Marshall Amp Gets No Sound

[slayer63636]

i have a marhsall valvestate 8200 and yesterday my brother opened it and took out the pre amp tube to look at since hes into that kinda stuff. anywho when he put the tube back in the amp will no longer give sound other than a loud hum. im thinkin its the tube he took out and put back in. can anyone help???

[crafty]

Did you reseat the tube in the right direction in the socket? Is it plugged all the way in? Is it glowing when the power is on? Are the itty bitty pieces of tungsten and copper rattling around inside the glass like a burned-out lightbulb?

[slayer63636]

no i havent seen it light up ill try it later today, as far as the other thing it dosent sounld like a light bulb when its burn out

[ansil]

you may have to place something around the tube to see it glowing.

they run the valve state pretty low ie the heaters. my advice is to turn it on and walk away and cut the lights off. no glow no go. next would be to check and see if you have filament voltage or if you have a spare tube on hand just go ahead and change it and see.

more than likely he swiped your tube cause his was dead. lol i would have done my brother like that but he is too stupid to use a screwdriver

lol no serious he is

[slayer63636]

i checked the tube and it golws REALLY LOW. is it normal for them to do that? ive seen a crate blue voodoo's tubes and those really light up. anyways its so dim you can barly see the light. ive gone ahead and ordered a new tube and untill then im stuck playin my little crate combo.

ansil-as far as my bro taking my tube i doubt it. he dosent play guitar or anything he just loves working with electrical stuff and like takin it apart to look at it.

Edited August 24, 2005 by slayer63636

[ansil]

i checked the tube and it golws REALLY LOW. is it normal for them to do that? ive seen a crate blue voodoo's tubes and those really light up. anyways its so dim you can barly see the light. ive gone ahead and ordered a new tube and untill then im stuck playin my little crate combo.

ansil-as far as my bro taking my tube i doubt it. he dosent play guitar or anything he just loves working with electrical stuff and like takin it apart to look at it.

←

ah ok man glad to hear it. if it glows real dimly then thats correct as they run a 12vheater on the valvestates.

actually the crates doesn't light up they have a small bulb or sometimes led behind them with an orange cap on it thats why the mirror is there to help reflect it so you dont' see tthe little booger back there. ho2wever it still glows a little brighter than the marshall but it uses a 6v heater

[slayer63636]

so then is it the tube or something else?

[crafty]

I'd take another look at the amp and ask him EXACTLY what he fooled around with when he took it apart. If you get the new tube in, go ahead and try it out, but I'd look for any loose parts or connections inside the amp before I took it to an amp tech.

The fact that the heater is glowing is good, but not necessarily indicative of a good/failed tube. I would be more suspicious that it's not the tube, though.

[slayer63636]

he said the only thing he touched was the tube. im gonna go and make sure evey thing is connected right and hopfull its just that cuz i dont want to take it to a tech, i dont have any money

[slayer63636]

ok, i checked it for loose connections and found nothing i also got a new tube in it and a new fuse and it still dosent work. i got some conatct cleaner on the solders on the transfromer and then relized that it was not the origanl one. its a cheap no name one that has a price tag for $25.49, the more i looked into it i noticed that it makes a loud hum when the amp is on. is it normal for it to make a loud hum? also how would i check to see if its still good?

[slayer63636]

its not the transformer. i went to a guitar center and they sent me somewhere else since they do not service amps but they are a "cetifed dealer". anywho im out of ideas on what it is. as of now im gonna take it to a tech unless anyone out there has any ideas.

[slayer63636]

atfer a closer look i realized that that there are two areas for fuese in the power amp. only prolbem is that theres nothing there. dose anyone know have a valvetate 8200 who is willing to look inside and tell me what kind it uses?

[slayer63636]

after looseing sleep and spending countless hours trying to fix it i decided to take it to a tech. i dont want to mess it up worse that it is right now.

[lmgash]

I am having the same problem with my valvestate (nosound except for loud hum). Did you ever get yours fixed?

[curtisa]

Just had a quick look at a schematic of an 8100 (OK, so it's not the same model, but I'd be reasonably confident that the preamps are pretty similar). If you pull the 12AX7 out you should still have a clean channel that works - the 12AX7 is only used in the distortion channel. If the clean channel still gives you loud hum I'd be looking elsewhere.

Also, if you plug straight into the FX return jack and wind the FX Mix control all the way to "wet", you bypass the entire preamp and go straight into the reverb section. Next stop, the power amp and speakers. If you still haven't got any noise it's either the reverb section, power amp or power supply. Haven't got a schematic for an 8200, so I don't know where in the amp the chorus section falls.

[lmgash]

Thanks for the response. I will check out the speaker connections first, then swap out the tube. I will repost on sunday to update. I hope it works. It was actually a pretty cool amp. I used to be a tube snob (had to be all tube or it was garbage) and most of my amps are all tube, but I really liked this amp. It sounded every bit as marshall as my freinds jcm9000. If you crank the clean channel it breaks up nice. The effect loop is also so easy and you can blend in the effects just right. My typical setup is to plug directly in to whatever I am playing and go from there, but all these toys we collect over time are very fun now and then. If I cant fix this amp I will have it fixed.