Does this noise mean something?

EricTheWeary

Long story but short version is OD channel on my ( ancient and knackered looking) Laney LC50 not being as, well, ODish as it should ( ie not very much pre amp gain)and if I switch my Toadworks OD pedal on there is a very loud swirling noise ( that doesn't go if I turn the guitar down). This noise doesn't happen through the clean channel and overall volume seems unaffected. Faulty pre amp valve?

ICBM

Yes, probably.

EricTheWeary

Bugger. If the pre amp valve dies will the clean channel still work? Although, I probably should get new pre amp valves ASAP,I know !

ICBM

It's unlikely to be the one that operates the clean channel or it would probably do it on that too. Assuming it is a valve of course!

EricTheWeary

The OD channel has probably only had a couple of hours use since it last had new valves. Annoying.

ICBM

EricTheWeary said:

The OD channel has probably only had a couple of hours use since it last had new valves. Annoying.

All the valves run all the time whether or not there is signal going through them, so it's had the same amount of use as the clean channel. Valves often fail when new... this is one reason you shouldn't really change all the valves at once - there's no need, and it increases the change of a failure.

It will be only one valve that's gone, so only get one spare, and use it to replace each of the preamp valve positions in turn until you find it.

EricTheWeary

ICBM said:

EricTheWeary said:

The OD channel has probably only had a couple of hours use since it last had new valves. Annoying.

All the valves run all the time whether or not there is signal going through them, so it's had the same amount of use as the clean channel. Valves often fail when new... this is one reason you shouldn't really change all the valves at once - there's no need, and it increases the change of a failure.

It will be only one valve that's gone, so only get one spare, and use it to replace each of the preamp valve positions in turn until you find it.

Ahh. change valve,power up, not worked, power down, change valve, power up, etc.

ICBM

EricTheWeary said:

Ahh. change valve,power up, not worked, power down, change valve, power up, etc.

Exactly. And if you try all of them and it still isn't fixed, you've only bought one valve you didn't need instead of several…

It still is the most likely cause, although not a certainty.

(And having a spare 12AX7 is no bad thing, either.)

EricTheWeary

Seems better, although part of the noise seems to be the pedal. Should get me through the weekend gig. And what a faff trying to find someone who stocks valves in an actual building, not just online. Many thanks @ICBM.