Seamoon Funk Machine

[tehfunk]

Anyone built one off of R.G's schematic? How did it go, and how does it sound? Thanks!

[Mark Hammer]

It sounds like whatever amazed us in 1976.  We were very easily amazed then.

Essentially the same circuit as a Dr. Q with a few differences.  At least the one posted on geofex.  My understanding is that there were several versions, and I think the posted one is a later version ( http://filters.muziq.be/model/seamoon/funkmachine ).  It can easily benefit from mods, but I don't think it ends up sounding better than a DQ/Nurse-Quacky/Dr-Quack.

The "Frequency shift" is actually a gain control that adjusts the Q of the filter.  One of the byproducts of this is that the frequency range also shifts, so that's what they called it.  I've implemented the same sort of thing on several filters.  The schematic indicates needing a 5M pot.  A 1M pot is more than sufficient.  If anything, using a 1M pot and a toggle for changing the value of those two .005uf (.0047uf actually) caps is probably a wiser move.  replace each .005uf cap with two .01uf in series and use a DPDT toggle or slide to shunt/bypass one of the caps in each pair.  That will give you the stock range plus an octave shift down.  The pot will adjust within each range.

The output cap is just hanging there, which means pop city.  It wants a terminating resistance badly.  Since the variable gain pot (5M/1M) alters the output level, make that terminating resistance a 100k volume pot (log) and you're in business.

The 100R resistor can be made smaller (e.g., 33-68R) to get a faster attack.  The 2.2M feedback resistor can be changed to a 2.7M to get a little more sensitivity.

[bluesdevil]

I tried breadboarding the circuit from the schematic Aron had in the members only section and did not work for me. I then went on to put together the Q-Tripper over in Markm's pcb gallery and had success. Good luck to you  and let us know if you get it quacking.

[tehfunk]

Well, I just got some information from a guy who built it and was unsuccessful. But, the point he made was that for both the replacement of the 40006 with the NTE160 and the 40006, itself, the schematic is incorrect. The pinout is PNP not NPN as shown. So, I think that might be part of the problem, my question is what changes need to be made to the schematic in order to accommodate the PNP transistor. Plus, there are multiple versions of the Funk Machine, so I've wondered what the tonal differences would be. I have compiled a few pictures of the circuit board though, might make some people happy. And, hey, they're both of different versions! Note: I first heard about the seamoon funk machine somewhere, but was brought under its hypnotism when I searched it and found a video on youtube of a guy using it with his sax (Michael Brecker), it's amazing notice he's using some other great effects, like an octaver or something. Here's the link, he starts his effects at like 4:10, I believe.

http://youtube.com/watch?v=TjTRO3ZXfbQ

It is truly great!
Here are the pics:



That one is version 2 (according to discofreq's fx website) it has two potentiometers, I believe it's the one in the schematic.

Here are some pictures of what is the supposed version 1, it has 1 potentiometer, but on front (facing you when laying flat) not on top.