Cavedweller Noise on higher Time FIXED!!!

[GarlandGuitar]

Hey guys

Built up a Cavedweller PCB, didnt substitute any parts except for the 740k resistor I believe it turned out to be 731k (511k+220k).

I am using A pots because I am waiting on B Pots to arrive. I used some A100ks on the top with a 100k Resistor from 1-3 on Dwell and Echo, which seem to do what they are supposed to - I would think the taper is not as smooth now though.

I have switched to a B25k pot, and get about 200ms of time with no noise up. With an A50k however, I got tons of noise past about 300ms on the pot.

I can only describe it as "Wooly Static that crackles in the background and distorts the Delay. Only past 300ms or so though. What gives?

[madbean]

As I mention in the project doc, and has been explained here in the forum: this is a minimally filtered PT2399 delay. Some amount of aliasing and artifacting is normal from the second half to max delay. This is present to some degree in all PT2399 designs, although more heavily filtered designs do tend to tune that noise out more succefully. It is possible to filter the Cave Dweller a bit more by increasing that 4n7 cap (C3) to a higher value. However, this will darken the delay and your regular guitar tone quite a bit more, so it is a trade-off.

You can also try swapping out different PT2399s. Some are just noisier than others and it's possible you might find a better one. But, you will also never eliminate the zipper noise completely. It's just a downside of this chip, unfortunately.

[GarlandGuitar]

I tried swapping, same thing happens. It's not just " some " noise. This is, unuseble!

You turn the pedal on, and if its anywhere past 50-60% it will start to cycle white/line noise back into my signal, when I am not playing. and it is LOUD. especially when my Echo is turned all the way to 100% right.

I dont hear the same noise in any of the demo videos I see of this circuit. I just know as soon as I try to pass it onto a musician they are going to complain.

Ill have to try to cap, if that doesnt work, Ill just put in a B25k and call it a day. I guess I can just offer this as a 300ms tops delay only.

Thanks for helping either way! I am determined to get this baby to a Time level where it will get decent delay but not lose control sonically!

[BraindeadAudio]

My personal one, I dont crank past 1 o clock on that pot. Im getting some pretty awsome tape machine like delay tones out of it using a kickdisk foot controller on the other pots. Sounds like my Echoplex but with more versatility(And I dont have to lug around a 1000$ unit live!)

[GarlandGuitar]

I chose a B25k pot I just received in the mail, and I think it fixed my Time probz!

I also never really go past 400-450ms on any delay, but now, maxed out - its that perfect U2 With or Without You Delay

I think we're all sorted out!! Thanks for the help

[GarlandGuitar]

THIS IS A SLAPBACK LOVERS WET DREAM!!!

[culturejam]

I think B25K on the Time pot is optimal for any 2399 delay. The damn thing is just noisy beyond that, and really wasn't designed for times much past 300ms. But with a little heavier filtering (drop the cutoff quite a bit on the second-order low-pass on the delay line output), you can push it up to about 400ms - 450ms with acceptably low noise. In my opinion, YMMV, allegedly, and all that jazz. 

Also, try swapping out the regulator. I find that a lot of noise can come from a bad or flaky regulator.

[gtr2]

Sounds like my Echoplex but with more versatility(And I dont have to lug around a 1000$ unit live!)

What version echoplex you have?

[GarlandGuitar]

CJ I agree, but I think I possibly went bad somewhere,

this is one of the first builds where, low on sockets, I didnt socket the Q1. I actually glanced at it for a second and thought hmmm, maybe theres a problem there -

But the B25k fixed what I was having issues with!! Great Pedal now, and a very satisfied customer!!!

[BraindeadAudio]

Sounds like my Echoplex but with more versatility(And I dont have to lug around a 1000$ unit live!)

What version echoplex you have?

EP-2, a little wonky and still needs some work but it is running.

[gtr2]

There's a good yahoo group you can join up with that I follow.  I've got an EP-4 and a Re-201.  Some of the guys on there really know their stuff.

http://launch.groups.yahoo.com/group/electroechochamber/

[BraindeadAudio]

I just saw this reply, thats awsome thanks!