Hi,I assembled this chorus,based on 2399,when the effect is off the signal pass-thru,but when turned on you can just listen a constant popping which slow down as you unplug the 9v. what can I do?
(https://i.postimg.cc/kB6g0Jd5/2fbfce2b-3434-471a-afee-f3632084c4fb.jpg) (https://postimg.cc/kB6g0Jd5)
welcome to the forum,
i guess its the LFO, but just to be proper, have you looked at this guide:
debugging guide (https://www.diystompboxes.com/smfforum/index.php?topic=29816.0)
cheers, Iain
Thank you for the reply and for welcome me ;D
These are the schematics,it came as a kit so I did not make any changes.
https://www.musikding.de/docs/musikding/angel/AngelV2_schem.pdf
VR1 (78L06) in=9v gnd=0 out=6v
Q1 (J112) drain=0,42v source=0 gate=0
IC1 (NE5532P)
1=can't say,change from 1 to 8 constantly
2=basically the same as 1
3=3,8-5,8
4=0
5=4,72
6=0
7=0
8=9,4
IC2 (PT2399)
1=6
2=3
3=0
4=0
5=5,2
6=0,42
7=0
8=0
9=3
10=3
11=3
12=3
13=3
14=3
15=3
16=3
I can add that on C8 I read more Voltage on negative leg.Probably IC1 is not ok?!
telll me if I did something wrong on this post and thanks again :icon_redface:
"Something" pulls IC1b out down to GND..
> IC1 (NE5532P)
5=4,72
6=0
7=0
There is a hard short from pin 7 (or something connected to pin 7) to ground. Stray wire, solder ball, bent pin, something.
(https://i.postimg.cc/SYq4zyyd/brujo-pin7-42.gif) (https://postimg.cc/SYq4zyyd)
Bright light and magnifier.
(A '5532 can't pull its output ALL the way to its negative pin. Something must be "helping" it.)
Re checking the reading,now it is:
NE5532p
1=5
2=4,8
3=4,7
4=0
5=4,72
6=4,7
7=4,9
8=9,4
Thanks again for the help
OK some wires contact between pcb's...looks it sounds something but the signal it doesn't seem to be effected.You can ear ,added to it , a noise responding to depth and rate values;not a hum's kind even if the whole thing really is.
What about some photos of both sides of the board?
(https://i.postimg.cc/67R9fH4v/IMG20210219165009.jpg) (https://postimg.cc/67R9fH4v)
(https://i.postimg.cc/RJCnW3Vq/IMG20210219165058.jpg) (https://postimg.cc/RJCnW3Vq)
Stupid question: did you isolate the back of the pots with "pot condoms" or adhesive strips?
Nope :icon_redface:
Anyway the back of the pots don't touch the pcb,they Need It?
Just asking. They COULD touch eventually which could short some pins and cause mayhem
Welcome Brujo! (Bienvenido?)
For the next build, fold the legs of the resistors before you put them through the holes so you can get them much closer to the board. There are special tools for this, but I just use small pliers. Once they're in, you can bend the legs outwards a little bit with your finger to stop them falling out, but you'll find that it keeps them tighter to the board and makes a neater job. You can do something similar for caps.
That's what I did :icon_redface: (bending before) I used to know that they should not touch the pcbs. Honestly It was my first build and I admit, solder works here are pretty bad. Anyway It doesn't work... suggestions? Re-build it? What about c8 strange behaviour?
Really thanks to everybody.
Also I build a fuzzrite kit for a friend (guitarpcb's) It works. Pretty noisy,I don't like It verymuch. :icon_rolleyes:
Oh dear, another frozen LA!
PT2399 pins 5 & 6 should be nearer to 3v. The readings you have indicate the delay chips timing clock is frozen.
Can you remove T1 safely?
Do you have another PT2399 chip to try?
I don't have others pt2399 right now but I'm searching for them. T1 you mean the j112?
I would suggest temporarily replacing T1 (yes, the J112) with a resistor fitted across the S & D holes (or between PT2399 pins 6 and 4 ). Any resistor from 1k to 10k will do. Need to see if that will let the pins 5 & 6 run at better voltage.
While you're doing that, take the PT2399 out and put it on a conductive surface so all pins are shorted together. This can get rid of any internal static charge which tends to build up in this chip when there's been a fault.
You may need to replace the PT2399 & it would be wise to order a replacement. For this particular build, only having one PT2399 to use seems like going hunting and only bringing one shell for your gun! It's not that the PT2399 is unreliable, but this design pushes it to limits and then a bit more.
I'll try and let you know. Thank you very much for the help.
Cheers
5=4,2-6
6=0,7
but it start working,but the LFO noise it's pretty present.
When you say its working, can you get chorus effect?
Which of the suggestions have you done?
I'd expect some LFO noise, because the LFO is in the same chip as the preamp, but it shouldn't be too big.
I placed the resistor in T1's place and discharched static from ic. Today I made some changes,I put in T1 a j201 ( I have some spares) and replaced C8 ( 10mF) with a 47mF (don't know really what I'm doing,honestly ;D),but it sounds a little bit less noisy and seems to have a more usable sounds, before I had chorus only in extreme pot position. LFO noise seems to be less too,but still present on extreme pot position. NEGATIVE thing is that when I pick a note you can ear a took-like sounds. What can be the reason of that thing??
Any suggestions? I would really like to know more about this things :icon_lol:
Increasing C8 will increase the LFO swing amount. Increasing C9 will smooth the LFO but lower the amount.
Alternately, an extra cap from PT2399 pin 2 to 0v will reduce any clicking that gets through. 1uF would be enough.
The kind of LFO circuit here can produce clicks. It alternately charges and discharges and feeds back via R16. Every time the output waveform voltage meets the voltage set by R14 and R15 (half the supply voltage), it switches over to change the direction of the waveform swing. It's when it switches it makes a click audible via a sudden change in supply and ground current.
The NE5532 is quite a fast and power-hungry opamp, and I do wonder if it's the best choice. A TL062, despite being noisier (for the signal pre-amp job), has a much softer switching action. You could also try an MC1458 or even an RC4558 although that last one could still be too fast.
... or before Iain says it, an LM358!
;)
0v = gnd? I tried but nothing changed :icon_question: should I use an ic gnd like pin3 or 4? I used the gnd from supply.
the click i'm talking about is from picking the strings,specially on high e and b.
I was advising about LFO noise (0v = ground in this case though). Pick attack is something else. It shouldn't make anything like that unless the delay isn't short enough and you are hearing a slapback echo which is more obvious on the picking attack. The purpose of the JFET is to pull the delay time as short as possible to hide the slapback delay. This circuit isn't actually capable of going to a short enough delay to completely hide the slapback - the PT2399 minimum delay cannot do it.