my new guitar

[bjg]

i finally finished building my guitar and have plugged it in.
i now have two problems that were noticeable right away and i was wondering if anyone could help me with them.

first, the guitar hums, but when i touch a switch or a pickup screw the humming goes away completely. i know this is a grounding issue but I'm not sure what to do to fix it.

second is the volume control doesn't work correctly. it seems to work in conjunction with the tone selectors for volume and tone between all three. i think i may just have the pots wired backwards but any thoughts would be helpful

thanks,
Blake

[sumgai]

Blake,

i finally finished building my guitar and have plugged it in.
i now have two problems that were noticeable right away and i was wondering if anyone could help me with them.

first, the guitar hums, but when i touch a switch or a pickup screw the humming goes away completely. i know this is a grounding issue but I'm not sure what to do to fix it.

second is the volume control doesn't work correctly. it seems to work in conjunction with the tone selectors for volume and tone between all three. i think i may just have the pots wired backwards but any thoughts would be helpful

thanks,
Blake

Congratulations on becoming a full-fledged member of the "I can't believe I did that" community, welcome aboard! ;D

Your first question is easily answered - it's supposed to do that. If the hum is objectionable without touching the strings, then you may be located in a high-noise zone. In a house, or on stage at a club, or even in a practice studio, dimmer switches, flourescent lights, neon signs, appliance motors, all of these can cause excessive hum. Touching the strings to make it go away is fortunate for us, for obvious reasons!

Your second question requires that we examine your current wiring layout. For instance, what's a 'tone selector'? Perhaps you are referring to a pickup selector switch, or you could maybe mean a separate control that switches various capacitors in and out, ala the "Varitone" circuit, I don't know. And what's 'all three'? Three pots, like a Strat, or three pickups, or....?

See what I mean, there are too many as yet unanswered questions. I think we'd be better able to help you if you were to post a copy of the schematic from which you built your rig. It needn't be exactly a schematic, it can be a wiring layout diagram, or anything similar, so long as it's fairly easy to trace out the signal paths.

HTH


sumgai

[bjg]

im sorry for the lack of details

im am running a strat like configuration with 3 lace sensor pickups, 1 vol and two tone. it is set up for seies parellell selection much like in the tone monster two except without the blend pot.

first touching the strings does nothing to the hum. it is only the actuall switches.

also my vloume only works depending on how the tone knobs are set(some settings give me more conroll and some give me none) and the tone knobs work kind of backward.


im not goign to open it back up tonight(homework *sigh*) but tomorrrow i am going to check the pots and see what happening.


p.s. this is the schematic im using (without the phase switch) people.smartchat.net.au/~l_jhewitt/circuits/3xseriesparallelschematic.gif
people.smartchat.net.au/~l_jhewitt/circuits/3xseriesparallelwiring.gif

[sumgai]

bjg,

Got it. Your guitar's failure to stop the hum when you touch the strings can mean only one thing, the wire going to the spring claw in the trem cavity is not connected. It should be easy to figure out where that needs to be fixed.

Your 'volume works with some tone control settings' is much more complex. The first thing I'd do is trace every connection you've got against the schematic itself. (Or against the wiring diagram, the second one of the two links you posted just above.) I *think* that you might have accidentally connected one of the volume pot terminals to the unused terminals of both tone pots. The tone controls should have only two of the three terminals connected to anything, the remaining terminal should be left untouched.

That's all I can think of to tell you before you dig back in. Hope it helps.


sumgai

[JohnH]

bjg - I had another check through those old diagrams of mine. As I noted in your other post, that design was an interim one, which developed into the TM2. I still think they are basically OK, but there’s a few things you should know about them!

• The wiring represents the switches and pots, as seen from the back of the pick guard as you wire them up – (moved around a bit to suit the diagram – but the connectivity is OK)
  
• The tone controls, I now realise, would be considered backwards in most cases. I have another guitar like that, so I copied it that way. But if you want ‘max treble’, instead of ‘max treble cut’, at 10 (fully clockwise), just swap the wires from the outer lugs connected, to the other currently unused outer lugs
  
• You didn’t mention switch operation, but in that layout, the three ‘on’ switches for the pups will be operating on, in the down position. This is standard for electric switches in the UK, Australia, in fact almost everywhere important except in the US. For the TM2, based on lobbying from Texas, the switches were changed to ‘up’ = ‘on’. I kept with that in deference to the origins of rock and roll and electric guitars.
  

The design is intended to be within a screened cavity, as in ‘quieting the beast’, on the original GN site. Do you have foil shielding the cavity? Highly recommended, and one thing it does is it automatically grounds the bodies of all the switches as they contact the pickguard shielding. If not however, try wrapping a bare wire around the shaft of each switch, and connected to ground. That may solve the hum. A quick test version is to clip a wire from switch to jack outer case to see if this will help. With the pg shielding however, then this is not needed because the pg foil is grounded by contact to the volume pot

There’s no accounting that I can see for the weird tone/volume interactions that you describe. With the tone controls turned to whichever end gives max treble, then the volume should work in a normal way. So watch for an installation issue of some kind, a difference from the diagram. It might be good to disconnect the tone controls, and get everything else working right first.

How are the basic sounds? Are you getting each pup on and off working correctly, in series and parallel? Do they all sound in phase (ie, when you have two or three engaged, the sound is fuller, not thinner)? Tap the pickup poles gently with a screw driver to hear whether a pup is active. One key feature of the design is that the series/parallel switch does not change which pups are on or off, but just changes how they are connected

Good luck

John .