Harmonic Percolator - make one!

[pinkjimiphoton]

where's the dang "like" button? 

[John Lyons]

Sounds great!

[~arph]

Yeah it does!

[~arph]

Hi all,

Here's a vero I did.. Was going to verify it, but I ran out of solder  yikes.

https://dl.dropbox.com/u/1849818/hfe-vero.png

BIG image

[pinkjimiphoton]

arph, do you mean 2n3904 or 3404?

i am on this sh*^ like white on rice...

[~arph]

You can use whatever transistors you like in a jerkulator. I tried 3906 / 3904 and that sounds great. I settled for a 3404 and a 2907. Btw intended it to fit in a hammond B size enclosure. Might be a little tight.

[pinkjimiphoton]

sweet! will try and verify it this weekend.. i'm balls to the walls the next few days, gotta clean my workshop (the dining room table) off for the feast of friends on thursday, that'll take a week!

[~arph]

Btw, the polarity protection diode is missing from that layout..It'll work without, but it's easy to add (move R19 one place to the left and put it on the rails to the right above it.)

[pinkjimiphoton]

cool, i'm sloooo oooo ooooo ooooo wly getting hip enough to ad that stuff to everything i build.

[~arph]

 

You'll notice it when you put it in backwards

[pinkjimiphoton]

lol...done that, too...lol

[jrod]

That sounds really good ~arph!

[~arph]

Yeah it's a great circuit. That clip is with a fender hot rod on clean miced up close and a touch of reverb.. I am entering the lab now to try a little noise gate at the end and maybe the stupidly simple wonderful tone control too.. But it's great as is.

-UPDATE-

Back from the shed.. Here's an updated vero with tone control (thanks Jack Orman) and some noise reduction on the two transistors. I added 220pF caps from Base to Collector on both the PNP and NPN, this reduced the hiss a lot, without sacrificing too much of the high end. This is the version I will build as soon as my solder stock is refilled. I am planning a PCB layout for this too. Should fit better in a Hammond B then.

If you don't want the tone control (it is really usefull) then you can omit the tone pot and take the output to the volume from the lug two wire of the tone pot.

https://dl.dropbox.com/u/1849818/hfe-vero-tone.png

[pinkjimiphoton]

even better...thanks arph!! soon as i get a chance and get past the wholesale holocaust on our turkeys here, i'm on it!   

[Mustachio]

So now that the turkey day contest is over I can get on this!

While I was waiting for paint and clear coat to dry I started putting this on the bread board. Was trying to follow the vero layouts from jimi and digi. I didn't get it working yet but I didn't have much time to play around with it. I think I am just missing a few connections , ill get it

I wanted to ask what  you guys think of these transistors I'd like to use on it. I got these matched pairs of ac128K and ac176K from minifux off ebay a while back and have wanted to find something I could use them in. In the past I used a 2n2222 and an ac176 in an NPN fuzz face which sounds great being half germ and half silicon.

I was going to try to use the 128 and 176 in this circuit since they are supposed to be matched and npn/pnp But I've read a bit around the forum here about ac128's possibly having to high of gains for some things and this circuit sounded like lower gain transistors sounds better. I have about 5 pairs of those and one GT308B on hand. I think the GT308B might have lower gain and lower leakage the 128s might have higher gain and higher leakage and I've heard in some circuits(maybe this one) leaky trannys work better.

Or should I go with silicon/germanium. I was also thinking about how in some fuzz's you will change resistors that feed the transistors to get things correct. Like how small bear will provide resistors with trannys for certain circuits (TB/FF). Will something like that work in this circuit? Ill do all the testing I just wanted to throw out what I had on my mind about this. From the samples Ive heard from Jimi and Digi this sounds like something I gotta play! I love the feedback and scoped tone that brings out the voicing of notes! (also you guys can play a mean guitar!)

The layout arph made looks awesome but I want to build the standard Harmonic perc alone first. I usually have to go over schematics and veros a few times with the eyes and get all the connections right when I bread board off of em. I'm not super sharp with reading all the schems and layouts but I'm getting better the more projects I complete!

Anyway thanks for all the info in this thread I've read through it a few times and will do a few more times. You guys make this stuff a lot of fun!

[pinkjimiphoton]

ha! i got the same transistor sets. i found 'em all to have too much gain, but your mileage may vary. the high gain transistors may be a sound you like...an intense octave fuzz kinda like a univox superfuzz.

i think you'll like it best with low-gain transistors, but try it... you may be able to bias it up to the point it works for you.

[~arph]

I started on the vero, I noticed the following errors in my layout:  C13 must be 22n also and R14 is 27k instead of 1k.. 

[pinkjimiphoton]

thanks for the heads-up, arph!

no more builds til i'm done with the turkey day scoring tho~~

[~arph]

It's verified 

And deserved it's own thread here:

http://www.diystompboxes.com/smfforum/index.php?topic=100164.new#new

Slight alteration to the VERO so it fits in the box. The other vero's posted here should be verfied too.

[pinkjimiphoton]

sweet, thanks arph...gonna go check the other thread now!