Conditions: Amp volumes are turned all the way down, no guitar is plugged in, no hum and noise while the amp is in standby mode.
Troubleshooting thus far is just replacing tubes one by one with known good tubes, noise persisted. I would say I'm 97% sure grounding scheme is not the issue.
Its sounds like I'm moving a scratchy pot back and forth, or plugging and unplugging a guitar, but this is not the case.
Any help would be appreciated.
What is this sound?
Moderators: pompeiisneaks, Colossal
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RyanThomas13
- Posts: 29
- Joined: Wed Feb 19, 2020 5:29 pm
What is this sound?
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Re: What is this sound?
Could be a lot of things, could you provide context? What amp? Is it old or new? Have you changed anything recently?
Isolating what stage the noise is coming from is probably the easiest way to figure it out and/or poke everything with a chopstick to see if it's a mechanical issue.
Isolating what stage the noise is coming from is probably the easiest way to figure it out and/or poke everything with a chopstick to see if it's a mechanical issue.
Re: What is this sound?
tubes or cold joint, resistors...
chop sticking with wooden stick everywhere to see where it is
chop sticking with wooden stick everywhere to see where it is
Re: What is this sound?
removing ecc83 from input to the PI to see where is is/disapearing/developing
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RyanThomas13
- Posts: 29
- Joined: Wed Feb 19, 2020 5:29 pm
2 others liked this
Re: What is this sound?
Yes, Sorry, that would be helpful.
see pics
New build, 50 watt Hiwatt clone, this is the fourth time I've built this amp (I keep selling them so I can build another
)
This particular build has been a bit of nightmare, I spent over a month tracking down an oscillation issue only to discover I had flip flopped wires going to the OT
see pics
New build, 50 watt Hiwatt clone, this is the fourth time I've built this amp (I keep selling them so I can build another
)This particular build has been a bit of nightmare, I spent over a month tracking down an oscillation issue only to discover I had flip flopped wires going to the OT
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WhopperPlate
- Posts: 1053
- Joined: Fri Apr 16, 2010 9:04 am
- Location: Santa Cruz, CA
Re: What is this sound?
How loud is the intermittent noise ? beyond obvious sources of human error in front of the amp , one thing in my experience that can do this is a faulty plate resistor . Any bad resistor in any position can make similar noises , but the plate resistor can get pretty loud like a cell phone interrupting the circuit . If it’s in the power amp like the evidence suggests that could be pretty loud .
I chased a resistor down in a new build recently that did this . Brand new Dale MF started doing this about a week after fire up . It was so intermittent I wondered if the neighbors had a new internet service plugged in or something. This was in the preamp.
Chopstick that thing and press down on those boards real hard and see if you can flex any gremlins loose. If that’s not revealing I betcha it’s a bad component .
Good luck , nice looking build btw , not your first rodeo
I chased a resistor down in a new build recently that did this . Brand new Dale MF started doing this about a week after fire up . It was so intermittent I wondered if the neighbors had a new internet service plugged in or something. This was in the preamp.
Chopstick that thing and press down on those boards real hard and see if you can flex any gremlins loose. If that’s not revealing I betcha it’s a bad component .
Good luck , nice looking build btw , not your first rodeo
Charlie
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RyanThomas13
- Posts: 29
- Joined: Wed Feb 19, 2020 5:29 pm
1 others liked this
Re: What is this sound?
Thanks everyone for the ideas.
I spent about 30 minutes with the amp this weekend, just chopsticking around. I got a loud pop when pushing on one of the V3 tube socket pins, the solder joint was fine but the claws that wrap around the tube pin itself (when you insert the tube into the socket) I think was not very tight. I tried to close the opening a bit, and cleaned the pin on the tube, and redid the solder joint for good measure. To my surprise I turned it on and the problem persisted, though it felt like a 20% reduction in the frequency of the crackling. I continued pushing on stuff and then pushed one of the pins on the bass pot right off, never seen that before but we have to assume it was barely hanging on. I was able to goop enough solder on there to temporarily get the pin restuck, just to see if the crackling remained. It did not, I left it on for a few minutes and didn't hear anything. I ordered a new pot from Digikey which should be here by Wednesday, I'll install the new pot and report back. Thank you again.
I spent about 30 minutes with the amp this weekend, just chopsticking around. I got a loud pop when pushing on one of the V3 tube socket pins, the solder joint was fine but the claws that wrap around the tube pin itself (when you insert the tube into the socket) I think was not very tight. I tried to close the opening a bit, and cleaned the pin on the tube, and redid the solder joint for good measure. To my surprise I turned it on and the problem persisted, though it felt like a 20% reduction in the frequency of the crackling. I continued pushing on stuff and then pushed one of the pins on the bass pot right off, never seen that before but we have to assume it was barely hanging on. I was able to goop enough solder on there to temporarily get the pin restuck, just to see if the crackling remained. It did not, I left it on for a few minutes and didn't hear anything. I ordered a new pot from Digikey which should be here by Wednesday, I'll install the new pot and report back. Thank you again.