"Little Angel" - Super Simple PT2399 Mini Chorus

[Govmnt_Lacky]

EPIC FAIL!! 

I tied the open lug (Lug 1) to the wiper (Lug 2) on both pots and the voltages on Pin 1 of the LFO are STILL not right!

I am left with one final obvious option. Swapping the Speed pot for a 500KB. If that does not work it will have to sit on the shelf for a while because I honestly cannot think of anything else to try.

[nick d]

            That's a bummer !   Running out of ideas here - it has to be around the LFO - if you are 100% sure there are no shorts , try searching for open circuits . Thats what I had on pin 6 , almost immpossible to see , found it after 3 days of hair-tearing ! DON'T LET IT BEAT YOU !

[Govmnt_Lacky]

Thanks Nick. I am sure there are no shorts because:
1) I checked ALL AROUND the board traces with a DMM and found nothing.
2) I would think if it was shorted, I would get NO voltage.

As it stands now, it appears that I get the higher frequency LFO sweep (2.5 - 3.5V) but when I back the Speed pot down, my lower/wider sweep (1.4 - 7V) is non-exsistant!

I will have to plug it in tonight and see if any of my tinkering has changed anything. I also had a problem with the Depth pot and the fact that it appeared to have NO effect on the circuit.

I will post more info about what I found later tonight. Thanks for all the help nick 

[Govmnt_Lacky]

Just plugged my Little Angel in and it is still NOWHERE NEAR the "lushness" that I can hear on the sound clips! I am gonna try one more 2399 in the circuit and then it is off to the shelf cause I am out of ideas on this one   

HAS ANYONE GOTTEN THIS TO WORK WITH THE 100k POT FOR DEPTH INSTEAD OF 470/500K? 

[nick d]

                   Sorry to hear you've not had a good result on this , I know you put in a lot of time and effort . Just listened to those clips again - mine does not sound QUITE that good - that could be down to Tele Custom + VJ clone  v   my cheap SG clone + Kustom 10 W SS amp  , and of course my appalling guitar technique .
                     As regards the 100k/470k , minimum pot resistance = max depth , so should not be an issue ( I think ) .
                     Better luck next time !

[Pigyboy]

Just plugged my Little Angel in and it is still NOWHERE NEAR the "lushness" that I can hear on the sound clips! I am gonna try one more 2399 in the circuit and then it is off to the shelf cause I am out of ideas on this one   

HAS ANYONE GOTTEN THIS TO WORK WITH THE 100k POT FOR DEPTH INSTEAD OF 470/500K? 

Hey Lackey,
Get your meter and check that the diagonal trace that runs beneath R20 & R16 is not shorting to the pad that connects R16 to C13 on the 1590A layout. I was checking the boards I made again for shorts and I found it shorted on one board.

[Govmnt_Lacky]

Get your meter and check that the diagonal trace that runs beneath R20 & R16 is not shorting to the pad that connects R16 to C13 on the 1590A layout.

Thanks Pigyboy. I checked that trace and it checked GOOD. I also ran over every trace again with the DMM and found no bridges. I checked component values again, all good. Looked over the offboard stuff, all good. I still have not tried a third PT chip so that is the last resort before scrapping and re-boarding.

For those of you joining late, I posted some voltages however, I have STILL NOT received any replys with voltages from a "known good" working unit. I have had a reply from nick_d but he even says that his Angel does not sound as lush as the sound clip from Rick.

It appears that the lo-speed setting on my Speed pot (higher resistance) is nonexistant. When I turn the Speed pot (100KB) all the way up I can get a subtle vibrato but that is only at the top of the rotation. MY Depth pot seems to have no effect at all.

I did put this on an oscope and I could see some signal change with adjustment of the Speed and Depth pot however, it was very... very small.

Basically, I need someone to post voltages of a good, working unit that sounds like Rick's sound clips.

Thanks a ton to all who have helped so far... 

[jable1066]

I know it doesn't help you much, but as I said before I'm having the exact same problem. The same is said about my speed pot - the only time I can get an effect is with full speed, full effect. I've posted somewhere else about voltages and emailed FC - the creator of the pedal and asked for his advice and voltages so I'll post them here when I'm done. I gave up on it today after wasting another few hours on it! Then I built an unsuccessful Bazz Fuzz - keeps getting a glitchy signal so I'm going to re-wire again. Here's a thought that just came to me actually... maybe you stripped off some excess stranded wire when stripping the covering off? I know I did with the Bazz Fuzz - which is probably why I get glitch signals. Try rewiring? I will do this at the weekend as I've probably wasted enough time on it for now - I'll let you know if it works for me.

[Govmnt_Lacky]

I know it doesn't help you much, but as I said before I'm having the exact same problem. The same is said about my speed pot - the only time I can get an effect is with full speed, full effect. I've posted somewhere else about voltages and emailed FC - the creator of the pedal and asked for his advice and voltages so I'll post them here when I'm done. I gave up on it today after wasting another few hours on it! Then I built an unsuccessful Bazz Fuzz - keeps getting a glitchy signal so I'm going to re-wire again. Here's a thought that just came to me actually... maybe you stripped off some excess stranded wire when stripping the covering off? I know I did with the Bazz Fuzz - which is probably why I get glitch signals. Try rewiring? I will do this at the weekend as I've probably wasted enough time on it for now - I'll let you know if it works for me.

Thanks jable. I would appreciate that if you get a response from FC or if you find an issue. As far as my Angel is concerned, my Depth pot is useless (to my ear) no matter what I do. My Speed pot ONLY changes the modulation when it is at 80-100% of the pot rotation and even then it just sounds like a subtle vibrato.
On a side note... the pedal does give a slight volume increase when engaged. And also, when I put a 440Hz/100mV square wave into the pedal, on the oscope I can see there are "spikes" that roll along the peaks that adjust with the pots. This is great but, it does NO GOOD if you cannot hear it through the amp 

[nick d]

                  Hi , just read some recent posts re Little Angel . Having listened to the clips again and compared them to my results , I would like to chip in with a couple of observations.
                  Overall , the sound I get is pretty much the same ( making allowance for differences in guitar , amp , and playing technique ) . Having said that , there is one bit at about 0.50
                   that is quite noticeably different .
                   On the controls , depth does pretty well nothing below 70% , and at low speeds the effect is very subtle , but still noticeable compared to dry.
                   My overall impression is that I have built a worthwhile pedal . If you consider the simplicity of the circuit , and the fact that the 2399 was designed never intended
                   to be a chorus pedal , the end result , I think , pretty good .  I could probably spend a bit more money and buy a Behringer pedal that MIGHT sound a bit better
                   but that misses the point - we are DIY builders , trying out new ideas , and thats the way I like it .
                   ( STOP IT Nick , you are starting to preach ! )
                   

                   In conclusion , not perfect , not bad , on to the next one ! 

[Govmnt_Lacky]

Thanks Nick. I just want mine to sound like the sound clip form Rick and no matter where I put the knobs and no matter what position they are in, I could not duplicate the lush tones that are on that clip. That is how I know something is wrong. It is not a matter of gear. The difference in that clip and what I hear goes way beyond gear setup.

[nick d]

                  This has got me thinking ( a dangerous practice ! ) - component tolerances.....
                   The shorter delay , the better the chorus  - but the limit is 100R . So , if I use a resistor  , 5% , which is at the bottom of the range = 95R , and you happen to get
                  one thats 105R , my delay will be shorter and so sound better . This could happen by random chance , or by selection .
                   This would apply in any circuit where values are critical . So , by careful component selection or using trimmers , you can fine-tune the circuit .
                   This is a well-known idea , and could well be more trouble than its worth , but its worth bearing in mind . Hmmmmmmm.......       

[frequencycentral]

Here are voltages just taken from my Little Angel, which sounds the same as the breadboarded version I did you soundclips on. Speed at 3 o'clock, Depth at 12 o'clock:

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)

It's pretty hard taking voltages from a moving LFO, guess accuracy depends on the resolution of the DMM, but you get the idea.

I really like mine. I have a half populated CE-2 PCB (3 times the size of the LA PCB!) which is looking sadly at me - it knows it isn't getting finished anytime soon now. Yeah, Little Angel isn't the best chorus you can build I'm sure. But it is the simplest. I dare anyone to design a lower parts count chorus.    I said early on in this thread that there would one day be an 'elite' version - that's still the plan, but the original Little Angel has always been a " how-few-parts-can-I-use-to-make-a-chorus?" concept.

[nick d]

                  I could of course be talking total crap , but who knows ?

[Brymus]

Did someone say Arch Angel ?   
The wait is agonizing...

[Govmnt_Lacky]

Ok... I just swapped out the 2399 and there was NO CHANGE 

Thanks for posting the voltages Rick but, I sadly admit defeat. Either this Little Angel I built is the most subtle chorus ever (does not even come close to sounding like your sound clip) or I need to just scrap this build and try again some other time. Now, I used 100K for both pots but.... when I set my pots to 3 oclock and 12 oclock as you said, my pedal sounds like nothing more than a VOLUME BOOSTER.

[Earthscum]

Hey, GL... try using a mixing mod on the output, either cut dry or cut wet, or maybe a blend pot between the two caps. I notice the effect more or less, depending on the blend. Also, I'm starting to think that the 100R from pin 6 may be small enough to show differences between chips, so you may be getting a bit less or more delay than others. On bass, I can say for sure that I needed a little more delay to get the lower notes to express properly.

And all of this effects how much of the LFO I hear. At shows, I usually have to run wet while I tune my LFO, then drop out the wet to my preferred level for that stage. At practice, I do the same thing, but that's just because I don't have a big enough STFU stick (drummers are annoyingly loud sometimes!)

So far, I'm totally happy with this, but I don't know how much I like the LFO part... but I can't come up with anything better myself, so I'm not complaining a bit.

[Pakaloabob]

A couple pages back I mentioned that my Little Angel build did not play well with my One Spot power supply but worked fine on battery.
I recently acquired a new power supply - Danelectro DA-1 that came free with a Vox V845 wah I got online (great deal BTW)
Little Angel likes the Danelectro power supply!
But again, if I try the One Spot, the circuit doesn't work. Hook up the Danelectro PSU again and wait a few minutes, success!
Has anyone else experienced, or heard of something like this? Should I open a new topic to fish for some comments?

[nick d]

               I got a Soundlab 450 , which will run 6 pedals with no problems . Puts out 8.6 V , not used any thing else apart from
           unregulated 9 V wall-warts , used on synth-type stuff with on-board 9-V  regulators . Never use batteries , 'cos I don't like them going flat on me .
            I've used Little Angel , BSIAB 2 , Phozer 2 , Tonebender , and others , never (touch wood !) had any problems .Am I just lucky or what ?

[Pigyboy]

Video Demo of the Little Angel built by El Musico Loco.
Thanks for the great design Rick!
http://www.youtube.com/watch?v=oxyk3c9YXQM