PT2399 Test Rig Build Report

[Jdansti]

I thought I'd share this little project. It's good for testing batches of PT2399 chips.

I'm in the process of building DeadAstronaut's Abductor II delay which uses 4 PT2399 delay chips. I like to solder chips if possible instead of using sockets, and I want to make sure that the four PT2399s are good before I solder them in.

I made a little test rig using a simple delay circuit and mounted it on the outside of the enclosure so I would have easy access to the test socket. I used trimmers for the pots and put them inside the enclosure. Once they're set, I won't need to adjust them. All I'm looking for when I test a chip is that I hear echo. It's battery operated and has an on/off switch.



If a chip is good, I mark it with a white dot, and I'll keep a good one in it so that I can always make sure the tester is working properly. Right now I have to plug a guitar into it and run the output to an amp, but I might add a small signal generator, amp and speaker inside so it would work stand-alone.

I tested 7 chips that I had bought from Tayda and they all work. So now I'm ready to solder four of them to my Abductor PCB.

The circuit I used is the Ersatz Verben found here: http://tagboardeffects.blogspot.com/2012/03/ersatz-verben-psuedo-reverb-by.html?m=1, but any small delay or reverb that uses a PT2399 would work.

[bluebunny]

Good idea John.  Steve at Dr Tweek used to test all his PT2399s in a Rebote before shipping them to customers.  Just need to find a skinny ZIF socket...

[Elijah-Baley]

Thank you! Very useful.

If the IC is not good what happens?
I mean, I have a PT2399 on my Little Angel, I can hear a background noise just while I play. So I decided the IC is not so good, and I will buy 2-3 further PT2399. One is for a Rebote Delay 2.5.
Am I right?

[bluebunny]

I think noise is OK - they're not hi-fi.  But if they don't delay, then bin them.

[deadastronaut]

cool idea,  yeah i,m with you on sockets, they are nasty looking, but saves a lot of grief..
i,d hate to unsolder one of those buggers...let alone 4...

i may have just been lucky, but ive never had a bad one..............yet.

but i,m sure i will......crossed fingers.

[Jdansti]

Yeah. I've heard some complaints about Tayda's PT2399s and was a little nervous about using them blindly.

[italianguy63]

I know where you can get a Rebote kit for $17 as a test rig.   

MC

[Elijah-Baley]

I think noise is OK - they're not hi-fi.  But if they don't delay, then bin them.

Somepne said some pt2399s are quiter than others. Somebody can confirm this?
Indeed, I can hear on youtube several little angel noiseless or descripted like that.

[bluebunny]

i may have just been lucky, but ive never had a bad one..............yet.

I can send ya some, mate! 

[deadastronaut]

cool, are they from poundland...

[~arph]

You could also add a switch that sends in a pulse and an envelope follower + led at the output of the pedal. This way you can see if it delays. No need to listen. (even fancier would be a set/reset flipflop... )