From kent@inav.net Fri Mar 1 07:55:08 1996 1 Mar 96 10:54:59 +0500 27 Feb 96 14:04:55 +0500 Date: Tue, 27 Feb 1996 12:27:42 -0600 (CST) From: Kent Williams Cc: shockad@primenet.com Subject: DR 55 sync I got the DR55 schematics from anthony bowyer-lowe today (thanks anthony!). This thing is actually a modifiers dream since a lot of the strategic points to cut run through bare metal jumpers on the top of the board. All the individual triggers come down to either snipping a jumper, or clipping a resistor lead. Sound modifications would depend on you knowing more than I do about analog sound generation, but most progrably would just involve substituting a pot for a resistor. Here's the low down on how to sync it to external clock. Disclaimer -- I've not tried this, but it shouldn't be that tough. The mode switch (play/write) is a 4 pole, double throw switch. One pole of the switch changes whether the clock comes from the buttons/foot pedal (for write mode) or off of the clock flip flop. Out of this switch, the clock goes to the counter and to clock enable on the SRAM chip As luck would have it, the switch (play/write) goes out into one of those bare metal jumpers on the circuit board. All it would take would be this. 1. cut the jumper going to chip enable on the RAM. 2. cut the jumper carrying the clock to the hi hat switch 3. add a wire from the far side of the cut to the CE to the far side of the hi hat switch jumper. 4. Put a jack in so that it makes and breaks the connection between the play/write switch and the far side of the CE jumper. This jack is now an insertion point for a 4 PPQ clock pulse. You can probably plug a trigger out from a TR X0X right into this jack, and program the X0X to send a trigger on each 16th note. If you want to do DIN sync you'll need to divide down to 4 PPQ. This is going into a pin labeled CE -- does this mean it's a positive going trigger? Before I go and wreck mine, let me ask this: Is it safe to feed the pulse clocks from a X0X box right into CE on an SRAM? Anyone in the US (Stuart? Dave?) who didn't get the docs from anthony drop me a line. --------------------------------------------------------------------- In an expanding universe, time is on the side of the outcast. Those who once inhabited the suburbs of human contempt find that without changing their address they eventually live in the metropolis. -- Quentin Crisp Kent Williams kent@inav.net (319) 338 6053 (home) (319) 626 6700 x 219 (work) (319) 626 3489 (fax) From kent@inav.net Tue Feb 13 11:52:23 1996 13 Feb 96 14:52:17 +0500 12 Feb 96 11:03:13 +0500 Date: Mon, 12 Feb 1996 09:29:39 -0600 (CST) From: Kent Williams Subject: Syncing a DR55 On Mon, 12 Feb 1996 abowyerlowe@mindscape.com wrote: > >I've played with a Dr-55 from a guy that went to the studio. > > I've said it before and I'll say it again - the DR55 is the new 909! (Kinda). > If you believe that, I'd gladly sell you mine for $900 ... > I've not worked out how to sync the li'l bugger to anything external yet, but I As was mentioned in passing in someone else's post -- If you plug a trigger pulse into the foot switch input (I've used 606/707 -- which is apparently a 5-7volt positive going pulse) and put the 55 into 'write' mode (as though you were going to program in a pattern), then the 55 triggers on each pulse, sort of. 'Sort of' means that at least on mine, it is sensitive to how fast the triggers come. Sometimes it will decide to stop and not play any more, sometimes it will get behind on tempo, but if you fiddle with it, it works. EXTRA SPECIAL EXTERNTAL TRIGGER TIP FOR DR55: The snare sound is gated by the next clock pulse. SO if you send a trigger on a time step where the snare is supposed to fire, and then wait a while to send another trigger, you get a continuous white noise "Shhhh" Has anyone an actual MANUAL for this sucker? What is the foot switch input supposed to do??? Advance the sequencer during programming? Is this sucker starting and stopping the sequencer on each pulse??? Someone said they were sending out service manuals for this sucker to me, but it hasn't come. I'm not complaining, mind you, since this was a free offer, but I still feel kind of in the dark about this thing. --------------------------------------------------------------------- Personally, I love nothing more than to jam out to a greasy groove. -- A Guy Named Phillip Kent Williams kent@inav.net (319) 338 6053 (home) (319) 626 6700 x 219 (work) (319) 626 3489 (fax) From shockad@primenet.com Fri Mar 1 10:54:26 1996 1 Mar 96 13:54:16 +0500 27 Feb 96 15:14:27 +0500 From: shockad@primenet.com Date: Tue, 27 Feb 1996 12:22:56 -0700 (MST) Subject: Re: DR 55 sync >I got the DR55 schematics from anthony bowyer-lowe today (thanks anthony!). > >Before I go and wreck mine, let me ask this: Is it safe to feed >the pulse clocks from a X0X box right into CE on an SRAM? > >Anyone in the US (Stuart? Dave?) who didn't get the docs from anthony >drop me a line. If I read you correctly you are throwing a trigger of unspecified and possibly varying positive voltage at the Clock Enable pin?? If so one would want to measure the internalpulse/trigger that the unit itself throws at the CE and than buffer the input jack for the external unspecified pulse/trigger with a value of resistor that would keep the highest possible external pulse/trigger to the same voltage level as that of the internal pulse/trigger generated by the DR-55's internal clock circuit (this would be located outside the actual microprossecor chip-as *most* microprocessor chips of the time did not have internal clocks, Z-80, 6500 series etc) the circuit should be readily marked on the service docs-it would have a crystal in it-valued for the clock rate. Another issue here may be the *duration* of the pulse/trigger. One would measeure this with the aid of a scope and use capacitors to lengthen the pulse. ShockAD " everyone knows electronics run on smoke, only they don't run too well when you let the smoke out of 'em"