived the next day, so thumbs up for quick delivery, but i went on holiday that week so i havent yet had chance to replace them and see what they sound like.
Ironically the hum has since dissapeared (either that or my hearing has :) ) so the urgency to change them has gone.
I'll probably replace the Jmp-1 valves first to see what that does to the sound.

Ive now replaced both the valves in the Jmp-1 but havent been able to use the rig at gig volumes yet.
Both the valves replaced were marshall branded so i kinda think they're the original ones. :eek:

I used the rig on sat for the first time at volume and i gotta say the new valves have definately added something.
The amp has much more growl now, more presence and its like a totally different animal all together.
I cant believe how much difference there is consdering that most valve purist say the valves in the jmp-1 dont do much.

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Originally Posted by Bignorm

I used the rig on sat for the first time at volume and i gotta say the new valves have definately added something.
The amp has much more growl now, more presence and its like a totally different animal all together.
I cant believe how much difference there is consdering that most valve purist say the valves in the jmp-1 dont do much.

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I suppose another swapparoonie and some A/B .wavs are out of the question?

Dave.

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Originally Posted by ecc83

I suppose another swapparoonie and some A/B .wavs are out of the question?

Dave.

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Sorry Dave
The rig lives in the van, I only take it home for repairs.

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Originally Posted by Bignorm

I used the rig on sat for the first time at volume and i gotta say the new valves have definately added something.
The amp has much more growl now, more presence and its like a totally different animal all together.
I cant believe how much difference there is consdering that most valve purist say the valves in the jmp-1 dont do much.

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That's because they're valve purists, and presumably think that because the JMP-1 is a hybrid circuit with digital control that the valves are just there for show.

In fact the valves noticeably affect the tone - that's what they're for. Most of the distortion is provided by IC gain and clipping diodes, it's true - but then that's fed through a valve tone stage. The clean modes are almost all valve.

But if there's a *huge* change, it's probably because the old valves were knackered :).