is it my layout or my "fine tuning?"

[foxfire]

with the pedal on and the guitars volume rolled down/off it sounds like there is a steady stiff wind coming out of my amp. i built it up on my bread board again but it's just feeding back on me so while i try to get that sorted i figured i'd ask if you guys could have a look at my work...thanks. 

http://www.aronnelson.com/gallery/main.php/v/foxfire/SMOOTH+FUZZ/

[foxfire]

quick note, ignore the 780K resistor (from pin 6 to ground) on the schematic...

[will queue for free stuff]

Ryan,
I'm no expert, but it looks to me as if D1 is backwards.
The arrow on the diode symbol points to the anode....... negative.
(IN4001 nested beside your 100uF cap for power conditioning)
What happens when you turn the diode around?
Good luck
Here's hoping your circuit springs to life!
Craig.

[John Lyons]

Actually the Cathode/stripe is negative. The arrow points to the cathode.
The diodes in the feedback loop are correct as "asymmetrical clipping diodes."

[Galego]

Ryan,
I'm no expert, but it looks to me as if D1 is backwards.
The arrow on the diode symbol points to the anode....... negative.
(IN4001 nested beside your 100uF cap for power conditioning)
What happens when you turn the diode around?
Good luck
Here's hoping your circuit springs to life!
Craig.

D1 or the 1N4001? Which is backwards? The 1N4001 can't be reversed, or there would be a short circuit. It's like that on purpose, for protection if you reverse the polarity.

[foxfire]

I just spent a solid hour or so swapping parts on the bread board without any luck...I can't get the pedal tone both "quiet" and retain it's tone. It's sounds great in front of my sunn beta lead until I roll the volume down.

[jkokura]

Have you tried buffering the circuit?

jacob

[Derringer]

shot in the dark here ..

could those 100K resistors in series with the non-inverting input of the first opamp be adding noise?


what is the design of the first stage ... I'm guessing a band-pass filter with gain ?

my knowledge of op-amp stages is limited

[foxfire]

I haven't tried a buffer in front and I did fiddle around with those series resistors but there are a few more options I can try...I'm pretty sure the noise is coming from the front half.

[will queue for free stuff]

Actually the Cathode/stripe is negative. The arrow points to the cathode.
The diodes in the feedback loop are correct as "asymmetrical clipping diodes."

I was of course wrong wrong wrong.
My apologies
Here's hoping you get it sorted out
Regards

[foxfire]

a few more hours of tinkering later and i'm still looking for a solution. everything i done that gets rid of the noise changes the sound of the pedal too much...

[John Lyons]

Someone who knows what they are doing is going to have to chime in (not me).
I don't know the answer Rylan...sorry.
I think it's something with the 100k/100k/ .002 area though.
Did you try to connect the 330k from vref directly to pin 3 of the op amp?

[foxfire]

i was about the reply that yes i had tried that, but i had hadn't really. i tried it on the bread board, but not on the pedal itself. so i fired up the iron, and this is what i ended up with i think, http://www.aronnelson.com/gallery/main.php/v/foxfire/SMOOTH+FUZZ/SMOOTH+FUZZ+SCHEMATIC_2.png.html?g2_imageViewsIndex=1. i tried it without any resistance in front of pin 3 and it was all but dead quiet, but i changed the tone too much. the thing i love about this pedal is the "%^&*ed wah" tone it has which was completely gone when i removed the resistance between the input cap/330K and pin 3. so for now i'm gonna settle on 10K in there.

i'll take it to practice this week and give it a go at volume and with fresh ears. i all but let this pedal eat up and ruin my entire weekend and my ears are still messed up from seeing Sleep on tuesday...i'm sure i'll be messing with this thing after work tomorrow so i'll be sure to give a proper follow up. THANKS to everyone who replied...         

[foxfire]

i've finally gotten to spend sometime playing this pedal and it's still noisy but it may not be the all pedals fault. i'm running the pedal in to a Sunn Beta Lead which uses a 4069 for the drive circuit so it's kind of like running a dirt box in to another dirt box which is bound to be noisy. if i roll the dirt on the amp down the "wind tunnel" in the back round drops to a reasonable level. of course i don't think it sounds as good but it's way more usable.