Casio RZ-1 Circuit Bent

[playthatbeat]

heh rz-1 pics..

before the ZIFing, after the Ziffing with nice red wires to the bend switching, a closeup of the righthand side :top row is for EP6, bottom for EP5, knobs are rotory switches, a closeup of the left corner - the switch to route the LTC1799 to either of the timing xtals and a pot to tune it, and the original shop sticker with some delicious wires poking out to prove we mean business!!!"!£!"!"£

[playthatbeat]

here are the bin files for the custom roms for the rz-1.. some of them are extracted from the roms published here

mostly both 512 and 256 versions of the bins are included, plus my custom rom as used in the Youtube clip.

also in there are rips of the 2 stock roms..

BEWARE - some perfectly good eproms will not work well in the RZ-1 - you will never get a glitch-free burn from them.. I really don't know why, nor do i care.. Just be aware, if You cannot get a clean burn, try a different brand of eprom!

[playthatbeat]

THE STORY:

So we had an RZ1 lying about for years, bought in the local music shop 2nd hand as someone had traded it in in the early 90's for something less crappy.. It was cheap - like 75 punts.. I love the clap and hats on it, grrrreat for Hardfloor or Todd terry impressions, but it had issues.. Like the Main (right) output jack was flakey, and the 'brightness' pots at the back were also gammy.. I still used it a fair bit for it's awesome hats and claps though.. So, our one defo needed a service, and it would be rude not to bend it up some while we were there.. I wanted to make a matrix using a multiplexing chip, so i could use 4 switches to develop various combos of bends, but a week playing about with this brought dismal results, meaning i had to look at a traditional switch-shorting bend scheme. I thought about using an s-trigger setup to allow me to use GATEs to commit the bends, paralleling these with switches so i could automate bending - that will be the next thing i do, maybe. The end plan was to make it easily PLAYABLE, with only 1 knob and 4 switches per eprom, and a single LTC1799 in the mix. So out went any patchbay nonsense, this was to be a hands-on jammer..

Alot of heads rate the RZ-1 as the daddy for bending.. I'm not so sure, it's no way as wild-sounding as a TR-505 or HR-16B, but definatly easy to get into, and has a lovely well-spaced board, with plenty of room for holes over the PSU.. So, in we went. re-soldered the gammy jacks, replaced the Brightness pots with ALPS lookalikes - had to keep the metal sleeves from the old ones - and started poking about with eprom 5 & 6 marked CM5 and CM6.. 5 has the first 8 pads on it, 6 has the last 4, but bends to this rom ALSO effect the 4 sample pads Some nice addressline bends on both, and some typical dataline distorto bends found quite easily, i'll leave that to You - just use the datasheet from any 512k eprom to suss what is what and poke away.. Alot of the legs have jumpers on the board nearby if You don't want to tap the pins themselves you can get at these real easy..

I removed both eproms and ripped them for a look.. its all simple 22050 8bit mono raw PCM - open it in SoundForge (or whatever) and have a go at replacing stuff - there is plenty on the web about this to get You going (see above).. There is a custom rom out there with 4 kits on it, for use in a switching setup, so i split this into individual 256k roms to make new chips, and made my own one too (see attached zip) for use in the ZIF socket i put in for each rom. Oh, i doubled the size of the roms as all i had here were 512k eproms.. just FYI - you'd be changing the copy at the END of the rom if you were to edit any of my 64k roms in the zip. never mind, it's the original roms you need to pay attention to for the correct placements..

I mounted the ZIF on some board, wired into the mainboard directly, with lines coming off this board to the various shorting switches and blah.. This means i can swap roms and so on, and my tap lines are to the daughterboard, not the mainboard. The mainboard is VERY fragile. It has some very thin tracks in places, so be very very gentle with the heat when You are doing the ZIF transplant if You go there.. I had to make 3 major rescues in the end, after ending up with a perma-bent machine thanks to TINY tracks lifting..

I used 2 rotory switches, with 2 x 5 ways on each.. On rom5 i used both sets of 5, but switched with a 'left-off-right' toggleswitch (bottom row, 2nd from the right) to give 10 destinations. On rom6 i only used 1 set of 5, leaving 1 blank as an 'off', so it's a 4-way really. They came from fleabay, and are of HORRIBLE quality, stiff and messy.. Same with the various switches i got batches of - some were very ropey quality, but at like 29c a pop, you cannot complain

I wasn't so keen on the dataline bends, they were just degrees of distortion, so i used only 2 of them on rom6, the lightest one, that seems to smear the hi-end nicely, and the 2nd heaviest one that makes for good aliasing & splat. The Address lines were most fun.. Everything from startime offsets for the samples to s-s-s-s-tutter was in there depending.. I spread them as i saw fit, ignoring the less musical ones, or ones that messed with the timing too much..

There were some sweet cross-rom bends there also, i only used one of them and it creats a different offset to the '1 rom' offset bend, the others were too similer to already found ones, also, cross romming did cause some lockups when alot of bends were on. As is, the machine is safe.

I am quite happy with how it runs now.. The rom swap isn't as awesome as i hoped, since alot of the RZ-1's awesome comes from it's stock hats and clap, but it was a relief to get that shite kickdrum and snare out of there and trade a tom for a nice meaty FM stab The only odd issue is the 'drone'. Some of the bends are distractingly accompanied by a drone that CAN annoy You, but this is a symptom of the bends and has to be tolerated in the interests of making your ears bleed. Most of the time You dont notice, but if You dial in a serious bend without playing the machine, you can clearly hear it howling in the distance.. ah well..

Yes - the RZ-1 ALSO samples, and this is nice, but you only get 2 voices to use with samples, so it's not that great.. But combine control over ALL the sounds and 4 samples and You can really cook socks in hell..

http://www.youtube.com/watch?v=KhXcEu7r6m8

The Youtube clip is all one take, in SONG mode, using my custom rom for rom 5, audio taken from the stereo output. The box does have the advantage of seperate outs - 10 in total - with a usefull mixer, and the MIDI and internal timing are both spot on.. It's a nice bit of kit really, one of the last great 'crap' drum machines, and i think you COULD make a whole album with JUST this
machine if You really wanted to..

heh.. casio..

DREAM MACHINE:

This box with GATE in & midi controlled bends (highly liquid??) & CV in for the 1799, in a larger all-metal case..

[digitalallstars]

You are a man that knows what you're doing !

[vst]

All my parts are in to start my RZ-1, and I just flashed some Windbond W27C010's!

Gonna do a 4MB sample expansion on a six-way rotary too.

I'll let you know how it goes with pics n shit.

Wish me luck.

[playthatbeat]

Heh.. that sounds epic.. You must do a jam-vid when you get it together.. DO IT FOR TODD TERRY!!

[Tarelizer]

Hey there,

i just saw your Mod for the RZ1. Since i sold my 909 which was big mistake, i look for an equivalent solution. The RZ1 looks amazing and could extend my new 909.

Can anybody provide me detailed installation instructions?

i found from exfade.org some schematics.

but they are not so much detailed.

thanks for your help

cheers

[playthatbeat]

The mods i did only really cover 2 things - installing a getlofi clock to change the pitch of the sounds, and 'scrambling' the data lines to the sound roms using switches..

Putting new sounds into the machine on new eproms is a little bit more involved, but nothing You cannot do if You have eproms, an eprom burner and some skills with a wave editor. In fairness, the sound of a PCM drum machine that has been circuit bent is a unique, but limited experience. If you just work on the bends (the corrupting of the datalines on the sound chips) you will satisfy all your lo-fi and grind needs i think.

The RZ-1 is also a sampler.. this is what makes it more awesome then other PCM drum boxes.. You really can just use it's sampling function, and some bends and win..

If You want a 909 sound, then get a 909 again.. i'm afraid no PCM (digital) drum machine is going to sound like the 909 - the 909 is analogue (minus hats and so on) - end of story.. Of coarse, the TR-707 has almost the same PCM sounds, plus some more, and it will bend real good and is cheap as hell nowdays, but the kick, snare and toms of the 909 cannot be done elsewhere. You can come close with modular synth/eurorack devices, or try one of the X0X boxes like the JoMoX or even try a build like this: http://www.synthage.com/ using the midibox engine.

The other option, is to look at something like the Arturia Spark which is basically a sample-based drum device, but has a synth engine available also, and it intigrates to any DAW as a VST etc.