Echo Base - a new PT2399 delay

[Calamardo]

Ok  ,thanks Barcode80. Time to order another PT2399...

[npx]

I wired up the pots on my echo base build (afc layout) today and I'm in the process of debugging.

At the moment I get no delays, but the guitar comes through fine... however, if I flick the tails switch, I hear the delay tails and all pots respond to them. Can anybody point me in the direction of what I might have done wrong?

[npx]

UPDATE: Here are some of the voltages I’m getting… the ones that Slacker posted are included for reference, mine are in brackets.
The PT2399 seems fine, but the 4066 is weak on most pins. Pin 2 of The first TL072 (U3) is half what it should be.
The other TL072 (LFO) has a much higher pin 4 reading and the pins that are supposed to fluctuate don’t do so.

The only place that connecting or disconnecting the bypass seems to make any difference is at the 5089 – the base changes voltage but the collector doesn’t.

PT2399
1. 5v      (5.05v)
2. 2.5v   (2.52v)
3. 0      (0)
4. 0      (0)
5. 2.89v   (2.69v)
6. 2.5v      (2.52v)
7. 0.5v      (0.54v)
8. 0.5 v   (0.63v)
9 - 16 all 2.5v    (All 2.52v)

4066
1. 4.6v      (2.91v)
2. 4.6v      (2.91v)
3. 0.4v      (0)
4. 0.4v      (0)
5. 0              (0)
6. 0.45v off 4.5v on   (0.08v) No difference bypass off/on
7. 0              (0)   
8. 9v              (2.05v)
9. 3v on 0.32 off    (0) No difference bypass off/on
10. 4.6v           (2.05v)
11. 4.6v           (2.05v)
12. 8.5 on      (1.14v)
13. 8.5 on           (6.77v)
14. 9              (8.25)


TL072 (U3)

1. 5v        (5.05v)
2. 5v        (2.43v)   ***
3. 5v        (5.05v)
4. 0        (0v)
5. 5v        (5.05v)
6. 5v        (5.05v)
7. 5v        (5.05v)
8. 9v        (8.38v)

TL072 U1 (LFO)
1. changes        (7.45v constant)
2. 5v           (5.1v)
3. 5v           (5.05v)
4. 0.8v        (5.65v)***
5. changes        (5.1v constant)
6. 5v           (5.05v)
7. changes        (7.48v constant)
8. 8v           (8.07v)

5089
E. 0                 (0v)
B. 0.63v off 0 on           (0.74v off 0v on)
C. 0.89v off 8.5v on   (0.79v off 0.79v on)***


Any help is much appreciated!

[slacker]

The first thing you need to sort out is why the 2N5089 isn't working, if the the collector stays low then the effect is always bypassed, that's why you can't hear any delay. Make sure the transistor is the correct way round, on my vero layout the collector is at the bottom. After that check for shorts or wrongly placed components or component values.

Same things apply to your funny pin 4 voltage on the LFO opamp, it looks like it's shorted to one of the other pins, also check the value of the 220R resistor to make sure it's correct and that it's connected to ground. Hopefully once that's fixed the LFO will work.

Hope that helps

[slacker]

Thanks Slacker I can't wait to build this... and would love to see a butchered layout...

Here you are

http://www.aronnelson.com/gallery/main.php/v/slackers-stuff/album170/echobasebutchered.jpg.html?g2_imageViewsIndex=1

I couldn't be bothered corrected the component numbering, but it should be easy enough to figure out.

[npx]

The first thing you need to sort out is why the 2N5089 isn't working, if the the collector stays low then the effect is always bypassed, that's why you can't hear any delay. Make sure the transistor is the correct way round, on my vero layout the collector is at the bottom. After that check for shorts or wrongly placed components or component values.

Same things apply to your funny pin 4 voltage on the LFO opamp, it looks like it's shorted to one of the other pins, also check the value of the 220R resistor to make sure it's correct and that it's connected to ground. Hopefully once that's fixed the LFO will work.

Hope that helps

Thanks for the help, Slacker! I pulled out the 2N5089 and the delays started working, even without it. I've socketed it now and it's working. Bypass works as it should.

I'm getting good voltage on pin 4 of the LFO opamp now which is a start, but the other pin voltages that are supposed to change still don't. The Modulation Depth pot seems to just act like a second Delay Time pot. I can't see any obvious mistakes. I'll have another hunt through this epic thread for answered posts about lfo problems.

Cheers!

[slacker]

Cool, glad it's almost working. The LFO doesn't like a weak battery so try a fresh one or use a 9 volt power supply and see if that fixes it.

[npx]

Battery is measuring 8.2v. No difference with a power supply. I'll poke around the lfo section some more...

[championdjk]

Thanks Slacker I can't wait to build this... and would love to see a butchered layout...

Here you are

http://www.aronnelson.com/gallery/main.php/v/slackers-stuff/album170/echobasebutchered.jpg.html?g2_imageViewsIndex=1

I couldn't be bothered corrected the component numbering, but it should be easy enough to figure out.

Thanks Slacker!!!! You are the best!!!

[npx]

I finally got the LFO working... Woohoo! There was a short UNDER the lfo IC socket. Lots of crazy sounds hiding in that pedal!

I've promptly broken it again however, attempting to add the extra time mod. Hehehe, back to the troubleshooting!

[kierc]

Got my PT2399's from Futurlec today    Can't wait ot build this!

Does anyone have the dimensions for the tiny layout? or even better the DPI of the image so I can drop it into a photoshop document?

[andrew_k]

I'll crack mine open and measure the PCB for you tonight.

[Barcode80]

hmm, any other suggestions about brighter repeats? i lowered the cap going to the feedback pot down to a .068, but that introduced a lot of noise. Also, my pedal has developed a good bit of white noise in the background, anyone had that?

[kierc]

I'll crack mine open and measure the PCB for you tonight.

That'd be great!  Cheers! 

[doc_drop]

I just finished perf'ing up a Rebote 2.5. My plan is to put this in a box with an Echo Base to create the ultimate delay box. I am just going to give each 1/4" in and out jacks so I can patch them together in either order.

Anybody ever try running one delay circuit through another like that? Is there anything I need to watch out for?

Thanks!

[MikeH]

Anybody ever try running one delay circuit through another like that? Is there anything I need to watch out for?

Ummmm... chaos?

Seriously though, I used to do this.  It's great for some awesome-crazy noise, but I found it coolest when the first is set really fast like a slap-back, and the other is set slow.  You can get this nice, morse-code type texture;  di-di-dit....... di-di-dit........ di-di-dit.........

Know what I mean?

[doc_drop]

Oh yeah Mike, I know what you mean. That is exactly the kind of madness I am curious about...

I'm really a synth guy, so the more chaos the better. Depending on the type of chaos. I am looking forward to seeing what I can squeeze out of those guys!

[newperson]

here is a good link for you,
http://www.youtube.com/watch?v=HGGtgL91GG4
he is a synth person also.  you might want to make yours switch the same as his.

[doc_drop]

Cool "New P."

I will check out the video at home tonight. Thanks for the link!

[andrew_k]

I'll crack mine open and measure the PCB for you tonight.

That'd be great!  Cheers! 

sh*t, forgot all about this, very sorry! I've written myself a note to do it when I get home.