Shorting a feedback pot for infinite repeats

[LaceSensor]

Hi

can someone tell me what lugs on a PT2399 delay feedback pot Id need to short to get infinite runaway repeats going on?

Im sure it can be done.

Ian

[culturejam]

I think you'd want to bypass the feedback pot to get runaway oscillation with a switch.

[gtr2]

You'd also want to add back 2 back diodes in that loop.

Josh

[LaceSensor]

I was sure I read somewhere about someone using a momentary to short across some lugs of a feedback pot.

My plan was to have a toggle switch wired up, on the neptune, so one throw was the standard modulate LED thing, and the other way throw, would be wired to short feedback to infinity while the momentary was depressed.

Guessing ive either misread or taling bs

[culturejam]

I don't think you *need* the diodes unless you want to put a strict limit on how much feedback you get. Just shorting the pot will work, but it will runaway pretty intensely and get really loud in a hurry. You might want to increase the feedback limiting resistor (R9) to something like 12K or 15K.

After having built several of them, I would recommend R9 at 10K for general use. 1K is way too low.

[LaceSensor]

I notice so far that the feedback kicks in fast on this neptune.
Is upping that 1k to 10k your suggestion to fix that?

Thanks

[culturejam]

Yes, 10K is a much more reasonable value. You might even go 22K.

[jimmybjj]

What do the diodes do?

[midwayfair]

I notice so far that the feedback kicks in fast on this neptune.
Is upping that 1k to 10k your suggestion to fix that?

Thanks

Lace, you can also strap a 10k-15K resistor across lugs 1 and 2 of the dwell pot. It will move the runaway oscillation to ~3:00, and also retaper the pot, flatting out the increase in repeats in the center of the control. I did this on a cave dweller and have started going back to add it on all my PT2399 delays. I highly recommend it.

Some discussion here:
http://www.madbeanpedals.com/forum/index.php?topic=4869.0



jimmybjj: They are to clamp down on the volume in the oscillation. I didn't have any luck with it, though I might have done it wrong.

[LaceSensor]

I notice so far that the feedback kicks in fast on this neptune.
Is upping that 1k to 10k your suggestion to fix that?

Thanks

Lace, you can also strap a 10k-15K resistor across lugs 1 and 2 of the dwell pot. It will move the runaway oscillation to ~3:00, and also retaper the pot, flatting out the increase in repeats in the center of the control. I did this on a cave dweller and have started going back to add it on all my PT2399 delays. I highly recommend it.

Some discussion here:
http://www.madbeanpedals.com/forum/index.php?topic=4869.0



jimmybjj: They are to clamp down on the volume in the oscillation. I didn't have any luck with it, though I might have done it wrong.

Dwell pot or feedback pot.

[midwayfair]

I notice so far that the feedback kicks in fast on this neptune.
Is upping that 1k to 10k your suggestion to fix that?

Thanks

Lace, you can also strap a 10k-15K resistor across lugs 1 and 2 of the dwell pot. It will move the runaway oscillation to ~3:00, and also retaper the pot, flatting out the increase in repeats in the center of the control. I did this on a cave dweller and have started going back to add it on all my PT2399 delays. I highly recommend it.

Some discussion here:
http://www.madbeanpedals.com/forum/index.php?topic=4869.0



jimmybjj: They are to clamp down on the volume in the oscillation. I didn't have any luck with it, though I might have done it wrong.

Dwell pot or feedback pot.

It's the feedback (repeats) pot on the Neptune.

[culturejam]

I think "dwell" and "feedback" mean the same thing. I never understood why it would be called "dwell". Nothing lives there. 

[eldanko]

I was sure I read somewhere about someone using a momentary to short across some lugs of a feedback pot.

My plan was to have a toggle switch wired up, on the neptune, so one throw was the standard modulate LED thing, and the other way throw, would be wired to short feedback to infinity while the momentary was depressed.

Guessing ive either misread or taling bs

I did this in my Sea Urchin build... I believe it was lugs 2 and 3, IIRC... but it's easier to just jumper them with a spare lead or something to be sure!  The feedback actually didn't come on as quickly as you'd think doing it that way.  It was nice.

[alanp]

I think "dwell" and "feedback" mean the same thing. I never understood why it would be called "dwell". Nothing lives there. 

Are you going to dwell on this?

[LaceSensor]

I was sure I read somewhere about someone using a momentary to short across some lugs of a feedback pot.

My plan was to have a toggle switch wired up, on the neptune, so one throw was the standard modulate LED thing, and the other way throw, would be wired to short feedback to infinity while the momentary was depressed.

Guessing ive either misread or taling bs

I did this in my Sea Urchin build... I believe it was lugs 2 and 3, IIRC... but it's easier to just jumper them with a spare lead or something to be sure!  The feedback actually didn't come on as quickly as you'd think doing it that way.  It was nice.

cool! Will try on another build sometime. I have another neptune that I might build in time.