Fun With Log/Antilog pots!

[SteveG]

Hi

I recently needed a 10k dual log/anti-log pot. for a project, so these not being readily available, I ordered a dual Alpha 10k log pot. and a single Alpha 10k anti-log pot. The plan, of course, was to transplant the anti-log 'wafer' into the dual pot. to make the required part.

The parts arrived today, and here's the twist. The anti-log wafer had to be turned upside-down to fit into the dual pot., a procedure which instantly converted it into an ordinary log taper!

What I actually needed was a 10k log taper wafer, which would have become an anti-log when transplanted into the dual pot.

Confused? I was!

The best laid plans, etc etc.

Steve

[Morocotopo]

Or two dual log pots, you take the log wafer from one and put it into the other in place of the, ermm, log wafer but inverted. Or is it the other way around?
I´m confused.

We DIYers, here in Argentina, where there´s no available antilog pots in the shops, do that routinely! No sweat!

http://foro.cuartitodiyer.com/viewtopic.php?f=9&t=958

I´m Mostro there.
Well, actually it´s been some time since I´ve done it, ´cause now I order those from Smallbear, so I´ve forgotten the specific procedure. We can´t get pots with solder lugs, either, just with PCB ones. We make do with what we can get!

I seem to recall that getting the axle free on the Alpha pots was very difficult, since the metal shaft it´s held in place by stamping/flattening the inner end, and undoing that mostly ended in destroying the wiper´s piece. The pots we get here in argentina have a plastic axle, so it´s easier to get it free. How have you done it?

[SteveG]

"I seem to recall that getting the axle free on the Alpha pots was very difficult, since the metal shaft it´s held in place by stamping/flattening the inner end, and undoing that mostly ended in destroying the wiper´s piece. The pots we get here in argentina have a plastic axle, so it´s easier to get it free. How have you done it?"

I drilled them out. If you're careful (and lucky!) you can drill just enough so that the plastic part can be coaxed off and replaced (It would have to be glued to work again). I didn't actually need to re-use the single pots, though, so I wasn't that bothered as long as the wafer was intact. Installing the wafer onto the dual pot is a breeze in comparison - it's just held in place by four tabs.

The pot is for a replica Boss SP-1 Spectrum, BTW.

Steve

[pedalgrinder]

what i do is carefully drill them then use a tapping screw like that used in glasses you wear to see very fine with a hat type screw part where the screwdriver goes so it holds the wafer and whatever else in place. I purchase the screws from glasses places and they do the job nicely. fidely job though. i have muttered a few obscenity's while doing it.