Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Solid State => Topic started by: Bantam on September 16, 2019, 05:34:36 pm
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I'm completely stumped with this. the symptom is a small popping sound akin to the soft pops on a record album.
not a overly loud pop, but def enough to bug me.
I thought i fixed it, when after opening it and spraying it out (the pots are somewhat sealed, CTS i think, normal pc mounted) checked/cleaned connects/inputs, and found broken solder joints where the large diodes had been trimmed. they had almost imperceivable rings around them, that would open when pushed from the other side. i of course re-soldered, and touched up some pads that were light.
i didn't want to do too much shotgunning, for fear of not knowing what the fix was, and was happy when after closing it and power up it sounded fine. I played for 6 hours with no pops, and for a little bit the next day.
you guessed it! its back, after a couple days, i kicked it over and popping was right there within seconds. I've been looking into learning/getting a scope, but all i have are multi meters, a dead bug type sig-gen, bad eyes, and some decent magnifiers.
I had expected to find bad joint, or bad cap in the typically seen 4700@50V electros. I would have just changed them, but no longer have most of my parts.
all I can think of now is heat related (big jumps from inside air conditioning to outside hot) along with I just stopped playing after a few hours and thinking back on it, I didn't notice any popping towards the end, or while idling when done.
UPDATE...it made the sound while unplugged from any input. also it made/makes the sound while on battery power, or while plugged into wall wart. I've usually run it with effects from outboard multi-fx into whatever input I'm using, but noticed a noise similar, if not exactly alike, while turning pot associated with onboard fx. when changing fx, it makes the sound alike, whether the send/amount pot(s) are all up, or down. If i can find footswitch, i'll try to defeat fx, and see if it goes away.
while assembling it back I noticed speaker connects at speaker were less than stellar, but not falling off. If i had not put away the station, I would have fixed 'em better, and will when i'm back in.
any help, similar experiences?
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Turn all cellphones completely OFF.
Might un-power your wi-fi.
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You are The Man! ....at least I think it's fixed! You are still Aces with me either way, but I really think your advice worked. I'll look into a HF filter/shielding if it bugs out when playing outdoors---with the 1000s of screaming adoring fans
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> with the 1000s of screaming adoring fans
It's a popular-price piece of fluff from the days before wide use of cellphones. Before you get into the Big Arenas, get something newer (or much older), it will be more likely to reject cell/wifi bleeps and boops.
Or blame the drummer.
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AES standard 48... XLR's prone to scin (shield current induced effect)....ferrite core... Just been reading up on this since being ushered in that direction by your post.... Again you are correct it's easier to just blame the drummer!