Cave Dweller Dwell Pot Range Adjustment? FIXED

[calciferspit]

Just finished my Cave Dweller and really digging all the fun. But all the useable range of the dwell pot is in the first half, after that it oscillates. And it goes from 2-3 repeats to 20-30 repeats in 1-2 clock hours of sweep. is there any way to make the first 55-60% of the sweep be the entire sweep? thus creating a less sensitive range of usability with oscillation only at the very top? My initial thought it to replace the dwell pot with a smaller value around 30K. Any thoughts?

[culturejam]

Try switching tapers?

[calciferspit]

Try switching tapers?

tried linear and audio 50k with no noticeable difference. do you think a reverse audio taper would work? it still has the same amount of signal passed at the top range so I don't think so.

[culturejam]

If you've already tried linear and log, I'm not sure reverse log will help.

Generally, more resistance = less feedback. So I don't think going with a smaller pot is going to help.

Perhaps increasing the resistor that sets the minimum feedback resistance would be a good place to start.

[midwayfair]

The OP's difficulty is that the feedback increases very quickly in a short space. Increasing the value of the pot will just make fine adjustment more difficult. Increasing the minimum resistance will make the problem occur later in the sweep.

My suggestion? One of these:



You're going to end up putting a resistor on lugs 2 and 3 of the pot to create a big flat area in the middle. I suck at math; I'd probably end up doing this by brute force and testing every resistor I had on hand.

"Changing the Law of a Pot
Using pots can be done in the conventional way, or you can get adventurous and achieve a lot more. A good example is the "Better Volume Control" shown in Project 01. The other ideas presented also show how you can make modifications to the way a pot behaves, just by adding a resistor (R). The "ideal" value by calculation is 22k for a 100k pot, and this gives a maximum deviation of +1.58 and -1.7dB from a real log curve. This is contrast to the original article, where 15k was suggested, and although the error is greater (+2.89dB and -1.12dB), the overall behaviour is almost ideal in listening tests."

http://sound.westhost.com/pots.htm

[culturejam]

The OP's difficulty is that the feedback increases very quickly in a short space.

And that there is too much total feedback, thus my suggestion to increase the resistance.

But I agree that mucking around with the way the pot tapers is probably the best fix.

I've also noticed that the lower the cutoff frequency of the low-pass filtering on the delay line, the more easily the circuit will self-oscillate. Not sure why (I also suck at math), but it something that is quite repeatable.

[calciferspit]

The OP's difficulty is that the feedback increases very quickly in a short space. Increasing the value of the pot will just make fine adjustment more difficult. Increasing the minimum resistance will make the problem occur later in the sweep.

My suggestion? One of these:



You're going to end up putting a resistor on lugs 2 and 3 of the pot to create a big flat area in the middle. I suck at math; I'd probably end up doing this by brute force and testing every resistor I had on hand.

"Changing the Law of a Pot
Using pots can be done in the conventional way, or you can get adventurous and achieve a lot more. A good example is the "Better Volume Control" shown in Project 01. The other ideas presented also show how you can make modifications to the way a pot behaves, just by adding a resistor (R). The "ideal" value by calculation is 22k for a 100k pot, and this gives a maximum deviation of +1.58 and -1.7dB from a real log curve. This is contrast to the original article, where 15k was suggested, and although the error is greater (+2.89dB and -1.12dB), the overall behaviour is almost ideal in listening tests."

http://sound.westhost.com/pots.htm

TITS! this is perfect, AND IT WORKS!.

[culturejam]

Haha, cool. I don't mind being wrong. 

[calciferspit]

Haha, cool. I don't mind being wrong. 

Actually, i don't think you are. i forgot to mention that i switched to a 100k log pot for this mod (adhering to the specifics of the link), so the solution is a blend of both ideas. thanks again!

[midwayfair]

Yay! I think I'll use this on my next Cave Dweller build.

[trickpony]

Haha, cool. I don't mind being wrong. 

Actually, i don't think you are. i forgot to mention that i switched to a 100k log pot for this mod (adhering to the specifics of the link), so the solution is a blend of both ideas. thanks again!

So, you used a 100k log pot and a 22k resistor? How much of the "haunting" is left? Can you still get say 10 repeats?

Thanks,
Ben

[icecycle66]

Just finished this mod.  And oh yeah, it's nice.

[midwayfair]

After some breadboarding, I found that just putting a 10K across lugs 1 and 2 of the Dwell pot @ 50K (stock value) was adequate. It still oscillates on the very last of the pot's sweep; the infinite repeats happen much later on the dial, and there's a slightly smoother control in the middle.

I found a 100KA with the 22K resistor on it, just awkward. Almost the entire first half of the sweep was a single repeat, and it was very tough to dial in anything above 3 repeats without going into oscillation.

Anyway, that's what worked for me. I want to do a little more experimentation with the dwell pot before boxing this one up. I also did the bright mods this time around.

[Stomptown]

After some breadboarding, I found that just putting a 10K across lugs 1 and 2 of the Dwell pot @ 50K (stock value) was adequate. It still oscillates on the very last of the pot's sweep; the infinite repeats happen much later on the dial, and there's a slightly smoother control in the middle.

Wow! This is an amazing mod! I love my Cave Dweller now. The 10K across lugs 1 and 2 really tames the Dweller without losing what makes it special. THANKS!!!

[jimilee]

Now is there a way to put this mod on a toggle so I can turn it on and off? I love these haunting sounds for some songs but then need to go back to short repeats.