Weber 5C5 popping/cracking

[shuffle]

Hi y'all!

I got myself a Weber 5C5 kit, worked like a dream for about two months.
Played at a gig, next time i turned it on it was popping and cracking really bad.
Behaves the same way with Sylvania NOS 6SL7 as well as bundled tubes, output/rectifier makes no difference.
No difference if a guitar plugged in or not.
The whole amp is microphonic, it doesn't matter where I tap to induce pops, and really sensitive too.
No visible arching in dark.

What I've checked so far:
-Volume dependent, vol ->0=no pop
-Both channels affected
-Pulling both preamptubes stops pop
-Changed filtercaps (I was planning to anyway)
-All components look fine (not burnt etc.)
-Retensioned input sockets

I don't know where to go from here, any ideas greatly appreciated!

/Janne

[6267]

I'd check all solders in the preamp before the volume control, one may have warmed up and gone intermittent. I'd also replace any ceramic caps you may have used, these have a tendency to go microphonic. Chances are it's a solder in the preamp, but I'd check the B+ dropping resistors too...I had a popper that was a power resistor that would heat up & start getting intermittent. It could also be a bad tube, I guess, based on the microphony but a cold solder can do that too.

[Amp Kat]

You did change the power tubes right especially if they are WXT's. Check all of your grounds real good and connections to all of the pots. Sounds like a bad connection. If that isn't it check all of your voltages on the power tubes and preamp tubes and make sure they or ok.

[shuffle]

Thanks!

Powertubes are NOS Blackplates and some used Svetlanas and the bundled Chinese tubes, all the same... (popping that is!)
I'll get my nose in there to check the joints!

/Janne

Edit: Should the reading on the output of the OT only show 0,2 ohms? OT shorted?

[shuffle]

HI!

Found a bad joint on the brassplate, need to get myself a bigger, badder soldering-iron i guess!

Thanks for your time an effort!!!

/Janne

www.bluestompers.com (5C5 in action)

[bnwitt]

HI!

Found a bad joint on the brassplate, need to get myself a bigger, badder soldering-iron i guess!

Thanks for your time an effort!!!

/Janne

www.bluestompers.com (5C5 in action)

Or you could stop using brass plates and go to a grounding buss on the back of the pots themselves. Those brass plates are a corrosion problem down the road.

[Mandopicker]

If one was using the plate for historical reasons, perhaps drilling a few small, appropriately positioned holes would be helpful for a more "mechanical" connection?

Food for thought.

[bnwitt]

If one was using the plate for historical reasons, perhaps drilling a few small, appropriately positioned holes would be helpful for a more "mechanical" connection?

Food for thought.

Yeah I guess. I just think that the brass plate along with the old Fender fish paper circuit cards and the death cap are three things that should'nt be cloned. With the plate you've got potentiometer pot metal contacting brass then brass contacting steel chassis. Luigi Galvani would have a cow.

I've never understood the drive to make a clone exactly like an original down to the gnats pituti including what I call the logo lie. No matter what you do, it isn't an original, its a clone. However, if you make improvements, its not a clone. It's an improved version.

[kor]

When you first turn the unit on, before the tubes get really hot, wiggle each one in it's socket. Most popping & crackling can be contributed to loose tube sockets.

[shuffle]

I'm thinking about rewiring my 5E3 clone, sounds like a grundbus might be the way to go!

/Janne

[Diablo]

Yeah I guess. I just think that the brass plate along with the old Fender fish paper circuit cards and the death cap are three things that should'nt be cloned. With the plate you've got potentiometer pot metal contacting brass then brass contacting steel chassis. Luigi Galvani would have a cow.

I've never understood the drive to make a clone exactly like an original down to the gnats pituti including what I call the logo lie. No matter what you do, it isn't an original, its a clone. However, if you make improvements, its not a clone. It's an improved version.

Good advice. My Tweed Bassman kit came with the brass grounding plate.....it sits in my box of useless parts. I used the grounding buss soldered to the back of the pots. My goal was to clone everything but the hum of the original....