2 HH Controllers into one input?

[Wangagat]

Hey everyone,

electrically speaking, would it be possible to split a HH Controller input and feed 2 x FD-8s (or other controllers) into it? I don't want to use both pedals at the same time and I know that even if this were to work it would only still allow for the control of one HH sound source, but what I am really looking for is a way to practice my ambidexterity, having kicks and HH pedals on both sides and practicing lefty and righty.

Issues that I am specifically wondering about are the kind of splitter that would enable this as well as any foot controller calibration issues by having 2 inline HH controllers instead of one.

Thanks!

[racer52]

interesting idea.

I'll jump in with a stab at it.. maybe some else can add some live application input,, or - a more accurate theory

from what I understand:

1- the Roland variable controllers are effectively a variable resistor moving between some max resistance (Rmax) to some minimum value, but not down to zero(Rmin) . this resistance is applied across the control input and is affected by whatever internal resistance is in the module, yielding a total value that is calibrated and sets the HH value.

2- resistance value of a parallel circuit drops well below the value of the lowest resistor (if your are connecting two pedals to one input at the same time, that would be in parallel)

picking arbitrary values here, .....
when both pedals are open you have Rmax from both pedals (pedal1 & pedal2)
the formula says the total will be [(Rmax1)x(Rmax2)] / [(Rmax1)+(Rmax2)
so if the Rmax was 25000ohms for each pedal, then [25000*25000] / [25000+25000] = 12500... about 1/2 what you had with only one pedal - the module thinks the pedal is 1/2 pressed.

when pressing one pedal the difference will always be less than the lowest resistance of the pedal pressed.
if pedal1 is depressed to a low value... say 1000 ohms, then the pedal circuit value will be below 1000 ohms
[25000*1000] / [25000+1000] = 961 ohms. - but this would be the same from either pedal - just different than one by itself. so maybe your mind can adapt to where your foot needs to go.

You might try putting a series resistor after the pedals join together to pad the value. but your calibration will probably not be dead on from pedal1 to pedal2. and the circuit Rmax will still be significantly lower than Rmax of just one pedal

what does that mean to the controller?
?? depends on the controller, depends on if I am right with my guess work :-D

my guess is that you could probably get 1/2 to full closed doing this.

[Sylv1co]

Racer52 is right, but I think it could work for one reason : the module does an autocalibration each time it is power on, this mean that it takes the Rmax value that is read on power on as the full open value. but this value must not be too low, it will not work with 1K I think.
To be sure, we need to know the Rmax value of one FD8 and then test the module with a resistor of half this value to see if it is able to use it as full open value.

[Wangagat]

man... thanks guys for the detailed analysis and input. I understand the gist of what you are saying! maybe I can go to a shop and ask to try it with their FD-8s. If sylv1co is correct in that the module calibrates and thus there is no need for an added resistor, then am I right to assume that the adapter needed for this would be a TRS to dual-TRS (duplicate stereo signal)?

[Sylv1co]

then am I right to assume that the adapter needed for this would be a TRS to dual-TRS (duplicate stereo signal)?

Yes or even TS to dual TS as the Roland HH input is mono

[Drumagination]

Racer52
I'm sorry to ask this, but I am away from my shop for awhile. What resistance value do you get from a full-up FD-8? How about full down?

If you have parallel circuits and you cut the wires to one path, the other will control. I'm guessing that the resistance of a full-up pedal is much more than 25K Ohms (more like 350K?), and will essentially cut off the current, allowing the (unusual) configuration to work with each pedal responding pretty-much as normal. Again, sorry but I'm on the road or I would do some experimenting myself.

Sylv1co
I think you are the inventor from Italy (?) with the Stuffed floor tom......I have admired your work for a long time.

Mark
Drumagination.com

[Sylv1co]

Racer52


Sylv1co
I think you are the inventor from Italy (?) with the Stuffed floor tom......I have admired your work for a long time.

Mark
Drumagination.com

No, i'm not... I'm a french inventor of nothing !

[Sylv1co]

I think that a full up FD8 is about 20K, not more. And I think that 10k is enough for a roland module to use as full open after power on autocalibration, that why I think that using two FD8 in parallel should work.

[racer52]

Racer52
I'm sorry to ask this, but I am away from my shop for awhile. What resistance value do you get from a full-up FD-8? How about full down?

...

Mark
Drumagination.com

Sorry - I do not have an FD8 to test.

I do have whatever these pedals are called...

from a Roland HD-1 kit:

http://www.rolandus.com/products/hd-1/

these pedals have a plastic resistor strip and a rubber wiper that presses against it.
there are two leads leaving the resistor
I measure 20 K ohm open pedal, 1 Ohm fully pressed