Echo Base - a new PT2399 delay

[BubbaKahuna]

Chawk, I'd also like it if possible.
In fact if anyone has the DIY:Layout program file for this, that would be great as well. 

Cheers,
- JJ

[Chawk]

Here's the resized layout based on anonymousfacelesscoward's version.

http://chawk.wordpress.com/files/2008/02/echo_base_pcb.pdf



By the way... Slacker, is there any way to get an led rate indicator modded into this circuit. I imagine it could be placed on the trace leading from pin 5 of the pt2399 but I'm just guessing. Any thoughts?

Matt

[Chawk]

I imagine it could be placed on the trace leading from pin 5 of the pt2399 but I'm just guessing.

Correction... I meant pin 6.

[Chawk]

bump

[slacker]

Do you mean a delay time indicator? I'm not sure you can do this, there were some threads a while ago about pin 5 having a a frequency on it that related to the clock speed. I think someone was working on a circuit to convert this into something you could use as a delay time indicator, but I'm not sure how it worked out.

If you want an LFO speed indicator just hang an LED and current limiting resistor off pin 1 of U1.

[Chawk]

excellent.. i'll give the LFO indicator a try... thanks for the tip! And thanks again for this killer pedal. 

[DimebuGG]

The latest one is here http://www.aronnelson.com/gallery/v/slackers-stuff/album170/echobase.png.html?g2_imageViewsIndex=1

thank's slacker....

i think i find a error in the schematic ...
At U1B, i think you invert PIN 4 and PIN 8 ,  you put LFO+ on pin 4 and on the layout http://blogs.yahoo.co.jp/anonymousfacelesscoward/19192939.html you put it on the pin 8
and vice-versa with pin 8.....

Bent

sorry i don't know. where is that error??

[slacker]

The error is only on the schematic, the layout is OK. Whoever made it must have noticed the mistake and corrected it.

All the other layouts are correct as well.

[Chawk]

Quick question...

I was going about fitting the finished circut into the box I had just drilled and when I fired it up everything worked fine but the mod speed pot no longer was functioning. I thought it might have been a short of some kind so I took everything out of the box, but it was still not working correctly. I thought I may have burned out the pot so I swiched it up with another but no luck. I got frustrated and just put it down for the night. This morning, however, I went to take a look at it before heading out to work and, ta-dah, everything was working perfectly. I played with it for a few moments and then it crapped out again. Is it possible I have a bad cap in there? I'm wondering if I burned something when I was putting it into the box. Any ideas?



Thanks,
Matt

[Michael Allen]

Mine was pretty finicky when it came to the power supply. Make sure you have a fresh battery or a good 9V adapter..

[slacker]

Did you ever get yours working Michael?

[Michael Allen]

Yeah I use a dedicated 12v supply now and it works fine!

[fifi]

happy easter to all ya!

ive planned to build a delay long time ago, and this project finaly got me working on one. thanks slacker for sharing this!
ive built one using the japanese layout: http://blogs.yahoo.co.jp/anonymousfacelesscoward/folder/903906.html had to scale it a bit
to make it fit to the components, but in the end the pcb came out perfect.

i used a 50K pot instead of a 47K for the time pot, and i didnt had BC560 here so i used a 2N5087G, which was reported to be fine.
the sound of the delay is super, i really like it, but there seems a little problem with the modulation.
trying to describe what happens, its a bit confusing, so if its unclear just ask back

i started out with medium delays, and started to turn mod depth knob, but in a way it not only add's the modulation it also seems to affect the delay time. when i have repeats in the delay and i turn the moddepth knob up you get that sound like youre turning the delaytime knob to a slower time, the tone of the repeats decreases.
on slapback i get around 300-400ms echo that way, even on long delay it sets delays slower.

when i set on long delays it also add's crackle noise when i turn time knob up  (starts about 75% open, might be the 50Kpot?) and when i turn the moddepht up the crackle gets a bit louder and turns to a slower rate.

strange.

ok, i skipped the project for a few days and got back to it, doublechecked the solder side for cuts/bridges, seems to be fine, no strange spots there. also a friend checked it for me, because i might oversee something. then ive checked the cap values and the colorrings of the resistors, also that polarized caps. ic's are ok.
with the trannies im not shure, i might have put the 2N5087G the wrong way in, ive checked on alldatasheet.com but stupidly i took the 2N5087 datasheet than the G which has diff. pinout so it was wrong around first. turned that trannie then to have collector looking to the time pot (its the other way around than displayed in the layout.)

pinout is
(|
C
B
E
if i look from above when the piece is insertedin pcb. maybe ive @#$%ed that trannie when ive puttet it the wrong way round?
i have some spare here but first i need to have it clear which way it has to be, before i @#$%up another one.

today i had some time to check the voltages that slacker posted, heres my measures, the arrow points to my results.
ive runned it off a stab. dc supply, also changed that to a boss PSA but that didnt help with the problem.

PT2399
1. 5v -> 5,03v
2. 2.5v -> 2,5v
3. 0 -> 0v
4. 0 -> 0v
5. 2.89v -> 3,03v
6. 2.5v -> 2,5v
7. 0.5v -> 0,56v
8. 0.5v -> 0,58v
9 - 16 all 2.5v -> alle 2,51v

4066
Some of the voltages change depending on if the effect is on or bypassed (off) so I've shown the voltages for the different states.

1. 4.6v -> 4,37v
2. 4.6v -> 4,37v
3. 0.4v -> 0,15v
4. 0.4v -> 0,15v
5. 0 -> 0v
6. 0.45v off -> 0,19v 4.5v on -> 4,26v
7. 0 -> 0v
8. 9v -> 8,8v
9. 3v on -> 1,8v 0.32 off -> 0,19v
10. 4.6v -> 4,68v
11. 4.6v -> 4,68v
12. 8.5 on -> 8,7v
13. 8.5 on -> 8,7v
14. 9 -> 8,89v

When the effect is off depending on which position the tails/Boss switch is in either pin 12 or 13 will be 1.25v the other will be about 8.7 volts. -> 1,2v + 8,7v = ok

The TL072 voltages are

U3 top left of vero

1. 5v -> 5,03v
2. 5v -> 5,03v
3. 5v -> 5,03v
4. 0 -> 0v
5. 5v -> 5,03v
6. 5v -> 5,03v
7. 5v -> 5,03v
8. 9v -> 8,89v

U1 bottom left of vero, this is the LFO

1. changes -> changes
2. 5v -> 5,03v
3. 5v -> 5,03v
4. 0.8v -> 0,8v
5. changes -> changes
6. 5v -> 5,03v
7. changes -> changes
8. 8v -> 8,1v

The voltages on the 5089 should change depending on the position of the bypass switch.
E. 0 -> 0v
B. 0.63v off -> 0,63v 0 on -> 0v
C. 0.89v off -> 0,86v 8.5v on -> 8,5v

so, the voltages seems to be fine except for the 4066.
any suggestions to hunt the error down ?

thanks in advance

[Chawk]

Mine was pretty finicky when it came to the power supply. Make sure you have a fresh battery or a good 9V adapter..

Hey Michael,

Thanks for the response. After poking and prodding around in the trouble area near the LFO stage it magically began working perfectly. I have no explanation as to what went wrong or why it started to work again but it IS working so I guess that's all that matters. Ian believes that I may have inadvertently knocked loose a solder bridge. Thanks for the suggestion about the battery though. It may be that was the problem as well.

Matt

[fifi]

k, worked further on this baby.
ive found some bc560 i had around so now that part is fixed now.
but, i still get longer delays as i turn mod depth up.
after inserting the bc560 ive checked again the voltages, and discovered this:
4066
pin1 4.37v off | 4.68v on
pin2 4.37v off | 4.68v on
pin8 1.8v off | 8.8v on

maybe that helps a lil bit forward

[Valoosj]

Here's the resized layout based on anonymousfacelesscoward's version.

http://chawk.wordpress.com/files/2008/02/echo_base_pcb.pdf



By the way... Slacker, is there any way to get an led rate indicator modded into this circuit. I imagine it could be placed on the trace leading from pin 5 of the pt2399 but I'm just guessing. Any thoughts?

Matt

I'm interested in building this, but what are the specifications? As in what is the max delay time, what does that toggle do,...

[slacker]

The 4066 voltages won't be related to the delay time problem. Does the bypass work properly? If it does don't worry about the 4066 voltages.

Turning the mod depth up will make the delay slightly longer, because the modulation works by increasing and then decreasing the delay time. It shouldn't increase it by enough to be really noticeable though.
First thing I'd check is the 39k resistor across the BC560, that sets how much the maximum modulation is. If it is a larger value then the delay change will be bigger so that might be the problem.
Another thing to do to check if everything is working properly is to set the delay time pot and mod depth pot to minimum and then you should get a very short delay almost like a chorus sound rather than a definite echo. If you get an slapback sort of delay or a longer one with the settings on minimum then you might have a larger problem. Hopefully not

[slacker]

I'm interested in building this, but what are the specifications? As in what is the max delay time, what does that toggle do,...

The max delay time is about 700ms. For an explanation of the toggle read the first post in this thread

[fifi]

thanks slacker for help i appreciate it.
just came home and checked the things you said. so first off the bypass works perfect.
ive checked the suspected 39K near BC560, measured it with an ohmmeter to ground -> 39K.
also doublechecked from the lug of the BC560 and from lug 3 of the time pot to make sure the connections there are ok -> 39K.

then i set time and mod depth to minimum, no slapback or so, i dont even can hear a repeat, as you said the pedal
reminds more like a chorus (set very decent) or a booster in this way. so no major probs
im gonna measure out the rest of the circuit later this evening, now its time to cook something.

[Chawk]

Here's the delay all boxed up. The etching didn't come out as perfectly as I had hoped but it gives it a vintage look that's kind of cool.