EchoBase Help (Sabro Vero Layout)

[canman]

Hi everyone,

I tried to build Sabro's EchoBase layout a few weeks back and when I tested it I got bizzare sounds...naturally, it wasn't working.  I got dry signal just fine, if I remember correctly, but the wet signal was very strange.  Quiet, not really delaying, modulation would do weird things...the details aren't important.  Anyways, I benched it for a while, but now that all my other projects are done, I want to get this one working.  It's a cool delay from what I hear in the videos!

EDIT:  Suppose I should link to the layout, haha...



So, onto the voltages.  My TL072 voltages are both normal, and I believe my PT2399 voltages are OK too.  So I won't bother you with TL072 voltages, but if you guys wouldn't mind taking a look at my other voltages, I'd appreciate it:

PT2399:
1.  4.9
2.  2.4
3.  0
4.  0
5.  2.4
6.  2.4
7.  4
8.  4
9.  2.5
10.  2.2
11.  2.2
12.  2.5
13.  2.5
14.  2.5
15.  2.5
16.  2.5

4066:  (Keep in mind on this layout, it's upside down.  So pin one is the bottom right corner of the IC)
1.  .74
2.  .74
3.  1.3
4.  1.3
5.  1.48
6.  .66
7.  0
8.  1.39
9.  1.37
10.  0
11.  0
12.  0
13.  1.38
14.  9.4

5089:  (Top to bottom)
E:  0
B:  0
C:  5.2

5087:  (Top to bottom)
C:  .6
B:  0
E:  0

The voltage regulator is also working properly, giving me 4.5ish volts.  What's confusing me (and maybe this is supposed to happen) is D1...on the side that connects directly to the 9v supply, I'm getting 9.4v (duh).  But on the other leg, I'm getting nothing.  Is that supposed to happen?  I tried jumping the diode to see what happens, and my power supply starting flashing at me.  Tried a battery and it got pretty warm so I quickly disconnected the battery.  I thought this was weird, but is that supposed to happen?

Anyways, I'd appreciate if you'd give me your thoughts on the voltages I've got and hopefully point me in a direction to solving the problem.  Thanks!

[slacker]

Something is very wrong with your CD4066 voltages. Pins 1, 2, 3 and 4 should all be about 5 Volts. With the base of the 5089 connected to ground, the bypass switch closed you should have about 9 volts on the collector of the 5089 and pins 5, 6 and 13 of the CD4066. If you've used a socket I would remove the CD4066 and then measure the voltages on the socket. If you get the voltages I listed above your CD4066 is probably bad.
If you get the correct voltages with the 4066 removed and want to test the rest of the pedal temporarily jumper pin 1 on the socket to pin 2 and pin 3 to pin 4, that will hard wire the effect on.

D1 is acting correctly, it's there for reverse polarity protection. With power connected the correct way it just sits there doing nothing. If you apply power backwards then the diode conducts, shorting out the power supply stopping the negative voltage damaging the pedal.

[canman]

OK.  I did some testing.

With the 4066 removed, I first checked the collector of the 5089...I'm getting close to 9v (8.8 or so) when the switch is in one position and the same reading at pin 5 of the 4066.  However, I'm getting .6 at pin 6, and about 7.5v at pin 13.  In the other switch position, I'm getting 1v at the collector of the 5089.

Pins 1-4 of the 4066 socket are reading 2v.  So, not quite the 5v you stated I should be getting.  Which tells me I went wrong somewhere, haha.  Obviously.  I should be getting 4.5v through R12 and R14, right?  Aren't they connected to the output of the voltage regulator? (In parallel?)

[slacker]

From your voltages I'm guessing you've got a cheap meter, the voltages you're getting are what you'd expect with a meter with about a 1Meg input impedance which is typical of cheap meters. What happens is the impedance of the meter affects the reading due to measuring the Voltage through large resistors. For example on pin 13 of the 4066 you've got a 220k resistor going to 9 volts, so when you connect your meter you're making a voltage divider from 9 volts through the 220k and then through the 1Meg input impedance of you meter. So you measure 9 * 1000k / 1220k = 7.5 Volts close to what you get. Same with pin 1 to 4 voltages you've got a 1M5 resistor from 5 Volts so you measure 5 * 1000k / 2500k = 2 Volts. So your voltages are probably fine and your meter is fooling you. You can test this by flipping the tails switch and then measuring pins 5 and 13 you'll hopefully find that the voltages switch and pin 5 becomes 7.5 volts and pin 13 becomes 8.8 volts.
I would jumper the pins I mentioned before and see if the rest of the pedal works, if it does then get a new CD4066.

[canman]

Wow, I'm extremely impressed...my meter is a $5 job from Harbor Freight I picked up just because I thought it would be handy, haha!  I've been seriously considering buying a better meter, I suppose now is as good a time as any. 

Anyways, I was literally about to jumper the pins you recommended and test the circuit and was checking here to double check what needed to be done and saw your post.  I'll report back in a little bit with my findings!

[canman]

First off...I tested pins 5 and 13 with the tails switch flipped, and as predicted, the voltages switched spots.  Interesting.  So one problem solved...I need to upgrade to a better meter!

Second...I hardwired pins 1 and 2, 3 and 4...when I plugged it in, I'm getting very strange results.  My dry signal works perfectly fine.  The wet signal...very different story.  It's a constant barrage of noise, if you will.  When turning the knobs, I can tell they are all doing something.  If I had a normal delay sound, I suspect all the knobs would be working properly.  I am getting a bit of delay, but it's not clean, and it's very hard to hear through all the noise.  When I turn the time knob and hit a chord, I hear it delay faintly through the noise.  So I know that knob is *kind of* working.  The level knob certainly works, because the noise gets louder as I turn that knob.  The feedback knob is doing something, because I can hear a shift in the noise when I turn the knob, and the rate and speed knobs for the modulation seem to work, because they make the noise get all wobbly.  The switches all seem to work as well, as they affect the noise...when I hit the humbucker switch, the noise gets quieter.  When I hit the mod switch, the wobble starts.  When I hit the dry switch, I don't hear the dry signal anymore.

So...I suspect that the 4066 may not be the problem, but rather something else that I can't seem to find.  I've switched out the PT2399 and I get the same result with other chips. 

Does the crazy noise make any sort of indication as to where the best place to start looking for the problem might be?

[slacker]

I've seen that meter problem a few times, so it's quite easy to spot, definitely worth upgrading to a better meter.

First thing I'd do is double check that your level and feedback pots have a connection from lug 1 to ground, the level should go all the way to silent. If that connection is missing from the feedback pot the pedal will be self oscillating all the time and will make horrible noises like you describe. If they are both OK I would double check all the connections and the component values down the right hand side of the PT2399, a bad connection or wrong resistor value could cause the problems you're having.

[canman]

Update...this is really confusing me.  

I checked all the resistors, caps, etc. on the righthand side.  Everything looks good, reflowed the solder joints, and tested it out.  Still getting wild oscillation, but that got me thinking.

I built a Rebote 2.5 Delay with the feedback switch that gets you crazy oscillation, and I have the same switch wired up for the EchoBase.  So I held down the Feedback switch (it's a momentary stomp) and the oscillation went away.  Strummed strings while holding it down, and I'm getting delays.  It doesn't sound quite right to me, I'm sure there's more going on, but this seems to be part of the problem at least!  Oh, I also switched the two wires to see what would happen.  Didn't fix the problem, just made a different type of oscillation. 

So I tested all the knobs, they all do what they're supposed to, "ish."  The feedback knob starts oscillating VERY rapidly.  I don't know if that's normal, but after about 1/4 of the sweep, things start to go nuts.  

Also, when the modulation is turned off via the switch, the rate knob still seems to have an effect on the delays.  The depth knob doesn't.  When I turn the rate knob I hear the delays get weird, and there does still seem to be a touch of modulation even when the switch is off.  

With all this stuff going on, I don't even know where to begin to look for the problem  

Thanks for all your help slacker, I really appreciate it.  I hope we can get this figured out!!

[slacker]

I would try disconnecting lug 2 of the feedback pot and the disconnect the feedback switch, hopefully that should stop is oscillating if that's what it's doing. If that stops it then double check the values of R34 and R36 and check the trace cuts on the same rows as the feedback pot and feedback switch connections, a missing or partial trace cut could be feeding back signal.
I'm not sure about the modulation issue that's an odd one, with the modulation switched off the rate knob doesn't do anything and there should be no modulation signal. Hopefully this is just a result of whatever else is wrong.

[canman]

Almost excellent update!

With the 4066 jumpered, I tested what you suggested...disconnected the feedback switch and lug 2 of the feedback pot.  Fixed the oscillation, so I examined the board...nothing stared me in the face.  So I reconnected lug 2 (and HB switch, naturally) and everything worked, no oscillation.  Sounds GREAT.  Hooked up the feedback switch again, but put one wire on the opposite lug...no oscillation!  Seems I just stupidly wired up that switch backwards and didn't catch on until now, haha.

The not as excellent update...I put the 4066 back in, and in either switch position, I only get bypassed signal.  I replaced the 4066 with a different one and am getting the same issue.  So I figure I don't have two bad 4066's, I must have something wrong elsewhere.

Thanks again for the help, I really like how this delay sounds!  Now if only I can get the bypass switch to work!!

[slacker]

Great news sounds like we're getting somewhere. What voltages do you measure on the CD4066 now?

[canman]

So when the bypass switch is in position A, I get:

1: 2
2: 2.8
3: 2
4: 2
5: 1.4
6: .1
7: 0
8: 4.9
9: 0
10: 0
11: 0
12: 0
13: 7.74
14: 9.4

And when the switch is in position B, I get:

1: 2
2: 2.8
3: 2.8
4: 2
5: 7.86
6: .8
7: 0
8: 4.7
9: 4.7
10: 0
11: 0
12: 0
13: 7.7
14: 9.4

I know my meter is cheap and is throwing off the readings as you mentioned earlier, but I'm not familiar with the 4066 so I have no clue what these voltages should be at.  How do these look now?

[slacker]

Hmm, your voltages look correct. The CD4066 is four electronic switches, pins 1 and 2 are one switch controlled by pin 13 and pins 3 and 4 are another controlled by pin 5.
When the control pins are a low voltage the switches are open, so no signal can pass and when the the control pins are a high voltage they switches are closed letting signal pass. Position B looks like it's the on setting, pins 5 and 13 are high so the switches should be closed allowing signal through so I'm not sure why it isn't working.  It looks like the switch for the LED pins 8 and 9 is working, does the LED work?
I think the best thing to do is trace the audio signal using an audio probe and see where it is stopping, check for signal on pins 1, 2, 3 and 4, this should help narrow the problem down.

[canman]

Interesting...yes, the LED is working, as you observed it would be.  (I didn't actually have an LED hooked up, just wired one in real quick and it works)  The LED also pulses with the rate knob when the modulation switch is engaged, pretty cool!

I did some probing, mostly on the IC's and transistors because I didn't have a schematic with me while I was probing.  I'm getting sound through the top right TL072, but not the left 72.  I don't get any sound from any pins of the 4066, PT2399, or transistors.  (Definitely not through the 78L05, haha)

I haven't had a chance to look over the schematic and probe, I wanted to get this up real quick and see if you noticed anything out of the ordinary.  I'll see if I can follow the schematic and probe, but my schematic reading skills are not very good so I may require some assistance 

[slacker]

This is getting weird.  We know that signal was getting to the 4066 because when you removed it and jumpered the pins the delay worked, so where is the signal disappearing to now?
If you trace the signal you should get it on pins 6 and 7 of IC2 it should go to C6 and from there through a jumper wire to pin 3 of the 4066. Where does it stop?
What arethe manufacturer and part numbers on the 4066s? I'm wondering if you haven't got 5 volt parts by mistake.

[canman]

I agree, this is VERY weird...I probed everything as per your request, and now the signal goes all the way through.  But I'm not getting delays.  Here's the weirdest part...when I probe pin 3 of the 4066, I get no sound.  But when I probe the socket of pin 3, I get sound.  So then, when I do the same to pin 2, sometimes I get delay, and sometimes it's dead silent.  Again, probing the socket of these pins.  Probing the actual pins yields no sound, unlike when I probed IC2...I get sound right from the pin, as well as the socket.

What the heck??

The 4066 is labeled as CD4066BE, and I can't make out the manufacturer...it looks like some kind of EY?  Or E4 maybe?

The rest of the label reads 05AKZNM and then that weird EY thing (which is underlined).  I don't know if this helps?

[slacker]

I'd ignore the fact you can't get a signal on the CD4066 pins for now it might be a red herring if the signal is making it to the delay it must be working. If it says it's actually a CD4066 on it then it should work fine on 9 Volts, you can get versions of the chip that only work up to 5 Volts but they shouldn't have the CD prefix.

Try tracing the signal along the paths I've shown here.



Start with the green line, if you get signal there move on to the blue, then the yellow and finally red. With the delay on you should get signal on all those paths. Hopefully this will narrow down where the problem is, if it sometimes works then it's probably a bad connection somewhere.

[canman]

Wow, I'm at a loss...I traced everything you suggested and reflowed all the joints along said traces.  Still only getting signal at the green line, nowhere else.

What I described earlier I may not have been as accurate as I should have been...if I strum while checking pin 3, and then quickly move to pin 2, I get loud delays.  But when I try to strum again while on pin 2, I get nothing. 

So now, when I strum pin 3, I'm getting very faint delays.  (This was after I reflowed all the solder joints)  I still experience the same phenomenon of moving quickly from pin 3 to pin 2. 

If I hardwire pins 1-4, the only downside is I wouldn't be able to use the tails switch, correct?  Having the tails isn't essential I guess...it's definitely one of the reasons I wanted to build this one though!

[slacker]

If it works fine when you jumper pin 1 to 2 and 3 to 4, but doesn't when the chip is in the socket I can only think that it's a bad CD4066  or it's a bad contact between the CD4066 pins and the socket. The fact you can't get signal on the pins makes it sound more like a bad contact.
If you want, you could try temporarily soldering a jumper between the traces going to pins 3 and 4, or if you've got some alligator clips clip the two vertical jumpers going to pins 3 and 4 together. This will bypass that section of the CD4066 so if that's where the problem is it will temporarily solve it.

Any chance you could post some decent pictures of the board front and back?

[canman]

When I clipped the two vertical jumpers together to link pin 3 to pin 4, I got the faint delay in bypass, without having to probe pin 3...so that's good news, kind of!  The bad news is that the delays are really faint.  The time and feedback knob change the delay sound, but the volume knob doesn't.  Which doesn't make sense to me at all, because when I hardwire the effect on, the volume control works fine.  I also get sound straight from the pin 3 and not just the socket when I probe it, but again.  What??  

Anyways, here are the best pictures I could get (my Dad has his nice digital camera stashed away somewhere, haha):


OK for whatever reason, the image is vertical...I rotated it in photobucket but it's not recognized here...weird.  Here's the link to the rotated image: http://s1030.photobucket.com/user/jacobcanady/media/3C2E5DF7-7264-4BFC-A1DA-E2C7977FADBB_zpsam7fnxf2.jpg.html

This shot of the back is taken as if you were to take the image above and flip it over top to bottom, if that makes sense: