earth sound research graphic fuzz vero layout

[thg]

thanks! sorry if i missed that explanation last night.

[John.Ore]

Hey, than you for the layout!

I have built this and I get plenty of fuzz but it does oscillate constantly regardless of the settings.

Only thing I had to substitute was the 10k log pot for the Volume, I used a 100k.

I found a schematic online and I spotted that 100nF cap on the left of the IC goes from pin 2 to ground but in the layout it goes to pin 4, are you sure this is correct?


Any advise how to tame the oscillation? Thanks!!

[fx-fidden]

I guess the two veroboard layouts in the previous page are a bit different from the schematic you posted, modified versions, I think.
A filter control is added, the input cap, a pulldown resistor (to avoid the pop when you engage the pedal), the voltage asset...

Did you try it with a battery? If with the battery you don't got the oscillation you need to add a 100uF or so between the 9v and the ground (look just at you layout, not the schematic).

[heuermh]

John.Ore wrote

Any advise how to tame the oscillation? Thanks!!

If you read the comments here, on the main site, and other places that attempt layouts for this pedal, you will find lots of frustration!  The modded layout by zosotone here in this thread worked great for me, it is in fact one of my favorite pedals.

Even with this modded layout, there is oscillation in the very last 0.1% of the turn of the filter pot.  The feedback frequency tracks the filter pot quite well, to the point where I've thought of adding a second very precise high resolution pot to fine tune this oscillation.

[John.Ore]

Hey thanks for the reply.

No I didn't try it with a battery, I never use battery tbh.
I used an independent 9v plug.

Is it worth trying the 100uF trick? I'm guessing positive lug to row A and negative lug to row i.

[John.Ore]

Good news everyone!

I put a buffered pedal before the fuzz and the oscillation disappeared. The buffered pedal (boss bd-2) was off.

I don't think it affected the tone of the pedal but anyway this way makes the pedal perfectly playable. It had lots of creamy fuzzy goodness!

So my plan is to build a small basic JFET buffer like this one:
https://tagboardeffects.blogspot.com/2014/08/buffers.html

[kizzer]

The gigrig virtual battery worked for me, gets rid of any oscillation.

[fx-fidden]

I tried to search something about that in the past. I found not much. I think it's a sort of 9v regulator with noise filter, but I'm not sure.

Here's an image I can't post: https://static.gearspace.com/board/imgext.php?u=http%3A%2F%2Fblog-imgs-51-origin.fc2.com%2Fr%2Fo%2Fc%2Frocksince1978%2FIMG_1542.jpg&h=ba831694bedf27ec63eb6e85cbec5c84