whats up with my amp?

[ibanezdiehard]

could someone be nice enough to read this and give me an estimate of what my problem is?

i have a MARHALL JCM 900 SL-X 100WATT head, i run it through a MARSHALL 1960A cab. i have 4 effect pedals directly in line after the amp and then a noise suppressor and a BOSS SD-1. and 2 RG7s

After playing for 20 mins or so my guitar sounds dull as.
and the amp really hisses, not like it used to.
also when i kick my SD-1 or tap on the metal parts of the amp i can hear it through the speakers very loudly.

WTF is going on?

Cheers
Michael

[honky_tonk]

sounds like tube problems.....preamp most likley

[ibanezdiehard]

Originally Posted by honky_tonk

sounds like tube problems.....preamp most likley

so if i buy all new pre-amp tubes and get the amp re-biased with a new set of output tubes it should be fine?

[j.arledge]

yep new set of tubes should do it . i think it is more then likely a power tube though .

[carlos grijalva]

Show your problem to a tech.

[ibanezdiehard]

cheers
while i'm getting that done would anyone recommend changing from the 5881's to EL34's?

[wallie!]

err touching metal parts makes humming :S

ground wires perhaps? Maybe not ;P

[jim777]

Originally Posted by IBANEZDIEHARD

cheers
while i'm getting that done would anyone recommend changing from the 5881's to EL34's?

Everybody seems to be going with the JJ E34L's now. I'm not sure of the difference between the EL34's and E34L's though (I'm a straight 6L6 guy myself)

[ibanezdiehard]

Originally Posted by wallie!

err touching metal parts makes humming :S

ground wires perhaps? Maybe not ;P

thats what i thought aswell, could that be costly?

[red5]

I'd strongly recommend SED Winged C (not Svetlana) EL34s in the power section over JJs. JJs should be nice in the preamp of a SL-X.

However I think the problem MIGHT be caps and not tubes. However neither explains how if you touch the amp it makes noise - that leads me to think there is a possible short somewhere in the amp.

[ibanezdiehard]

Originally Posted by red5

However I think the problem MIGHT be caps and not tubes. However neither explains how if you touch the amp it makes noise - that leads me to think there is a possible short somewhere in the amp.

F#CK!

[Ant1981]

Originally Posted by IBANEZDIEHARD

cheers
while i'm getting that done would anyone recommend changing from the 5881's to EL34's?

NO! That would be a big mistake. 5881's are fuller and deeper and warmer sounding, the EL34's are a bit brighter, not as warm.

[ibanezdiehard]

Originally Posted by Ant1981

NO! That would be a big mistake. 5881's are fuller and deeper and warmer sounding, the EL34's are a bit brighter, not as warm.

Cheers, i won't do it then i play metal so bright is not what i'm looking for.

[wallie!]

fixing grounding wires isnt that expensive (the cost is in somebody doing the work) but its not good to have bad grounding wires, ive heard the odd story about a dad removing a kids grounding wires to fix a hum problem :S During a big storm the kid was electricuted and died ( i think his guitar was shonky and the ground wire also wasnt properly connected)

[red5]

Originally Posted by Ant1981

NO! That would be a big mistake. 5881's are fuller and deeper and warmer sounding, the EL34's are a bit brighter, not as warm.

I'm all for EL34s (and they are very much warmer than 5881s - 5881s are just bassier) but I'm thinking if putting 5881s in my SL-X just because they hold their lows.