Is it my schematic or my ?

[jchumley]

Hmm. Well, I came up with a schematic based on this one:

http://www.seymourduncan.com/support/schematics/2hb_1vol_1tone_3way.html

Only I added push pull pots to split the coils. It doesn't work. Before I go looking for a bad joint or a misplaced wire, Can anyone confirm that the schematic should work if I execute it correctly?

http://home.comcast.net/~jchumley/schematic_2.jpg

 

[Artie]

Re: Is it my schematic or my ?

It looks to me like it should work fine, although, you do have it a bit more complicated than it needs be. You can just connect the red and whites together, with the top push/pull going to the neck black, and the bottom going to ground, like this:

Artie

 

[jchumley]

Re: Is it my schematic or my ?

Ah. After staring at your changes for a few minutes, I understand. I have resolved some issues and the switching seems to be working so I am not changing it for now. THere was a ground issue on the three way swich so I got all pickups all the time. I fixed that. But there are still odd problems. First of all, the pots are 500k audio taper (or they are supposed to be). I am wondering if the pots are actally linear.

Here are the symptoms:

1. The volume knob only works for the last few degrees of travel. From zero, as you turn it up, you get nothing, nothing, nothing then everything kicks in in the last 1/8" of travel.

2. The tone knob is similar except most of the tone change happens suddenly at the opposite end of travel from the volume knob.

3. And this is odd, On my son's fender frontman practice amp, it only works on overdriive. I get barely any sound with the overdrive off. On my Mesa Boogie Studio 22+, it is the opposite. If I hit the lead button, I get nothing.

Electronics are magic and I am no magician?

 

[Dave Z]

Re: Is it my schematic or my ?

Hm, another clarity question - why is the hot from the neck going to the pushpull at all? Just needs to go to the switch.

Vol & tone pot hookup look correct, are you certain of the tone cap value? Check for interaction - of the volume changes when you move the tone pot you have an issue. Also, make sure that the red & whites are connected, always...to split you just need to ground them.

 

[Artie]

Re: Is it my schematic or my ?

Hm, another clarity question - why is the hot from the neck going to the pushpull at all? Just needs to go to the switch.

If you short the red/white pair to green, you select the "stud" coil. If you short to black, you select the adjustable coil. Since green is also ground, most diagrams show it that way, and we sometimes forget that its actually the green wire thats being used.

By selecting the stud coil of one pup and the adj. coil of the other, when both are on it remains humbucking. Also, the stud coil of the bridge and the adjustable coil of the neck, tend to produce the best sound. IMHO.

Artie

 

[Dave Z]

Re: Is it my schematic or my ?

Aha - thanks Artie, forgot about the adjustable vs. slug issue.

 

[jchumley]

Re: Is it my schematic or my ?

Yes!

Looks like changing the schematic as Artie Too suggested did the trick for most of the problems. THe only one left is the pots still jump up at the last 8th of a turn or so. Is that how linear pots would respond?

 

[Artie]

Re: Is it my schematic or my ?

Is that how linear pots would respond?

No. A linear pot would have the opposite affect. The volume would be full up on the 2-3 side. I would double-check the volume control's ground connection. Make sure that it actually goes to the sleeve side of the output jack, and not just to the back of the pot.

Edit: I'm re-thinking this. A linear pot might do that after all. Even though I have a meter and pot right in front of me, this linear/log thing always trips me up. :blackeye:

 

[neosadist]

Re: Is it my schematic or my ?

Here's a set of schematics that should help you:
http://www.aukv44.dsl.pipex.com/images/hb_multisounds.jpg

 

[jchumley]

Re: Is it my schematic or my ?

It wasn't the pots. It was a place at the jack where the hot wire barely touched the side of its hole which was coated with stewmac conductive paint. Just bent the pole in a hair and the problem went away. BTW, I really like the conductive paint. I wasn't sure about it at first because my multimeter shows it to be much less conductive than copper foil but in practice, it works great. I took a one inch square of copper foil tape and taped it down to the bottom of the cavity ( already painted with conductive paint) And used it as a sloder attachment point. Works just fine. The heat from the solder on the copper tape melts the glue and makes it adhere to the painted surface extremely well.

THanks for the help. I still need to finish dressing the frets and do a final rub out of the finish but it should be done this weekend. My Brother in-law, who is an excellent guitar player, put it through its paces yesterday and it sounded great.

 

[Artie]

Re: Is it my schematic or my ?

Ah . . . Murphy's Law, alive and kicking.

Glad you found it, and thats one to add to the notebook.

Artie