DEMO Atomizer Half 'Cock (Harmonic Percolator)

This post contains an audio or video demo
DGWVI

DGWVI

Well-known member
Build Rating
5.00 star(s)
I built this for a friend's birthday gift. He's incredibly fond of the @Aleph Null Peacock I'd given him, but had brought up wanting a standalone version of the Percolator from that circuit, and has always loved the Atomizer graphics, so here's this guy

Mods are (resistor values taken from the Peacock)-
  • R1- 470k
  • R2- 150k
  • R4- 33k
  • R5- Jumper
  • C2- toggle between 22n and 220n
  • C3- 2.2u
  • C4- 22u
  • C5- 2.2u
  • Diodes are an infrared LED and UF4007
  • The harmonics pot has an 8.2k between lug 1 and ground
  • Transistors are 2n5087 and 2n7000

On its own, the Percolator in the Peacock sounds amazing, but a bit too thin for everyday use, and I wanted to give him something he could stack with the full Peacock, so I increased the size of all the caps. Still does the clang, but also offers up a lot more wool. He primarily plays an electro-acoustic, and this take on the Percolator plays a lot better as far as microphonics go, so hopefully he'll be stoked on this. I dig that it can go from an overloaded console type of drive to totally overblown. Used the C-Buffer because I'm fond of it.

I did have a chance to compare BS170 against the 2n7000, and I wouldn't have thought so, but the saturation characteristics are fairly different,, with my preference being for the crunch of the 7000. The BS170 has more of a kind of brittle attack that sounds cool, but not quite what I was wanting with this one.

Kudos again to @Aleph Null for his awesome work on the Percolator topology. My favorite thus far 🤘🏻😻

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The demo sounds mean! That cap swap is like night and day. The graphics are fun!

I found some correlation between R2 and splattiness. The larger R2, the harder you hit Q2, and the splattier things get. You might be able dial it in or out by adjusting that value.

Now you've got me wanting to develop a five knob percolator: input, output, pre-bass, post-treble, and a splat or clipping symmetry control. I'll throw an extra mosfet boost in front so you can make it cave in completely.
 
Aleph Null said:
The demo sounds mean! That cap swap is like night and day. The graphics are fun!

I found some correlation between R2 and splattiness. The larger R2, the harder you hit Q2, and the splattier things get. You might be able dial it in or out by adjusting that value.
Click to expand...

I've got an Antithesis board I was gonna do up in this fashion, so I'll play around with that resistor too. Was thinking I might also throw the transistors on a switch

Aleph Null said:
Now you've got me wanting to develop a five knob percolator: input, output, pre-bass, post-treble, and a splat or clipping symmetry control. I'll throw an extra mosfet boost in front so you can make it cave in completely.
Click to expand...

Dibs on a board or two if'n you have some made up 🤘🏻
 
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