Pot value for blending pups in series

[ChristoMephisto]

What's a good pot value and taper for blending pups in series like the SPlender and such. Read over a few good posts from years ago and mostly 100k linear was used. More recent schems that's been posted here use 250k audio. But also talk of too much wasted space/taper after a certain point.
Were the 250KA more readily available in people's parts bin or was it determined that 250k a better value?
I've worked out how to add a single blend pot to the classic T-riffic wiring on a tele with a bridge SD Broadcaster and a neck BL Keystone using 500k pots.

[JohnH]

There's a few ways to do series blending, and the best pot depends on which you propose. The one in Ozboomers SPBlender, as with two that I did, uses a linear pot which you open up and disconnect part of the track to make a no-load zone at the centre. Then as you move away from there, it progressively shunts one or other pickup. I tried 100k and 250k linear, and both were fine. I think I liked the 100k best but both are ok to give you some gradation and find the in-between tones. Wirh tge 100k, by the time you have removed part of the track, there might be about 40k left each side, and most of the potential variation usually happens in that range, leaving the last increment as a small step-change.

But my current strat just fades out one pickup, leaving the other unaffected. A log pot is best for that and I use a 250k log no-load pot. It gives lots of control from 1 to 5, then a bit more up to 10 where it stops shunting.

My LP uses the usual seperate volume pots, with treble bleed, with the whole pickup/pot module is in series with the other. These are 500k log.

[ChristoMephisto]

I'm going for the in between sound where most of the play is in the latter half of the rotation, 5-10.
Going from your reply, a 50KB pot would work out best for a blend with greater variance. The first half of a 250KA is about 25k then jumps so could see how you have extra steps.
Need to order a pot so might as well get both in case the smaller one isn't enough, doesn't hurt to try.

Thanks again

[col]

Aug 19, 2016 3:46:40 GMT -5 JohnH said:

There's a few ways to do series blending, and the best pot depends on which you propose. The one in Ozboomers SPBlender, as with two that I did, uses a linear pot which you open up and disconnect part of the track to make a no-load zone at the centre. Then as you move away from there, it progressively shunts one or other pickup. I tried 100k and 250k linear, and both were fine. I think I liked the 100k best but both are ok to give you some gradation and find the in-between tones. Wirh tge 100k, by the time you have removed part of the track, there might be about 40k left each side, and most of the potential variation usually happens in that range, leaving the last increment as a small step-change

So (assuming i understand this correctly), when in the middle, there is no load from the pot. And when shunting one of the pickups, there is no load on the other pickup or any effect/load from the other section of track. That's a nice, simple solution.

[JohnH]

Yes, theres no compromise on 100% of one or both, at the ends and middle.

Never tried 50k with cut track ( that will only give about 20k each side of the cut section). 100k is quite smooth for this. You get aboyt 40k of variation each side.

[ChristoMephisto]

Wasn't planning on cutting tracks, just blending one pup like your strat.
Found a 100k pot in my parts bin, and salvaged a 5 way switch no now I can strat this project sooner than later.

[JohnH]

I thought you were doing the blending like on ozboomer's diagram that you pointed to. That design relies on the track cutting to work properly.

If you are only blending one pickup in, eg like you blend just from Neck to Neck x Bridge, then you need a log taper pot wired across the pickup being blended in and if you want to approach the full series tone it needs to be 250k unless you make a no-load 100k.

[ChristoMephisto]

So had the 100k linear blend no load pot in for a little over a week now, and initial impressions were good. Altho the value is good, a different taper could be used.
Thinking of trying a no load 100kA next. At half way the pot is about 10k. Just past where the resistance is equal to your pickup. Rolling the pot up to 7-8 is roughly equal to 50k to 70k, which almost become a sweet spot and almost full blend.
Also when you roll back the pot to where it starts to effect the internal resistance of the pickup, some interesting tones come out. Hard to test with a 100kB pot, the resistance is too short of a rotation.
The idea here is to have all the action of the blend pot in the 5-10 area of the pot, much how we use the volume n tone in the last half of the rotation.

[JohnH]

Sept 10, 2016 14:11:31 GMT -5 ChristoMephisto said:

So had the 100k linear blend no load pot in for a little over a week now, and initial impressions were good. Altho the value is good, a different taper could be used.
Thinking of trying a no load 100kA next. At half way the pot is about 10k. Just past where the resistance is equal to your pickup. Rolling the pot up to 7-8 is roughly equal to 50k, which almost become a sweet spot and almost full blend.
Also when you roll back the pot to where it starts to effect the internal resistance of the pickup, some interesting tones come out. Hard to test with a 100kB pot, the resistance is too short of a rotation.
The idea here is to have all the action of the blend pot in the 5-10 area of the pot, much how we use the volume n tone in the last half of the rotation.

I'd expect that with the one direction blending ie A blends to AxB, the 100kA (ie log taper), going to no-load as it approaches 10 will be ideal. All the in-between tones will be available, spread around the dial, and there will be the last small increment as you get to 10. This small increment will be significant, but small enough that you wont feel that you are missing the ability to subdivide it further. Then at 10, you get full series.

On my Strat, I have a 250kA no-load for series blending. There's plenty of provision for finding the various tones, but there's hardly anything added in the last 1/3 of the turn up to full series, and nothing audible from the no-load cut-out at 10. This suggests that 250k is enough to make all the transitions, with some spare, and that most of it is in the first 100k.

Can you buy a 100k no-load? Id expect you may have to convert it yourself. I've done quite a few and never had a problem, but it works best on a full sized pot. I do it by taking out the track and clipping a multimeter across the ends. Then small smooth scrapes across the end of the carbon track and you can watch the resistance increase, k by k until it goes off the scale. Another way, that I haven't tried, is without cutting, put 'nail polish' (or more likely something else, I finished my 40 gallon drum) across the track end.

[ChristoMephisto]

The Alpha dime pots (16mm) are easy to pull apart to convert to a no load.
Easier than using a toothpick or a jewelers screwdriver and going through the small opening by the tabs to apply the glue or polish.