Wednesday, January 16, 2008

STG Mankato Filter Now Available!

Suit & Tie Guy's *incredible* looking Mankato Filter is now available in 'FU' format (Frac Rack) at
Analogue Haven. Without even going under the hood, I have to say this one is up there with the Wiard JAG for the 'coolest looking frac module' award. Amazing job on the layout of this one!

The Mankato is a 4-pole lowpass filter designed by synth guru Thomas Henry, with some very interesting features not found in your everyday VCF. For one, it has an ENORMOUS range, from deep sub audio ranges to far above the audible frequencies - all in a continuous sweep, no range switching required. However, that's probably the least interesting thing about it.

Next on the 'cool list' is the fact that it will self-oscillate at ANY frequency, even the really really slow ones. So it can be used as a pretty funky LFO if you have the need.

But it gets better still, as you may have surmised from the photo. A wide-range VCF that can self-oscillate at any frequency - hmm, sounds strangely like a VCO, doesn't it? Ok, so it's a sine-wave only VCO as well, that's cool - but that's also true of a lot of modular filters.

What sets this one apart are the phase outputs, all eight of them. It goes beyond quadrature oscillator to provide you with 8 phases of your sinewave output - you get outputs for the 0, 45, 90, 135, 180, 225, 270 & 315 degree positions of your sine wave.

I'm only just starting to wrap my head around ideas for this. I know there's going to be some very interesting FM tricks available, and I think I may be able to cobble together some sort of frequency shifter using this as well - I'll be searching for that famed 'barberpole' Shepherd infinite phasing effect. I suspect it may be possible with this module, however no-one's been able to let me know if if can or not. In fact, I've just ordered the very first one from AH (thanks Shawn!), so I will be sure to let you all know how I make out with it once I've had some time to try some things. I'm new to quadrature-land though, so please bear with me here ;)

I do have a hunch that those 8 outputs will be able to make a Wiard JAG do some really incredible things

One last thing - the signal inputs are DC coupled, which allows one to use the Mankato as a voltage controlled slew limiter. While this is a cool feature, I wonder what effect (if any?) the DC coupled inputs have when using this as an actual VCF, to process audio? I know it's probably mostly intended to use as a modulation source but damn, it has FILTER right in the name!

I do know the PCB (which is manufactured by Magic Smoke Electronics) allows for AC or DC coupled inputs. It's a pretty option-rich board, and I really thank Suit & Tie Guy for taking advantage of the vast majority of synthy goodness on tap, and in particular for giving us those 8 juicy outputs. Anyway, perhaps it may be easy to add an ac/dc select switch? Hey STG, you read this blog sometimes, any idea on this?

Anyway, very cool stuff, I'm really excited about this module, it's 'something different' from the modules i've been into and I'm really looking forward to that. Thanks again STG and thanks Shawn @ AH for giving me the heads-up that these were in. It's not every that something surprising and different comes out for your modular synth!

Again, KILLER design job on the front panel of this baby. It's just gorgeous.

Hey! Check out AH's Mankato page right here, you're only ONE click away

And one click here brings you to STG Soundlabs!


suitandtieguy said...

i decided to forego AC coupling as it doesn't really matter as long as you don't have some nasty DC offset going into it, and if you do that might make for some interesting distortion effects. it doesn't affect normal operation of the filter, and it's more useful DC coupled.

the board _is_ the Magic Smoke board, but i've jumpered over the AC coupling area and didn't even put the caps in there. if you'd like to add the feature, feel free but you run the risk of damaging the board.

i also thought it just looked better with a simpler interface.

thanks much for the kind words.

suitandtieguy said...

i should add that i don't know if the circuit could be damaged by severe DC offset, but as it is intended to be used as a slew limiter it should be able to handle _some_. i should ping Tim Parkhurst to make an observation about this as he is much smarter than me and it's his board.

Richard said...

is it a deep module like blacet, or shallow like the wiard 1200's. that's as in size, nothing re wiard sound is anything else but deep

Tim Servo said...

Hey Everyone, Servo here. A DC offset in an audio signal can cause a 'thump' if the signal changes level quickly. The problem can show up in VCFs and VCAs, and is a common cause of clicks and pops when guitar effects are switched in and out. Also, a DC offset will change the results when you mix signals together. There may be cases where this will be annoying, but it would have to be REALLY bad to damage most modules. Basically, you'd have to exceed the power rails and, well that is something to be avoided with ANY module. What I might do is put caps on one or two of the inputs, and keep at least one DC coupled (no cap). Note: I've got three Mankati, and I've set mine all up as DC coupled without any problems. YMMV.

As far as the module size, the PCB is 5" deep x 4" high, so it's not too deep (physically, that is). Fits okay in a PAiA frac box.

BTW, if you use it as a slew gen, the different outputs slew at slightly different rates (due to the phase diff in the outputs). I've been having fum with that lately.

Tim (Servo) Parkhurst