Old analog drumatix TR-606 & LP Stage II?

[TheRocco]

Decisions decisions: just got an old Roland TR-606 Drumatix analog drum machine and now want to hook it up to a synthesizer that has an arpeggiator. The old Roland TB-303 is too pricey now, the xOxbOx looks good, even a new Roland SH-01 might work--but I just read about the Moog Little Phatty Stage II with Blue LEDs and thought, "would it work, can I plug my analog Drumatix TR-606 into a real Moog synthesizer and trigger those arpeggiators?"

I'd love to get a Voyager Electric Blue (someday), but the Little Phatty is in my price range today, and has the plus of having an arpeggiator!

I see it has MIDI triggers but that would only work with a MIDI drum machine, not my old TR-606. Can it be plugged in somehow?

[topman26]

thumps up for your article, great post...

[jeepo]

With the cv mod it has a gate input, which should step the clock. novamusik sells the phatty with cv already.

[TheRocco]

Is the Nova Music CV Mod something additional to these standard LPII features (note where I added Bold):

Moog Little Phatty Stage II Keyboard Synthesizer with Blue LEDs Features:

* 37-keys transmit polyphonic MIDI note On/Off with velocity
* 2 Voltage Controlled Oscillators
* Voltage Controlled Filter
* External audio input
* CV and KB gate inputs
* Connect directly to a computer running the Little Phatty Editor/Librarian
* 100 presets
* Full MIDI controller
* MIDI over USB
* MIDI Clock Sync
* Arpeggiator
* Tap Tempo
* Black finish
* Blue LEDs
* Monophonic audio out
* 1/4" TRS headphone jack
* LCD display 2x16 characters
* Master and preset mode switches
* Pitch and Modulation wheels

[jeepo]

Yes, the cv mod is to get cv outputs, which can be used to control analog gear using the phatty

[Bääx]

I'm unsure as to the arpeggiator mechanics between the 606 and the LP, but a CV gate input is definitely a standard feature on all LP's. The CV mod is for outputs: gate, pitch, volume envelope, filter envelope, and mod bus

[EMwhite]

Indeed, you'll want a LP with CV OUT but the Gate output will not help you if you want your LP's ARP to drive a pulse that the 606 will see as a pulse for clock.

My first frustration with this dealt with my desire to step a MuRF pedal via Arp, in fact, that was the first thing I wanted to do when I got my mod'ded LP back from the factory. But it doesn't work, which is to say that the Gate out on my LP Tribute goes 'high' when the ARP is first enabled and stays there and that's just no good.

I posted something about this and 'Demondan' responded (he works at Sweetwater and gets to play with this stuff full time) that the time on/off or high/low of the signal wasn't adequate for the MuRF to pick it up. Meaning that the width of the pulse or time at 5V was either too long or too short. His recommendation (which was a very good one) was to tailor either the Filter envelope or pitch envelope to be more pulse-like (which is what you would typically want with a punch arp anyway) an then connect the CV OUT from either of the ENVs to MuRF's input.

I played around with this quite a bit using a) MuRF, b) Voyager OldSchool and gate to ENV CV-in, c) a voltmeter and found out (surprisingly).

- LP Gate out works as it should when playing normally; keys pressed kick gate high/low instantly and this is good for driving other keyboards
- LP Gate out doesn't work at all when the ARP is running, or more accurately, when the ARP starts, the gate goes open and stays that way registering precisely 5V. If you choose a patch with long sustain, you'll simply surmise that the gate is doing what it should do, you started it and it's 'running' or 'on'. In my opinion, however, it would be useful for there to be a parameter for ARP GATE TIME which could be a value from 1..10 (or 0..15) and dictated the amount of time during the interval that the gate was open, vs. closed. Analog sequencers based off of Decade chips typically have this and it's useful for a) patches with high Sustain values and b) serving clock to devices that are finicky

But... don't despair, the envelope method is perfectly suitable and as mentioned, I've used it to drive the MuRF clock, Voyager, and other equipment.

Let me know if this isn't clear and I'll throw up a YouTube video demonstrating.

[jeepo]

If indeed the gate does pulse w/the arp, just very quickly, a muli meter may be too slow not pick it up. If this is the case, then it is also possible to derive a trigger pulse from it using a couple flip flops and an inverter, or maybe a 555. But if the gate stays open the flip flops won't work. A 'scope would be helpful for determining how the gate functions.

@ EMwhite Have you tried using the gate in latch mode w/o holding the keys? maybe the keys supply a constant gate if they are held down.

[EMwhite]

My multimeter isn't the quickest, but even turning tempo down the bare minimum will not do anything but show 5V. I would think the gate time would be proportionate to the time spent between (ie. 1/8th vs. whole+whole at a very slow tempo might show a blip on the meter but not the case.

I have an analog (old fashion needle) meter in storage that I'll drag out this weekend.

And yes, all of what I was doing is Latch.

[jeepo]

My multimeter isn't the quickest, but even turning tempo down the bare minimum will not do anything but show 5V. I would think the gate time would be proportionate to the time spent between (ie. 1/8th vs. whole+whole at a very slow tempo might show a blip on the meter but not the case.

I have an analog (old fashion needle) meter in storage that I'll drag out this weekend.

And yes, all of what I was doing is Latch.

You could also try plugging the gate into a cv in and listening for clicks.

[jeepo]

I like the envelope idea because a longer attack can be used to phase shift the sequencer cock with the LP's clock. But I don't have the cv mod, so i don't know how well this works.