replacement speaker/amp repair help :)

figured theres enough guitar slingers…

I have had a marshall 8040 valvestate since about 1995, when is started playing guitar. It has been through the ringer, for sure.
The preamp seems totally busted, i dont know what happened there, just starting fading out over time.

But i use the power amp in for my podxt, and man, i love the sound of it. It really makes the tones come alive, imo… however, it seems that bass produces this shhhhhhhhhhhhhhhhhhh sound a bit… ill record it.

ok, i got a patch with alot of bass, it doesnt sound good but it shows what the problem is clearly:

ok i put the bass up even more to make it clear to everyone:

so, this noise is especially sucky when im playing a nice deep clean tone and i get this fzzzzzzzz sound underneath it (and no, its not bloody fizz – joke for the pod people in case you dont get it)

so my friend tells me he thinks the speaker is shot. What type of replacement should i get?

here are pics of my speaker

here are the only sites i found with info

8040 - This 40 Watt, 1x12, twin channel combo features an ECC83 (1 2AX7) valve in the Boost channel’s pre-amp section for authentic valve distortion. Contour, Reverb and an Effects Loop make this amp equally effective at home, on stage or in the studio. (mine is the 8040 on the top chart)…estate+ 8040/100/1

here I see mine is the lowest amp in the series to have a preamp “valve” pretty nice i guess – but since im only using the power amp i suppose theres no tube in there o well. maybe the tube died on my preamp? and i just need to get another????

any thoughts on this?

would be quite appreciated.

It’s hard to tell from the sound, without hearing the sound un-effected.

But, if it’s a constant buzz added to the sound that is normally clean then it could very well be the speaker. It could also be a bad solder joint in the amp.

If it’s the speaker then more than likely the voice coil has some loose windings. They will buzz and rattle at first, and this can happen even at low volumes. Eventually, the wires will break and the sound will stop…totally…like no sound at all. (sorry - I’m being funny). It’s not a totally blown speaker, but a speaker in the process of blowing.

Most of the time a loose voice coil happens because the speaker has been constantly overdriven. The voice coil heats up and that causes the glue that holds the windings on the cardboard tube to fail. The windings come loose and the buzzing starts. Eventually the windings can become so loose that they will rub in the gap, and that can lead to a quick no-sound failure.

This is different than a speaker blowing that just fries and stops working. That would be when the winding becomes totally broken.

Soyy, I didn’s address any of you other questions…got to go eat. :)

i should have made an unnaffected sample, but i put a compressor on it so you could hear it clearer, its like something is loose and shaking. which would make sense per what you said.

thanks for the ideas!

is this something i could fix myself???

Yeah, that sounds like loose windings on the coil (the heat actually makes the glue melt). It will be a slight buzzing at most volumes. The less harmonics in the original tone the more obvious the buzz will be since ther should be none with a sine wave type sound.

The only fixes are to get the speaker reconed or replace it. Reconing isn’t for almost anyone in the real world, and many reconing services don’t do a great job. I was lucky enough years ago to find Frank Lemmond in Charlotte, NC (Barefoot Drive). He and his wife did reconing out of their garage. They met while working for Altec-Lancing a long time ago. Both really knew their stuff. They were in their late 70’s in 1980 so there’s little chance her or she would still be around. There’s always a chance to miracles I guess. :)

I did a search and found a few links, totall picked at random. I know NOTHING about any of them.

I thought this was an intersting link in any case:

Also, ther’s a few speakers for sale on Ebay. Yours isn’t the log grean back 20 watt model. If you are playing bass through it you could look for a more robust speaker and not worry about getting a “replacement”. Those Celestions are pretty flemsy but sound great. There’s a universe of possiilities if you just need a speaker that holds up.…=Search

nah dont play bass through it but thanks for the links!

Probably an idiotic question but anyway: Have you re-tightened the speaker mounting screws lately? If not, does anything change is you do tighten them?

Probably the preamp tube’s shot and you’ll get it back with a new tube.

Quote (Mwah @ Nov. 23 2006,16:15)
Probably an idiotic question but anyway: Have you re-tightened the speaker mounting screws lately? If not, does anything change is you do tighten them?

Probably the preamp tube's shot and you'll get it back with a new tube.

the first thing i did was tighten the mounting screws :(

no love...

i would try putting a tube in but not sure if its hard or dangerous.

glad to know there are some pretty informed people here, even tho i dont use the n track ;)

thank you!!!!


THESE guys usually have a good selection of Celestion speakers at decent prices. Their service and delivery is outstanding as well.


I’ve got the exact same amp. Signed on the grill cloth by Jim Marshall himself in 1995.

It is my backup at the moment but it is a very cool amp.

I would try and replace the speaker with another Celestion to try and keep the sound the same.

If you can’t get that then I would go for Phoo’s suggestion of any 12" that fit the bill.

Btw - chances are that if you want to dive into the amp to replace that 12ax7 you might find that that was the reason for the gradual fade (not guaranteed tho’). Replacing the valve(tube) is not an issue at all. Unscrew the holding screws and the whole thing comes loose from the cabinet. Easy thing.

Good luck !


Btw, this might help if you ever need to take the amp to a tech to try and figure out how to fix something …


thanks for all of this help!!!

you guys are tops!