Debugging The Depths by EQD on Vero

[pinkjimiphoton]

hey harry
dude, yah, until the voice is about 40% it doesn't really do much. if ya subbed linear for audio anywhere or vice versa it would bunch everything up really funny at one end of the pot's rotation, too.

but diggit... you GOT it working. its just not dialed in right. that alone is a hell of an accomplishment, cuz its not the easiest vero project to do. i was lucky that aish burned and populated a board for me (lol and it didn't work when i first fired it up, had one of them internally decapitated resistors) and i misinterpreted the layout so had all the pots backwards
but it worked. i was like... ah, fudge the damn thing. but i figured it out.
so will you.
i hear ya on the no money thing. i'm a professional musician (read: impoverished) too.

listen. take a break from it for a few. go back with fresh eyes, and take a look at the project. go node to node, confirm everything's good.
make sure the values are spot on. sometimes mistakes happen, something can be off by a factor of 10 to a million ffs with very little effort.
also check your soldering. look for bridges. run a knife or something thru the cuts on the back of the vero.

its passing audio... thats a plus. it probably sounds more like a tremolo with the voice and intensity backed off. its supposed to sound like that. if ya peg the intensity and voice its pretty much a colored phasey univibe sound. the throb control don't do shit really til the other two knobs are cranked up. there's a LOT of fine adjustment possible, i like it backed off a little so it sounds like almost real vibrato. this thing is transparent and beautiful when working.

post some voltages and we'll compare notes. i'm betting there's a solder bridge somewhere or an intermittent cold solder joint, especially cuz ya said it makes the e and b strings sound funky. do ya have it all the way up? this circuit has some gain to it. it could overdrive your amp in some cases easily.

you'll figure it out. start with voltages. and we'll go from there

[Harry Muff]

hey harry
dude, yah, until the voice is about 40% it doesn't really do much. if ya subbed linear for audio anywhere or vice versa it would bunch everything up really funny at one end of the pot's rotation, too.

but diggit... you GOT it working. its just not dialed in right. that alone is a hell of an accomplishment, cuz its not the easiest vero project to do. i was lucky that aish burned and populated a board for me (lol and it didn't work when i first fired it up, had one of them internally decapitated resistors) and i misinterpreted the layout so had all the pots backwards
but it worked. i was like... ah, fudge the damn thing. but i figured it out.
so will you.
i hear ya on the no money thing. i'm a professional musician (read: impoverished) too.

listen. take a break from it for a few. go back with fresh eyes, and take a look at the project. go node to node, confirm everything's good.
make sure the values are spot on. sometimes mistakes happen, something can be off by a factor of 10 to a million ffs with very little effort.
also check your soldering. look for bridges. run a knife or something thru the cuts on the back of the vero.

its passing audio... thats a plus. it probably sounds more like a tremolo with the voice and intensity backed off. its supposed to sound like that. if ya peg the intensity and voice its pretty much a colored phasey univibe sound. the throb control don't do shit really til the other two knobs are cranked up. there's a LOT of fine adjustment possible, i like it backed off a little so it sounds like almost real vibrato. this thing is transparent and beautiful when working.

post some voltages and we'll compare notes. i'm betting there's a solder bridge somewhere or an intermittent cold solder joint, especially cuz ya said it makes the e and b strings sound funky. do ya have it all the way up? this circuit has some gain to it. it could overdrive your amp in some cases easily.

you'll figure it out. start with voltages. and we'll go from there

im going to breadboard it but I have some questions. the schematic is in 3 blocks. I know the power supply connects to vref, but how does the lfo connect to the rest of the circuit ? I have trouble with logic gates and assuming I can use any inverting/non inverting/out pins off the opamps ?

this vibe doesnt sound as good as all the other in the demos I been watching. I made two madbean harbingers and didnt like them at all either, would a GGG neovibe sound like a dry bell ? maybe I should order JD's pcb board but it uses a transformer I am not familiar with that method

the bell sounds just like woodstock tone with that chewy phase to it



if i had about 400 bucks I would buy one of these

[pinkjimiphoton]

i gotta dig out the schematic and look at it. aisha built mine for me as a gift, so not sure as i wasn't involved with much beyond boxing it and debugging one rogue resistor.

check the black cat vibe, this is my personal fav. but i suspect you and i are looking for different things in a vibe pedal


https://www.youtube.com/watch?v=nyyGSW_EdLQ

the strymon is hip, but i doubt its fully analog.

if ya want something you can have that much versatility with, check out rick holts (frequency centrals) causality 4 project. very tweakable, can do just about everything a phaser can do. does some nice chorusing and almost flanging, too.

[duck_arse]

im going to breadboard it but I have some questions. the schematic is in 3 blocks. I know the power supply connects to vref, but how does the lfo connect to the rest of the circuit ? I have trouble with logic gates and assuming I can use any inverting/non inverting/out pins off the opamps ?

harry, if we are still talking about the EQD depths thing circuit - the lfo connects optically to the phase stages. the lfo does nowt but flash a led. the phase stages all have a part of their phase-shift network in the way of the light produced by the led, those parts being light dependant resistors. there is no physical connection beyond the photons, and I don't think they count.

as for the opamp pins, no, you can't just willy nilly them. all the (-) inverting inputs in the phase shift string are connected to provide feedbacking loops, and all the (+) non-inverting pins have the cap/ldr combo attached, to do the phase shifts. and the ouput pins are for outputting.

[Kipper4]

Welcome Harry.
That EQD circuit should own the vibe sound.
Where it me I'd probably breadboard it first and experiment with led/ldr (vactrol)
First port of call would probably be a 5mm red led and 1M dark ldr. Then some 500k dark ldr.
I'm not sure what the circuit calls for. Not having researched it more than a quick squiz at the link.

Both of the sample videos you posted have a much bigger signal chain than just vide in the picture.
I'd probably buy the picture based on the recording and mixing.
But still end up disappointed with my playing compared to the video.

As Duck says the lfos sine wave output will make the led flash which shines right next to the light dependant resistor. ldr. The ldrs resistance will change depending on how bright or dull the led is.

Imagine that on each phase stage input is an RC filter 

C4 R6 (R6 being the ldr) the filters corner freqauncy will change depending on the ldrs resistance.

I hope this explains a little of how the led/ldr combination plays it part.

[snk]

Hello,
I am resurrecting this thread, because i built this circuit using a similar veroboard layout yesterday, and i am experiencing some issues :

- There is no audible effect;
- output signal is below unity gain;
- sometimes, audible input distortion is heard (a bit like crackles).
- The LFO seems to work fine, according to the LED blinking when I turn the pots.

I am using the layout with the external LDR daughterboard from here (which uses 3 x TL072).
The schematic is here, or there.

I have used 4xGL5516 and a yellow 5mm led.
I think that my build is quite clean (I checked several times, and didn't notice any trace or cut error), you will find a picture below.
I have measured the voltages at the IC and transistors pins : they all share the same "voltage pattern" (values between 1 and 1.4V, except pin4 which is 0 and pin 8 which is slightly below 9V) :

IC1
1.43
1.43
1
0
1.30
1.7
1.75
8.8

IC2 (left)
1.38
1.36
0.95
0
0.95
1.37
1.39
8.79

IC3 (right)
1.40
1.38
0.90
0
1.95
1.38
1.40
8.70

Both transistors have 0V at their Emitter, around 0.3 and 0.6 at the Base, and changing values around 3.5 and 4.80 at the collector.




I have read on the net that i am not the only one experiencing such issues, but i couldn't find any hint to fix the issue. I'd be grateful if anyone could point me toward a direction where to look at...
Thank you in advance for any help

[duck_arse]

we do want to see the topside, and the offboards, but, I think you've done mirror image board cuts.

[snk]

Hi, DuckArse, thank you for your kind help.

I think my cuts are ok : at least, when i was soldering every components fitted in their place (by lack of better words). But it's a somewhat big layout, so maybe that an error occurred indeed. I am uploading pictures to Imgur as we speak, and will post a link in a minute.
The wiring looks a bit messy, and it's quite difficult to take a good picture, but hopefully it will be good enough.

[snk]

Here is an Imgur album with several pictures.

Obviously, when I tried the effect, the led/ldr daughterboard was'nt exposed to light.

[snk]

With your mirror suggestion, you made me curious to try an overlay with the layout and my build.
It's quite rough, but it fits... It fits enough to show me that i forgot a 1µF at the top right 

[duck_arse]

yeah, I think I'm losing my mind, all this flipping and mirroring. well spotted w/ the cap.

[snk]

Unfortunately, the missing cap didn't change anything...
Back to scratching my head and losing my mind, too

[snk]

This is how it sounds (DRY/WET/DRY again) :  whyp.it/t/eqd-depths-issue-35826

I'm thinking it might be either a faulty op-amp (i never experienced that yet), or the power path coming into the audio path (with a wrong wiring, or a trace, but i have checked a dozen times and didn't see anything suspect).

I have tried audio-probing, but the circuit is more complex than a fuzz, so it isn't that easy 

[snk]

Hello,
Further attempt at debugging this circuit.

I have audio probed the TL072 pins :

- The only point where i get a WET signal (ondulating, pulsating) is at PIN 3 of chip 02 (on the left of the veroboard), but it is low, way below unity gain.

I also get some DRY signal at CHIP1 (upper part of the veroboard):
- PIN3 (of course, it's the input);
- PIN6 (DRY signal, low volume). Pin6 goes to the output of the circuit through the Level pot.
- PIN7 (DRY signal, very low volume).

I also get the DRY signal, very low volume at CHIP 2's pin 2.




I will try to understand where the issue can come from by comparing my findings with the schematic, but i don't have a good understanding of the schematic, so it might not be easy 
If ayone has any hint or advice, i'd take it

[duck_arse]

I'm looking at some of your resistor colour bands, esp around the top right corner, 47k's and 10k's. can you please go thru ALL resistors with your meter and check those bands that look orange to me are in fact red?

[snk]

Thank you for your answer, Duck Arse.

I'm looking at some of your resistor colour bands, esp around the top right corner, 47k's and 10k's. can you please go thru ALL resistors with your meter and check those bands that look orange to me are in fact red?

Yes, I will do. But i am a bit unsure about what you mean : do you want me to check the value of the resistors (especially around the top right corner, 47k's and 10k's), or to check the continuity of the veroboard strips (and checking that the cuts in red are indeed cuts)?

[snk]

By the way, in the meantime, I audioprobed each TL072 pins, and tried to make the vero match the schematic better (I mean that the veroboard layout uses 3 TL072, while the schematic uses 1X tl072 and 1x TL074).

So here is a picture of my findings :



My questions :
- Am I right to find suspicious to get no signal at all at any of the 3d chip ("ICA2A/B" on the schematic)?
- Is the sound arriving at chip2 pin3 (on the layout, and "IC2C pin 10" on the schematic) supposed to be that low?

[snk]

Continuity test done:
- the DMM didn't beep, which is a good sign.
- However, I was surprised to see on a few rows values going above zero, but no beeping occurred.


I am measuring the resistors right now, and started by the upper right corner as suggested.
-most of the resistors gave the expected value...
-... but one 10k resistor kept rising its value (from something around 15k to... 100k, then i gave up but it was keeping rising) 


-With a green check mark : all the checked resistors (giving the expected value).
- circled in purple : the resistor with the "neverending going up value"

[duck_arse]

I am wanting you to be testing the resistance value of each resistor. that circled resistor is one of a pair of 10k's, except that the multiplier on one looks red, and the other, the one that counts to 100k, looks orange, which would be ...... 100k.

I also see red/orange confusing me on some 47k's, but I'm not going to tell you where. also, all your voltage measures are bad. please pull the IC's from the sockets, and then do another round of volts measures on the empty sockets.

one further, and expected by some, question - is there a circuit diagram that matches the dual opamps version of this circuit?

[snk]

I am wanting you to be testing the resistance value of each resistor.

Ok

the multiplier on one looks red, and the other, the one that counts to 100k, looks orange,

What do you mean by "multiplier" (sorry if it is a basic question, but i don't get that term)?

[edit] ah, I understand : you are talking about the color codes of the resistors on my build, right? I thought you were talking about the veroboard layout.  :icon_redface:Sorry about that!

also, all your voltage measures are bad. please pull the IC's from the sockets, and then do another round of volts measures on the empty sockets.

eerk! Yes, I will do!

is there a circuit diagram that matches the dual opamps version of this circuit?

I fear not. I searched the web, but I didn't find any. I think the regular circuit use one 72 and one 74, but this layout used 3 x 72 so the led/ldr combo could be put on a daughterboard to avoid ticking.
Some people said it was verified and working fine, but i am rather sure that the original schematic use 1 x 72 and 1 x 74.
I think I have posted above the sources :
-schematic here : http://guitar-fx-layouts.42897.x6.nabble.com/EQD-The-Depths-gut-shots-td34241.html
- and there : https://www.pedalpcb.com/docs/Abyss.pdf
- both layouts here : https://tagboardeffects.blogspot.com/2016/11/earthquaker-devices-dephs.html
- and there (unverified) : http://dirtboxlayouts.blogspot.com/2020/11/earthquaker-devices-depth.html