"Little Angel" - Super Simple PT2399 Mini Chorus

[jfrabat]

I think I know what is going on here...

Thanks to my previous error, I unplugged the pedal, and changed chips.  Put the new chip in, but forgot to plug the battery.  Since everything was running, as soon as I plugged the battery, I put the probe on the OUT pad, and VOILA!  MODULATION!  So I ran over to my guitar, but NOTHING!  Hmmmm...  Went back to the bench, and tested the signal; no modulation.  Now, the only explanation I have is that my PT's are going into lock up.  The thing is that I have 16 of them, and they all act the same way!  Is there a way to prevent lock up?

The odd thing is that the pots do not affect the modulation I am hearing.  In all the videos I have seen when you turn the pots, the PT will make an ATARI like sound while they are moving....  But not here.  I tried to make a video, but it is difficult to note the modulation sound on the video, but there IS modulation.  That is a step forward!

I will post the video tomorrow (it is loading).  Maybe it helps (but as I said, it is hard to hear the modulation in the video).

Hete's the video:

[jfrabat]

Just had a quick look at the smaller board. Noted the following;

R1 appears to be 68R (or is it 6R8) not 68K. D1 and Q2 may be toast.
R7 appears to be 10K not 330K
R12 is obscured and not readable. Supposed to be 4k7.
Q1 (78L05) regulator appears to be in backwards. Remove PT2399 and measure the voltage on pin1 of the socket. 5V is expected but will be much higher if in backwards.

All these observations were taken from the doco on the deluk website.

PT2399s can and do lock-up. Usually this happens when too much current is taken from pin6 before the chip has stabilized after power on. That is the reason for the delay circuit (Q2, etc) on pin6, it gives the chip a chance to stabilize.
Sometimes a locked-up chip stays that way after power down (weird but it happens). Take the chip out and short out its legs on a conductive metal plate (copper clad board is good) wait a minute and try the chip again.

Haven't checked out the first board yet (other than the LM13700 oops). I'll get there or someone else will.

Thanks a lot!

You are absolutely right on all the wrong resistors.  I will replace both of them (R12 is 4.7K, so it's good)



I will also rotate Q2, as I think you are correct and it is on backwards (I will measure voltage first, but I think you are right).  I will also ground out the PT and then I will try the pedal.  If I still get no wet signal, I will replace D1 and Q2.

Sounds about right for this board?

All the test and videos were on the other board, which was my focus for the debugging, but tonight I will focus on this one.

Felipe

[EBK]

Felipe, this continues to be my favorite ongoing mystery.  In my head, I keep pushing back the thought that this circuit only works outside of Costa Rica.  At one point, I even wondered if it had something to do with what your kitchen countertops are made out of. 

I'm glad you are willing to revisit this. 

[jfrabat]

IT WORKS!!!!!

IT REALLY WORKS!!!

IT WASN'T JUST A CONSPIRACY TO MAKE ME WASTE ELECTRONIC COMPONENTS!!!!

IT ACTUALLY WORKS!!!  And rather well, I should point out!!!

I should point out that the board that works is the last one I made (the one from DelykPCB).  I still want to get the other one running as well!

Of course, I still need to do something about the way the voltage regulator is soldered on...  But I had a heck of a hard time getting it soldered in even the way it is, so I have NO IDEA how I will fix it (worst case scenario, it stays like that in the pedal; I think it would fit, actually!).



And the required sound clip:

https://drive.google.com/open?id=0B88Re3K-59SyNmhMMklNNFBTOFU

Setting for that one is about halfway on the speed and 2/3 on depth...  It just a couple of chords, BUT IT WORKS!!!  LOL!

Thanks everyone for bearing with a rookie!  You guys ROCK (literally!)

[Slowpoke101]

Well done! You have beaten the "doesn't work in Costa Rica" phenomena!

Don't worry too much about the regulator's mounting, just make sure that it can't move. It would be better to have it mounted lower on the board but it should be OK.
Take some voltage measurements before you box it up. This may be useful for the other board.
Have fun with your new toy.

[jfrabat]

Well done! You have beaten the "doesn't work in Costa Rica" phenomena!

Don't worry too much about the regulator's mounting, just make sure that it can't move. It would be better to have it mounted lower on the board but it should be OK.
Take some voltage measurements before you box it up. This may be useful for the other board.
Have fun with your new toy.

Thanks, man!

Sent from my SM-G950F using Tapatalk

[duck_arse]

we knew you could do it, jfra, nice work.

if'n you wanted to lower the reg, you could cut the leads just below where they bend in the pic, then heat each lead still in the board in turn, and pull with pliers. you could use your fingers if you wanted to. then you'll have less board heat-stress and mess and worries.

good luck.

[maiko]

sir im sooo glad you finally got this to work

It was also baffling me as how a prebuilt board could have given you soo much problem

Ive built 2 of these from my own etchings and well had to trouble shoot them to work
but nothing like the experience youve had

I admire your perseverance and keep on building.

[jfrabat]

I got so excited that it work, that I wanted another one (I put the original into a multi - 5 - effect pedal that I built to leave at the practice room in a friend's house, and I wanted one for my pedal board, which are individual pedals).  I tried troubleshooting the JMK ones, but no dice.  So I ordered another board from Delyk.  It is up and running as well, so you can definitely get these to work in Costa Rica!  LOL!  Anyway, the only thing missing from that one is the decal (the Hammond 1590B is drilled, primed and painted; decal is also printed and clear coated.  Tomorrow, after it is fully dried, I will place it, and then, when that dries, I will clear coat the top of the pedal - the bottom is already clear coated).  Once again, thanks to all for your patience!  I will post a picture of that one once it is in my pedal board.

[jfrabat]

As promised...  Here's a shot of my pedal board with the Little Angel (my second) in its Hammond 1580B case in the pedal board.  Except for the Ditto Looper, all the pedals are DIY (with LOTS of help from this site!).  The unmarked one is an EA Tremolo.



My only gripe with my pedal board is that I accidentally switched the VOLUME and GAIN labels on the Vulcan Rat Overdrive, but that's a small issue!

[EBK]

My only gripe with my pedal board is that I accidentally switched the VOLUME and GAIN labels on the Vulcan Rat Overdrive, but that's a small issue!

Just rewire it to match your labels. 

[jfrabat]

My only gripe with my pedal board is that I accidentally switched the VOLUME and GAIN labels on the Vulcan Rat Overdrive, but that's a small issue!

Just rewire it to match your labels. 

Pots go directly to the board...

[EBK]

Pots go directly to the board...

Ok, so one extra step: 

[jfrabat]

Pots go directly to the board...

Ok, so one extra step: 

LOL!  Nah, I think I'll just leave it as it is...  Fact is, if I can remember what my pots are in my DIY multi effect pedal (which has NO labels), I figure I can remember these two pots are inverted!



From left to right: Screechy Cat Overdrive, Vulcan Rat Overdrive, Rocket Booster, Little Angel Chorus, Tap Tempo Delay (last one I still need to get to work; all the rest are up and running).  I have no issues using it...

[Perrow]

I accidentally switched the VOLUME and GAIN labels on the Vulcan Rat Overdrive, but that's a small issue!

Oh, been there, done that 

[rankot]

I have built this and it works fine, but I changed pin 2 resistor from 33k to 10k (as proposed by AMZFX site) and had to reduce both pots - depth to A100k and speed to A20k to have audible results and usable control.

However, I am experiencing some faint hiss when playing - pedal is dead quite with stings damped. I have no idea what to try, so any hint is appreciated. Hiss was there even before changing resistor and pots, so it is definitely not connected to them.

[Slowpoke101]

Try several different PT2399 chips.
Some are more noisy than others.

[rankot]

Try several different PT2399 chips.
Some are more noisy than others.

I have five of them, so I will try. But I must desolder this one first, 'cause I didn't use a socket 

However, could it be a problem with digital/analog ground? I had very similar problem with AMZ Q&D Compressor (hiss at note decay), and I was never able to fix it. SM2166 also has digital ground pin.

[eatfeta]

Hello, I opened a mini pedal I bought and found that it has a 78l05 and a rs2399(I am guessing it is a renamed pt2399) .
I was a bit disappointed because I thought it would be analog
but my question is :is the output signal of it fully digital?
Ι  am guessing it is a little angel circuit , it has depth, level and speed controls.

[anotherjim]

is the output signal of it fully digital?

It's so common for brand marketing to claim analog when it's not completely true, that it no longer has the power to make my blood boil.
With PT2399 circuits where you may mix the clean/dry signal with the delayed signal, only the clean part of the sound is from a completely analog  path.
It is possible to engineer the PT2399 delay to sound similar to BBD based designs, and some consider that an "analog" sound. In truth, the BBD has a digital element to its workings - but musicians have come to consider the BBD as analog technology, at least compared to the purely and obviously digital ones such as from Digitech etc..