Marshall JVM players - I need some help

[QuarterTone]

Hi all,
I've been playing a Marshall DSL40C for over a year and just upgraded to a JVM210C which I bought used off of ebay. I mostly loved the DSL40C but wanted the more tones, better footswitch, dual EQ, and better onboard reverb of the JVM among other things. I'm mostly liking the JVM but I've got one problem with it and I plan on taking it to my local amp tech to get it fixed, but I wanted to run the problem by you folks first and make there is really an issue here or if I'm just doing something wrong!

The issue is I've got close to zero clean head room on the clean green channel. When I'm on clean green If I turn the gain up anywhere past 1 (yes ONE) I start getting plenty of break-up like I'm on a light overdrive channel. Moderate strumming will break it up quite a bit and anything other than very light picking will break it up too. Again, this is with the gain anywhere past 1 and in all positions of master volume from low to high.

So I assume that I'm right to think that this amp needs to go into the shop? I'm thinking bad tube or bias adjustment needed or something but I don't much about amp maintenance and would rather pay a tech to work on it.

 

[afjungemann]

I have a jvm410 and I feel like that is how it is with mine too but I would have to verify. I haven't touched the gain knob on the clean channel since I got it set to my liking.

 

[Piston Hurricane]

Sounds like your best bet is to start swapping pre-amp tubes, what is in it now?

 

[QuarterTone]

Sounds like your best bet is to start swapping pre-amp tubes, what is in it now?

Marshall branded ECC83's.

 

[Piston Hurricane]

Marshall branded ECC83's.

Folks claim the marshall branded 83s are either jj (red label) or chinese (gold label), when I pulled the red label and compared it to a jj I noticed the plates are different - same layout but the plate edges in the red are rounded while the plates in the jj are squared. I installed the jj 83s and lost alot of gain (DSL1c). that might be a good and cheap tube to start with - oem jj 83. You could also check into installing a eec81 for the first stage tube in that channel. Proper info should be readily available through marshall amps website - perhaps someone on this board as well.
I hope this is of some help