Analogue Drum Modules

[Jaicen]

Ok guys, i'm not sure how many people here have quite the same fixation for analogue boss/roland drum machines that I do, but I thought i'd post this anyway. 

I'm working on building up a modular drum unit based on my favourite sounds from all the old TR, DR and CR series. I figured i'll start small with the kick and rimshot from the DR-55 (which I love! first drumbox I ever heard). They're pretty simple little circuits, so they're easy to mod too. The layout below incorporates two seperate (identical) kicks and a single rim shot which can all be individually triggered by a +5v pulse. I think it would be nice to layer two kicks, one very low and long (say 60HZ) and another short & high (150Hz??). Luckily I found a single mod on the net that would do both with one single pot. The same goes with the rim shot which can be pitched up and down using the emitter resistor. It's also possible that i'll put these parameters under CV, using the techniques shown here:http://www.hoohahrecords.com/resfreq/mods/dr110.html

I'm working on cloning the snare and hats from the DR-110 at the minute, but i'm not exactly sure how they work so bear with me (assuming anyone cares!).

If anyone's interested, i'd appreciate any feedback regarding the accuracy of the layout below (i've included the schem for reference. I have both DR's. 808, 606 and 909kick schems if anyone wants them as well as the CR-78 too).

I've tried to keep things as small as possible. Trig1 & Trig2 are the kicks, same with out1&out2. The pad for out2 seems to have gone awol on the layout though ???

I'd appreciate it if anyone can shed any light on how the schmitt trigger gates the noise signal for the snare and hats, as i'm stumped by that at the minute.

[stryd_one]

Seen this: http://xlargex.xl.funpic.de/ ?  :)

[Jaicen]

Yeah of course!

I actually plan to make some of those voices as well I just don't need the cowbells and stuff.

So far, i'm definitely cloning the DR-55 kick & Rim (Done), the DR-110 Snare (half Done), hats & cymbals. I'm also looking to clone the hats and snare from the DR-55 when I work out how they're implemented.

I guess I should clarify that i'm not looking for the typical 808 soundset, I want something a little different.

I'm looking for a usable CR800 or CR-78 schematic if anyone has a copy (I want the tambourine and guiro sounds!).

[Jaicen]

Hey guys, it seems that not a whole lot of people on here care but I've made steady progress with my Dr Rhythm modules. Below are layouts and PCB's for the DR-110 snare, cymbal and Hi-Hats. The noise and chime/filter generator will be on a seperate PCB to try and cut down some of the hiss you get on real DR-110's. I'm very proud of the hats layout, that's some tight work!  8)

Oh, I should also mention that I think it's possible to get close to the DR-55 hats sound using this circuit by taking out the chime tone, effectively leaving gated noise. I might still make a dedicated module from the 55 circuit, as it would be nice to have them simultaneously.

[stryd_one]

Hey guys, it seems that not a whole lot of people on here care

Hey bud,

I'm actually really really interested in this, as I absolutely hate sampled drums, I'm a drum synthesis nutter... I just haven't had much time to respond (you'll understand why shortly)

I can do digital stuff, but analog synthesis circuitry is a myth to me. Keep up the good work, I am quietly watching, and being very impressed :)

[Jaicen]

Thanks man! I hope it didn't look like I was sulking or attention seeking!

The hats layout has some slight errors which i've now corrected, and I also added Decay controls for the open hat and cymbals.  The hardest part is still to come, when I have to do the layouts for the chime generator which is mixed with the noise to produce the cymbal tones. It uses a 14069 hex inverter, which is a shame as I would have liked to keep the signal generators completely transistorised. That said, the hat & cymbal noise shaping filters use an JNM4558 op-amp anyway so it's no big deal. The question is, do I use the pseudorandom (digital) noise generator of the DR-110 or the transistorised noise of the DR-55??

So far, i've come to understand the workings of this circuit a lot more in doing these layouts, so if nothing else it's a good learning excercise.

[stryd_one]

The question is, do I use the pseudorandom (digital) noise generator of the DR-110 or the transistorised noise of the DR-55??

The digital noise might sound more metallic or glassy, the transistor would be smoother... Depends what sound you're after...

Make the board with both, and a switch to select ;) hehe

[Jaicen]

Yeah that's pretty much what I was thinking. I think it would be nice to be able to use one noise source for the hats, and another for the snare. The digital noise is definitely less smooth, and apparently creates some interesting effects when decay times are increased. I figure the circuits are small enough that I can put them both on one module with seperate outs and a mixed signal to cover all bases!

[Jidis]

I hope it didn't look like I was sulking or attention seeking!

Definitely not! ;)

I'll ditto stryd_one's interest. Sometimes not having people qualified to answer or comment has no connection to some of the other's interest in it. Some of us just patiently sit by and wait  for you to make something we can selfishly clone and use for ourselves. ;D

I've been trying to restrain myself and keep my DIY projects in realistic perspective, so I'm not sure how many new ones I'd be wise to take on, but I've been watching this since it showed up, and saving the images and text. At the very least, I'm interested in how some of the older sounds were actually created, if just for the electronics knowledge.

I'm also a drummer myself, and while recent years have brought us several different means of DIY trigger to MIDI interfacing, and the various DIY pads and triggers for them, I haven't really seen many easy projects for the "sound module" half of the system. It would be nice to be able to build a simple piezo/pad system for quiet practicing, ideally with a really basic set of more "conservative" sounding onboard drum voices. From what I've heard of the CR-78,etc., I'm not sure most drummers would be OK practicing rock drums to those sounds, but some lo-tech Oberheim or Linn type sounds may be adequate, especially when paired with a cheap reverb or effects unit.

Take care, thanks, and please keep working on it!

George

PS- Not sure how much sense it makes with modern digital storage, but I've thought how nice it would be to have something like the old Oberheim or Simmons stuff I've owned, where you could customize a small sound set by dumping short wav's into some EPROM's or whatever. (again, even with minimal parameter/tuning control, no multi-sampled voices or anything else) 

[Jaicen]

Thanks for that man, it means a lot!

With regards to the layouts already posted, most of them will have at least one error, and a number of improvements to add so keeping copies is only really useful to see how they've developed. For instance, the dual kick & Rim layout now has a pair of - to + converters to allow them to be triggered by the same -'ve pulse as the rest of the DR-110 modules I'm making. It also has decay and pitch controls for all sounds.

I will say that they're all untested so far, I haven't even gone through and error checked them against the schem.

With regards to the CR-78, i'm interested in the more esoteric sounds it makes, like the guiro & tambourine, which are pretty unique to that box. The stock DR-110 sounds are actually quite good for more generic drum sounds, though I'm not really interested in another x0x box if you get what I mean.

I can't say I care a lot for the Linn-Drum type sounds. I don't really like PCM samples, though the low sample rate does give them a certain character. I don't know anything about building one of those!

For what it's worth, I think it would be relatively easy to interface the modules i'm making with some piezo's and a Schmitt trigger to trigger all the drum sounds if that's what you're looking for. There's a good article on sound on sound about DIY drum triggers. I'd personally want to trigger these sounds in conjunction with a live kit, that's more my kinda thing.

[Jidis]

With regards to the CR-78, I'm interested in the more esoteric sounds it makes, like the guiro & tambourine, which are pretty unique to that box.

I hear you there! ;D

My first experience with those, was either from my S-550's sound library, or after purchasing a Canadian vintage drum machine compilation library on audio CD. I remember hitting one or two of it's sounds and just thinking "what in the hell is that supposed to be"? I'm pretty sure it was the Guiro or the Clave sound. I also remembered some weird "noise" artifact behind all the sounds, which made me wonder what was wrong with the particular machine or system they had sampled it with. Cool stuff for sequencing and DAW work, but probably not for playing drums. I've flipped to various "808 type" sounds on occasion, while practicing, and they do inspire some unconventional styles of playing, but the novelty wears off rather quickly. 

The stock DR-110 sounds are actually quite good for more generic drum sounds

That's great to hear! Like I said, even generic, "bland" sounding stuff is good enough for practicing.

I can't say I care a lot for the Linn-Drum type sounds.

Believe me, none of us do. 8)

All those machines leaned more toward the "old" side than the "old classic". When I was younger, I used to have to take the DX's outputs to tape, and use them to trigger different sounds from a delay unit with sample/trigger capability. All I was usually left with were maybe hi-hats, and those often got processed too. As bad as most of that stuff can sound, it still can suffice for drum practice, if you're able to take the tuning down fairly low, and maybe run it through a cheap reverb. What you describe sounds plenty good! I'm interested to hear that DR-110 now. If I can remember, I'll try to dig up the sounds when I get to the studio later.

I may have weird taste, but for beat sequencing and music, I sort of liked the flat "two-dimensional" sound of the sampled drum hits being triggered from analog sources or pulses. It's something between the lack of velocity changes, the exactly consistent  sound between any two hits, and the unnatural, "out-of-place", gated ambience which often surrounded a sound which had been "extracted" from a separate mix. Even with what I've got now, I have trouble reproducing the sound I got with that primitive system. I'm pretty confident it was not a result of any "analog tape" sound, but the lower bit rates & digital conversion may have been involved somehow, as well as even the Oberheim's sequencer.

BTW- On that drum machine sample CD, I remember hearing one machine in particular that I would have loved to have had back in my DX days. Some weird Akai crap, like an XR-10(?) maybe. I don't think I ever saw one in real life, but I think I went around fishing for a picture once, and saw it. Really sharp sounding and "cartoon like", if it's the one I'm thinking of. I've thought about loading my DX EPROM's with it, but I'm not sure what the memory or sound requirements will be.

Take Care,

George       

[Jaicen]

If you want to hear the DR-110 then head over here: http://www.keyboardmuseum.org/d_machines/dr110.html

I love that place, i'm sure it's feeding my obsession somewhat  ::) I actually just did an A/B against my unit, quite surprisingly there's a fair bit of difference in the sounds (Mine sounds much nicer of course). The hats are less harsh and the kick is fuller. The virtual one seems to be pitched down slightly too, strange.

Sounds ilke you had a much harder time back in the day than us young pups.

From what I can find out, the XP-10 was one of the first of the crop of 16-bit digital boxes, along with the HR-16 (&16b). You don't see many about so i'm guessing it wasn't as popular.

[Jidis]

Jaicen,

Yeah, the Akai did sound like samples (but rather "sharp" ones).

I had an HR-16 too. I'd be surprised if it wasn't as rare as the Akai now. That thing was built like a giant version of a cheap plastic calculator. The body of mine ended up breaking at the screw joints, causing the PCB button pads to "lift" from the board and ruin their accuracy. I think this was actually done by it's previous owner. I called Alesis, and the tech asked for my address and shipped me out a new plastic body within a few days, free of charge. I always liked some of it's sounds. My SR-16 is supposed to have some, but they never quite sounded the same. It's also got sort of a crappy "tinny" sound, like it has that "smiley face" consumer-appeal EQ curve on it. I've wondered if any of their stuff might have the ability to split a digital signal to either a S/PDIF output, or to an additional chip, which could convert it to one. They've got some of the common Alesis-branded DAC chips you see mentioned places.

The crazy workarounds back then were pretty educational, and as I mentioned, that had a very "unique" overall sound to them. Fortunately, it didn't last too long. The Roland 330/550 stuff arrived after a few years, giving me the ability to run live multi-output sample sequences, synced to FSK/SPP, and also had a mouse/CGA hookup, which was a bit ahead of it's time. The Ensoniq EPS stuff showed up later and brought the whole market way down in price, with lots more features.

You want to feel sorry for people- All the local guys I dealt with for rap production were afraid  of real samplers, all the way into the end  of the EPS16+ line. While I was on the 550 ,they actually used DigiTech delays with a few seconds of memory available for a single sample location. They used to add DigiTechs to get multiple samples, and I think they either only triggered from the click/pulse output on the 909's and stuff, or only on certain "short" voices. They would chain drum machines and crap to get more DigiTechs running simultaneously, manually trigger extra sample loops on each measure during the live mix to tape, or land things on 4-track and restart additional free-running sequences for the next pass. Their fear of the technology cost them about ten times what a 550 or Akai 900/950 may have run them. I usually had to accompany people to local studios, just to bring in their sample mixes and stuff I had no part in creating. Otherwise, they went to the more expensive "sampler equipped" studios and paid a fortune to sit around ripping vinyl into loops before the real session started.                                 

For a while, I was the only one in that genre of music here with a real machine, and most of them had way more money for it than me. There was good sample gear here, used by a couple composers and commercial studios, and a local friend doing R&B stuff, kept up with it more than I did, but he didn't deal with the same people. I fought my ass off  trying to get those guys to buy "real" gear, with floppies and all, but they refused. The Akai's were already common a couple states up the coast, but I guess we were "slow" here. Only a couple years later, one or two of them got EPS16+'s and MPC's, and all of the sudden, they were everywhere . I was partners with a guy a few years ago, where we had the ASR-10, a Korg Trinity, an MPC60II, and some "limited edition" SP12 with a brass nameplate on it. Everything in there was maxxed out "memory/option-wise", and he didn't even know how to use most of it, and didn't bother keeping most of the manuals. The computer & recording half of the place was even worse.  - nice town huh?

Sorry for the nostalgic rambling ;D,

George         

[DrBunsen]

Read 136 times it says at the top there :)

Ditto - analogue drum nut here.  One Simmons SDS-8 triggered from a 707 and a cardboard box full of SDS-V modules awaiting power supplies and extra mod knobs.  A couple of tweaky old 9v preset rhythm boxes (all discrete components) awaiting circuit bending.  One Mattell Synsonics.  And a sharp eye on ebay...

Got a bunch of bookmarks on building pads and triggers, and a box of piezos.

[Jidis]

DrBunsen,

That's funny, Synsonic pads were my first drums about 25 years ago, thanks to a "gimmicky" Buddy Rich commercial. Didn't take long to figure out they had no relation to real drums, so I bought a snare and went in for lessons. Wish I still had them though. ;)

The Simmons head for my pads was making a nasty ground buzz, years ago, IIRC. I may have enough junk now to open it and try to check/replace some stuff to make it work. It's got blank holes for MIDI, but the pads and stuff are on the PCB. It would be great to have on there, if anybody happens to have one with the MIDI option. I can check the guts to see what chips look to be missing, but there's probably a firmware image which I'd need to find too. I "thought" mine was an SDS-1000 (8 drums with one sampled sound for snare).

Take Care,

George 

[Jaicen]

I'm not sure if anybody is still interested in this particular topic, but I thought i'd give you all a quick update.

I got a bit sidetracked workin on a couple of projects for other people, but I found an hour this morning to do a quick 'test' of one of the drum circuits i'm working on. Basically, I wanted to make sure of a couple of things like, how the modules can be triggered, and if they'd be ok on 9v etc.

Anyway, I had planned to test the rimshot but didn't have the right components, so I built a clone of the DR-110 kick instead (Simplest of the Modules). On perfboard that took me about 45mins from start to testing, which is pretty good. On a PCB I imagine that would be about 15 minutes.

Worked first time using a 2N3904 with a gain of 170hfe. Produces a sound that's to my ears is identical to my real DR-110, nice & short with that 'clean' tone that 808 users love so much. I'm running it on 9v which gives a better signal to noise ratio (no self noise I could hear anyway) and slightly more output. No time to test any of the mods I plan to implement, but i'll let everyone know when I do.

I guess this was a bit of a waste of a post, but I wanted to share my success with everyone.  ::)

[stryd_one]

Way to go dude :)

I love it, can't wait till it's done, and I can copy it like a mad percussion plagiarist  ;D

[Jaicen]

Thanks for the support stryd, I only hope you're still around when I have questions about using the midibox core for a midi - trigger converter!  ;)

I'll definitely be able to give some more info on sunday night when I get back from my easter break, If possible, i'll upload some soundsamples to putfile too. Unfortunately, this is the the easy bit, that snare/hat design still scares me ;)

I've worked out how to get the maracas sound from the CR78 too, so i'm going to build my noise source and try that next. Small steps is the way forward ;)

[DrBunsen]

Currently the top bidder on a busted CR-68 here - if you need board scans when it comes in let me know.  The only problem with it seems to be the internal clock, and a DIN sync or trigger mod should fix that :)

[Jaicen]

An aussie in our midst eh? Still smarting over the ashes??(sorry, we rarely get to gloat over such things ::)).

I'd very much like to see some internal shots of the CR68. As far as I know, no schematic is available for this particular unit, so it will be interesting to get a look inside. I believe the voices are similar, but not the same as the CR-78, but again the schem for that is unreadable. As I think I said in an earlier post, i'm interested in the more esoteric tones like the guiro and tambourine. The kick is interesting as well, it's quite soft so it's good for ambient music.

OOh, i'm getting excited now, hope you win it! FWIW, if I had that, i'd use it as a sound module and attach MIDI triggers to it. The sounds are all triggered off the legs of one IC, so it's a doddle to use them as trigger points. Good luck!

[DrBunsen]

An aussie in our midst eh? Still smarting over the ashes??

Ah, that's something to do with sport, is it?

The sounds are all triggered off the legs of one IC, so it's a doddle to use them as trigger points.

Oooh, now you're talking.

[Nu-Audio-Science]

Just wanted to add my interest here too ;)

Just found out that i can get some spares from that company that did the internal MIDI mod for the DR110, They say they have enough to nearly make me a full kit and i can source the rest anywhere :)

Just need to find a second DR110 to hack it into.

Are you thinking of having some of these PCBs manufactured ?

I can probably cover something like five sets maybe more :)

[DrBunsen]

Oh I forgot my poor little Boss Dr Pad. 6 lofi ROM samples with much tweakability in a drum pad.  Apparently they bend nicely :-)

Right now it's out of service with a broken voice select knob, but it is definitely a lofi digital favourite.

[Jaicen]

Yeah I had the chance to get a DR-220 and a DR-Pad for a ridiculous low price, but at the time I couldn't stretch to it having just got my TR-505 to bend.  The 220 definitely sounds great bent, so i'd imagine the Pad will too. I'd be in there straight away!

NAS, by spares are you referring to the MIDI kit or the DR-110 itself? I've been looking for a spare voice board for a DR-110 for some time without success, hence the clone idea.

When I started this project, I was a little unsure what to do with it. So far i'm pretty sure I just want to make a standalone voice board, which can be triggered via MIDI. I'll probably be using my TR-505 to trigger it live, so i'm not sure wether to implement any kind of CV/accent control. I guess it would be a simple enough thing to add tho. Looking at the MIDI128 project here, that's probably going to form the basis of the MIDI trigger module.

I have no plans to make this a commercial venture whatsoever, at the minute I don't have the funds for something like that. I was just planning to make some PCB's at home, good old fashioned DIY ;)

[DrBunsen]

I'll probably be using my TR-505 to trigger it live, so i'm not sure wether to implement any kind of CV/accent control.

I realise a 606 != a 505, but I remember that instruments triggered off the outs on my old 606 would respond to accent.  Must put out a slightly stronger pulse or something.

I found the trig out points for a 505 documented here.  Same site has mods and trigger info for the Synsonics, 626 and HR-16