Why do my guitar amplifier crackling like a campfire whenever I plug ANYTHING into the input jack? Cable, adapter, wireless adapter.. anything. Silent when input jack is empty. Both channels, clean and overdrive. Sometime it's more prevalent in the clean channel, sometime more pronounced in the overdrive channel. Does it no matter what volume it is. Tried it at four different homes with a Furman power filter, still sound like a campfire. Any help would be appreciated. Thank you.
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I think the Princeton 112 is Solid State.
My guess is there are bad solder joints on the input jack...
You can also try a different input cord - my friend has a very expensive Mesa Boogie that he was going to take in due to having radio station transmission come thru amp - I told him before sending to shop, try a different cable - all fixed. I saved him a couple hundred bux.... he thinks I am Elon frickin' Musk of guitar amps now.
My guess is there are bad solder joints on the input jack...
You can also try a different input cord - my friend has a very expensive Mesa Boogie that he was going to take in due to having radio station transmission come thru amp - I told him before sending to shop, try a different cable - all fixed. I saved him a couple hundred bux.... he thinks I am Elon frickin' Musk of guitar amps now.
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This is a long shot, because crackling is (normaly?) not related to ground loops, and probably you already tried the amplifier 'stand-alone'.
But if the two amplifiers are connected (via effects) to each other, you could try temporarely 'unearthing' one of them from the earth terminal of the mains socket and see if the crackling changes, or even stops (that amplifier will still be earthed via the connection with the effects and the other amplifier that stays earthed throught the mains socket).
I wrote 'temporarely' because I think its against safety rules to do so. But in my setup in my attic, I only have one of my amps earthed, not to prevent crackling but to eliminate ground loop hum. To 'unearth' an amplifier, I made an adapter using something like this: https://www.deboerdrachten.nl/productafbeelding/247256/0/1240/1240/Kaiser-contrastekker-wit-ongeaard.jpg
But if the two amplifiers are connected (via effects) to each other, you could try temporarely 'unearthing' one of them from the earth terminal of the mains socket and see if the crackling changes, or even stops (that amplifier will still be earthed via the connection with the effects and the other amplifier that stays earthed throught the mains socket).
I wrote 'temporarely' because I think its against safety rules to do so. But in my setup in my attic, I only have one of my amps earthed, not to prevent crackling but to eliminate ground loop hum. To 'unearth' an amplifier, I made an adapter using something like this: https://www.deboerdrachten.nl/productafbeelding/247256/0/1240/1240/Kaiser-contrastekker-wit-ongeaard.jpg
Plug guitar into the return jack on your effects loop. See if you still have cracking there. This will identify what part of the amp the issue is - if it does not have cracking its the preamp side - my guess is bad solder joint on input jack or the wires from input jack to the PCB board...
Will test on it in the morning....
I've moved the amp to different house with my Furman and still sound like a campfire whenever I plug ANYTHING into it...
I've moved the amp to different house with my Furman and still sound like a campfire whenever I plug ANYTHING into it...
The input jack has a bunch of extra contacts, one set of which run the INH line - inhibit, a mute function. All functions part of U7. So unplugging from input turns off parts of the circuit. I doubt the input jack itself is the noise source. You report the volume control has no effect on the noise, so that reinforces the noise not coming from the input stage.
I tend to think the power amp is not at fault, as the input jack lines have nothing to do with it.
Turn the reverb up, when it crackles, does the crackle noise also get reverberated? That will tell us how far back the problem lies.
At this point my wager is on either U7 itself or U3. U3 is a common TL072, and U7 is a common enough 4053 CMOS IC.
I tend to think the power amp is not at fault, as the input jack lines have nothing to do with it.
Turn the reverb up, when it crackles, does the crackle noise also get reverberated? That will tell us how far back the problem lies.
At this point my wager is on either U7 itself or U3. U3 is a common TL072, and U7 is a common enough 4053 CMOS IC.
try a short jack cord between the "pre amp out" and "power amp in" jacks to see if that makes a difference i'd also run some contact cleaner and "exercise" the headphone jack, i've seen sooo may problem with those,especially if unused corrosion/oxidation makes them go bad.