EarthQuaker Disaster Jr DELAY PEDAL WITH TAILS - HELP

Started by ic_, July 05, 2020, 07:33:12 PM

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ic_

Hello!!

I'm working on the EQD Disaster Transport with Tails mod from
https://tagboardeffects.blogspot.com/2017/12/earthquaker-disaster-transport-jr.html

Everything seems to be working as supposed on the pedal, the effects work correctly and the tails mod too. but i hear a lot of noise, not a hiss, i dont really know how to describe it correctly but more like a white "grainy" noise sound (like rain).
I'm very new to building pedals, i would like to understand better how to diagnose problems. I replaced the chips TL072 and Pt2399, but it didn't change anything, i also checked if there was any bridges between tracks on the veroboard and cold joints, using a multimeter, everything seems ok. I tested my grounds and checked if they were ok too. I replaced some components and the trimpot but nothing changed.


I'm very new to building pedals and i know i still have a lot to learn. What may be causing the noise? What can i test or change? Someone has any tips or have built this pedal? Where should i be using an audio probe to find the problem? or what other technics can i use?
Thank you for your help  :)



andy-h-h

Hello

You may not get any help without posting photos of both sides of your build along with voltages.    ;)

ic_

hello!

thank you, i will try to get some pictures of the board and voltage measures.

antonis

Maybe an audio sample should be more helpfull..
(by guessing noise classification, e.g. shot, pop-corn or flicker noise, it should be easier to locate its origin..)
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

ic_

Quote from: andy-h-h on July 05, 2020, 07:49:33 PM
Hello

You may not get any help without posting photos of both sides of your build along with voltages.    ;)

Here are some pictures of the veroboard.
https://drive.google.com/drive/folders/1EnhLlngtznOtgLMN9F2_XCLph8fG5JQ1?usp=sharing

And voltage measures of the ICS

TL072

1 - 4.43 V
2 - 4.43 V
3 - 4.31 V
4 - 0 V
5 - 4.43 V
6 - 4.43 V
7 - 4.44 V
8 - 8.88 V

Pt2399

1 - 5.08 V
2 - 2.5 V
3 - 000.1 mV
4 - 019.6 mV
5 - 4.23 V
6 - 2.5 V
7 - 0.75 V
8 - 0.77 V
9 - 2.5 V
10 - 2.5V
11 - 2.5 V
12 - 2.5 V
13 - 2.5 V
14 - 2.5 V
15 - 2.5 V
16 - 2.5 V

Those are normal values for the chips? this is my first delay pedal, i would like to understand better what's causing the noise, before i try to build another one on other veroboard. I'm still learning. Thank you so much.  :)



ic_

Quote from: antonis on July 06, 2020, 06:05:05 AM
Maybe an audio sample should be more helpfull..
(by guessing noise classification, e.g. shot, pop-corn or flicker noise, it should be easier to locate its origin..)

Thank you Antonis, i will try to record something. its hard to describe it. not a hiss or pops or shot.

ic_

Quote from: antonis on July 06, 2020, 06:05:05 AM
Maybe an audio sample should be more helpfull..
(by guessing noise classification, e.g. shot, pop-corn or flicker noise, it should be easier to locate its origin..)

Here it is some sound recording

https://drive.google.com/drive/folders/1EnhLlngtznOtgLMN9F2_XCLph8fG5JQ1?usp=sharing

not the best recording, but i don't have another way of recording now.. but i think you can hear the noise sound..
I don't really know if the noise comes from mistakes that i made on veroboard or if its the chip pt2399 that has this kind of noise.. i bought them from tayda. i hope they are ok.


duck_arse

#7
I can't work it out on your diagrams, but from your posted voltages, pins 3 and 4 of the pt2399 are not connected together. this might not cure what ails you, but short those two pins together so they both read 0.00V.

also - a belated welcome to the forum.
" I will say no more "

ic_

Quote from: duck_arse on July 07, 2020, 11:34:59 AM
I can't work it out on your diagrams, but from your posted voltages, pins 3 and 4 of the pt2399 are not connected together. this might not cure what ails you, but short those two pins together so they both read 0.00V.

also - a belated welcome tpo the forum.


Thank you so much for that sugestion and welcoming, I'm looking forward to learn and share on this wonderful forum :)