Problem with my Laney

[Stevepage]

Just recently the amp has started to mess up on me. When I turn on the amp and just have the guitar plugged in, I get a loud hum. Like I've plugged a lead in without plugging it into the guitar.

This hasn't happened before so I changed the preamp valves for a new set, that done nothing. I'm still getting a loud hum. It's quieter when I set the FX loop to Insert, anything else and it's loud.

What the hell can I do with it except for sending it to a tech? I don't know of any amp techs near me and I haven't got my driving licence yet.

It's not a problem that needs a quick fix because I'm not gigging or rehearsing with the band right now.

[ailean]

My limited knowledge suggests to me it's either picking up interferance from another source, or it's a grounding problem.

Have you moved the amp recently, or have you put anything electrical near it? (including behind an adjacent wall).

If it's the grounding then it's going to be a tech job I suspect.

(I wait to be corrected by those who actually know what they are talking about)

[Fourth Feline]

Hi Steve,

What model is it ? I ask because an engineer  at Laney once told me of a common stock fault, where the adhesive grey foam strips that hold down the (silver backed card ) shielding on the pre-amp actually becomes conductive instead of insulating over time !

I have had no such problem on my LH50R-II, but it was common on the LC15. The cure is to pull off the strips, clean the board of their residue ( meths or similar will do ) - and then find some alternative method of re-seating the shielding material, such as sellotape sticky pads e.t.c.

[Infliktor]

Try a new or different cable?

[Stevepage]

I disconnected the reverb tank and that seems to have fixed the problem. It's been knocked about a bit so that's probably messed the reverb up. I'm not that fussed because I never use reverb any way. Hopefully with some more playing with tomorrow I can see if there's any other problem.

[HTH AMPS]

I disconnected the reverb tank and that seems to have fixed the problem. It's been knocked about a bit so that's probably messed the reverb up. I'm not that fussed because I never use reverb any way. Hopefully with some more playing with tomorrow I can see if there's any other problem.

I had an Ampeg VL-series head (the Lee Jackson ones) with a bad hum that ended up being the reverb tray too - the actual reverb spring has snapped inside.  A new reverb tray sorted it, but it sounds like you've figured this one out already.

[Oli]

I disconnected the reverb tank and that seems to have fixed the problem. It's been knocked about a bit so that's probably messed the reverb up. I'm not that fussed because I never use reverb any way. Hopefully with some more playing with tomorrow I can see if there's any other problem.

When i had a VH100R, a similar thing happened to me, when i switched the reverb on, there was an awful hum and screetching. I sent it back to Laney, and they sorted it, so i think it must be a fairly common fault.