amp oscilation?

OK AVI again
I thought i would make a new post about this as its not really related to the mis-representation etc..

Any way, all hooked up and im getting a kind of medium pitch oscilation through the speakers, if i touch the case of the amps the noise stop, can anyone tell me what might be wrong here?

 

Maybe, where it's been "Serviced" prehaps they forgot to 'tighten things down', maybe the tranny is loose in one, (Blimley, you aint having much luck here mate ) Tone

 

its both of them mate
if i touch the caseing the oscilation changes to a very quiet hum, but also a lot more hiss and noise from these than with just the shearne.
Ive tried a few different IC's and no difference.

I feel my luck has gone on vacation without so much as a by your leave

 

looks like

1/either the fundamental design is compromised, which doens't suprise me, as Avi got the pro9s cabinet size all wrong...that is SOOO basic..they have NO bass...nice midrange tho'..(.I like the avi philosophy but I really wonder what goes on with them sometimes...I wasn't that enamoured with the nuneutrons or biggatrons, and the gravitron roll off at 50 hz for a 120 litre cabinet...!!!! that's a big box for not much bass...)

2/or the service guy didn't fully understand what he was doing..
maybe replaced a few bits which has sent the design out of sync.

3/..or simply the amps are dud, jinxed, or have become damaged in transit or god knows what...

this is out of luck time, and the universe can be a gyet at times...esp if you don't have mucho cash...and you have shelled out...

I don't fully understand this, but maybe something getting in an earth loop into the mains earth, to which the case/chassis is connected....

or...sods law, oscillating transistors can easily fry loudspeaker drive units, so you could end up having to fork out big money for blown speakers...!!!!!! care.. needed...

actually a point to bear in mind, you won't legally have ANY recompense whatsoever if you start fiddling inside it....the seller doesn't know that hasn't caused the problems...and yes, I have done that, too fortunately my dispute is slowly getting sorted ok....

 

ill not touch inside unless i become lumbered with them