From mj20279@janus.swipnet.se Sat Sep 28 12:14:04 1996 28 Sep 96 15:13:45 +0500 28 Sep 96 15:13:30 +0500 Comments: Authenticated sender is 28 Sep 96 03:57:36 +0500 by gaia.swip.net (8.7.6swip/8.7.3) with SMTP id JAA02155 for ; Sat, 28 Sep 1996 09:50:04 +0200 (MET DST) Date: Sat, 28 Sep 1996 09:42:58 +0200 (MET DST) From: Ricard Wolf Cc: Analogue Heaven Subject: Soundmaster SR-88 sync input mod Hi! Ok, here it is, finally (so much stuff coming in on AH I don't have time to do anything else :-)), the Soundmaster SR-88 external sync input! Enjoy. Soundsmaster SR-88 sync input mod --------------------------------- Well, this isn't a TRUE sync input, in that after the mod the SR-88 will not slavishly follow an external clock. Rather, the sync input functions a bit like soft sync on an analog synth, in that you can get the SR-88 to synchronize with an external source only if the SR-88 TEMPO control is adjusted properly. The upside of this is that you can sync the SR-88 to sources running faster or slower than the SR-88. The SR-88 uses one clock per step which is far below the 24/48/96 PPQN standards used by other machines, and in many instance you'll want to sync it to that, or even to something running slower (like running the SR-88 at 1/16th notes while the external source is running at 1/8th notes). For instance, I've successfully synced my SR-88 to my Yamaha RX-11, which outputs a clock of 24 PPQN. Note however that it becomes more difficult to adjust the SR-88 properly the faster the input clock is relative to the SR-88, and that it will have to be re-adjusted for changes in tempo. So, not useful for live use perhaps. The mod is designed to accept positive-going clock pulses. I've successfully synced it to a Sequential Pro-One and Yamaha RX-11. The actual mod is very simple and involves adding a few components to the board. On the SR-88 board you'll find a 4011 CMOS NAND chip, and the mod is connected to pin 8 of this chip: 9 --\ ...---| \ ------- | /| | |o---... sync in >--| 47k |-----|< |------*------| / ------- | \| | 8 --/ 1N4148 | existing 4011 gate | +-... When you open the SR-88 however, you'll find that the you've only got access to the underside of the board, and although the board can be removed it's a bit awkward (it's mounted using the front panel pot/switch nuts, and input/output jack nuts, as well as using screws and being a general tight fit). On my unit, I didn't want to add any extra holes for the external input (there's not a lot of space in there anyway), so I decided to sacrifice the external footswitch start/stop input. The ASCIIgram below is the interior view when the bottom plate has been removed, showing this mod: rear ----------------------------------------------------------- | | | | | SR-88 PCB | | | | | | | | | 4011 pin 8 | | | | | | | | | | | v 1N4148 | | B | |\ | | | | * *-----| >|---+ | | A | * * |/ | | | | | * * | | | T | * * | | | | * * | | | T | * * | | | | * * | | | E | | | | | | | | R | --- | | | | | | | I | | |47k | | | | | | | E | --- | | | | | | S | | | | | | | | | * * * * | | | \ | | | *--* X b * * | | | a | | | | / | | | / * * | | | .../ | | | | ----------------------------------------------------------- footswitch output Notes: a - short these two pins on the footswitch connector b - cut the PCB track leading from this pin on the footswitch connector (where the X is!) (These two items disable the external start/stop footswitch function) Anyway, that's about it. Happy syncing! /Ricard -- Ricard Wolf (ricard.wolf@swipnet.se) Analog synth, railroad and Citroen GS fanatic -- "Ich bin der Musikant mit Taschenrechner in der Hand" --