Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dude on August 04, 2018, 01:42:20 pm
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With a humbucker guitar the amp is dead quite, a strat a lot of hum just with this amp. Single coil strat is shielded, pickguard, pockets, strings and jack input pocket. Almost no matter how far from the amp I get I have hum, a very few spots I stand I "lose it", usually at least 10 feet away at a certain position but just turning a bit, hum back. The hum is almost anywhere within fifteen feet of the amp. Only two pick up selections, neck/middle or bridge/middle the hum goes, middle is probably reversed wound. I play with a blender pot on a tone knob, blending neck and bridge, get a lot of hum.
Any suggestions? I have the amp, a head, totally enclosed with a bottom metal shield, still hum. Could this be lead dress inside the amp, it's a JTM45 clone I built.
OK, just tried another strat, no HUM. It's the guitar, what can I do, it's already shielded. Could it be the blender pot I just installed. I got the wiring diagram from Lindy Fralin.
al
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Could this be lead dress inside the amp
Not likely. Probably some noisy electrical appliance or lighting. Turn off all nearby lights and appliances. Or take the amp and Strat to a friends house. Same results?
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You missed the added note. It's not the amp but the strat. reread the post for added info.
Also, this same strat with same amp didn't hum with a push/pull pot for the neck and bride. I like the blender pot instead of the push/pull as I can blend the amount of the bridge with the neck.
Must be something in that Lindy layout...?
al
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Play the other strat! :icon_biggrin:
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Ha, ha :icon_biggrin: pretty clever! I opened myself up for that :laugh:
I just noticed that Fralin diagram doesn't have the tone pots grounded...? But the pickguard shield should have covered that, hopefully not, can't hurt to run a ground wire from the volume ground to the tones. Such a hassle to get inside a strat wiring.
I guess if the added ground doesn't work, then go back to the push/pull knob but no blend, my favorite strat too. OH well, sh-t happens.
al
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https://www.ebay.com/itm/25-Tinned-Brass-3-8-Potentiometer-Switch-Grounding-Lugs/191928884664?hash=item2cafda5db8%3Ag%3AGw0AAOSwARZXkjgD&_sacat=0&_nkw=potentiometer+ground+lug&_from=R40&rt=nc&LH_TitleDesc=0 (https://www.ebay.com/itm/25-Tinned-Brass-3-8-Potentiometer-Switch-Grounding-Lugs/191928884664?hash=item2cafda5db8%3Ag%3AGw0AAOSwARZXkjgD&_sacat=0&_nkw=potentiometer+ground+lug&_from=R40&rt=nc&LH_TitleDesc=0)
I know nothing about guitar wiring but if I did I would have some of these. Anytime you have to solder to the back of a pot you (me) are looking for trouble.