Mod circuit for SB-2

[LoveThatBass]

https://i.imgur.com/CBewvdt.jpg

This is how I modded my SB-2. I saved the original circuitry in event I ever wanted to sell it but I cannot see that happening. It shows the circuit with and without the tone control. I used the tone control stacked Pot but cut the trace so it will effectively be out of the circuit unless I want to use it. I used a .022uf cap in conjunction with 500KA pot so that it gives me easy ajustment without going too dark. It allows me to use the bridge and neck pickups full on if I wish and still knock off some treble when strings are new. By being No Load at full on I never have to remove it. The Master Volume is wired to give the least load to the pickup circuit when you lower master volume. I put the 200pf cap as a treble bleed on the Master Volume but frankly I think I like it better without.

I just posted a link directly here because the image suffers if I do with the Img or URL buttons

[Ken Baker]

I don't see any difference other than a slight truncation on the extreme right side.



Ken...

[LoveThatBass]

I don't either on the one you posted, however when I did it it came out small and when tried to zoom in it was very blurry. Just did it here and result is, same as yours (slight truncation on the right) thus not a big deal. Must have been an Imgur issue. Who knows. As I stated in the original post I will probably remove the 200pf cap on the Master Volume as it seems to rob tone (may be my imagination but don't think so) as it worked beautifully before I opened it up and added the small treble bleed cap. Also, I do not like the way they left the pickup leads much longer than needed to even remove the pick guard easily so I will go back and shorten them so they aren't wadded up in the neck pickup channel.

[Ken Baker]

I don't either on the one you posted, however when I did it it came out small and when tried to zoom in it was very blurry. Just did it here and result is, same as yours (slight truncation on the right) thus not a big deal. Must have been an Imgur issue.

It's actually your image, not a copy.

Who knows. As I stated in the original post I will probably remove the 200pf cap on the Master Volume as it seems to rob tone (may be my imagination but don't think so) as it worked beautifully before I opened it up and added the small treble bleed cap.

Paul once described the effect of the 200pf cap as kind of like the loudness button you might see on stereo receivers. It provides a little treble bleed at low volume levels.

Ken...

[LoveThatBass]

It's actually your image, not a copy.
OK




Paul once described the effect of the 200pf cap as kind of like the loudness button you might see on stereo receivers. It provides a little treble bleed at low volume levels.

Ken...
Right but in this case my tone seems to have lost some of the "chime", sort of flatter sounding. As I said, it may be in my head but I liked the tone before I put it in place.

[Ken Baker]

I've done a couple electronic rebuilds on G&L L Series basses and those little 104 caps seemed to never make it across.

Ken...

[LoveThatBass]

I've done a couple electronic rebuilds on G&L L Series basses and those little 104 caps seemed to never make it across.

Ken...

I cleaned the stock pickup wiring up. I removed the 200pf cap. Put together and bass sounds good so not my imagination. With the Master volume pot wired to be a constant load to the Pickup volumes it doesn't really get dark when I lower the Master as it does when you lower the individual Pickup volumes wired to the wiper lug of the pots. I understand why Leo wired that way so when you lower one pickup to zero it doesn't kill both so that is the only way I would want any dual pickup passive circuit wired. On a single P pickup you would want it wired to the outer lug of the volume for constant load with the tone coming off the volume pot's wiper and going direct to the output jack.

[ACEn8s]

I got a question for Gary and Ken,

In the set up with master volume with tone pot is it possible to add a 3 position switch wire to have the following positions;

- P pick up direct to master volume and tone by passing stacked V/V pots for each pick ups i.e. just like a SB-1

- P pick up and J pick up wired in series by passing stacked V/V pots for each pick ups

- position to have all controls functioning like your mod having V/V pots for each pick ups and master volume with tone pot


Just thinking out loud or maybe over thinking,

Scott

[ACEn8s]

I got a question for Gary and Ken,

In the set up with master volume with tone pot is it possible to add a 3 position switch wire to have the following positions;

- P pick up direct to master volume and tone by passing stacked V/V pots for each pick ups i.e. just like a SB-1

- P pick up and J pick up wired in series direct to master volume and tone by passing stacked V/V pots for each pick ups

- position to have all controls functioning like your mod having V/V pots for each pick ups and master volume with tone pot


Just thinking out loud or maybe over thinking,

Scott
ACEn8s

Posts: 1
Joined: Thu Apr 07, 2022 9:50 am

[Ken Baker]

In the set up with master volume with tone pot is it possible to add a 3 position switch wire to have the following positions;

- P pick up direct to master volume and tone by passing stacked V/V pots for each pick ups i.e. just like a SB-1
- P pick up and J pick up wired in series direct to master volume and tone by passing stacked V/V pots for each pick ups
- position to have all controls functioning like your mod having V/V pots for each pick ups and master volume with tone pot

I don't think this would be feasible. Certainly not using a single control to do the switching.

Ken...