Dirtbaby 2015 white noise on repeats - 03/28 sound sample added(zero point mini)

[madbean]

I have chips from different sources, but I have a couple from smallbear that are low-noise which I keep for evaluation purposes. It's good to have one or two around so you can benchmark other chips against them. They are basically all over the place in terms of specs and Tayda ones may very well be out of spec (just a hunch).

Still, I do not understand why a few people are getting so much noise. It is a pretty quiet circuit by PT2399 delay standards. I'll think on it a bit.

[slimtriggers]

Yeah, I got mine from Tayda as well.  I have quite a few of them from different batches, but I've only tried 2 so far.  Same results with both.  I'll pull the ones from my Multiplex tomorrow and give them a try.

I did sub tl072's for the tl062's because that's what I had.  Not sure if that would matter.

[MAO]

I've been getting my 2399s from Tayda, I must have gotten lucky on my 1st order as the Zero Point SDX sounded great. That was a few months ago.

I'm convinced the ICs are the issue as the only constant between the 2 Dirtbaby's and the Zero Point Mini is my guitar, patch cables, and the solder. I'm pretty sure none of those are causing the problems with all 3 builds. Also, the other constant is the 5 PT2399s I have, have all been purchased from Tayda. 

For now I did all the C8, C9, C10 and C19 cap changes, didn't really change much, but it may have taken the edge off the white noise a bit. I also added a 220k across the Delay pot bringing it's value down to 40k. This seems to allow acceptable, or less noticeable, noise up to about noon on the pot.

One other thing I noticed is when feeding the Dirtbaby with a Boss CE2 Chorus clone, the noise wasn't so apparent on the repeats.

Anyway, going to try another source for more 2399s.

[selfdestroyer]

I grabbed a bunch of PTs from MKlec and had great luck with them. Worth a try.

Cody

[MAO]

Just received 10 PT2399s from Nooelec , no improvement. I also tried them in a Zero Point Mini, same noise issue.

Going to give MKlec a try before I give up on these builds. Very frustrating!

[MAO]

Here is a reply I received from NooElec about the noisy PT2399s I received from them.

"We are an ISO certified facility and purchased these parts directly from the factory. We have sold thousands from the lot that was shipped to you. There is about zero chance you received 10 defective parts. Please send full details of your testing methodology, thank you. Kind Regards, Sarah NooElec Inc."

Does anybody have a sound sample of a Dirtbaby or single chip Zero Point you can post? I'd like to hear how yours sound with Delay knob at noon, Feedback down, Mix up and you hold a note or chord and let it ring out.

Both my Dirtbaby and Zero Point mini have an annoying white noise on the repeat.

Thanks,
Mike

[Govmnt_Lacky]

I wouldn't deal with them much longer if I were you...

A common tactic with these sellers is to string you along with requests, messages, and chit-chat until the return period passes.  Besides, I highly doubt that Princeton knows or would appreciate that their patented design is being sold out of the factory back door.

If you truly feel that the products are defective, you should just file a claim now.

[madbean]

Does anybody have a sound sample of a Dirtbaby or single chip Zero Point you can post? I'd like to hear how yours sound with Delay knob at noon, Feedback down, Mix up and you hold a note or chord and let it ring out.

Both my Dirtbaby and Zero Point mini have an annoying white noise on the repeat.

Thanks,
Mike

I'm sorry you are having so much trouble with your builds. I am going to a demo of the ZPSX2 soon so I will hook up the Dirtbaby too and do one for you. That should give you a basis for comparison.

[MAO]

Thanks Brian, appreciate all that you do.

It has to be the PT2399s. Still waiting on the ones I ordered from mklec.

I was able to record a sample of my Zero Point Mini. It's essentially the same noise issue with the Dirtbaby. All 15 PT2399s sound about the same. 5 are from Tayda, 10 from NooElec.

Mix is all the way up, feedback off, no modulation.

Recorded strait sound, slap back, delay knob 1/2 way, then full on.

Sounds a little dark because I recorded with an Air Zone neck pickup and have 2n2 for C7 & C17, and 47n for C18. I also used a dual gang pot for the delay and tone control, as the 50k delay is turned up, the simulated 25k tone is turned down. Was hoping this would help. Seemed like a good idea, but didn't do much.  Haven't had a chance to reverse all the changes yet.

I'd be curious if this is the same issue as the others who have been having noise on the repeats. 

[MAO]

I received 3 PT2399s from mklec, 2 have no delay at all and the 3rd is noisy.

Another $12 down the drain.

 

[jighead81]

Dang, I was waiting to see how you did with mklec. Sorry man. I think I may have to give up on PT2399 stuff.  Maybe when dr tweek's site is back up, (if it's not already),he'll have some tested ones to sell

[MAO]

I had decided to throw in the towel a couple times as I've spent more hours troubleshooting these 2 Dirtbaby's and a Zero Point Mini than it took me to build the last 10 pedals! But I'm re-determined (is that a word?) to get them acceptable.

Some success, turns out my Zero Point Mini locked up the PT2399s.  I've since added an LED to pin 7 and tied the other leg to both pins 3 and 4, thus grounding pin 4. The new PTs came back to life.

One of the mklec PT2399s is tolerable in the Dirtbaby, until the Delay pot resistance is about 25k and as long as I keep the mix volume low. Sounds really good with all the stock cap values...until the noise creeps in on the longer delay times or if I turn the mix up to loud.

I'm going to replace the Delay pot with a 25k and limit the Mix volume with the trimmer to see if both the noise and the delay times are acceptable. And if that works, I may also increase the 1n caps to 2n2 to see if that will allow for a little more delay before the noise is irritating.

[slimtriggers]

I think I screwed something up on mine.  I swapped the pt2399 from my Multiplex Jr. and got the same distortion.  Conversely, the PT2399 from the Dirtbaby sounded great in the Multiplex.

I'll have to come back to this one when I have some more time to troubleshoot it.

[MAO]

Major improvement!

C13!!!

I noticed C13 is a much higher value in other circuits such as DBD and Multiplex. Swapped in a 33n and for the 1st time the noise is greatly improved! I almost don't want to touch it anymore. 

Can't believe it took me 3 weeks to stumble on this, especially considering I knew the noise began at pin 14 of the PT2399. I had tweaked C8, C9, C10 and C19 but completely overlooked C13.

Going to try a 47n and 56n tomorrow.

I don't know if this CAP change takes away from the intent of the Dirtbaby's DMM-like sound, but my main goal is to reduce the noise and it appears C13 is the key.

May actually wrap this up tomorrow

[blearyeyes]

All I know is PT2399 chips are the bane of DIY existence. They seem to be in the middle of several ongoing issues. I do know the first time I built a PT based delay I was a bit disappointed and had to except that the drawbacks that are apparent with this chip are just the way it is.. Isn't there a different digital chip that sounds better?