Circuitbenders Forum
Circuitbenders Forum => Drum machines => Circuitbending discussion => Korg => Topic started by: Circuitbenders on April 03, 2007, 09:34:28 PM
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Does anyone have any information about the sampling board for the Korg DDD-1 drum machine. Has anyone ever even seen one?
I've bent a few DDD-1's but i've never seen one with a sampling board installed. Whenever you see them on ebay they are usually listed as 'sampling drum machine' or something but if you ask the seller to look to see if it actually has the sampling board then it never has it.
I'm beginning to think that its all a cunning fabrication. :-\
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HI,
I have a DDD-1 that I think has the sampling board installed. I haven't used it, but certainly looks like an optional board!
Happy to send a pic along.
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I think the sampling board slots in under that cover than unscrews from the back, at least theres some kind of rails in there with an edge connector on the main board inside. Also if you try to select the sampling option on one without the board in it nothing will happen, you just can't select that option.
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I have had a Korg DDD-1 for almost 20 years now and I had never seen one with the sampling board until recently. I found one with the sampling board on Craigslist and it is a lot of fun.
Sure, the sampling is not as sophisticated as what's out there now but it was nice to finally find one!
If anyone wants some pics of the board let me know and I will see if I can get some.
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A sampling board went on ebay a week or so ago for more than you'd pay for a DDD-1!
Am i right in thinking it slots into those rails through that cover on the back?
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Yes, I believe that is where it goes. I haven't opened up the "new" one yet. I did test the sampling feature with (of all things) my Casio SK-1 and it is a lot of fun.
I would like to see someone reverse-engineer a sampling board for the thing. Maybe it could incorporate more samples or longer sample times.
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I would like to see someone reverse-engineer a sampling board for the thing. Maybe it could incorporate more samples or longer sample times.
Shouldn't be too hard. Thanks to the JEDEC pinout standard you can mostly put in a double size ram/rom chip with only one or two lines/traces on the board to modify.
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On a DDD-1 without the sampling board installed you can't even select the sampling option on the menu grid, the buttons won't work.
Would this be because it needs to detect memory or it won't work? Or maybe its as simple as installing teh board closes a switch.
It seems unlikely that the sampling apart of the OS would be on the extra board.
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If someone with a sampling board could post good, high-res pics of both sides of the board, I might be able to figure a few things out.
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Hey Y'all, new 2 the forum here but I come bearing gifts....
http://kittenpurse.blogspot.com/2008/10/new-toy-korg-ddd-1-sampling-board.html
It has a pic of the sample board with a pretty Hi-Res pic up too.
Hope this helps you in your fabrication/modding!
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So on the sampling board, we have:
A mask-programmed CPU (65010)
64k x 8bit memory
A PIO (8255)
A 2069AD VCF/VCA similar to the ones in the Poly-800
A compander (uPC1571)
A VCA (13700)
Some glue logic and some opamps, presumably for preamps etc
A comparator (311D)
Nothing jumps out at me as being a DAC or ADC. It might be that the DAC is implemented by one of those resistor packs, like in the Roland drum machines, and the ADC uses the DAC and comparator.
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Nothing jumps out at me as being a DAC or ADC. It might be that the DAC is implemented by one of those resistor packs, like in the Roland drum machines, and the ADC uses the DAC and comparator.
I'm pretty sure it needs no DAC because it simply uses the existing one(s) in the DDD-1.
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I'm pretty sure it needs no DAC because it simply uses the existing one(s) in the DDD-1.
You'd need an ADC though,and quite often they're implemented with a DAC and a comparator.
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A sampling board went on ebay a week or so ago for more than you'd pay for a DDD-1!
Am i right in thinking it slots into those rails through that cover on the back?
I believe I bought that one. $125.00 I think I paid for it.
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UUH UUH UHH thats what that is.. I was at my very very secret electronics dumpster area today.. I found various nice items including a battered but working Korg DDD-1.. It has the sampling board installed ! + 4 rom chips "Gate Reverb 1" and Latin 1,2 and 4.. Unfortunatly it does NOT have the ram board.. So I can't sample ??? I think ??
Also the open hihat, cowbell and cabasa are very very faint sounding.. Do someone have a SERVICE manual for the DDD-1 ?!?!?!?
Also does anyone have a suggestion for a replacement of the battery ?
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You can sample without the RAM card.
I don't have the RAM card and I have sampled a few times.
I think the samples disappear when you turn it off but if you have the RAM card you can store them there.
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Yeah I found out I could sample. If your sample dissapears then the sampler batteries are dead.
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What about that battery question? One of my DDD-1's has finally lost its memory. I remember reading something about changing the battery in the manual but I don;t have easy access to it right now.
Does anyone know off-hand which batteries I should feed these things?
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CR2032 for the pattern memory backup i would imagine.
If the sampler board has its own battery i don't know what that one would be.
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There's ofcause the CR2032 but there's also some other batteries in there.. Looks very much like re-chargeable batts. but I think they're not.. I'll take a pic when I find my cam.. :)
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Actually you CAN sample without the RAM card. I thnk the samples are stored in the internal memory.
Speking of internal memory, I have been under the impression that the internal memroy was the old-fashioned kind where you had to give it a constant supply of voltage from a battery. Last night I opened up one of my DDD-1's to change said battery since it has been losing its memory upon shut-down. Imagine my surprise when I fould no battery in the compartment!
Now, I have had this particular machine for about 20 years and never had a problem with memory until a few months ago. There were patterns, settings, and songs stored in the thing from 1990 or so up until recenlty. I always thought it was strange because I had heard that the battery only lasts a few years but I figured it wasn't broke so I didn't try to fix it (some circuit-bender I am, huh?).
Anyway, my question is how did it keep its memory for so long with no battery? Did someone sneak in my house in the middle of hte night and steal my battery out of the thing? (I'll answer that one - nope.. They would have taken the whole machiine or perhaps the MiniMoog or something really worth stealing...)
I am baffled.
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OK, so maybe that explains my situation. Where is the CR2032? I found the rechargeable-looking battery pack one one of my machiens but not in the other.
Is the CR2032 (or whatever it is) easily accesible? I can't figure out where it is.
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And, LoFi-Ninja , I won;t try to get the location of that super secret dumpster from you but if ever wanted to share I am not above dumpster diving.....
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Cumulus the CR2032 is on the motherboard itself.. It's one of those "Not accessible by user" kind of deals.. I'll see if can find my camera and snap some pics for you today.. Your storage problem should just be that the battery is dead. If not maybe you did a factory reset on the DDD-1 by accident.. It only requires 2 buttons to be pressed so it's a possibility.
It's not about you sharing with others, it's if I share with you. Then there's less stuff for me. ;D
But seriously go "dumpster diving" You will find so much treasure.
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Thanks. I guess I'll have to take it apart to access it.
Dumpster diving can be pretty lucrative. I have not found much in the way of electronics and certainly never any drum machines but I have found many other useful items.
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I just got a DDD1 with the the sampling board through the post to modify, and it seems to have the standard CR2032 on the board for the pattern and setup memory, and in that mysterious compartment you can open up on the bottom of the thing theres a battery pack connected to the empty connection block you can see in there.
It appears to be two AA batteries of some sort and is labelled 4.8V. The one in this machine is completely dead but i can only assume that this battery is for the sample memory backup as you don't see it in DDD1's without the sampling board.
EDIT: Well heres a weird thing. This DDD1 appears to sample fine but either the D/A convertor is doing something not quite right or i'm doing something wrong. I've followed the sampling procedure in the manual and it appears to work, but all i hear when i play back the sound is the kind of high pitched digital noise you used to get loading games from cassette on a ZX spectrum. Its like its playing back the digital data straight from the RAM rather than converting it back to audio. All the other sounds work fine so i'm thinking theres probably a problem with the sample DAC, unless i'm doing something completely wrong. Anyone got any ideas whats going on here?
While i'm here, does anyone know what the TEST switch on the sampling board does?
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Ghost post resurrection!
The battery is just 4x1.2 v nicad. Old enough that it was still called cadnica.
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"Cadnica" was the name of a particular manufacturer's range of NiCad batteries. They will be pretty old, by now.
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I have the sampling option on mine. It works perfectly if you replace the NiCad battery pack. I tried it with the original battery and I got the same digital noise you described. I replaced the battery with four AAA NiCads in a battery holder. Now it works great and the batteries can be replaced if needed. Haven't bent it yet though. Anyone know where to find info on the ROM pin outs? Or does it not really hurt to pock around on the two ROM chips?
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so it actually needs battery power to sample properly, instead of it being just for backing up the sample memory?
Wouldn't that indicate that something essential like the RAM is isolated from the power rails of the machine itself and is permanently battery powered? That seems like a very odd way of doing things. :-\
If you avoid the positive power pins on the ROM's you should be alright. If you don't have a pinout then i'd imagine you can find them pretty easily with a meter.
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I'm just glad it has some way to hold sample memory. My Boss RSD-10 loses the sample after power down. Wonder if there is a way to back it up? Oh well, that's another thread. Thanks for the tips about the ROMs. I think I'll start with my old DDD-1 that's full of roach guts and God knows what else. Still runs like a champ though. ;D
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The ROM pinouts will be standard JEDEC, as will the RAM chips. You can replace the failed nicad with a nimh battery, because they are a straight drop-in replacement.
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Hello!
The DDD1 service manual (which is easily found online) has a nice description of the sampling board, as well as full schematics, pin-outs for connectors, etc, etc.
It turns out it's an incredibly simple affair, and completely isolated from the main system. Really, the communication consists of three signals, whether sample or play, which of the two banks to play, and when to start doing it.
This communication goes through a 82c55, completely standard chip that puts three 8-bit registers on a 8085-style buss.
The sampling and playback itself is implemented with the gate array that also controls the RAM, but if one were to reimplement it, one could basically ignore whatever Korg did and build a sampler based on those three signals, no need to reverse engineer it bit-for-bit. Samplers that match the sophistication of the Korg board are basically a set of up-counters and some battery backed RAM.
The 82c55 is also used to generate two control voltages, one for the pitch and one for the amp envelope, so you can set these from the main interface. You could duplicate the Korg schematics if you wanted to, or just handle the incoming digital values. Or ignore them -- the sampler board just passes analogue audio out.
HOWEVER
That's not what I'd do if I were to do it. No.
First I'd make a ROM emulator. Basically, you have a microcontroller with some memory, either flash chips or SD card, that pretends to be a ROM. This is fairly trivial, especially given that a modern ARM Cortex-M has I/O that's 10x faster than any signal in the DDD1.
Then I'd make a small board which plugs into the sample board slot, and takes the audio signal and the digital signals coming in from the main board and goes to the ROM emulator. The DDD1 thinks it's talking to the sampler board, and tells it to start sampling. But it's not sampling into battery-backed RAM in the sampler slot, it's sampling into the ROM emulator. So instead of assigning the pads to the sample slots to play sounds, you assign them to the ROM slot the emulator is plugged into. And now, instead of two slots for samples, you've got however many sound slots are on a ROM card. Multiplied by N, if the ROM emulator presents some interface for bank switching.
The only thing I'm a little hazy on is how to select which sound to sample into, but the ROM emulator could probably tell from the address that was last accessed -- i.e., the sound that was just played. So you assign a pad to the ROM slot you want to sample into, hit it, enter sampling mode, play your noise into the DDD1, and the sound is now in the ROM emulator. No changes to the UI necessary, and most likely no irreversible physical changes to the DDD1.