Noisy amp?

machina · Post by **machina** » Thu Dec 08, 2005 8:31 pm

Hey guys, as I was jamming today I noticed a shiteload of feedback/noise (like a big low hum) coming through my setup. I played around replacing potentially dodgy leads etc and I think that its my preamp causing it. Its a tube preamp (ADA MP-1) and I have it running into a marshall JCM800 head. I plugged directly into the marshall and that all seems to be fine, so that just leaves the MP-1. Im thinking it could be worn tubes or something? Any help would be great, as i've planned a jam tommorow and dont want to have this annoying bloody humming going on.

Thanks

ash · Post by **ash** » Thu Dec 08, 2005 8:36 pm

Sounds like it could be a tube issue. Hopefully not something worse. Clarry at 34 Audio isn't far from you. 34 Pentland ave... he can tell you what the story is.

machina · Post by **machina** » Thu Dec 08, 2005 8:43 pm

Thanks man, i'll go see him tommorow. Damn tubes. Are they something you can change yourself?

Mike_Hosking · Post by **Mike_Hosking** » Thu Dec 08, 2005 9:00 pm

tubes arnt to hard to change on a tube amp, providing the bias is a none adjustable one, so theres no fiddling, but on the preamp it mite prove to be a lil more difficult.

machina · Post by **machina** » Thu Dec 08, 2005 9:34 pm

I was looking at getting the tubes done anyway. Does anyone have an idea of some good replacements? It has 12AX7A's in it now, and I fiind that they break up too easy for my liking on a clean channel. I'm after something that'll stay clean even when I turn up to 11.

fooey · Post by **fooey** » Fri Dec 09, 2005 9:50 am

yeah im after 6 12AX7's come to mention it and i dont want to pay the $50 a tube someone is trying to charge me

Post by Bg » Fri Dec 09, 2005 11:58 am

there are a couple of good places in the US that ship here at a fraction of the cost. You should find info on them if you do a search here. Failing that I'll try and dig out the reciept from the last ones I ordered.

machina · Post by **machina** » Fri Dec 09, 2005 1:02 pm

Thanks guys. I took ash's advice and have taken it to clarry at 34 audio. It may not be the tubes, but the earth in a cable i had made for the MP-1 so it dosent fry the old marshall. He's working on it now. Seems like a pretty good guy, and his little shed/workshop kicks ass.

Polar Bear · Post by **Polar Bear** » Fri Dec 09, 2005 1:12 pm

bluesgeek wrote:there are a couple of good places in the US that ship here at a fraction of the cost. You should find info on them if you do a search here. Failing that I'll try and dig out the reciept from the last ones I ordered.

Tube Depot is pretty good. http://www.tubedepot.com

Post by Bg » Fri Dec 09, 2005 1:32 pm

yeah Clarry is a hero, I reckon he's pulled a few guys out of the shit over the years. Cool cats too

Thats the link PB posted, they're great to deal with and fast shipping