Bassballs controlled by treadle - interesting filter

[Ronan]

A couple of clips from a breaded bassballs and 10K pot in a wah shell:

https://dl.dropbox.com/u/61170900/brassballs1.mp3

https://dl.dropbox.com/u/61170900/brassballsclean1.mp3

I used a dirt box on the first clip, just set to the usual settings. I think I clipped the soundcard input on the second "clean" clip, but it gives an idea. I'll do a schematic later, very simple circuit.

[Jdansti]

Talk to me!  Sounds great!

[Ronan]

Here's a sim of the freq response (with a 1k resistor representing the 2N5089's)

https://dl.dropbox.com/u/61170900/brassballs%20freq%20resp1.GIF

[Mark Hammer]

Very nice.

Next stage in your conquest of the spectrum: integrating foot control with S&H so that you foot control the range of the randomness.

[pinkjimiphoton]

great idea ian.
i wonder if you could use a dual 22k pot like in the vocalizer, and set the filters to sweep against each other?

i've gotta couple boards thanks to some anonymous forumites, so i guess i'll give it a try!

i gave dino my black russian one when he was visiting a couple days ago, so i guess i should get off my lazy...

[Mark Hammer]

It would work well.  Given that rack-and-pinion setups rarely move the pot all the way to the end of travel, a 10k dual-ganged would work fine too, albeit with some restrictions in overall sweep.  Just be sure to use a linear dual-ganged pot so that the direction of sweep isn't accompanied by weirdnesses in the feel of the sweep.

[joegagan]

sounds cool, i like it. and it looks like you come from the escobedo school of minimal parts circuits. dig it.

[pinkjimiphoton]

It would work well.  Given that rack-and-pinion setups rarely move the pot all the way to the end of travel, a 10k dual-ganged would work fine too, albeit with some restrictions in overall sweep.  Just be sure to use a linear dual-ganged pot so that the direction of sweep isn't accompanied by weirdnesses in the feel of the sweep.

should be able to add trimmers to each side of the pot to get whatever taper is needed, right? should be able to dial in the right sweet spot that way i'd think.

[Ronan]

The Craig Anderton anti-wah circuit is worth a look for using a single pot to control 2 sweeps in reverse. I haven't tried that circuit, yet. The bassballs has a real synthy sound to it, its filters are arranged slightly different to most others MFBF. Makes me wonder what a EH talking pedal or Dipthonizer might sound with bassballs type filters...

[Ronan]

Simple build, but I forgot about the position of the battery cover....doh! But with the battery case removed, I can access 4 of the 5 trimpots.

Sounds fine with a TLC2262 which reduces the total current draw to under 2 mA, battery should last a very long time, so I didn't bother with a 9V DC socket. I updated the schematic in a post above, that schem is what I have built, I just changed the control voltage details from the earlier schematic (2 trimmers instead of one), and added the optional 47k resistors and 560pF caps.

[joegagan]

make sure you put the batt cover back on right away, or the mojo leaks out 

[nocentelli]

Sounds great, almost like the Parapedal in places. Many thanks, will try this out at the weekend.

[garcho]

filter, CV, low parts count, bravo! can't wait to try it out

[nocentelli]

Thanks again for this, going to be tweaking this for ages - LFO/envelope/treadle switch, resonance or mix/depth control.... the list of possibilities is vast.

http://www.youtube.com/watch?v=D7l3BbULr2M&feature=plcp

[nocentelli]

[Ronan]

Nice work nocentelli! I did some more adjustments on mine yesterday to change the tones a bit, it is a circuit that begs to be tweaked. I sometimes wonder if there would be any benefit from a wet/dry mix control, which would require another op-amp. My time is short just now, so I won't be able to try any more mods for a month or 2.