Category Archives: Drum machine

LinnDrum, SCI Drumtraks 400

LinnTraks – SCI Drumtraks with LinnDrum samples

I occasionally get asked to burn some eproms. Twice I’ve been asked to fix LinnDrum sounds for Drumtraks. The good thing about many old drum machines is that they use the same type of eproms and audio compression. For example, you can take the kick eprom from a LinnDrum and put it directly in a Drumtraks.

In some cases, two sounds share the same eprom. One example is the Drumtraks where the first 4 kB in an 8 kB eprom is the clap and the last 4 kB is the tambourine. In the LinnDrum each sound has a 4 kB eprom each. Most probably because the larger the eproms were, the more expensive they were. And the Drumtraks is a couple of years newer than the LinnDrum, hence the larger eproms. So the thing is that sometimes you have to merge and sometimes you have to split. And sometimes it just fits. This process is 100% non-destructive, not a single byte is changed!

Anyway “Thomas Q-force” asked me to replace all sounds except the ride and crash in his Drumtraks with LinnDrum samples. He chose the standard sounds with the exception of the toms, where he selected the alternative, but official, “tom7”. Sounds great in my opinion! The LinnDrum sounds are much better than the stock Drumtraks sounds. This really shows the potential of the Drumtraks and I find it strange that it’s so cheap compared to a LinnDrum.

View video on YouTube (opens external site in new window)

LinnDrum

LinnDrum midi kit from Dtronics

I recently ordered a “Linnterface” midi kit from Dtronics and a kit for the Juno-60 from them as well. To be honest, a big part of the joy with the LinnDrum is using the internal sequencer and its’ shuffled timing . You can always sync it to your DAW using clock pulses. But in some cases it’s convenient to have midi.

The kit is not as advanced as the Forat or JL Cooper ones, on the other hand it’s just a fraction of the price. It simply has a GM midi-mapping and supports only note on/off. It’s only midi in, not out.

It works by simply hijacking the signals between the cpu-board and voice board of the LinnDrum.  This is done by placing a new midi board inside the LinnDrum, disconnect the flat cable between the LinnDrum’s cpu board and voice board an connect it to the midi board instead. From the midi board a similar flat cable is then connected to the voice board. The kit comes complete with all mounts and a midi connector and no non-reversible modification is required on the LinnDrum. You have to solder power and ground to the kit, but thats all.

The first midi board I got had some kind of problem, when the LinnDrum was turned on, all leds lit up and the numbers 00 were shown. This was very scary – had I destroyed my LinnDrum? Panic! I emailed Dtronics who were very helpful and immediately sent me a new board. I installed it and it has been working flawlessly ever since. I recommed these guys, the do great products and are very supportive!

I decided not to write a step-by-step guide of my installation since there’s already a nice one at Dtronics web site.

Roland Juno-60, Roland TR-626

Roland Juno-60 & TR-626

Today I did a great package deal, bought a Roland Juno-60 & TR-626.

My Roland Juno-6 is one of my absolute favorite synths, and nothing I’d ever sell – but it has one “problem” – no patch memory. To be honest that isn’t exactly a show stopper –  it’s a simple synth, and writing down the settings on paper isn’t that hard. However, when a Juno-60 in about the same condition appears locally for the same price I paid for the Juno-6, “upgrading” to the Juno-60 was a no-brainer.

By incident, the guy was parting with all his stuff and also offered me a TR-626 as a part of the deal. To be honest, I don’t know what to do with it since I’ve got the heavy digital machines like the LinnDrum and Oberheim DMX, but it has actually grown on me. It actually sounds quite gritty and louder than the beige box suggests…

Korg Polysix, LinnDrum, Roland Juno-6, Roland JX-3P, Synth

Syncing LinnDrum, Polysix, JX-3P and Juno-6 with Logic (or other sequencer) using ReCycle files for external clock

Download RexSync files

The longest title of a post so far, but it describes exactly what this post is about. Syncing those vintage instruments with a modern sequencer without any additional hardware. The only thing needed is a sound card with more than two outputs.

How the vintage stuff works

In this tutorial I’ll be using three different instruments. They all have different kind of functions that deal with time. The LinnDrum is a drum machine and therefore has a built in sequencer which you can set at a certain BPM. The Roland Juno-6 has an arpeggiator with a simple slider – you never know the exact BPM it plays back on. The Roland JX-3P has a very basic 16 step sequencer which also has a simple slider and therefore unknown BPM.

For the instruments to know when to hit the next note or drum sound they have a built in clock. The clock generates pulses, and a pulse is simply 5V for a couple of milliseconds.

All the instruments each have one input jack at the back allowing us to feed them with our own pulses instead of the ones from the built in clock.

The Rolands are the most simple ones. Each time you feed the Juno-6 with a pulse in the “arpeggio clock in” input, it plays the next note in the arpeggiator.  The JX-3P works in a similar way, feed the “seq trigger in”  with a pulse and it plays the next note in the programmed sequence. This means that if you want your sequence or arpeggio to run play 16th notes, you just feed it 16 pulses each measure.

The LinnDrum works in a similar way, but it expects 192 pulses each measure to its “sync in” input jack. This might sound like a lot – and it is. If you listen to the sync signal sent to the LinnDrum it’ll sound like a very loud, annoying buzzing sound, whereas you in a 16th pulse signal would hear each pulse as a “tick”.

In addition to the sync in jack, the LinnDrum also a sync out jack. Back in the day, when recording a song with a synced LinnDrum, you’d do like this:

  1. Connect the sync out from the LinnDrum to your mixing desk, preferably to the last track, eg 24. The reason for putting it at 24 is that the signal is very strong, and could “leak” to the neighboring track (23). Track 23 might have to be unused of this reason.
  2. Run the LinnDrum for a little longer than the song duration and record the sync signal to that track.
  3. Connect the output of channel 24 to the sync in on the LinnDrum which would make LinnDrum sync to the recorded track.

To sum it up: External syncing of these old instruments work in a very simple way – you override the pulses from the built in clock with  your own external pulses.

How my convenient solution to this works

So, from where do you get the pulses? There are hardware solutions like the Doepfer MSY-2 available, and software solutions like AU/VST sync generator plugin.

My solution is very simple and convenient. I’ve sampled a clock pulse from my LinnDrum and created a couple of Recycle files that each are one measure long. These Recycle files has pulses from 1/4 note up to 1/192 note. As you probably know, Recycle files are like Apple Loops, they automatically adjust to the tempo of the sequencer by using a “slicing” method.

How to use (in Logic)

  1. Create a new mono audio track.
  2. Set no input and choose the output to eg output 3 of your sound card.
  3. In your sound cards mixer application, make sure that output 3 isn’t patched to your stereo output. You don’t want to listen to the sync signal, it’s quite annoying.
  4. From the output 3 jack of your sound card, connect a cable to the sync in on your instrument.
  5. Drag and drop one of the Recycle files to the track. You’ll get an error message, here it’s important that you choose Don’t fix, otherwise Logic’s “fix” will make it go out of sync.
  6. Press play in Logic and hopefully the instrument will start to sync!

Roland Juno-6 instructions

  1. Insert the cable with the sync signal in “Arpeggio clock in”
  2. Turn on the arpeggiator
  3. Try to play on the Juno-6 (nothing should happen)
  4. Run your sequencer
  5. Try playing again, arpeggiator should now sync to the sync signal

Korg Polysix  instructions

  1. Insert the cable with the sync signal in “Arpeggio trig in”
  2. Turn on the arpeggiator
  3. Try to play on the Polysix (nothing should happen)
  4. Run your sequencer
  5. Try playing again, arpeggiator should now sync to the sync signal

Troubleshooting

Q: Nothing happens!
A: Make sure that the sound card’s output really outputs the sync signal.

Q: I can’t stand the noise!
A: You have to configure your sound card not to include the audio output that’s used for the sync signal in the master stereo mix. On my sound card, the RME Fireface 800, this is done in the Fireface Matrix.

Q: Sync is not synced!
A: The output level of the sync signal is important. A level that’s too low can make the instrument miss certain pulses.

 

LinnDrum

LinnDrum bought

I just scored a LinnDrum on eBay. It’s located in NYC and hasn’t got Midi. My plan is to try to have the seller to ship it to Forat in California that hopefully can add the Midi kit and then send it to Sweden.

Drum machine, Oberheim DMX

Battery mod and Midi upgrade in Oberheim DMX

Today I did two things on my DMX that should have been done long ago.

First task was to solder in a new battery. The old battery was removed a couple of months ago, but I never put in the new one (bought from Electrongate).  Since I don’t think it’s a good idea to solder the new battery  in the same spot due to possible leaking disasters, I soldered two new wires. The battery was then placed in the bottom right corner and insulated with tape.

A non working chinese iPhone charger cable was used. The battery is placed down to the right, far away from the board.
A non working Chinese iPhone charger cable was used. The battery is placed down to the right, far away from the board.

The next thing to do was installing the Midi upgrade from Electrongate. My Midi upgrade was actually a special order – normally you place the Midi jacks on one of the walnut side panels. I didn’t want to do it for two reasons;

  1. I prefer to have all connections at the rear and second
  2. And most important – mine are mint. It would be shame to drill in them

So I mailed Paul, the owner of Electrongate, asking if it was possible to get the Midi jacks in a breakout box instead. To avoid drilling holes, Paul made a special cable that goes from the Midi board to the 12-pin Molex that was used for triggering. Then the breakout box was connected to the trigger Molex.  A very neat solution – the trigger in functionality was sacrificed – on the other hand I don’t need it when I have Midi.

This breakout box is a special order. Since the walnut panels are mint on my DMX I asked Paul for an alternative. He suggested to use the trigger input port back to get the midi cable through without drilling.
This breakout box is a special order. Since the walnut panels are mint on my DMX I asked Paul for an alternative. He suggested to use the trigger input port back to get the midi cable through without drilling.
This cable is also part of my special order. One side goes to the midi card, the other goes to the cable that is connected to the trigger Molex.
This cable is also part of my special order. One side goes to the midi card, the other goes to the cable that is connected to the trigger Molex.

Installing the kit is fairly straight forward, there’s an excellent guide with photos that is very simple to follow (so I didn’t take any photos). My DMX had the memory upgrade board, in the guide the upgrade is performed on a non memory upgraded DMX, so there were some differences, however – they are pointed out in the text. The Midi board replaces the memory upgrade board and a bonus is that the Midi board actually upgrades the memory as well.

The midi upgrade card itself.
The midi upgrade card itself.

The installation procedure is mostly about taking chips from one place (the main board or memory board) and putting them on the Midi board. I recommend having both an IC puller and a small flat screw driver for this. The hardest part of the upgrade is soldering two tiny wires (“E1” and “F1”) to the main board. It was hard because in one case you have to solder the wire directly to a copper lane, in a very tight place. Another challenge is to cut the copper lane next to it, and then avoid soldering the wire over the cut so that the cut isn’t cut anymore.

I’m not a soldering expert, but if you know someone that can do it for you, or if you live close to Paul, pay him to do it for you!  It took me a couple of hours, and I wasn’t very comfortable cutting and soldering on such an old expensive piece. On the other hand, doing such stuff is the best way to learn.

I took the DMX back to the studio and connected the Midi – it worked flawlessly! Even though the DMX is very fun and easy to program, it’s just more convenient to have Midi. I really feel that I have to modify my Boss DR-110!

Drum machine, SCI Drumtraks 400

Miami Vice snare for Drumtraks, LM-2 and other drum machines

[soundcloud]https://soundcloud.com/nattvardcom/snare-demo[/soundcloud]

Today I spent a couple of hours converting a wav-sample of Jan Hammer’s snare drum to my Drumtraks.
Download it here VICE-SNARE.ZIP, and read more about it below (this is the readme.txt included in the zip).

 

Jan Hammer's Miami Vice snare installed in my Drumtraks
Jan Hammer’s Miami Vice snare installed in my Drumtraks

Jan Hammer’s Miami Vice snare for vintage drum machines
——————————————————-

BACKGROUND STORY
This is the legendary snare that Jan Hammer used on several Miami Vice tunes like the Main Theme, Chase, Last Flight, Tubbs and Valerie, to name a few…

I’ve heard rumours that Jan himself sampled a real snare and put it in his Linn LM-2.

A couple of years ago I found a file called VICE-SNARE.WAV in a Miami Vice forum some years ago and saved it on my hard drive. This wav is a heavily reverberated recording, probably from the output of a Linn LM-2. Getting the original EPROM data would be a dream come true, but this will have to do!

TECHNICAL INFO
These are the steps I’ve performed:

1) Resampled the file to 24 000 Hz, which is the normal sample rate
2) Cut away the first 4096 samples, because this is the length that the snare has in the Linn LM-2 and SCI Drumtraks. I discovered that this is just the length needed, the rest is the reverb tail.
3) Converted the wav to the special audio format that these drum machines used using WAV2DMX from Electrongate
4) Saved the final result to a bin file. This can be burnt to a 2732 EPROM if you have a Linn LM-2. For the convenience of the Drumtraks users, I also joined it with the Linn LM-1 rim (downloaded from Electrongate) that can be burnt to a 2764 EPROM. On the Drumtraks, the snare and rim shares the same EPROM.

TIPS
The sample has a very abrupt end, and this is probably how it originally was. Jan used reverb, like most engineers did at that time, to mask this. If you listen to the recordings, you can hear that there’s a lot of reverb on every one of them.
Another thing that is important is the tuning. Both the LM-2 and the Drumtraks allows tuning, and you can hear on Jan’s recordings that the tuning varies from song to song.

FILES
VICE-SNARE.WAV – the original file found on the Miami Vice forum. This is probably sampled from his drum machine (Linn LM-2) and fed in to a reverb unit.
VICE-SNARE cut.WAV – this is what’s left of the above file, the first 4096 samples.
VICE-SNARE.BIN – the above file converted to the drum machine format. This should be used if you have an LM-2.
VICE-SNARE_LM1-RIM.BIN – the above file joined with the rim sound of the LM-1 (this is not sampled, it’s the original binary data). This should be used if you have a Drumtraks
VICE-SNARE demo.mp3 – short demo tune recorded from my Drumtraks. First a beat with a reverberated snare. Then all the possible tunings of the snare are demonstrated.

Credits to Jan Hammer for creating it in the first place.
Credits to the guy who uploaded the

Converted by Carl Jakobsson, http://www.nattvard.com/cmi , 10th November 2013

Drum machine, SCI Drumtraks 400

How the hihat in SCI Drumtraks works!

I just wanted to share how the SCI Drumtraks creates the closed hihat (ch) sound from the sample that is actually an open hihat (oh).

The hihat chip in the Drumtraks is a single 2764 containing a whopping 8 kb of samples.  Remember that electronics where much more expensive back then, and costs must be cut. One method was to use the same sample for the oh and cc. This was the case on the Linn LM-1, Oberheim DMX / DX,  Drumtraks and probably a lot of other digital drum machines from this era.

The trick is to use the last part of the oh sample and add some envelopes to it. Below is the Drumtraks hihat chip loaded in Adobe Audition.

The red marker marks sample 4096, which is exactly half of the total 8192 samples. It's approximately here the ch starts.

The red marker marks sample number 4096, which is exactly half of the total 8192 samples. It’s approximately here the ch starts. But, when recording the ch, it doesn’t look exactly like that. Take a look at the recorded audio below:

This is the ch recorded, as you can see an envelope is added by the Drumtraks to fade it out.

To make the ch fade out quickly, an envelope is added by the Drumtraks.  If you don’t believe me, compare this image to the first one, the peaks are easy to identify.

What about the oh, does it only play until sample 4096? The answer is no, the oh plays the whole 8192 bytes. Take a look at the screenshot below:

First part is the oh recorded from the Drumtraks. Last part is the data from the chip. As you can see, they are 'identical'.

The first part is the oh recorded from the Drumtraks. Last part is the data from the chip. As you can see, they are ‘identical’. This means that when the oh is played back from the Drumtraks, the whole sample is used.

Notice how different it sounds when processed by the Drumtraks, and that’s the reason for having a Drumtraks. 🙂