Sequencer Rate Control

Sound Diver · Joined: Mar 26, 2010 Posts: 16 Location: Preston U.K

Hi All.
would it be possible to add a fine adjust to the rate control of the 16 step sequencer, i'm finding it really difficult to sync the sequencers timing to my other instruments and drum machines, if its not possible to add a fine adjust is there another way around this problem.

jordroid · Joined: Jan 17, 2010 Posts: 193 Location: ithaca, new york

I have been thinking about this as well, the range of slow to fast speeds is great but it gets a bit tweaky to dial in a tempo in the fastest third of pot travel.

Looking at the schem, the rate adjust pot is just a 1 meg variable resistor, fast speeds occur with the pot adjusted for less resistance, slow speeds with more resistance. Not the classic Ray Wilson voltage divider coarse and fine tuners, like you see on oscillators.

What i am thinking of doing is adding another, smaller value pot wired as a variable resistor in series with the existing 1 meg already there, so that the rate is a product of the total resistance of both pots in series. This will result in a slightly slower slowest speed.

I think that ought to work, but it might take some guesswork to find a value for the fine tuner pot that feels right. If i am missing something obvious and this won't work the way i think it will feel free to shoot it down, i have not tried it and i probably won't for a while.

On another note, to get your sequencer to really sync up with other gear you will need to run them off the same clock source. Barring that an idea i have been toying with recently for using sequencers live with other musicians is to build a tap tempo clock, this thread discusses a tap tempo tremolo, which could probably be used as a clock source with some hacking http://electro-music.com/forum/topic-40981.html and Small Bear electronics sells this chip http://www.smallbearelec.com/Detail.bok?no=795 that might be fun to play with. I think it will be much easier to be able to tap along to keep in time than to constantly adjust the rate control, which is pretty much impossible to keep up for more than a few bars.

yipes, long post, have fun.

RF · Posted: Thu Apr 29, 2010 5:56 am Post subject:

globe town free arts lab · Posted: Thu Apr 29, 2010 7:20 am Post subject:

Do you have a drum machine with a trigger out jack?

I use the trigger out on my tr-626 to step my sequencer
as in this video:
http://www.youtube.com/watch?v=DlQK_II_OBI

You can get irregular step lengths by changing the pattern.
It syncs up perfectly to midi clock when i connect the 626 to my computer.

drew

Sound Diver · Joined: Mar 26, 2010 Posts: 16 Location: Preston U.K

I HAVE TWO DRUM MACHINES BUT THEY ARE BOTH MIDI AND ALL MY OTHER GEAR IS MIDI TO APART FROM MY DOEPFER SYSTEM I USE WITH THE SEQUENCER.

Sound Diver · Joined: Mar 26, 2010 Posts: 16 Location: Preston U.K

Would the sugested 100K pot go in between R19/1-2 or R19/3. As my sequencer is still in a working prototype facia, i could try it before i have a finished facia made.

RF · Posted: Fri Apr 30, 2010 4:20 am Post subject:

Just put it in series - either before or after the existing pot.

I was thinking about this, and for fine tune you might try a smaller one than 100k- like 10k or 50k. Experiment a bit and see what feels best to you, and gives the resolution you want.

bruce

Sound Diver · Joined: Mar 26, 2010 Posts: 16 Location: Preston U.K

Just had an idea (but not being heavily into electronics, it just an idea) would it be possible to use a multi turn pot with a vernier knob for a lot finer rate control. If its possible what size pot?

jordroid · Joined: Jan 17, 2010 Posts: 193 Location: ithaca, new york

Sound Diver · Joined: Mar 26, 2010 Posts: 16 Location: Preston U.K

Thanks for the response and the posative comments on my sequencer, it ran stright out of the box,
On the rate side what i had in mind was these on the RS.com website.
100k pot RS Stock No. 460-7605
Vernier Dial RS Stock No. 625-1579

What do you think?

jordroid · Joined: Jan 17, 2010 Posts: 193 Location: ithaca, new york

Not sure what you mean but if i go to rs.com i end up at rocket software? I checked the radio shack site too but the #s you show don't turn up there so i guess that's not what you meant either. Sorry if i'm being dense but i'm not sure where you are looking.

Sound Diver · Joined: Mar 26, 2010 Posts: 16 Location: Preston U.K

Sorry about that the site is RS Components try
uk.rs-online.com or
rswww.com
could have been worse it could of been a dogging site!!

mikebike · Joined: Apr 06, 2010 Posts: 6 Location: MPLS

if youer gonna use a multiturn just replace the 1meg with a 1meg multi.

that should be plenty of fine adjustment

nyd · Joined: Jul 15, 2009 Posts: 8 Location: Sweden

I think you're fooling yourself by adding the fine adjust for speed, unless you want to use the Seq16 as your master clock. In your case, where MIDI seems to be the master clock of things I would suggest to trig the sequencer from a drum machine (rim shot out if you have no sync out) or a synth / sampler where you load a simple short sound to trig with.

Pipe the audio from the DM / synth / sampler to one of Ray's attack-release generators, these have schmitt trigger inputs which will be activated by the audio, set the AR to triggered mode, zero attack and a moderately short release, pipe the AR output to ext clock on the Seq16.