houston, all systems are go...

i tested all the sytems this weekend on the DRAX 2.5. thumbs up! i still ahve to check all cvs and gate voltages and such bu as for what the leds should be doing, we're on point.

heres a pile of pics...

dawning of the levaithan..

so it was a super nice interlude doing the diy synth from doepfer.. but it only honed me up for the second round on the sequencer. after my incredibly botched test from a couple weeks ago, i decided that since there were far too many mistakes and shortcuts taken on that main board.. i decided to get another from MFOS. so i repopulated it very carefully, and with forthought of any mods and kluges neccessary. so the other day i got to test the heart of it and the see it run..:) YES! i tested the A channel of gate and cv. all was good. the gate can use the 4 bit inversion mod or run normal while the cv line runs moded. i made a little switcher tester set-up for the bench and then hooked p and connected the b line and that gate as well. DING another winner! then last was the slide and its led generator.. OHH SNAP! 3 for 3. all the connections have .10 headers to connect them with corresponding pots, buses, jacks, buffers etc, so it took quite a while to do the connectors and to get all the wiring coded, and discernably labeled.

so far its all good. i havent been able to see every channel running yet though since i dont have 3 sets of mod switchers on the bench test set up. so i would run one at a time to test the lines and connections. really the last thing will be testing the actual functions to make sure the cvs aer correct and that the gates are correct . i also have to wire the slide bus to the corresponding normal and portamento outs. then its trimming the pot shaft lengths with the dremel, wiring the connectors for the clock and rest links to the previos sequencers, finishing the rear panel connections for external 4 bit outs and power etc, and attaching the opening door/case for the entire enclosure, then last but not least putting on all the knobs and the rosewood trim strips. once all thats donr.. the very very last thing will be to make the 3- 12 conductore cables that go to the 4bit mod line inverters. then its install time. about fuckin time. whew....

beginning to take a very nice form...

i had about 2 hours today to work on the MINIMONO some more.. i got all holes machined to the right tolerances and then set the face overlay in play and did the double bond adhesive. i use 3M SUPER77 . its fantastic on metal and plastic and cleans up real nice with naptha. so it went on like a DREAM! everything was exactly where it should have been. nice change. :) anyway, in that 2 hours i also got about a 3rd of the harware on and set in place.. the pacthfield jacks are always a pain to me.. i just hate doing them.. but its all good. and i wanted to see just a couple (literally) knobs on it before i had to leave. i also got the case assembled, but still have to fabricate the inside mountin rails and the face trim/spacers for the faceplate. i also have to make the armature that supports the tiny pcb for this synth. which is an incredibly minor task compared to the sequencers..

oh... i also cleaned out the holes for the hardware with the dremel and a conical shaped rotary edged blade. it is fantastic for the job and if needed can final trim/grind any faceplate material that is hindering correct placement of the hardware. i heeeeeeeaaaaaaaart the dremel.

the case is maple ply for the top and bottom panels and the sides are solid sepelea. they are actaully book leafed from l to r and the same iece was sliced down the middle long ways... im attentive to detail on the cases lets say.

anywa heres some pics of the the process and current status until i next building session.

one year... wow.

so its been almost a year since i started this DIY adventure into the land of sequencers and CMOS.. ive been working on the last one for a long while now.. i tested the heart of it last weekend. it was a horrible failure. i had soooo many things wrong and mis-connected. i couldnt believe what i was seeing. i also couldnt get the cd40193 to advance the count of the cd4514 multiplexor chip... in essense the sequencer wouldnt move from its initial step (0) . so there were soooo many bets hedged and gamed on the system., i thought i could just go ahead and wire everything and it would work. what a foolish idea. so.. i had to desolder the main control board and all connex to the panels and triggers/gates. no fun. actually it was demoralizing. but after a bit i looked at it as a step in the right direction. so i went back to zero: i ordered another control board and started at 0. im re populating it all very carefully and am going to hedge only 1 bet: the 4 bit control line hack/inversion. thats the only varaible i want to introduce new into the equation here. i also want to check EVERY switch and connection. i had all the dpdt switches for the gates and leds wired incorrectly.. so i had to undo that mess as well. anyway. i made a switch tester/simulator so i can check the hack mod without having it down in the studio itself and do it on the bench.

so as this project was moving slowly (now) foreward.. i had also gotten as present from my wife a DOEPFER DIY synth for xmas.. its a one of everything complete analog synth pcb thats assemebled and working. all you do is connect the power supply to it and wire all the pots and such and fabricate the case/enclosure to your liking. its incredibly patachable and has nice features. state varaible filter and nice mod points. so i was sending the ARP oddysey faceplate to the printers so i picked up the pace and added the doepfer to it as well. i named it the MINIMONO. since it has one everything. and its an incredibly small pcb. and had a good ring to it. so i sent that , the arp and a redone faceplate for a control voltage mod dual row unit out to the printers here in town. gotem back with the machining mechanicals. fan fuckin tastic. i have the control voltage (DSVC is its name) on and am beginning to clean out the holes and getting ready for harware install. the MINIMONO is all drilled. all parts have arrived (pots/ switches/headers) minus 2 switches for the env timand the lfo mode.. i have also made the case for it and have that just about ready. it sepelea endcaps with just 1/2 super finished painted black ply between. looks pretty nice and classy old school style. no 90's bad typefaces or anything. class. the MINIMONO and ODY will match design wise. both use the classic ARP styling from the last version of the ODY. i like that . i used black and orange with white letters and boarders. looks stlylish and scientific without being corny or cold. GENEVA was the typface that is almost 99% identical to the ARP stuff. love it. anyway.. heres pics of all the stuff.

gate hold module fabrication/wiring

so heres the super cool switches all set in their repsective spots.. i used angle aluminum from home depot to fabricate the housings/faceplates. i made a template for the mounting screws and then figured out the correct spacings from front/side to side for a 19" rach unit with enclosure. so after i got the measurments i laid out all the holes and punched them (to minimize drill bit drift) and then used a fence on the press bed of the drill press to even minimize variance further. worked pretty well.

i then used a dremel to cut the u shaped holes into the aluminum for switches. i didnt cut the horizontal of the u but rather scored it about half way thru. this allows then to snap the alunimum off in a very precise sharp corner with no ugly over cut marks. i then cleaned the u out with a nice file. very efficient. what wasnt efficient and time consuming was tapping the holes (32 in each row ) x2 rows. for the switches. that took some time and delicacy. (4/40 taps dont like to be twisted or torques to hard. theyll say no and snap)

i used 3 pieces of angle stock to make each row. (oddly enough this is just a 1/16th over the actual size of one U rack measurments) i have this sitting in ait own area so its not directly touching any other rack gear so its no issue... the bottom is just face plate surface and will have the step numbers and info on it. the second is the switch row itself and the 3rd is a 3/4 size piece that will house a bi-colour led (red-green) for staus and scroll/count/step indication. so because of the nature of the mechanical switch you can see to parameters at once. - the hold faetures all together via the yellow mechanical flip, and the current step AND status of that step via the dual color led. so its not too bad.

im re-using an old set of rack ears from an s700 that has been canniballized for another project.. the rear panel for this module will have several db -25 connectors on the back the interfacn/connections to the main sequencer unit. so its all about figuring out now exactly where in the circiut this fucker needs to go...

one biiiiiiig step closer. id say about a month to 2 month it will be testable...:)

trudging on...

as ivve now spent almost a year doing this never ending sequencer project.. i reach a point where ive actaully been able to see the end.. this last sequencer is so encompassing to create, with so many interconnections. switches and just complexity that its daunting at times. today WASNT one. all cv channels, gate channels, and the slide channel are all now manufactured and connected. all digital line buffers are in and awaiting connection to the main switchers. the gate hold module is about 40 % done. ive uploaded pics of the way ime going to mount the super duper sweet dpdt push buttn latch switches im going to use for it. i found them for a buck a piece from a surplus supply place. they have a machanical status indication inside the button (which allows mw to see a series of gate holds together to know where they start and stop) i count ask for a better switch. they are THE SHIT! and they are double sided as well which really makes the assembly free-er. so these will be used to hold the gates and slur them between steps. (so envelpoes will tie together and open up like a 303 or funky slurs/legato portamento on the minimoog). a very nice little feature that really isnt too terrible amounts of work really.
its all relative.

well heres the pics.

ideas as well

ive also found an imterestimg cmos ic. : the cd 4066 quad switch. basicly it 4 switches integrated into one small 14 pin dip ic. you ask how this may be useful? i ll explain.. say you have a row of triggers with physical switches. you have to drill holes for everyone and wire everyone and have faceplate realeastate for each one. thats all well and cool, but depending on how much money u want to spend.. can be costly and time consuming depending on style of switch.. so ive been thinking of this chip for a drum programmer unit. basicly a large trigger sequencer with a ton of rows for triggering drums and envs or whatever. say 4-8 rows depending. so i can have one row of 16 step switches (like the 808-909) and then selelct between the instrument rows for their use. the only issue im trying to solve is one of power to that row after selection is done..

the chip uses and the vdd volatge as the on status for the switch input and the vss voltage (or lack of) for the off. basicly system power and ground. mine would be +12 an ground in this case. i guess i can just switch the power from another source to "hold" the stauts of each switch after i remove the row from the programmer circuit. like a "lock" switch. another issue is that upon powering down all sequences will be lost. but it would enable me to put all of this into say 3 or 4 rack spaces then for 8 rows of gates and triggers. one row of programmer switches (reeeeeal nice ones) and then a 4-8 x 16 grid of leds that correspond to each rows triggering status and one row of counter "current step" leds. just an idea....

also this would involve me going one more step into all of this stuff and etching my own boards. it would only be wise to do this for such a large amount of ic wiring and repeating circuits. and size as well. im working on how to make each row independant lengths and modes as well. (bi directional, reverse, random etc) it would be a seriously ridiculous analog drum programmer unit, that would be super original.