Messages

Same problem, two delays. Isn't that strange? I used different potentiometers for both pedals too.

So last night when I checked I thought there was an audio signal on lug 2 of the fdbk pot but I checked just now and there is no signal there. The signal is faint as it goes through R41, it is going into C48 but it is not passing through C48 into the fdbk pot. What should the signal sound like through R41?

I used a big 100V greenie for C48 . Do you think that type of cap may be causing a problem? I have used the same cap in other ZPSDXs that work...I'm not sure if I should just replace C48 with a different greenie or if I should get a different type of 220 nF capacitor.

Composition of the caps won't matter.

This is actually good news that you've found a place where you're losing signal. It makes it more likely that the problem can be found.

R41 is a limit on the feedback. Let's examine the feedback path. Signal exits the tone shaping after the mode switch and is divided between the path (when off) and feedback pot. One repeat always goes to the mix pot.

The feedback pot is a voltage divider between the output at the mode switch and the input of the PT2399 stage. It's just like a volume pot; when you turn it down, resistance is 0K between the "output" back into the delay section and ground; when it's fully up, resistance to ground is at its maximum (the most signal is retained), and there is zero resistance between the delay output and R41. The slam switch jumpers the lugs, just like you'd dimed the feedback pot.

You've essentially traced the signal backwards in your description. The faint signal you're hearing on the R8/R41 junction is the dry signal. It's very faint because you've only got 5.1K resistance to ground there! And you don't hear anything on the other side of R41 because the signal is grounded. In fact, I bet if you switched to the continuity setting on your multimeter, you'd find that lug 2 of your feedback pot is grounded.

Unfortunately, I don't have a trace mask, BUT, reflow your solder on everything that touches the feedback pot. Lift D4/D5 maybe to make sure that one didn't blow. There's a via right next to the diodes -- make sure there's not a solder joint. It might be really, really small.

It's available from Mouser and only $3.30. SMD only, though
A bit concerned that it's a 5V chip.

Probably because 5v is more than sufficient for its stated purposes, none of which are guitar pickups.

A humbucker can distort that on its own, without any gain at all.

Only 5 years! He was with you for such a short time! I just gnome he'll be sorely missed by you! But I'm fairy sure you could repair him with some glue!

lo-og, lo-og, it's better than bad, it's good!

This looks like it should be very fun.

I've got some. They've got short knurled shafts. The quality of the pot itself seems to be comparable with Alpha if not slightly more rugged. They're very good for certain small/short knobs, but considering how often I need to position a pot slightly off in a 1590A, I'm not sure they're good for universal use.

The other issue is that they don't have the widest range of values or tapers -- much, much smaller selection than the Alphas from Smallbear, which he carries in almost every value and taper you can get. The Bourns do have a pretty decent selection of multi-gang values, though.

I am also having this problem with a Cave Dweller I built. I have successfully put together both the ZPSDX and the Cave Dweller in the past...but this one repeat issue is getting the best of me.

You're having exactly the same problem in two different delays?

If too much signal gets sent to ground by the feedback pot, you won't get any repeats. Did you happen to use the same potentiometers for both pedals?

These look great.

Yours is the alcohol inks one, right?

Awesome, awesome demo.

Brian, are we going to do December PIFs this year?

This looks awesome, and I can't wait to hear the demo, but I have to ask: how exactly are those controls labeled?

Are you asking about material? It's handpainted. Otherwise, the controls labels are listed in the last paragraph.

Looks great! hope your foot gets better soon so you can commence with th' rockin'.

I'm wondering what it sounds like - is there any chance of a demo, Jon? [Edit: sorry, ignore that, i just re-read your post where you said you might well make one]

As I said near the end of the report, I will try to get one done. Not sure how soon, though. I have another demo in line ahead of this one.

Not to derail, but have you tried pinkjimiphoton's Juergulator yet? I'd love to hear your thoughts on it. I've been playing around with the transistors in mine and am wondering what you think about transistor choice.

I breadboarded it, but I wasn't thrilled about it enough to make another one while I was busy (I still like the Albini specs perc I made a while ago). I just use the button 3565s that Smallbear sells and a really low gain PNP (just whatever I have around that's 40-60 hfe), and that's it. The better thing to worry about imo is the Fv on the diodes. It sounds better to me when you raise the Fv a little. I also think it helps to lower the gain of the whole thing a little. To me, the real issue with the perc continues to be the noise level, not the functionality (which is great even stock, and jimi's perc control is awesome), and so far as I know no one has found a good solution ... mostly because PNP transistors are always noisier in NPN circuits, and germanium is noisier, too.

What happens when you flip the path switch?

Do you have audio signal on pins 12-16 of BOTH PT2399s?

Audio probe the appropriate pins of the TL074 (filter section). Go through the modes one at a time. Verify that you have signal.

Also, use your multimeter's continuity settion to check all the pins on the rotary connection to verify that there aren't any solder bridges. I had that happen. You have to be very thorough and make sure nothing's connected when it shouldn't be.

The TL072 has nothing to do with the repeats, there shouldn't be any need to touch it.

EDIT: Also, please post pictures and voltages per the tech help rules.

Isn't  that enclosure a bit big for your standards? lol

Yeaaaaahhh ... that enclosure shipped to me from Smallbear on 4/19/12. I figured I should just use it finally. I drilled it forever ago and just never decided what I wanted to put in it. Plus it let me use full-sized pots, which are cheaper, and I'm out of low-profile jacks for a while that aren't already spoken for, so no 1590As for me a bit.