HELP: MB Fusion and Accugroove .... Hiss!!!

[michele]

Need some help, guys. Today my MB Fusion arrived and I plugged it into my Accugroove Tri112L and in addition to the WONDERFUL sound I experience a damned hiss that blew away all the excitement for a new piece of gear!
I cannot say if it's head or cab related.
1) It's not always there but it comes and goes. Sometimes it's there when you turn the amp on sometimes it suddenly appears, then disappear, then here it is again and so on. Sometimes it's tolerable sometimes it's a needle in your head. This hiss kinda modulates when you tweak the màster knob (both channels).
2) At the beginning I thought it came from the tweeters and it certainly is less audible with the tweeters off but it (or part of it) definitely comes from the 12" cone.
3) Disconnecting the cab eliminate the problem: it's not an electrical hiss coming from some component of the amp. But the cab was ok last time I plugged my Ampeg V4B: no hiss. I can't plug the Ampeg in right now... it has a short.
4) I recently had all my house properly grounded, all my outlets checked and yes ... I tried various outlets around the house.

Please help me!

[BassmanPaul]

No speaker cabinet creates hiss. All any of them can do is to reproduce what is sent to them. Hiss and other noises come from the amplifier. I would try to exchange the amp and see what a second does for you.

[michele]

Damn!! Something told me not to rely on those new chinese lightweight crap! After all they had in stock an Rb700II and all I was searching for was the glorious 800rb sound I recently experienced!
Maybe I'd better go with a time proven product...

[username1]

I just picked up an mbfusion and i think it is a fine amp. The head can get quite bright and i noticed a hiss with one of my basses but when i touch the strings the noise went away making me realize it was just poor sheilding on that particular bass and the amp being capable of alot of hi end just magnifies it if treble is boosted too much. Works great with my other basses. Could possibly be a bad tube also, might be worth it to have it looked at because they are great amps when working properly.

[ddbassGA]

I bought an MB Fusion new from MF and loved it. About a week in I stated getting a real bad hum through the speakers. It occurred with the mute on or off, with a bass plugged in or not. It was pretty bad, making the amp unusable. I sent it back to MF and got my money back and before ordering another one I wanted to find out from GK what that was all about. I wrote to GK about it and got absolutely no satisfactory explanation from TS, CS, or Robert Gallien himself. In fact I was pretty much just blown off. I was a 20 year GK man, but no more.