"Little Angel" - Super Simple PT2399 Mini Chorus

[Govmnt_Lacky]

Recommend you follow this link:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Repost after reading through the link and following what it says. You will get it fixed 10x faster!

Good Luck 

[bluesman1218]

Recommend you follow this link:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Repost after reading through the link and following what it says. You will get it fixed 10x faster!

Good Luck 

Thanks, GL. I printed and read through the debugging pages (helped me eliminate DC hum), but didn't see this one. I'll go through RG's steps and take it from there. He is such a terrific resource to all of us hobbyists.

[bluesman1218]

RG Keen Debugging checklist

1.What does it do, not do, and sound like?  Constant crackling and can’t hear effect. When turned off (true bypass) all is well, so I don't think it's an off-board wiring issue.

2.Name of the circuit = Little Angel Chorus (VERO layout)

3.Source of the circuit (URL of schematic or project) = Vero Layout I used http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg737758#msg737758
Original layout/parts list http://www.diystompboxes.com/smfforum/index.php?topic=86297.msg723128#msg723128

4.Any modifications to the circuit? N

5.Any parts substitutions? If yes, list them. no.

6.Positive ground to negative ground conversion?  Don’t know

Voltage readings
Voltage at the circuit board end of the red battery lead = 8.34
Voltage at the circuit board end of the black battery lead = 0

Q1   78L05   
Out = 4.97   
In =   7.94   
Grnd =0.01

IC1 NE5332
P1   0   P4   0.01           P7   varies   
P2   3.35   P5   varies   P8   8.20   
P3   2.93   P6   varies         

IC2 PT2399
P1   4.97   P4   0.01   P7   3.23   P10   2.48   P13   2.48   P16   0.01
P2   2.47   P5   0.95   P8   3.28   P11   2.48   P14   2.48   P17
P3   0.01   P6   2.32   P9   0.27   P12   2.10   P15   0.08   P18

Z1 (zener)
A (anode, the non-band end) =   0.01
K (cathode, the banded end) =   8.12

Voltage on all Electrolytic caps is higher on (+) pin than on (-) pin

I have PCBs coming and will do a fresh build on them. Until then, I would love to get this working. Any help would be greatly appreciated, as I'm not a circuit design guy, but can follow directions and build.

Steve

[Pigyboy]

Can you post a pic of the board and the inside of the build?
Chris

[Renegadrian]

5.Any parts substitutions? If yes, list them. Vero listed 7 – 100nF caps. Since this count/value didn’t match Rick’s original, I used .1uF values.

Really?!? Now THAT'S the reason it doesn't work! lucky you it didn't explode...why did you use .1µ instead of the 100n!!!
That can be dangerous...I warned you.

[bluesman1218]

5.Any parts substitutions? If yes, list them. Vero listed 7 – 100nF caps. Since this count/value didn’t match Rick’s original, I used .1uF values.

Really?!? Now THAT'S the reason it doesn't work! lucky you it didn't explode...why did you use .1µ instead of the 100n!!!
That can be dangerous...I warned you.

As I said, I'm not a circuit guy and unless the circuit was changed for the vero layout, I didn't understand why the values would differ from Rick's original circuit. If I'm missing something, please let me know.

[Taylor]

Bluesman, he's just messing with you (a rite of passage, but perhaps a little unfair).

.1uf (also written .1µ or rarely .1mf) is the same value as 100nf.

This page will help you get familiar with the conversion between uf, nf, and pf. Luckily it a base 10, metric thing, so it's pretty logical and simple once you get used to it.

http://www.justradios.com/uFnFpF.html

[bluesman1218]

Bluesman, he's just messing with you (a rite of passage, but perhaps a little unfair).

.1uf (also written .1µ or rarely .1mf) is the same value as 100nf.

This page will help you get familiar with the conversion between uf, nf, and pf. Luckily it a base 10, metric thing, so it's pretty logical and simple once you get used to it.

http://www.justradios.com/uFnFpF.html

Thanks, Taylor, I had a brain fart. All values are correct and I have fixed the original request above.

[bluesman1218]

Can you post a pic of the board and the inside of the build?
Chris

Here's a shot of the board with the same orientation as the vero layout diagram. I'm not really happy with it, but  I would like to get it working. BTW, the LED is disconnected temporarily, hence the loose yellow wire.



BTW, I made this cable so I don't have to keep hooking up the batttery in the pedal. It's also a handy backup on stage if you use batteries when performing live and one fails.

[Renegadrian]

+1 on the battery cable! I have several of them.
The pic of the board doesn't help, it looks like the vero layout but how can we see if there is something wrong?!

[Govmnt_Lacky]

I dont have my numbers handy HOWEVER,

A few things stick out to me. Particularly your voltages on IC1 Pin 1 and IC2 Pins 15 & 16.

You may want to construct an AUDIO PROBE and use it to track down some of your problems. Just go to the search function above and search for "Audio Probe." Its a simple item to construct and is invaluable in troubleshooting.

Good Luck 

[bluesman1218]

+1 on the battery cable! I have several of them.
The pic of the board doesn't help, it looks like the vero layout but how can we see if there is something wrong?!

Re: cable - I always stock the hard plastic 9v snaps instead of the ones that bend and break from repeat use.
Re: pic - I just right click on it, <Copy Image> and paste it to MS Photo Editor to enlarge and scroll. I'll see if Photobucket has a way to show a larger one if you click on it.

[bluesman1218]

I dont have my numbers handy HOWEVER,

A few things stick out to me. Particularly your voltages on IC1 Pin 1 and IC2 Pins 15 & 16.

You may want to construct an AUDIO PROBE and use it to track down some of your problems. Just go to the search function above and search for "Audio Probe." Its a simple item to construct and is invaluable in troubleshooting.

Good Luck 

Thanks, GL.

I just built one the other day and will give it a shot. Should I trace from the ICs using those pins as starting points? Sorry for the question, but even though I don't follow circuits, I'm good at following directions and eventually it sinks in.

Steve

[Govmnt_Lacky]

Should I trace from the ICs using those pins as starting points?

Just start with the probe at the circuit's audio input and use the layout/schematic to follow the audio flow through the circuit. It is not ALWAYS going to sound loud and perfect however, as long as you are getting SOME SOUND you can be fairly confident that it is OK.

If you run into something that does not look or sound right, just create a new thread particular to your build and list all of the items from the debug thread that I referenced earlier + your questionable audio probe results. You will get lots of help as long as you follow these two rules:

1) You use the debug thread
2) You put some effort into finding the error/problem.

Good Luck 

[bluesman1218]

Should I trace from the ICs using those pins as starting points?

Just start with the probe at the circuit's audio input and use the layout/schematic to follow the audio flow through the circuit. It is not ALWAYS going to sound loud and perfect however, as long as you are getting SOME SOUND you can be fairly confident that it is OK.

If you run into something that does not look or sound right, just create a new thread particular to your build and list all of the items from the debug thread that I referenced earlier + your questionable audio probe results. You will get lots of help as long as you follow these two rules:

1) You use the debug thread
2) You put some effort into finding the error/problem.

Good Luck 

Thanks, that's my goal.

[bdevlin]

My Little Angel seems to have Speed and Depth controls that both can adjust speed depending on where they are set.  The only changes I have to the "official" circuit are the Mix control at R18 AND....I put a 50k trimpot in parallel with R13 that effectively reduces R13.  Wondering if that is why I am getting my results.  I can't help but notic that lug 2 of Depth and lug 3 of Speed are only separated by C10.  Any thoughts???

[gopher]

Bluesman,
I am a new member but I was just scanning the posts on this project. 

Thought I would let you know the following...
I just had some similar trouble in a project that used an NE5532 on a 9 volt supply. The Texas Instruments datasheet says this opAmp needs a 10volt supply minimum (+/- 5 volts). Other manufacturers (OnSemiconductor) lists +/-3 volts. Out of 12 chips, I found 2 TI chips that didn't work on a 9 volt supply. When I used a 9 volt battery giving only 8.4 volts, 2 more showed limited function. 

http://focus.ti.com/lit/ds/symlink/ne5532.pdf

http://www.onsemi.com/PowerSolutions/product.do?id=NE5532

-gopher

[bdevlin]

Never mind my last post....user error.  I will toss in however that I give a thumbs down to the Delay mod.  Unless you do not have a delay pedal and want some slapback.  Otherwise, if you want a Chorus pedal stick to the basic layout.

[bluesman1218]

OK, so I did a fresh build on a PCB and it worked right off the bat. Very cool. Now I have to re-read the thread for some fine tuning. I don't have a whole lot of depth or usable speed. I have tried 2 of my 3 PT2339 chips. I think there were some posts about this, now to find them.

I'm guessing the problem in my vero build was the traces and/or micro solder bridge(s). I'm much happier with the PCB build and will probably stick to PCBs in the future.

[Renegadrian]

Man, don't give up on vero! I am so fond of it...the quickest way to build for me...Glad you made it with the LA.