"Little Angel" - Super Simple PT2399 Mini Chorus

[blooze_man]

I wonder how this would sound if it had a tone control

[clamup1]

hey does the words on the LFO go toward the ic or away from it.

[Taylor]

An LFO is not a part, it's a circuit with a number of parts that make it up. So what are you referring to when you say "LFO"? Are you talking about the thing with 3 legs and a metal tab on it? That is called a regulator, and you appear to have it in right.

[clamup1]

thats not my pic but i put it in that way. thanks

[frequencycentral]

I wonder how this would sound if it had a tone control

I'm gonna add a 'dark' pot for tone to the elite version - "Archangel"

@ clamup1: did you use a NE5532 dual opamp? The circuit values are set up to work with a NE5532. Other dual opamp type will give different results.

[clamup1]

@ clamup1: did you use a NE5532 dual opamp? The circuit values are set up to work with a NE5532. Other dual opamp type will give different results.

yeah i used the 5532. i got everything in and its still didnt work. i get clean but no effect. ive seen 2 different ways to hook up 3pdt and cant get either one to work.

[frequencycentral]

i get clean but no effect. ive seen 2 different ways to hook up 3pdt and cant get either one to work.

Can you test the circuit away from the 3pdt? It may be your 2pdt wiring that's causing the problem. Maybe.

[clamup1]

my chips are facing the right way and i still have 8.29 on the ground. i had to buy a new solldering iron b/c the tip dissengrated so i was leaving huge solder bumps on the board. i think i have to either reetch a board or desolder and try again

[Earthscum]

clam: quick question... did you socket the IC's? If so, have you tried just swapping out IC's? There was a bad batch of (possibly counterfeit) PT's running around. I'm pretty sure that the normal DIY pedalbuilder sources are fine, I don't remember Steve or anyone saying that they came from their batches.

[frequencycentral]

my chips are facing the right way and i still have 8.29 on the ground.

Look for solder bridges anywhere where the (red) +9v trace is close to the (brown) ground trace. ie around C11, D1, R8, R9.

[Earthscum]

Should we Keen clam and refer him to This Page? 

I blew out a TL072 and got a short through the chip. I kept getting my 9V on the ground, regular VR's where they were supposed to be. I about fried my PS, and probably would have if I didn't catch the smoke from melting plastic... heat sinks are GOOD!

[clamup1]

both ic's are in sockets. i have swapped both ic's. i got my ic's from small bear i dont think they would sell bad chips. ill check for solder bridges, it wouldnt surprise me

[clamup1]

hey i think i fgured it out. the diode is blown or not hooked up right. im getting 8.72 on the neg side of the diode. which accounts for why i have 8.72 on the ground. i didnt know you could blow diodes. i hope this works. ive been staring at this thing for an hour.

[clamup1]

well that didnt work. im getting almost the same mv thats coming off the end of the diode. i dont know what it is. i gotta study for a test. later

[frequencycentral]

well that didnt work. im getting almost the same mv thats coming off the end of the diode. i dont know what it is. i gotta study for a test. later

Is the diode correctly oriented?

[soggybag]

I just built one of these for myself, from the layout here. I used a piece of perfboard, but followed the PCB layout.

Before adding any ICs I powered everything up and tested the voltage at the correct pins. Op-amp pin 8, 5V at the regulator and PT2399. Everything checked out. When I put the chips in I wasn't getting any oscillation. After a long "close" inspection I couldn't figure it out. Came back later for a quick look and see an obvious solder bridge. Fixed that and everything started working. Never under estimate the effect of taking a break on your productivity.

I haven't given it much of a test yet. First impressions seem to say that everything is working correctly. Sounds to me like the LFO has sort of a wobble to it. Like it's not quite a triangle. This seems to change as the speed and depth are adjusted. I'll have to test it some more.

I did sub the 100 ohm resistor from PT2399 Pin 6 to ground with 82 ohm, as this was the closest I had on hand. I figure this wouldn't make much difference? I'm thinking about adding 50K pot to ground at this resistor to get regular delay and chorusy sounds. I assume this should work.

[Earthscum]

I'm starting to wonder if C11 (power filter cap) isn't bad? What typically happens to caps when they go bad?

I've had a cap that I suspected was blown and it read as a resistive short (aluminum electrolytic), but I don't know if that is typical behavior... I threw it away without an autopsy, but I'm guessing the dielectric  material melted and allowed the 'plates' to make contact.

[clamup1]

i have gone over the + rail and scraped all the melted plastic away from everything else. the diode is put in the same way as its in on the schem. i didnt check the cap. i did break both of my small drill bits so i had to use a 1/16 on the end where the pot, +,-, wires go. soldering those was fun. i also unhooked the switch and took out the ic's.   

[clamup1]

  im not gonna tell you what i did wrong but i got that fixed

now i get clean with ossilation, switch on have to turn my amp all the way up and only get a little bit of signal.

[clamup1]

i have a ? about how to hook up the jacks. im not at my home computer so i cant find the website but. does the board have to be grounded to the encloser and do the jacks have to be grounded to each other.