Double speed on a tremolo

[midwayfair]

So, I can't believe I never thought of this before tonight, despite all the times forumites have pondered the double speed mod.

Some friends of mine came over tonight for dinner and gearing, and one brought his SupaTrem. Of course, I knew I wanted to look inside it. It's got a speed switch that doubles the speed, and I picked the thing up and was talking about how some people have talked about modding their trems to do double speed and how most of the time it just doesn't work too well, and I said:

You know what I'd do? I'd put the speed on a dual gang pot, so that when you switched it on, it would always be exactly half.

Unscrewed it to take a gander at the circuit (three op amps, photocell, hard/soft switch is just both extremes of a wave control, yawn), and peeked under the foam covering the speed pot ...

Bingo. Dual gang pot.

Well, that was a nice feeling to guess so accurately!

In other news: This is how you do a 100% perfect double speed switch. You use a dual gang pot and a switch that connects the second gang to be in parallel with the first. Match the pot for best results. I believe a linear pot is also necessary.

[Ettore_M]

Nice guess! And it sounds right and seems dead simple!
I'll be using this! Thanks! 

Hector

[culturejam]

In other news: This is how you do a 100% perfect double speed switch. You use a dual gang pot and a switch that connects the second gang to be in parallel with the first. Match the pot for best results.

I wonder if Fuller gets his pots made to spec to avoid having to measure 10 or 12 to get one that has matching gangs. I'll bet run-of-the-mill Alphas are all over the place.

[midwayfair]

In other news: This is how you do a 100% perfect double speed switch. You use a dual gang pot and a switch that connects the second gang to be in parallel with the first. Match the pot for best results.

I wonder if Fuller gets his pots made to spec to avoid having to measure 10 or 12 to get one that has matching gangs. I'll bet run-of-the-mill Alphas are all over the place.

Of the 6 dual gang 100K I got from Tayda, two were within 5%. The others weren't too far off. Sometimes you get one that's really all over the map.

But Fuller is known to use custom pots. They've got more friction than most, too.

[culturejam]

5% is plenty close enough. I just assumed it would be much worse. Mos of the single-gang pots I get are all over the place.

[pickdropper]

In other news: This is how you do a 100% perfect double speed switch. You use a dual gang pot and a switch that connects the second gang to be in parallel with the first. Match the pot for best results.

I wonder if Fuller gets his pots made to spec to avoid having to measure 10 or 12 to get one that has matching gangs. I'll bet run-of-the-mill Alphas are all over the place.

Of the 6 dual gang 100K I got from Tayda, two were within 5%. The others weren't too far off. Sometimes you get one that's really all over the map.

But Fuller is known to use custom pots. They've got more friction than most, too.

Did you check at various points along the taper, or just at maximum resistance?

I"ve seen some inexpensive stereo pots (albeit more expensive than Alpha dual gang) that tracked quite poorly

[midwayfair]

Did you check at various points along the taper, or just at maximum resistance?

Just at max.