Laney Cub 12R fizz/noise question.

nwalden

Hi,

I'm new to valve amps and have a question. I recently bought a Laney cub 12R and so far I'm happy with it except for one issue: When I turn up the gain and the master volume past a certain level and play I notice a sort of fizzing sound coming from the amp. It's over and above the overdrive sound, almost like it's a high frequency mechanical rattle coming from the cabinet or speaker. At even higher volumes this becomes more prominent up to a level where it's really irritating. It never seems to change frequency, but seems like some soft of noise being generated somewhere. This occurs only when playing at gain settings of above 3 on the amp. Having no previous experience I don't know whether this is normal, or if there is something wrong with my amp and I need to do something about it.

Please advise???

Gearhead

Because we cannot hear what it is you are hearing, it is kinda hard to tell from here. Ask someone else to play chords on your guitar and figure out yourself whether there is something loose in the amp. If not, it could be a microphonic tube. Search the forum, it is explained elsewhere.

nwalden

Gearhead wrote: If not, it could be a microphonic tube. Search the forum, it is explained elsewhere.

I tested for microphonic tubes by turning up the amp to the level where I usually experience the problem and lightly tapping the tubes with a pencil (as the guy in the video explaining microphonic tubes did), but heard no sound coming from the amp... I've also removed and re inserted the valves to make sure they're not loose in their sockets, still no difference.

After setting the amp to a clean sound and turning the volume WAY up and playing some chords while listening to the amp I couldn't find any mechanical noise coming from the cabinet... ☹ As I said this only happens when the gain is set above a certain level. The closest sound I can compare it to is that harsh silicon diode clipping sound in high gain distortion pedals.

Gearhead

Time to start rolling tubs I'd say. Get yerself some nice ones, swap them in and see if it helps. If it does not, you will now have spares and yer money is not wasted. If it does solve the issue, happiness!

bottledtone

The other problem is that some valve amps should just not be in combo form. Try to run amp into seperate cab, and if it stops you know that it is due to mechanical vibration.
Combos are due to portablity, but should all be head and cab.
I still build combos though ?

nwalden

Oh dear... After some further investigation and testing I found out that the sound I'm hearing is due to fret buzz (DUH ??? .... ) ... Now rather sheepishly I ask : Can anyone recommend somewhere I can take my guitar for a service and setup? I'm in Pretoria east, so somewhere close by would be a plus.