Hopefully someone can shed some light on this, my old DC3 has been on the fritz for quite a while and I am finally doing something about it(I hope), getting a intermittent rustling noise on the power section, new tubes are in all known to be good, I am also getting a DC sounding scratching on my guitar volume on the dirt channel, this happens with every guitar.
Cheers in advance
Mesa DC3
Moderators: pompeiisneaks, Colossal
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Stevem
- Posts: 4637
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Mesa DC3
That amp has two caps on pin 2 of V1 that could be getting leaky and letting DC pass back to the Input jack, can you measure any DC at the end of the plugged in cable?
Is the output stage still making the noise with V6, the PI tube pulled out of the amp?
If so it may be time to clean, lube and retention the output tube recivers in the tube sockets.
I have found that the best way to do this is with a short section of a round wound bass string that is of a gauge that is large enough to open up the recivers some.
Passing the string in and out 6 to 8 times should polish up the contacks, than spreading some cleaner/lube with a Q tip on the output tube pins when re-installing the tubes will kepp corrosion at bay!
Be sure to unplug the amp and place the standby switch in the on postion for 1 minute to drain out the power supply so you stay safe.
Is the output stage still making the noise with V6, the PI tube pulled out of the amp?
If so it may be time to clean, lube and retention the output tube recivers in the tube sockets.
I have found that the best way to do this is with a short section of a round wound bass string that is of a gauge that is large enough to open up the recivers some.
Passing the string in and out 6 to 8 times should polish up the contacks, than spreading some cleaner/lube with a Q tip on the output tube pins when re-installing the tubes will kepp corrosion at bay!
Be sure to unplug the amp and place the standby switch in the on postion for 1 minute to drain out the power supply so you stay safe.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Mesa DC3
Got a little bit of dc on the cable, 0.04v clean, 0.07v dirty,
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Stevem
- Posts: 4637
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Mesa DC3
One of those two caps is getting leaky so just shot gun it and replace both of them and button it up!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Mesa DC3
Thanks for the "string" trick, Stevem. Great idea!
D
D
There are no stupid questions, just stupid people.......
Re: Mesa DC3
Replaced both and no difference lol, , this amps a bit of a turkey I think, looks like the dc is leaking in from the drive circuit as it appears after the drive is engaged, lost the reverb as well now, something is not well at allStevem wrote:One of those two caps is getting leaky so just shot gun it and replace both of them and button it up!
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Stevem
- Posts: 4637
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Mesa DC3
Well unless it's the circuit board starting to conduct like fender tag boards have been known to do the only other thing would be the cathode cap on V1b, and that's not all that likely as it's feeding thru a resistor.
Have you swapped tubes for a test?
Have you swapped tubes for a test?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!