madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: jghfslk on June 18, 2016, 06:33:21 PM

Title: Moodring noise
Post by: jghfslk on June 18, 2016, 06:33:21 PM
Hey everyone

I've been working on and modding a moodring for a while and am getting a lot of noise with it.  I used the input level control mod from this thread:  http://www.madbeanpedals.com/forum/index.php?topic=20056.0  I also added an extra space pot for fine tuning the time (25k and 5k).  I also added an insert loop.  I have it wired so I can switch between having the loop inserted at lug 3 of the dwell pot or lug 3 of the ring pot.  I wired the trim pot externally and added modulation to the pt2399.  I had everything working with no noise except the input level wasn't doing anything.  I replaced the pot and it is now working but I am now getting a lot of noise even with the input level turned down low.  I checked all of my voltages and they seem to be fine.  I probed it and the noise starts at the first TL072 (pin 1).  I tried replacing both TL072 chips, the pt2399, and the 7805 but that didn't fix the issue.  I noticed that if I have one hand on my test box and another on my table the noise is a little reduced but there is still a lot of it.  I tried  using a 470k resistor instead of the input level pot with no luck.  I tried the same power supply with another pedal and that one works perfectly.  Does this sound like a grounding issue?

I will try to get a video up soon

Any help is very much appreciated!
Title: Re: Moodring noise
Post by: midwayfair on June 19, 2016, 03:22:29 AM
What kind of noise? High-pitched whining, buzz, 120Hz hum, 60 Hz hum, white noise, "shhhh," hash in the delay line, etc?
Title: Re: Moodring noise
Post by: jghfslk on June 25, 2016, 12:37:02 AM
I am not getting any noise any more.  I had a lot of alligator clips connecting things and things spread out on my table and my guess is somehow it was picking up some noise.

I do have one more question though.  I'd like to have the option to bypass the pt2399 to have no pre-delay at all.  Could it be achieved by lifting the negative side of C9 and adding a switch to have the option of going straight R19? Would there be a better spot to place the new signal (maybe somewhere after R19?)
Title: Re: Moodring noise
Post by: Boba7 on July 02, 2016, 07:10:01 PM
If I were to try it, I'd try to go directly from C9 (negative side) to pin3 of the brick through a trimpot. I read it somewhere. Seems easy enough to try different locations though.
Let us know how it works! :)