FSH-1 and panning.

[jmasciswannabe]

I would like to be able to hear the FSH-1 bounce its sounds back and forth between left and right. I am familiar with the tremulous panneur setup and have read some over at geofex, but quite honestly have no clue where to start. Any help would be....well helpful!

[Processaurus]

Hi, the purple Line 6 filter modeller does something sort of like that with the stereo output in the mode that emulates the maestro FSH.  Its not a panning thing exactly, but its like 2 different sample and hold filters that make their random steps at the same time.  You could do that by making another FSH and slaving one of them to the clock on the other.

For the actual panning thing, maybe someone who knows the lfo/clock on the maestro could say if this is right, but I'm guessing it puts out a very narrow high pulse for when it samples, and then is low the rest of the cycle(or vice versa), to generate the random stepped voltage sequences.  If you fed the pulses to a 4013 flip flop, you would get a 50/50 square wave that is half the frequency of the sample and hold, so if you fed that to a panner, each sample and hold step would be panned to the opposite side as the last.

So to get an even more exciting sound, how about ditch the last idea, and make a second noise source and sample and hold circuit, that was slaved to clock of the first, and this second random stepped voltage goes to the panner, so the amount of pan is always different and random.  It would be easy to mod at that point to bypass the filter and have just a random panner, or with just one channel plugged in, a random tremolo, like the Zvex thingy in its random mode.

[jmasciswannabe]

thanks processuarus....i should have mentioned it is for a keyboard player. Not such a desirable effect for your every day guitar needs. i gotta do some more reading!

[Processaurus]

thanks processuarus....i should have mentioned it is for a keyboard player. Not such a desirable effect for your every day guitar needs. i gotta do some more reading!

Here's a good article on LFO's at geofex.

[Mark Hammer]

I'm still not quite clear on what you want it to do, given the multile "personalities" of the FSH-1.  Do you want alternate steps in the S&H sequence to show up on alternate channels?  Or were you looking for something like the (to my mind anyways) famous channel swapping "bwow" at the start of Rainy Day (Still Dreaming) from the Electric Ladyland album?  I ask because the one sort of "panning" requires a kind of low-level electronic decision-making, where the other is just a mindless auto-panner.

[jmasciswannabe]

Hey Mark! Ya, I should have been more specific! After thinking about it more there are two possible variations that I am interested in. Hopefully these illustrations will help.

One would be where the sample steps alternate between left and right:

left       right     left      right      left     right
beep     bop    boop     bop     beep    bop


or the other would be where the sample steps autopan:

left            center             right
beep bop boop bop beep bop boop

*it would be very convenient in both these scenarios for the speed of the alternating or panning to increase or decrease with the speed of the sample steps.

I hope that makes more sense. I have heard the circuit in action over here:

http://moosapotamus.net/THINGS/fsh-1a.htm

speaking of....are you going to be getting in on that ADA project? Or do you already have one in your vast arsenal of guitar gadgetry?

processaurus....thanks for the link on the lfo's!

[Mark Hammer]

Easy question first.  Courtesy of the generous Mr. Huge, I have an MN3011 ready and available for duty and have part of a prototype I was working on with a buddy about 40% wired up.  Until we decide that it *won't* be a commercial product, I can't tip my hand unfortunately.

AS for your main response, I suspect the alternating sample sound is perhaps the easier to produce.  The onboard clock of the FSH-1 feeds the gate of a FET to make that drain-source resistance go low and permit the storage cao to "accept" a sampled voltage from the noise generator...right?........RIGHT?

Okay, now suppose you have your standard discrete Boss flip-flop circuit that drives 2 FET gates, one off the "flip" side and one off the "flop" side, just like it would in a great many Boss pedals.  Okay...NOW suppose your FSH-1 clock drove the gates of not one FET but two FETs.  Where does the second one go?  EASY!  It goes where the momentary footswitch that connects to ground would normally go on a Boss switching circuit.  So, each clock pulse not only results in a new sampled random voltage, but it also results in a change in which add-on FET is switched to go low-resistance.  Those two add-on FETs each take their feed from the one common output, but FEED it to each of two different jacks.  So, clock pulse N, the A output is active, clock pulse N+1, the A is blocked (high resistance) and the B output is active.  And so on.

Make sense?

As for the auto-panner, here I will leave you in the hands of others, because there are all sorts of autopanner circuits out there.

One final remark.  A great many build this circuit planning on using a charge pump so that a single battery can be used.  I have my doubts as to whether use of the suggested add-on circuitry would permit any sort of reasonable battery life using a charge pump.  It's either true bipolar supply or wallwart 9v only.

[moosapotamus]

Okay, now suppose you have your standard discrete Boss flip-flop circuit that drives 2 FET gates, one off the "flip" side and one off the "flop" side, just like it would in a great many Boss pedals.

So, is the idea to "paste" the flip-flop ckt in right after the existing clock ckt and, for example, replace R30 & Q5 with one FET from the flip-flop ckt (going to the noise source just like in the stock circuit), and the other FET going to the main output and switching it alternately between two output jacks? Or does the existing R30 & Q5 stay in place with the clock driving the flip-flop ckt, too, with both FETs driving the output switching? I guess I'm not intimately familiar with how the boss flip-flop ckt works.

Either way tho, that would be very dramatic sounding, wouldn't it? When one output is switched on, the other is switched fully off? If so, that's cool but a clean blend feature (to both outputs simultaneously) might be nice to have in case you want to tame it down a little.

How would the S&H sound through something like Anderton's retro stereo?

RE: Charge pump, I used the MAX1044 in mine just to provide the split rails. Works great with a 9V wall wart.

~ Charlie

[chemosis]

is there any way to add a knob or switch to effect the overall freq rangeof the envelope filter side, to achieve a little more lowpass in the sound?  like the overall freq of the entire sound.

[blackieNYC]

I just did a panning stereo ROG tri-vibe.   Build a second audio channel just like the first - Q1, IC1, Q2, IC2. you see the 22 k resistors that bring the LFO to the two 3080 stages?  At the point where the two meet, split off from there to a polarity reverser (see geofex). I did the op amp version.  The LFO waveform probably looks like a city skyline. The peaks go beep, the valleys go bup, and the mid level goes boop. The output of the reverser goes to the 2nd channel's two 22k resistors. Left goes beep when right goes bup. I love it on the somewhat asymetrical sine wave of the vibe, and I'd like to do random waveform too.