Help! Hiss, crackle.....intermitent

[big stubby]

Okay so I now have my new (old)V4 cabinet with new eminence speakers inside and when I am playing it with my V-4B head it sounds great. Then out of nowhere a hiss will build up (even when not playing) and then a popping/crackling sound. I shut it down and if I turn it back on it will be fine. I noticed this was happening with the old Rola speakers that were in there when I bought it but I thought it was just because they were old and beat up. I have had my head plugged into a 2x10 cabinet for about a year and have not had this problem at all, so I am thinking it could be the wiring in the cab. any thoughts?

 

[Oldtimer]

Have you tried a different head through that Cab? My guess is it's Filter caps, tubes, or tube sockets from the head. If you have a working spare head, try that. Also, change patch cords, instrument cords etc. I think the last place I'd look for the sound you're describing would be the cabinet.

 

[big stubby]

Even though I never had this problem until I got this new cab?

 

[Oldtimer]

Even though I never had this problem until I got this new cab?

Ok, try a different cab with that head! It just doesn't sound like cabinet type of noises the way you described it. What is the impedence of the cabinet and what is the impedance recommendation for the head?

 

[JxBass]

Have you tried a different head through that Cab? My guess is it's Filter caps, tubes, or tube sockets from the head.

+1. Sounds more like a bad tube to me.

 

[craig.p]

Could be something cab-related or cabling-related is aggravating a pre-existing condition in the amp itself, something the 2x10 was unable to "wake up."

My first questions would be how is that 4x12 wired up (for what impedance) and whether you've got the head's impedance switch set to match.

Also maybe you can run the 4x12 louder than you could the 2x10, so the V4's output stage is delivering more current to that load, and the only time the problem shows up is at some minimum output-power level. (But that's a total SWAG on my part.)

 

[RickenBoogie]

+1 sounds like the amp, not spkrs. Spkrs only make whatever sound they're give, they don't make sound on their own.

 

[big stubby]

The 4x12 is wired for 8ohm and my head is set to 8ohm. Maybe it is something the 2x10 couldn't wake up. I'm going to rewire the cab anyway so maybe it will fix it and maybe it won't. But it's a quick fix if that is the problem. After that it's going to the tech. Thanks everyone!

 

[dincz]

Rola speakers

Wow, that dates and locates it!

 

[big stubby]

All is well, the problem was my V-4B head. All fixed and sounding amazing.

 

[Oldtimer]

Tubes?

 

[big stubby]

Tubes?

Yes, 1 power tube was shot and 1 preamp tube was as well.