Category Archives: 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)

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


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

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!

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.

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.

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, , 10th November 2013

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. 🙂

Axel F with JX-8P and Drumtraks

On the forum “99musik” where all the Swedish synth nerds hang, there was a thread titled “Axel F with different synths”. When I saw that, I recalled that I about half a year ago while drunk did a test recording with the JX-8P and Alesis HR-16. Everything was played from memory so the key is not right, the tempo is quite right.

I opened the Logic-project and realized that the drums sounded like crap. They needed to be replaced. For this I had two choices, the Oberheim DMX or my newly aquired SCI Drumtraks. Since I haven’t installed the midi mod on the DMX yet and the SCI Drumtraks kick and snare are more Linn-like, I chose the Drumtraks. My JX-8P was not connected so I decided to use the old recording and just loop it. Would of course have been more 80’s to play it live! Here’s the result:


Both the brass and bass are stock patches from the JX-8P. All drums are stock Drumtraks. Note how I test the different the different sounds on the percussive channel of the Drumtraks in the end. Claps, tamb, cowbell and cabasa are on the same channel and cannot be played simultaneously. The delay is a classic 80’s trick to get around that limitation.

The thread on 99musik


TOP853 programmer arrived

Today my TOP853-programmer arrived from China. It’s a cheap EEPROM-programmer that I intend to use for programming EPROMs for my Drumtraks.  At $40 it’s worth taking a chance, but I’ve heard others that have had great success with them.  I bought it from “BuyInCoins” and the delivery time was less than three weeks to Sweden. The thing to be aware of is that the TOP853 doesn’t work with 64-bit operating systems. That’s actually not a problem since I have a virtual Windows XP-machine that I use for a lot of old skool stuff.

Contents in the TOP853 box (USB cable was included but is not in the photo)
Contents in the TOP853 box (USB cable was included but is not in the photo)

In the slight dented box was the TOP853, a USB cable, a small cd with drivers + software and lot of documentation in Chinese. I ignored the cd and manuals and went directly to the TopWin download page (also in Chinese). The download of a few megabytes took about 10 minutes! I started the installation and chose English (should be Chinglish) and the installation started. After the installation I started the software which couldn’t find the TOP-programmer. I looked in the Device Manager and there was an exclamation mark on it, so I restarted XP. After the reboot the TopWin software found the TOP853 without any hassle. Having never done things like this before, I found the software very easy to understand. You start by selecting the correct chip by manufacturer, and if it’s not there, choose a generic profile with the same properties.

Since I don’t have any empty EPROMs and my UV-eraser-box haven’t arrived yet, I could only test the reading capabilities. My Drumtraks was supplied with some extra chips with unknown origin. After tweaking the reading settings (since the particular chips weren’t in the manifacturer list) I managed to read all chips. The Drumtraks use 2764 EPROMS for all voices except the kick which is a 2732. I compared the contents with the all the EPROMs available on Electrongate, they will probably be added here. Paul who own Electrongate is  a very nice guy by the way!

Next step is to burn some Linn LM-1 EPROMs for the Drumtraks!

Drumtraks arrived!

Today my SCI Drumtraks 400 arrived! Unfortunately I’m so fed up with work so I haven’t had much time to play with it yet, just a few minutes. But my conclusion so far – it sounds fantastic! The kick is so deep compared to the DMX!

A fun little trivia: I’m the third owner. The first owner was the german italo/techno/electronic/new beat producer Andre Fischer. He bought in back in 1984 together with an SCI Six Track. Two months ago it was shipped from Berlin and sold the second owner who used it on a few recordings and then sold it to me. I was actually offered to buy it a month ago but it had problems with the kick channel which was later fixed. Here are a few songs that this particular Drumtraks was used on:

Kim Cesarion – Sir Sampalot Remix

Expect a few demonstration videos in the near future!