Big brown fenders

[Jasonpatrick]

Question, something i have noticed on the three brownface fenders I have and have had, when powering up and coming off standby or even just flipping both on and waiting to come up, there is a series of quiet muffled pops, Almost like when a tube is warming up kinda. I have let it warm up before hitting standby and it seems there are less little pops, but it’s something I have noticed on the 5g13 I had, the super I have now and a concert I had a long long time ago. Is it just something these browns do because of how maybe the circuit is wired? Also, all electrolytics were new in all amps.

 

[AntonyB]

Have the tube sockets been cleaned during the last service? It is a reason for pops…

 

[Jasonpatrick]

Have the tube sockets been cleaned during the last service? It is a reason for pops…

Yeah they have. Maybe I need to do a better job? Just weird it’s a thing on all three!? Next time a turn it on I’m gonna pull the PI and see if it still does it.

 

[Jasonpatrick]

Cleaned sockets, changed tubes..some tubes louder then others, pulling PI kills it, pulling the pre amp tube next to PI makes the pops quieter. Cold solder perhaps?

 

[Jasonpatrick]

https://www.tdpri.com/attachments/1669560856302-png.1055351/
View media item 48278

 

[Jasonpatrick]

Recapping it ..

 

[ficelles]

How old are the amps? Old leaky caps can make popping sounds, I have an old AKG mic that does it.

 

[Lowerleftcoast]

Have you chop sticked? Pushing around on the resistors and terminals.

 

[Jasonpatrick]

Have you chop sticked? Pushing around on the resistors and terminals.

I have. Few times. Besides some microphonic ceramic caps, nada. The amp is dead quiet and Nothing else makes any noise. I’ve noticed different tubes in v5 change it a bit and after I recapped it yesterday it seems there’s less pops. Someone mentioned the dropping resistors perhaps but it’s odd my vibrasonic did the same thing. Could it just be how that circuit is? Or maybe it is a dirty socket that I just need to retention again or soak again .. maybe a good time to use the oscilloscope I bought and haven’t used!

 

[Jon Snell]

I would replace the 100k anode load resistors. They are known for being noisy.

 

[Jasonpatrick]

Have you chop sticked? Pushing around on the resistors and terminals.

Hypothetical , would this ceramic cap induce said muted crackle pop noise upon start up? (Not a pic of my amp) I think I have it narrowed down to around v5-v6 area.

 

[Lowerleftcoast]

I have only experienced microphonics with disc caps. That particular cap is a snubber. Never say never, but I highly doubt that one is causing the noise. Now... those two resistors it is snuggled between are highly suspect, imo.

FYI those resistors get hot and that snubber cap should have more distance to keep cool.

 

[Jasonpatrick]

I have only experienced microphonics with disc caps. That particular cap is a snubber. Never say never, but I highly doubt that one is causing the noise. Now... those two resistors it is snuggled between are highly suspect, imo.

FYI those resistors get hot and that snubber cap should have more distance to keep cool.

Next time I'm in the amp I’m gonna check these that I’ve circled.