Building the Echo Base PCB

[Govmnt_Lacky]

Help! Taylor, or anyone who can help.

After having this board sitting around for God knows how long, I'm finally populating it. But I managed to strip the pads for one of the resistors--don't ask, I didn't even know this level of cluster@#$% was possible with a plated through board--and I am having trouble figuring out where to tack the resistor onto other components.

The resistor in question is the 47k on the right side of the PT2399, between the 1n cap and the 10k resistor. Referring to the schematic, I'm not sure if it is the 47k that connects to pin 14 or pin 15 of the PT2399, and, that said, I'm also not sure how the various components line up in the layout--that is, even if I was sure which components it's supposed to connect to, I don't know which side is which.

TIA

Its the 47K that is coming directly off of Pin 14 of the PT2399. The schematic on Taylor's site will show you how the other side connects. So.....

One side connects directly to Pin 14 of PT2399
Other side connects to BOTH 10K resistors directly below it AND one side of the 15n cap directly below the LFO DEPTH pot.

P.S. You can see all of this if you blow up the PCB pics on the site.

[Ben N]

Thanks, GL, good call on the pic of the pcb from the site. I ended up pushing the resistor into the holes anyway, in the name of mechanical stability, and wiring them to the IC socket pin and the cap lead using good old fashioned perfboarding skills and some judiciously placed shrink tube. All good now (at least until my next Tayda order rolls in and I can finish).

[Ben N]

One more (sheepish) question: the 50k hanging off pin 8 of the 4066 - the schematic says 10k-50k, while the board and the BOM both say 50k, which is kind of an odd value. Any reason not to use 47k or 51k? Is there any purpose in using a lower value? (Apologies if this is covered already in the thread--I couldn't find it with a search, and I'm not about to reread all 38 pages.)

Ack, never mind--it's the LED resistor, of course. This is what happens when I go into paint by numbers mode, and it's not pretty. Sorry.

[telebiker]

The problem with the bypass has gone (solder bridge on the tails switch) and I've had a go with the audio probe... Nothing conclusive. I'm wondering if it's the PT2399. I bought 10 of them from Ebay a while back and they were CHEAP !! Maybe they were cheap for a reason.

What makes it so frustrating is I can hear everything is working as it should !?!? All the controls work correctly, just this horrible distorted noise coming out of it.

I shall endeavour to persevere.

Looks like I have the same problem. Yesterday I was checking the pcb and it was working with some components not yet wired, today I've wired them and I can hear the sound, but there are a lot of background gray-ish noise out of it. However, the pots are working. What voltages can help to investigate it? Also, the LED is not working and 7805 is getting hot pretty quick.

Thank you.

[telebiker]

UPD: looks like like I've reversed 7805. After reversing it back LED started to work.

However, the noise has not disappeared (although the amount of it reduced). There is one more thing which does not work: modulation. LFO depth pot changes the sound only while turning it, no modulation appeared, but it should be (it was yesterday). LFO speed pot is not affecting the sound at all. Would be grateful for any ideas what could be wrong there...

I'm having 8.8V on 7805 output, is this expected?

[telebiker]

So, the LFO is made up by the TL072 on the right side of the board, and surrounding parts. First check the voltages on that IC, and post them here. Check over the soldering in that area for a short or iffy solder joint. Potential reasons it might not oscillate could be that there's a short across the 1uf film cap, the LFO SW pads are bridged, too low of a voltage at pin 8 of the '72, or a cold joint on one of the resistors in the feedback path around that IC.

I have the following voltages on TL072 in the right side of the board:

Code Select Expand

7.5     8.05
2.15    2.16
7.46    7.46
0.8     5.59
And the following on 7805:

Code Select Expand

7.46    0    8.9

[Taylor]

Hmm, well the 7805 is a 5 volt regulator, so you may have fried it when you had it in backwards, since it's now putting out around 7.5v. I would replace that and see if the modulation starts happening.

As far as the noise, this chip does produce some noise, and more of it the longer the delay time is set. Does the noise mostly go away if you turn the delay time very short?

[telebiker]

I definitely fried something, probably, something more. Tried another 7805 and modulation still isn't happening and 7805 is getting pretty hot quickly.

If I'm connecting 9V battery to the 7805's input and having 5V at the output, can I assume that 7805 works fine?

Does the noise mostly go away if you turn the delay time very short?

Nope, it's always present. Is there sense to change all the ICs and transistors or better to go one by one?

[duck_arse]

if you really have less volts on the input of a regulator, and more volts on its output, you have a short somewhere else on the board.

[telebiker]

if you really have less volts on the input of a regulator, and more volts on its output, you have a short somewhere else on the board.

Thanks, will verify this.

May I ask a silly question regarding 7805 orientation: is it the left pin near 47 uF cap "IN"?

[Taylor]

if you really have less volts on the input of a regulator, and more volts on its output, you have a short somewhere else on the board.

Thanks, will verify this.

May I ask a silly question regarding 7805 orientation: is it the left pin near 47 uF cap "IN"?

No, the voltage input is close to the edge of the board, the side near that cap is the output that should be 5v.

[telebiker]

And if I'm connecting 9V to the 7805's input and having 5V at the output, can I assume that 7805 works fine?

[Taylor]

Yes.

[telebiker]

I have installed working 7805 properly and now I have the following results: at the output I can hear dry signal without changes, potentiometers do not affect the sound at all, the LED does not working. I'm having 5V at the 7805's output and 0.7V at the LED's positive lug. Also, I have not wired bypass switch, I used effects tester PCB with in, out, +9V and GND wires connected.

I have found the post with referenced voltages, and after quoting here is what I have:

To help with the debugging here's some voltages and other info that we found useful when me and Mike F were debugging his.

PT2399
1. 5v
2. 2.5v
3. 0
4. 0
5. 2.89v
6. 2.5v
7. 0.5v
8. 0.5 v
9 - 16 all 2.5v

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
2. 4.6v
3. 0.4v
4. 0.4v
5. 0
6. 0.45v off 4.5v on
7. 0
8. 9v
9. 3v on 0.32 off
10. 4.6v
11. 4.6v
12. 8.5 on   
13. 8.5 on
14. 9

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.

The TL072 voltages are

U3 top left of vero

1. 5v
2. 5v
3. 5v
4. 0
5. 5v
6. 5v
7. 5v
8. 9v

U1 bottom left of vero, this is the LFO

1. changes
2. 5v
3. 5v
4. 0.8v
5. changes
6. 5v
7. changes
8. 8v

The voltages on the 5089 should change depending on the position of the bypass switch.
E. 0
B. 0.63v off 0 on
C. 0.89v off 8.5v on

These are audio probe results from the PT2399

16. very quiet signal
15. delay
14. loud delay with cyclic noise
13. nothing, or possibly a very quiet signal
12. delay with hiss
11. very quiet delay with hiss
10. very quiet delay with hiss
9 . delay with cyclic noise and hiss

Highlighting values that severely differ from slacker's reference:

PT2399
1. 5.02V
2. 2.48V
3. 0
4. 0
5. 2.98V
6. 2.48V
7. 4.54V (should be 0.5V)
8. 1.12V (slightly varies) (should be 0.5V)
9. 2.48V
10. 2.47V
11. 0.78V (slightly varies) (should be 2.5V)
12. 4.75V (should be 2.5V)
13. 3.92V (should be 2.5V)
14. 0.09V (should be 2.5V)
15. 2.48V
16. 2.48V

4066 (no bypass switch wired, connected to effects tester PCB with in, out, +9V and GND wires)
1. 4.7V
2. 4.7V
3. 1.59V (should be 0.4V)
4. 1.56V (slightly varies) (should be 0.4V)
5. 0
6. 1.14V (slightly varies) (should be 0.45V off and 4.5V on)
7. 0
8. 5.06V (should be 9V)
9. 0.75V (should be 0.32V off and 3V on)
10. 4.7V
11. 4.7V
12. 8.6V
13. 8.6V
14. 8.9V

The TL072 (non-LFO)
1. 5.02V
2. 5.02V
3. 4.6V (should be 5V, probably that's ok)
4. 0
5. 5.02V
6. 5.03V
7. 5.02V
8. 8.9V

LFO TL072
1. 5.08V (does not change)
2. 5.02V
3. 5.02V
4. 0.79V
5. 5.05V (does not change)
6. 5.02V
7. 5.03V (does not change)
8. 8.1V

2N5089 (no bypass switch wired, connected to effects tester PCB with in, out, +9V and GND wires, not sure what voltage should be in this case, it corresponds disabled effect, but I have measured when in was enabled)
E. 0
B. 0.61V
C. 0.94V

BC560 (from the left to right)
1. 0.76V
2. 0.25V
3. 0


Audio probe results from the PT2399
16. no sound (should be very quiet signal)
15. dry signal (should be delay)
14. quiet hum and noise (should be loud delay with cyclic noise)
13. hum and noise (should be nothing, or possibly a very quiet signal)
12. loud hum and noise (should be delay with hiss)
11. very loud hum (should be quiet delay with hiss)
10. very quiet dry signal with hiss (cannot notice delay)
9 . dry signal with cyclic noise and hiss (cannot notice delay)

Would be grateful for recommendations how to debug this further...

[Taylor]

Because this effect has its own buffered bypass, if you haven't wired anything to the bypass switch terminals, it might just be in bypassed mode, so no signal would be getting to the delay chip. I would wire up the bypass and tails switches while you're debugging.

Previously you had sound changing when you moved one of the mod pots, which would mean the delay chip was doing something, but now not? Do you have another PT2399 you can swap into the socket to see if that got damaged when you had the regulator in backwards?

[telebiker]

I have wired bypass and tails switches and something changed. The LED is working now (having 2.45V on positive lug), and it's changing blinking speed depending on LFO speed pot position. Still no delay at the output and pots do not affect the sound. Output is a bit louder than dry signal.

Previously you had sound changing when you moved one of the mod pots, which would mean the delay chip was doing something, but now not?

That's true. Previously I could hear sound changing, now it's not. I don't have another delay chip, but I'll get one and post here what I have. For now I'm getting the following voltages highlighting with purple what changed.

I have a bit different audio probe results from the PT2399 at 10, 14, 15 pins:
16. no sound (should be very quiet signal)
15. dry signal but louder than at the output (was just dry signal) (should be delay)
14. no sound (was quiet hum and noise) (should be loud delay with cyclic noise)
13. quiet hum and noise (should be nothing, or possibly a very quiet signal)
12. hum and noise (should be delay with hiss)
11. loud hum and noise (should be quiet delay with hiss)
10. no sound (was very quiet dry signal with hiss)
9 . dry signal with cyclic noise and hiss (cannot notice delay)

A bit different voltages on BC560:
BC560 (from the left to right)
1. 0.54V (was 0.76V)
2. 0 (was 0.25V)
3. 0

2N5089 now corresponds what slacker had.

The TL072 (non-LFO) voltages haven't changed

LFO TL072: voltages started to vary on pins 1, 4, 5 and 7 (now probably it looks good)
1. 4.5V–5.5V (was 5.08V)
2. 5.02V
3. 5.02V
4. 0.75–0.8, slightly varies periodically (was 0.79V)
5. 4.96, slightly varies around it (was 5.05V)
6. 5.02V
7. 0 which gets 4.8V from time to time (was 5.03V)
8. 8.1V

4066: having slightly different values on pins 3, 4, 6, 13 which probably are good, but I don't like what's going on on pins 8 and 9
1. 4.7V
2. 4.7V
3. 1.2V, slightly varies around (was 1.59V) (should be 0.4V)
4. 0.8V, slightly varies around (was 1.56V) (should be 0.4V)
5. 0
6. 4.3V (was 1.14V) (now ok)
7. 0
8. 2.45 (was 5.06V) (should be 9V)
9. 2.45 (was 0.75V) (should be 3V on)
10. 4.7V
11. 4.7V
12. 8.6V
13. 8.9V (was 8.6V) (should be 8.5V) (probably ok)
14. 8.9V

PT2399 is almost the same, only have little change on pins 8 (now probably ok) and 11 (not ok)
1. 5.02V
2. 2.48V
3. 0
4. 0
5. 2.98V
6. 2.48V
7. 4.54V (should be 0.5V)
8. 0.78V (was 1.12V) (should be 0.5V)
9. 2.48V
10. 2.47V
11. 0.68V (was 0.78V) (should be 2.5V)
12. 4.75V (should be 2.5V)
13. 3.92V (should be 2.5V)
14. 0.09V (should be 2.5V)
15. 2.48V
16. 2.48V

I think that I'm goind to change the delay chip. Also, I don't like what's happening with BC560 and 4066, should I also replace them?

Thanks for the help.

[telebiker]

I've replaced BC560, 4066 and the delay chip and now everything is working as expected. Thanks everyone for the help.

[eh la bas ma]

Hello,

I built an Echo Base kit and I have just one issue with the LFO.

Everything works fine until i turn the LFO SPEED pot near to maximum.

Then the LFO dissapear, the LED is always bright, until I restart the pedal .

If you could help me understand why does it happen, I would be very grateful .

Thank you for your help,

Justin

[Taylor]

There is a 27k resistor next to the TL072 on the right side of the board. If that was shorted out or the wrong value, it might act like that.

[taylorbusby409]

So I love the way this delay sounds but anytime I put an overdrive pedal into it it starts distorting bad. Is there a mod to fix this? Ive tried putting a green LED on pin 7 but there is a huge volume drop.