"Little Angel" - Super Simple PT2399 Mini Chorus

[Poste]

Does the polarity protection diode need to be a 4007 can it be a 4001?

Thanks in advance

[Taylor]

It can definitely be a 1n4001. Not sure why 4007 was chosen, probably was just the part that somebody had lying around. The only difference AFAIK is the amount of reverse voltage it can take, and the 4001 is good for 35 vRMS, which is more than it will ever see.

[frequencycentral]

Not sure why 4007 was chosen, probably was just the part that somebody had lying around.

Yup!

[funkyhead]

Hi, I have made this circuit couple days ago but it doesn't work properly. There is some change in the signal but no effect. Only when i'm turning the depth pot sound is a bit modulated. I changed the resistor from pin6 of PT2399 to 1k an then to 4k7 and only I had one repeat and nothing else. I checked for short circuits and cold joints and didn;t find any. The chip as well as the op-amp are ok. Any idea what's the problem?

[frequencycentral]

If you're getting a single delay the PT2399 part of the circuit (ie the audio path) is working. Sounds like your LFO is not functioning to me.

[ppaappoo]

check the speed pot connection.
disconnect the depth pot an place a led to see if the lfo works

[funkyhead]

I think you are right. Pots are fine. The led connected instead of depth pot didn't do a siongle thing. I kinda know what the LFO is but how to make it work? I think i'll use the osciloscope and if it'll showa that the LFO's not working I don't know what to do next.

[egasimus]

Hey, I'm planning to build this soon with Earthscum's mods. Can the circuit, however, work with line levels? After I saw ADT mentioned in this thread, I'm tempted to use it as an insert on vocals

[frequencycentral]

So I've been through my stash of PT2399 and found one that locks up intermittently. So I'm gonna forego the wedding tomorrow (    ) and add the Pin 6 Fix kludge:



The fix itself is verified but I wanna try it for myself. The layout above should sit in my 1590A Angel between the 9mm pots and the main PCB, I'm gonna bend C1 over to make the whole kludge flat. I guess also I should do a new layout incorporating the fix sometime. I think I could squeeze it so it's still a 1590A-able layout, or just 'spread out' so it's only 1590B-able. What do people think?

[Govmnt_Lacky]

I thought the lock-up fix was solved with a 1K resistor off of Pin 6 of the 2399 chip instead of the 100R. 

Then again, I cannot see the picture in your post so..... 

[frequencycentral]

Apparently the '1k at pin 6' fix works for some PT2399............and other PT2399 will work fine with 100R at pin 6. But mictester's pin 6 fix will make each and every little PT2399 in the whole wide world work in the Little Angel. With the added benefit that the resistance to ground from pin 6 is about 100R, which IMO is preferable to the extra latency that the '1k at pin 6' fix adds.

[GodSaveMetal]

Apparently the '1k at pin 6' fix works for some PT2399............and other PT2399 will work fine with 100R at pin 6. But mictester's pin 6 fix will make each and every little PT2399 in the whole wide world work in the Little Angel. With the added benefit that the resistance to ground from pin 6 is about 100R, which IMO is preferable to the extra latency that the '1k at pin 6' fix adds.

Thanks for the UNIVERSAL FIX 2399!!! it is a great idea!! I have some Pt's that don't fix for the LITTLE ANGEL chorus!!! I will tried this for every Pt's!!! great!!!

[egasimus]

Rick - why don't you use vertically mounted resistors and diode? They would still be shorter than the electrolytic, anyway, unless it's one of those extra-tiny ones.
I've also been wondering about this - I want to build the Little Angel with Earthscum's 10k+10R mod at pin 6 - can this be combined with the anti-lockup mod?

[frequencycentral]

Rick - why don't you use vertically mounted resistors and diode? They would still be shorter than the electrolytic, anyway, unless it's one of those extra-tiny ones.

Risk of grounding against the enclosure in 1590A builds. The electrolylics are layed out so as to be bent over and layed flat.

I've also been wondering about this - I want to build the Little Angel with Earthscum's 10k+10R mod at pin 6 - can this be combined with the anti-lockup mod?

Sure, just add the pot in series between the 47R and pin 6.

[funkyhead]

Halleluyah! Heil to the PT2399 unlocker! Heil to Frequencycentral! You're the greatest 

[cgibsong002]

Hey guys... desperate need of some quick help here. I'm actually building this as a project for my circuits class. We weren't allowed to do pcb so I used the bolstad vero layout. Bypass is good, and when switched on it sounds basically exactly the same as bypass, with a touch more noise. It seems as if my switch or something were shorted from input to output but i dunno. What is this 'lock-up'? I tried reading through all the pages about the pt2399 locking up but i haven't a clue what that means. would that cause a problem like i'm having? i originally used the 47 ohm that it called for, and then switched to a 470 ohm since i don't have a 1k. I figured I'd ask here before keep switching out resistors.

here are my values


5532 (Volts)
1.   5.19
2.   4.92
3.   4.79
4.   0
5.   3.65
6.   3.09
7.   8.80
8.   9.46
PT2399
1.   5.02
2.   2.40
3.   0
4.   0
5.   1.30
6.   2.36
7.   .55
8.   .69
9.-16. 2.42

2N3904
C. 1.69
B. 0.00
E. 0.00

Regulator
9.46 =IN  5.02=Out

[Govmnt_Lacky]

Hey guys... desperate need of some quick help here. I'm actually building this as a project for my circuits class. We weren't allowed to do pcb so I used the bolstad vero layout. Bypass is good, and when switched on it sounds basically exactly the same as bypass, with a touch more noise. It seems as if my switch or something were shorted from input to output but i dunno. What is this 'lock-up'? I tried reading through all the pages about the pt2399 locking up but i haven't a clue what that means. would that cause a problem like i'm having? i originally used the 47 ohm that it called for, and then switched to a 470 ohm since i don't have a 1k. I figured I'd ask here before keep switching out resistors.here are my values


5532 (Volts)
1.   5.19
2.   4.92
3.   4.79
4.   0
5.   3.65
6.   3.09
7.   8.80
8.   9.46
PT2399
1.   5.02
2.   2.40
3.   0
4.   0
5.   1.30
6.   2.36
7.   .55
8.   .69
9.-16. 2.42

2N3904
C. 1.69
B. 0.00
E. 0.00

Regulator
9.46 =IN  5.02=Out

Try the 1K resistor. If that does not work, then you may want to try a different 2399 chip.

Good Luck 

[cgibsong002]

didn't have a 1K so soldered two 480's in series... figured that was close enough (unless there's some magic number about the 1K mark). still nothing. tried two other different pt2399's... still nothing. tried a different power source, nothing..

wth??

[Govmnt_Lacky]

didn't have a 1K so soldered two 480's in series... figured that was close enough (unless there's some magic number about the 1K mark). still nothing. tried two other different pt2399's... still nothing. tried a different power source, nothing..

wth??

Can you post a link to the layout you are using?

I don't remember a 3904 being in Rick's circuit 

Also, I think that at least helf of your LFO should be wobbling and it is not by looking at your readings.

[frequencycentral]

I don't remember a 3904 being in Rick's circuit  

We weren't allowed to do pcb so I used the bolstad vero layout.

He's using Sabro's vero. Sabro updated it with the 3904 based Pin 6 Fix.  

http://www.sabrodesign.com/wp-content/uploads/2011/04/LittleAngelRev1.gif

Also, I think that at least helf of your LFO should be wobbling and it is not by looking at your readings.

+1, there should not be static voltages on pins 5, 6 and 7 of the NE5532. That's your problem.

I posted these voltages earlier in the thread. Note the voltages of the LFO part of the NE5532. By the way, the vero uses the 'other side' of the NE5532 for the LFO to the PCB version I built.

NE5532

1:  0.13  to   4.9
2:  2.9    to   3.2
3:  2.7    to   3.1
4:  0v
5:  4.79
6.  4.9
7:  5.14
8:  9

PT2399

1:  5
2:  2.38   to   2.42
3:  0
4:  0
5:  2.75
6:  0.61
7:  0.88
8:  0.88
9 through to 16:  2.41 (slight movement)