Fender Deluxe 112 plus - buzzing and want to change vol pots


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09-21-2010, 01:09 PM
Hey, hope you can assist.

I am planning on repairing my fender deluxe 112 plus amplifier, its been unused for a few year and survived a house move, ever since its buzzed real bad when anything is plugged in to it (low buzz even when nothing is in!). I think this points to either a poor connection on one of the jacks or a faulty earth connection somewhere.

Has anyone any experience in locating these faults? Im confident with a soldering iron and multi meter and happy to do this myself, just hoping for some pointers.

Also, whilst its in bits I would like to change the volume pots for ones that have an easier control range, at the moment it seems 1-4 is like 0-80% then 6-10 is 80-100%, I would like a pot that lets me adjust the volume at lower levels much easier, or even a linear pot so 1-10 is 0-100%. I use (will) the amp in the house for jamming so I want to be able to achieve good sounds at lower volumes, at the moment its very difficult to get a decent, low volume sound.

Can you help?


09-21-2010, 03:16 PM
I'd go inside the amp and look around for bad solder joints or things that have been disconnected.

Low buzz is common, as there are stray RF waves in the air that will cause that. As for when something is plugged in, if you're playing with single coils, that's bound to happen, especially if they're not shielded properly, although there is a chance it's something in the amp.

And the pot you want for your volume will be a log/audio pot, not a linear pot. I'd say look at what it is and try out different kinds if you really want to get into it.

09-22-2010, 03:59 AM
thanks mate, im going to take a look at it today and try to resolve the buzzing. its quite intrusive so I would like to at the very least reduce it.

ive been and got some contact cleaner and soldering kit and im going to redo the jack joints and check the earths.

assuming i can resolve the buzzing ill sort some new pots out

will keep you posted on progress :)

Invader Jim
09-22-2010, 06:54 AM
if it only started doing that after you moved, it may very well be the house wiring.

in which case nothing can be done, short of rewiring the entire house.

09-22-2010, 08:35 AM
was doing it before I moved too mate.

Ive just had it in bits and it seems to be an earthing issue on input 1. If I plug my guitar in and touch the lead and a housing bolt the buzzing goes away. I couldnt see any issues with the soldering so am hoping its just dirt building up in the jack, ive washed it out with electrical contact cleaner a number of times now and ran the lead in/out countless times. im also going to double check the leads.

It seems I can get rid of the buzzing by putting a small bit of pressure on the lead, as if its not getting a good enough contact inside the socket.


ps - first time in 2.5 years the amps been out, it still sounds sweet as a nut (less the buzzing!)

09-22-2010, 08:40 AM
putting pressure on the lead... how? pushing into the amp's input jack? or like pressuring itself by grabbing it? it seems like a ring (ground) connection on the lead is loose. i think trying another lead would be worth your time.

also, the buzzing is... an electrical buzz right? not an acoustic thing (rattling) is it like unplugging your instrument with the amplifier on? that kind? does the volume of that buzz go up when you turn up the volume?

09-22-2010, 09:17 AM
hey EC, you described it very well in your second paragraph, it is like the amp sounds when you unplug the guitar. it also increases with volume control.

Anyhow, I seem to have fixed it! I took the amp apart, drowned it in contact cleaner, cleaned the sockets out, cleaned the earth connections and cleaned any other connections such as the speaker, reverb box and transformer and it seems to be gone!

The only buzzing now is a VERY low hum, but thats to be expected given im testing it with my strat (SSS), might grab the SG and see if the humbuckers resolve it :)

Next up, volume pots. Does anyone know what pots (specifically) that I need? I read a comment above that I need a log/audio pot, but what resistance, scale etc?

I would like it so the current 0-1 is perhaps moved up so 0-3 covers the same range but after that it pretty much picks up as normal, is that possible?!

Invader Jim
09-22-2010, 09:33 AM
the ground connection is the SLEEVE. the RING is a second hot connection for stereo jacks. just had to clear that up.

look at the pot value. it should be printed right on the pot. something like B100k. B is linear taper. you want A, which is logarithmic (audio) taper. C is reverse-log taper. not too common but you still see them in amps. D is very uncommon anymore. it is "straight-line" log taper. instead of a nice curve, it changes abruptly.

09-22-2010, 09:38 AM
oops sorry, been up for around 20 hrs now unable to sleep, but i have no good excuses. :(