gate/trigger combination

[Usine Karate]

Hi all,

As the Klee now has it's own forum I thought I'd post this as a new topic, rather than in the main thread.

I have a question about the gate/trigger voltages.

I have some Doepfer equipment with 5v triggers, but I also have a few Analogue Solutions drum modules (808, 909 etc.) these accept anything up to 12v trigger (for accents).

Having looked at the schematic I see that the gate bus resistors are immediately before the jack (I guess they set the output voltage) So I thought I could split the signal on the output and make available both voltages. ie. gate bus 1 has both 5v gates/triggers and 10v gates/triggers concurrently.
Is this a good idea/possible? If not I could have a switch to set the level individually for each bus so that gate bus 1 could be set to 5v and gate bus 2 to 10v and then put them through a little DC mixer to have both on one channel.

Hope this'll work, I'd like to know any thoughts before I commit to a panel design with built in switches/mixer etc.

Usine

PS Soldering up all those headers was fun! I think I'll be making a 2-step sequencer next.

[Adam-V]

I don't think you need to worry about using 10V gate outputs from your Klee with your Doepfer gear, it won't hurt it. Even though the technical specs page of the Doepfer site mentions 0-5V gate levels, most of the Doepfer modules output higher than that; the A-155 Trigger Sequencer, for example, outputs 10V gate/trigger signals.

Cheers,
Adam-V

[loopcycle]

is that generally true for all modular design (that a 10v trigger/gate wont damage or malfunction with something that expects 5v)? if this is true, why build the klee with anything other than 10v trigger/gates?

[Usine Karate]

Thanks Adam-V,
That is good to know, I had been a little worried about levels, but would it still be possible to have both? I reckon it would be cool to be able to set the volume of the drums with a switch between normal and accent.

Thanks,

Usine

[Adam-V]

@loopcycle:
I wouldn't want to guarantee that 10V gates would be fine for ALL systems but I would have thought any modular synth designer worth their salt would surely protect their gate/trigger inputs against higher than expected input signals.

@Usine:
I can't really comment on whether or not you can have both 5V and 10V gates available simultaneously from the Klee as I am not yet that familiar with the circuit; I have only had a brief look at the sections that I wanted to modify for my own purposes. There is most likely a way to do it whether that be as simple as you suggested in your initial post or slightly more complex such as adding a small prototype board with extra circuitry to achieve the desired results. Perhaps someone from Team Klee can offer more information on this one?

Cheers,
Adam-V

[Scott Stites]

The 1K5/3K resistor combination divides the voltages down, while at the same time providing a 1K output impedance (which is made possible by the low output impedance of the LM324).

To reiterate this aspect: the LM324 puts out a max voltage 1.5V below the positive rail. This translates to an actual 9V for "10V range" and 4.5V for "5V range". We found these levels worked fine for the equipment we had on hand, and voltage level was never a problem. There are alternate values that can be used in case it ever becomes an issue with anybody.

Now, to the question at hand, and I'm wondering aloud here - if you configured it for 10V range output, and you substituted two 1K5s for the 3K resistor, then you would have a tap at 9V and one at 4.5V. If you ran the signal from the signal at the end of the first 1K5 resistor, it will be 9V, the signal from junction between the two 1K5s that replace the 3K resistor would be 4.5V. The impedances should still work out - both of these signals will presumably be going into high impedance inputs, so a voltage drop would not be a concern. I'd have to try it out, though, to see if my thinking is thunk rightly.

Cheers,
Scott

[Luka]

scott that klee quote in your sig in v.cool

i hope that by introducing the klee to the world we arn't making it a more horrible place, cos after reading the get to know the klee doc, i dare say only abstrakt noise is going to come out of my seq for a good while hehe

im almost done my build, just waiting on panel components, i hate this waiting for more parts buisness

[Usine Karate]

Hi Scott, Thanks for the reply, I'd like to try that out.

I wanted to operate on 12v, would it then be a series like this?

out of lm324 - 1kres - 10v tap - 1k res - 5v tap - 2kres - gnd

( I notice for 12v operation and 10v trigs there is no R71-78 )

I'm a little wobbly on electronic theory!

If you think it's worth some experimentation I'll try it out on a breadboard when I've finished making the boards.

Thanks again

Usine

[Scott Stites]

Ah! If you're doing 12V, I think it'll be somewhat easier. You can put in the resistors like you were doing 5V outs - the 2K/2K deal. That will be your normal 5V output (which, at 12V ops, will be pretty much 5V). Now, on the end of the 2K resistor that's connected to the output of the LM324, just curl the leg of a resistor underneath that leg and tack-solder it on - let the other end of the resistor stick up like a dog's leg at a fire hydrant - that lead is where you can attach the wire which will lead to the 10V output, which will be 10V (again 12V numbers work out pretty well in that regard). Both outputs will have a 1K output impedance.

Cheerios,
Scott

[Usine Karate]

Great Scott, that is

Thanks for sorting that,

Usine

[fonik]

[Usine Karate]

Hi Fonik,

Whilst browsing your site recently I noticed that you had cloned the 151, as I have (also the 150). I was slightly annoyed at the time to have cloned the 'wrong one' previous to it's redesign! (although both types have their merits)

I built 32 of each for a project and am thinking of using some Klee's to control them, thanks for reminding me as I would probably have forgotten the 8v thing and fried one or two!

Usine

[fonik]

[Adam-V]