Analogue Drum Modules

[Sebo]

Thank you stryd_one, I'll check it out.

At the moment I'm working in a MIDI to Trigger interface to my new

DR-110. I want it to fit inside the box, so it have to be really small.

I modified some code I downloaded for a PIC16F84.

I will do some test soon. My big problem at the moment is the clap

trigger. The clap have 2 sounds one is triggered 3 times (the clap sound)

and the other is triggered one time after the others (reverb noise).

My coding skills are limited so I'm having a hard time doing that in a

way that don't screw the timming of the other triggers.

I want to make a simple DR-110 Bass Drum to test the triggers, what

transistor you people use instead of the original?

Also I scanned the DR-110 PCB to make a clone. I gonna use original

semiconductors on this one, but to experiment a bit, a reemplacement is ok.

Thanks

[Jaicen]

If you get a working voice board clone going, i'd be very interested! I've pretty much given up on my DR-110 modules, they all ended up being so large that I figured it would be easier to just build an 808 clone ;)

I did add sync in to my DR-110 though, which is nice.

The transistors I used in my prototypes were BC548C's which are the same as in the original if I remember correctly. You can get them from Maplins.co.uk and RSwww.com, so i'd use them if possible.

[Sebo]

Hi Jaycen:

The DR-110 is an exact copy (I scanned the original PCB then

I retouched a lot in Photoshop to get a usable copy).

The original transistors of the DR-110 are 2SC something

(I can remember right now). TR-808 transistors are 2SA733

and 2SC945. But the Alucinogen clone uses BC transistors.

I was planing to use same as the Alucinogen clone in the DR-110

BD, so I think BC548 are OK.

I was looking at the CR-8000 schematics and the sounds are very

similar to the DR-110 sounds. Interesting...

[Jaicen]

As it happens they're also very similar to the TR-808 (well, some like the hats anyway).

The real difference lies in the noise generator sections. The DR110 uses digital noise, and the 808 uses discrete transistors. The CR8000 uses the same noise generator as the 606 and CR78  I think.

[Sebo]

Hi Jaycen:

I'm not shure if my last post was posted :) my PC crashed...

In any case, that's was I was saying:

I'm far to finish the DR-110 clone. But I finished the PCB. I scanned

my DR-110 and worked the image in Photoshop to get something

usable. Is not tested yet (use it at your own risk), but I think is

error free (some extra checking woldn't hurt). The PCB is solder side

view !!!!!

I gonna build the clone soon.

I'm about to test the MIDI to triggers for the DR-110, but I didn't

solve the clap trigger yet.

[DrBunsen]

Go on - I dare you  ;D

Vintage Valve Wurlitzer Drum Machine with Tube Amplifier

[stryd_one]

I was tempted ;)

Here's a new one via matrixsynth:

You can find schematics here Amdek PCK-100 Percussion Synthesizer

It's not bad eh...3 waveform osc+lfo++2-stageenv on 3 IC's... Maybe you SDIY geeks will know how rare or substitutable the IC's are?

[Jaicen]

I've got one of those actually. I think the range of sounds is pretty varied, but the stock setting has the pitch of the VCO set a little too high, you can't get low lows out of it, but it is a lot of fun :>

There are even some SID like settings in there somewhere. 

IIRC, Amdek sold kit versions of Roland/Boss stuff, I think this is the PC-2 clone. There was a Handclap clone too, but I've never seen that for sale.

[stryd_one]

More drum schematic links for you :)

http://members.fortunecity.com/uzzfay/drumfire/df.html

Drumfire DF500

http://www.electronicpeasant.com/projects/ssdrums/ssdrums.html

The Electronic Peasant's Solid State Percussion Synthesizer Page

http://www.hylander.us/moogschematics.html

Schematics and Manuals

Handclap Section pt.1

Handclap Section pt.2

TS-204 Synth Section pt.1

TS-204 Synth Section pt.2

TS-204 Synth Section, Detail of the Modulation circuit

and a mod

How are your projects going guys?

[MTE]

And dont forget this one -> http://edrum.for.free.fr  PFozz´s linklist is great, enjoy ;)

[Sebo]

Thanks Stryd_One & MTE !!!

At the moment I stopped the DR-110 and 808 project a bit because

I'm trying to finish the TR-9090.

[TheAncientOne]

Just discovered this thread. I'm part way through one of the last of Trevor's 9090's. Waiting for my last batch of resistors from RS before doing the caps.

I found a couple of ols Syntom and Synwave PCB's uncased from a previous lot of building - even found the Maplin fron panel stuff. If the diagrams aren't on line. let me know where to put them.

They did a 'SynBal', too, a sort of metallic sound gen, got the drawing btu never made one up.

My first drum synth was in the 70's. I started with a PE design and kind of went mad from there. It used 7489's for memory, and battery back up, when I did it, was for hours only.

I'll try and find the file of analogue module designs.

And  an idea: there a quite a few telecoms racks going surplus now everyone is upgrading networks. There are a lot of double eurocard rack cases, with backplanes etc. Double euro with a double width front is not a bad drum module size. It would be easy to hack the backplane into power, trigger  and audio distribution, and have a set of replaceable drumsounds, say eight to a rack. Rather than use the PCB's, just make a piece of alloy the same size as a double card, and bracket the front panel and rear connectors to it.  My later drum sequencer drove this sort of stuff from a BBC micro's user port, (no velocity), then later from a BBC 1Mhz bus card with accent outputs as well, though I got over deep into prgramming it, and never used the messy end result much. I might have another go, now, having got a load of free BBC's.

Need to get some pics up.

I'll have a trawl through the diagrams box when I find it.

Mike

[Sebo]

Hi TheProf:

I'm becoming a little bit mad about analogue drum DIY, I want to build

more than my time let's me :)

At the moment I have 3 projects running (9090, 808, DR-110), but

to complete my set, I'm thinking in some extra modules, and those

E&MM modules seems OK. I have the articles for the line (Syntom,

Syntom II, Synbal, Synwave, Synchime) with PCBs. But the scan

quality of Syntom, Synwave & Synchime are really poor. If you have

good quality scans of them, please share them here (you can post

files going to Additional Options in the Post Reply dialog).

Also if you can post some sounds of the Syntom, will be great. I'm

looking for Laser, Hi-Q, Zap kind of sound (very electro), and I want

to know what the syntom could do.

Thanks.

[Jaicen]

Have you seen the DIY digital drum module, The Alpha Drum? I think it was printed in Electonics & Music or something. You can find it at http:// hammer.ampage.org.

I've been wanting to build one to circuit bend and have a rack of them, but as you say Sebo, time is short  ::)

[Sebo]

Hey!! the Alpha Drum are the exact module I was missing. I want to

make 2 or 3 (for a nice Lindrumm snare & hat).

I don't know when... But I gonna build them.

Thanks

[DrBunsen]

http://www.electronicpeasant.com/projects/ssdrums/ssdrums.html

The Electronic Peasant's Solid State Percussion Synthesizer Page

Brilliant idea for knobs!

[TheAncientOne]

Hey!! the Alpha Drum are the exact module I was missing. I want to

make 2 or 3 (for a nice Lindrumm snare & hat).

I don't know when... But I gonna build them.

Don't build it just yet a while. The D->A converter in the design is pretty horrible, and could be better replaced by and R/2R ladder design as in the MIDIbox AOUT LC. I'm definitely going to have a try at that, as well as the simple mod of using more modern (bigger),EPROM, and adding some selector switches to allow different sound in each drum.

One thought I've had that one of our more mathematical members might be able to help with: If we did go for a multiple resistor style D->A, then it might be better to work up a logarithmic data model for the samples. This would give better dynamics from 8 bit samples, and could be made as a 'post processor'  program taking output from, (say), Audacity. Simplay make your sample loops in audacity, and then process them into the required raw format for the EPROM.

Mike

[Sebo]

Hi TheProf:

I think it's gonna take me some months until I going to start building

the Alphadrum modules. But I'm researching all info I can in the

meantime.

The R2R ladder D/A seems a great idea. To use bigger EPROMs

I think we don't need any mod to the circuit, the clock stops when

the EPROMs reachs the end. The selector thing is great too, could we

use the chip enable pin to do that?

About non linear samples, I don't know if the original circuit is linear,

I have to check that. But taking in account that most designs at that

time uses mu-law samples and converters (Oberheim, Linn) as oposed

to linear samples (Simmons), I think the D/A of the Alphadrum could

be non linear. Anyway If want to make a D/A non linear we could

borrow a Oberheim or Linn design. And we can use the original EPROM

images or made our own (any good wave editor could save in 8bit

mu-law format).

Another nice mod will be a decay control. It could be done with a few

resistors a cap and a pot added in the gate signal path (before or after

R5 in the schematics). I think I have a simple circuit to do that (I have

to look at it).

Let me know about your advance.

[Jaicen]

The AlphaDrum is a linear design, it will just read off the data to the end then stop.

I'm sure it would be a relatively easy thing to do to copy the DAC of an old machine, but then you're losing the simplicity, and that's a lot of the attraction with this thing.

The envelope section of something like the 505 would be easy to implement, in fact that's probably the least difficult part of the project!

Personally, I don't want to improve the fidelity any, I've got plenty of nice clean sample machines. A bit of grit never hurt anyone ;)

[TheAncientOne]

To use bigger EPROMs

I think we don't need any mod to the circuit, the clock stops when

the EPROMs reachs the end. The selector thing is great too, could we

use the chip enable pin to do that?

Not quite: the counter is reset on trigger, and runs until the Q12 output of the counter goes high, which means it cranks out 4K (4096) 8 bit samples, then stops.

We could use a 27256, or 27512, and get 8 or 16 x 4K drum samples, or we could use a longer counter, and get say 8 x 8K samples from a 27512. If we went for bigger EPROMS we could increase pro-rata. It might make more sense to use flash ROMs too, they can be pulled out of old motherboards for free and don't need UV erasing. I would simply put some pull up resistors and switches to ground on the remaining unused address lines, allowing binary selection, or use one of those neat binary encoded rotaries or, for a small number wire up a rotary switch to suit.

About non linear samples, I don't know if the original circuit is linear,

I have to check that. But taking in account that most designs at that

time uses mu-law samples and converters (Oberheim, Linn) as oposed

to linear samples (Simmons), I think the D/A of the Alphadrum could

be non linear. Anyway If want to make a D/A non linear we could

borrow a Oberheim or Linn design. And we can use the original EPROM

images or made our own (any good wave editor could save in 8bit

mu-law format).

Looking at the resistors in the original converter, we have:

4 x 301 K in parallel =    75.25K

2 x 301 K in parallel =  150.5K

1 x 301K                =  301K

2 x 301K in series    =  602K

1 x 1M2                = 1200K

2 x 1M2 in series    = 2400K

1 x 4M7                = 4700K

2 x 4M7 in series    = 9400K

Which looks like straight binary to me. Initially, let's try a binary R/2R ladder, then we can upgrade that to a uLaw once we've got a standard device worked out.

Another nice mod will be a decay control. It could be done with a few

resistors a cap and a pot added in the gate signal path (before or after

R5 in the schematics). I think I have a simple circuit to do that (I have

to look at it).

Let me know about your advance.

That's a cool idea. Perhaps a 'bounce' control could be added, if need be, for those that crave those 'synare' effects.

@Jaicen

I was just going to use 16 resistors, as in the MIDIbox AOUT LC, or the AVRsynth, and get a slightly better binary than the original, which is  rather messy.  A log law device is just a different bunch of resistors, but might give a better dynamic range.

You're right about the dirty/grainy sound. Sounds a lot less sterile.

Mike

[Jaicen]

Agreed!

I would say however that the dynamic range is not really an important concern for me. In machines like the 505 and 626 (probably the 7x7 boxes too), the the samples are hard limited to maximize the volume and reduce the signal to noise ratio. The natural envelope of the hits are then restored after the conversion to analogue. If a similar scheme was adopted, it would allow much greater flexibility in terms of pitch and dynamics, as well as noise specs. I think it's important to note that if you pitch up the samples, it will reduce their length so the envelope is also affected.

[Ashiman]

what about a custom 909 snare module ~ attempt to CV up some parameters? Found this , nice read: http://www.soundonsound.com/sos/apr02/articles/synthsecrets0402.asp?print=yes

[TheAncientOne]

Take a look at http://www.introspectiv.eclipse.co.uk/.

On the site there are PDF's with the circuit diagrams. A bit of dilligent Googling wil turn up the originals too.

Having done a lot of work with modulars in days gone by, I can say that it doesn't take that much parameter changing to loose the 'drum' sound altogether.

I'd certainly try playing with a few parameters mildly, (like you can on the free 'ReBirth' - you can get it here http://www.rebirthmuseum.com/). But as much fun and effect can be had by post processing the sound, through controlled delays and filters.

Best wishes

[Ashiman]

yeah it has versatility [well] beyond the 808 snare , this is why I started looking after it. I found Trevors website years ago, instead of real machine listened only samples yet, overall I like the 808 bongos much better than the toms in eitherone . So I wont mess with the complete 909 kickdrum howitzer : )) My particular targets are the snap and tone parameters. Yeah and builders, be sure to put in ST semicon manufacted 072 , any other TL can just bite dust compared to it. ST is teh Signetics of TL series ;D

[TheAncientOne]

Did you find this too?

http://www.colinfraser.com/tr909/my909.htm