Build Your Own Clone Message Board

Hey All

After a 18 year hiatus from building pedals (wow things are so much better!) I’ve picked things up again and thought I’d try a challenge with the Royal. I definitely had a hard time with some of it, but after re-doing the off board wiring I was able to get a signal though not the one I expected. In the video (https://youtu.be/EsCUV8lQv88) you can see that the dry output works correctly but the mix out is garbled/distorted regardless of if the pedal is on or in bypass. Also the pots still seem to be affecting the output regardless of the switch. I tried reflowing all the solder points and I did some simple audio probing, but I don’t think it’s a simple signal issue. I’m hoping that this is something someone has seen before and it’s just a wrong/bad component. Thanks in advance for the help!

That's weird. Let's just focus on the dry mix signal for now. Remove the 571 and 2 x PT2399 chips. What does the dry mix signal sound like now? Does bypass work better now?

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Ok! So I tried pulling out the ICs you mentioned and no dice, bypassed signal still sounds the same. However, I figured, why not try pulling out everything and what do you know, when I pull out the TL072 it sounds normal again! If I replace all the other components it still
Sounds normal with just the tl072 missing but when I switch the delay on, the led switches but I’m not getting any delay signal/the pots do nothing/it still sounds bypassed.

Not sure if that means the chip is bad or something else?

—AQ

when the pedal is on, does the mix knob work? It won't have any wet echo signal. Just dry signal. So it's not actually mixing anything, but you should be able to control the dry signal level with it.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

No, I wasnt getting any signal with the mix pot all the way down and the pedal on.

I replaced the TL072 and now if I probe around it and most places on the board I'm getting a good delay (ie pin 2 of 571 sounds great, though pin 6 sounds much quieter - not sure if this is normal) but still no signal coming out of the MIX output. I tried resoldering the output socket but that wasn't it either.

I'm trying to follow the schematic and see where the signal is dropping off but having trouble referencing it vs the actual placement of components. Is there a reference somewhere of the R/etc numbers in the schematic vs placement on the board?

---AQ

Here you go...

_________________
“To know, and not to do, is not to know”

OK! Thanks for that. I audio probed through the circuit and here's what I'm finding.

- At the end of the delay loop at pin 2/3 of IC2a I get clear loud delay
- At pins 6/7 you can hear the delay but its much quieter
- By the time the signal gets to C22 its almost inaudible
- r16/r18/r19 are all clean (but quiet) signals
- Pins 1/2/3 of Ic1a all sound similar to the mix output which now is super muddy and mostly hiss/inaudible.

Not sure where to look next? Could it be Ic2? Or maybe the mix pot?

Thanks for the help!
--AQ

The first thing you need to concern yourself with is the dry signal. Actually, you really need to just concern yourself with getting bypass to work. For now, just remove the 571, and two PT2399. Keep only the TL072 chip in its socket.


Power on the pedal and leave it in "bypass". Turn the mix knob full turn clockwise.

1. Test for signal at the south end of R18
2. Test for signal at the south end of R26
3. Test for signal at pin 2 of the TL072

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Also, please take voltage readings of your TL072.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Ok! With ics removed, in bypass, the signal is loud but clipping at r18 and quiet but there at r26 and pin 2 of tl072. Voltages at tc072 are 0 except for pin 5 which is reading at 8.43v.

—AQ

Please post pics of your build. Mostly, I'm concerned with your resistor placement, so make sure they are large enough, in focus, and lit so that the color bands show their colors correctly.

Please take voltage readings of the TL072 again. I'm pretty sure you aren't taking the readings correctly. Make sure your meter is set to read DC voltage, not AC. https://youtu.be/XRFtlUn4eBg Here's a vid on how to take voltage readings if you need help.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I've tried a couple times (the video is what I was doing) re: voltage readings, the one thing I did wrong was report pin numbers correctly. It looks like its only pin 8 of 072 that's giving a reading.

Heres a collection of images of the board.

https://imgur.com/a/u2ksBid

Thanks
--AQ

I don't understand how you can't get a reading at any of the other pins. Are you saying, it's just telling you that there's zero volts on everything but pin 8?

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com