Terror Bass buzz

[knirirr]

When I bought my Terror Bass 500 it used to buzz on certain notes when sitting on top of the cab. Orange replaced it under warranty.

The replacement is now doing the same; an example, demonstrated by some guitar noodling, can be heard at: https://www.dropbox.com/scl/fi/hcz9oy9m2jy79s3m2ssq6/Amp-buzz.m4a?rlkey=dkdp2m9ocn71xmgqmvzorndjx&dl=0

Putting the head on the floor instead stops this from happening, though this is not ideal as it can get in the way. Perhaps I should just buy a longer speakon cable...

Could this be a dodgy (microphonic?) valve? If so, how hard is replacing them? I've seen warnings to the effect that fiddling with the internals of a valve amp is potentially fatal for the unqualified, but perhaps the Terror Bass might not be that bad having only a valve preamp.

It's been happening for a while, but I normally play unamplified at home and so only notice at the beginning of gigs/jams/rehearsals and have forgotten by the time I get home.

I could perhaps take it here:
https://www.oxfordpowershop.co.uk/pages/amplifier & Speaker repairs.html

...as long as I wait until I'm on holiday, as they only open when I'm working.

[tauzero]

Would a foam pad under the head to isolate it help?

[knirirr]

3 hours ago, tauzero said:

Would a foam pad under the head to isolate it help?

 

That does appear to help.

But, it would be nice to fix it, if I can be certain of how to do so.

[tauzero]

It sounds like a physical buzz. Is there a headphone output, and if so, can you hear the buzz on there? If not, could you take the effects send to something you can use headphones with and see if it still buzzes? Might just be a loose screw.

[knirirr]

Thanks - I'll give that a try. 

[Matt P]

changing the valves in a terror bass is fairly easy, the one thing to look out for is the screws that hold the top cage section on are very cheap and prone to the heads getting chewed up. I swapped mine out for some black cap head bolts which are much more robust, I can't remember exactly what size but could check when i get home.

 

there is a thread on here somewhere that goes through the whole process of swapping the valves , if i get a chance to find it i'll add a link. but once the top cover is off it's take the valve covers off (bayonet fitting) and then pull the valves out carefully, then make sure the new valve is properly aligned and it should just push in, covers on and off you go.

 

I put some lower gain valves in mine but never really gelled with it, at some point i'll put it up for sale.

 

Matt

[knirirr]

I was also wondering whether lower gain valves might help; the sound so far is reasonable, when it's not buzzing.

[Matt P]

I fitted these   seemed a good price for NOS valves, they sounded pretty good, lower gain than the originals to my ears, but the whole amp is just too high gain for me and i've gone back to the Markbass F1 i was using originally.

 

Matt