ceriatone 20 watt lead and bass noises

[JoshBernstein]

Hi.
I built a ceriatone 20 watt lead and bass amp a few months back; this is my 3rd post about this amp.
Ive been getting some really bad hum and a bunch of crackling through the amp. The hum is effected by all the pots, and the crackle as well. Occasionally ill get a loud crackle even when all the pots are on 0. I got extremely fed up with the noises so i completely rebuilt the amp, with no improvement. The crackle is intermittent. Sometimes it happens constantly, sometimes not at all. Any help would be appreciated.
Here's a link to a video i took of the noise: https://youtu.be/fTvlMiBy2uk
I dont have a schematic, just the layout.
Thanks

note: i just realized that i took the video with the channels linked. When theyre not linked, the only knob that affects the noises is the volume on the lead (left) channel.

[JoshBernstein]

Gutshots:

[JoshBernstein]

Gutshots:

[xtian]

If tone controls affect crackle, the issue is prior to the tone stack, right? Pull V1. Does that stop the bad noises?

[M Fowler]

Did you get all the issues figured out from your previous thread?

https://tubeamparchive.com/viewtopic.ph ... sc&start=0

[Stevem]

Pull out all of your orange drop caps and make sure the leads are solid into the caps body, this will not fix a hum issue, but it sure may be the sorce of crackle!
Have you reflowed all the solder connections that deal with that end of the circuit?

[JoshBernstein]

Pulling v1 has no effect, pulling v2 quiets it considerably, but the noises are still there. Ill check the orange drops when i get home today. Also i did resolve the problems from that other thread just by replacing the coupling caps.

[JoshBernstein]

Another thing: the noise completely stops if i short the joint i colored blue to ground.

[JoshBernstein]

Just checked the orange drops. One lead on the .0047 looks a little loose. Could thay be the crackling issue?

[Stevem]

Yes, replace it with anything, even a .1 cap or one out of a section of the amp that is not part of this issue !

[JoshBernstein]

Well,
After reflowing every possible joint and changing all of the caps, there was no improvement in either noise. But something rather interesting happened today. I was tapping around with a chop stick to see if i could make the noise change at all. I barely moved the wire between the 480 ohm resistor and the standby switch and both the hum and crackle instantly stopped, and havent returned for about an hour. The amp sounds great, and has just a tiny bit of 60hz hum, which isnt a problem. What do you guys think could have caused this sidden change?

[xtian]

Well, crappy standby switch is what your evidence suggests. Or crappy wire!

[JoshBernstein]

well, the noises stopped for about a day, but they're back. i changed the standby switch, but it wasn't the issue. any other suggestions?

[Stevem]

Well replace that 480 ohm resistor then as it may be bad or sensitive to moisture in the air!

The same goes for any plate load resistors in the stages that still pass the noise when other tubes are pulled out of the amp.

I can't tell Ya how many 1500 ohm Carbon Comp resistors I have replaced over the years on Fender output tubes that looked fine, perfectly fine to the eye,yet they where cracked clean in half and yet would work at times!

[JoshBernstein]

hello, again.
My problem has been solved. After months of trying to fix these noise issues, i found the source. The rectifier diodes. Put a new pair of those and the noise was reduced to an acceptable level of 60hz hum. Thanks for the help and suggestions, they are greatly appreciated!