Mezcal Fuzz build report...and a problem

[Coriolis]

Dragonfly: I built the Mezcal Fuzz from your vero-layout last night, took me about an hour.    I subbed a few parts that I didn't have:

390R to 470R
22k to 20k
22uF to 47uF

It was a complete shot in the dark, since I'm not sure what any of them do!

Anyway, the thing actually works! Lotsa fuzz and sustain, and a balanced frequency response, so good job there!   There seems to be a problem though (probably from my using the wrong parts):

At low gain there is a crackling noise, which at first I thought was just interference or my bad cables. However, it's most prominent with soft picking, and almost disappears when I hit the strings very hard.

With gain wide open, that noise turns into a sort of high pitched sizzle, and again it goes away when I play hard. I btw changed the gain pot from 100k to 1meg, since I wasn't getting much range with the first one.

I don't have this thing in an enclosure, so there probably is some interference, but I doubt that is what I'm hearing.

So, could this be due to the wrong parts values? Are those resistors what you call bias resistors? Are the differences in value large enough to be causing what I'm hearing?
Also, do you happen to have a schematic of the Mezcal?

Anyway, I mostly wan't to tell you that I like your design, and was thrilled to get it to work (sort of ) :oops:. I'm really just out to learn a bit, and if this really is a case of misbiasing, then I guess I know what that can sound like now!  :wink:

Thanks for the layout, and the fun had!

C

[Dragonfly]

it sounds like its gating a bit, and thats normal...theres a slight amount of "misbiasing" inherent to the design, and thats on purpose...gives that nasty, raspy edge....

f youre adventurous, you can use either pots or trim pots instead of the "collector resistors" and then dial in how much of the "misbiased" sound you want.

as for the high pitched whine, thats a little odd...but your parts substitutions were fairly minimal in value difference (except for the cap sub...you might wanna try finding the right value for that one).....it'll probably go away when boxed up.

its real cool when you back the volume off your guitar just a "touch"...  

glad youre enjoying it...its a simple build, and has a good "old school" fuzz tone !

andy

[Coriolis]

Thanks for your reply!
The thing is, it makes that noise(and loud) when I don't even touch the strings, and then gradually shuts up as I start playing, picking harder and harder.

But I'll try a different cap, and maybe fiddle with the resistors, and see what happens. Who knows, I might even learn something... :wink:  :?

Thanks for the input tho, I'm looking forward to building some more of your layouts.

C

[Coriolis]

OK, I managed to find a 22uF to put in there, and it seemed to make things a bit quieter. Don't know if that makes any sense. However, then I put it in an enclosure, and that did the trick: now the noise is almost gone, so you were right about that! Guess I should learn not to worry... :wink:

C

[Dragonfly]

OK, I managed to find a 22uF to put in there, and it seemed to make things a bit quieter. Don't know if that makes any sense. However, then I put it in an enclosure, and that did the trick: now the noise is almost gone, so you were right about that! Guess I should learn not to worry... :wink:

C

it happens...i hope you get TONS of use from it....its a really cool sounding pedal !

andy
dragonfly fx