Category Archives: Synth

Korg Polysix arrived

Today my “new”  Polysix arrived. Cosmetic condition is quite good, with the exception of one major dent in the fake wood. It has the CHD midi kit, though I haven’t had time to test it yet.

It’ll need a cleaning and the factory presets, because the current presets are not very exciting at all. The filter sounds amazing, and I really like the built in effects!

Oberheim Matrix-6R

A couple of weeks ago I scored an Oberheim Matrix-6R on eBay. I’ve had a Matrix 1000 before, but we never became friends. It sounded too much techno and too little vintage. Therefore it might sound strange for me to go and buy a Matrix-6, since their guts are nearly the same. The thing that convinced me was the video review by my favorite Japanese guy, Katsunori UJIIE. He really brings out the nice brass and strings this machine is capable of!

Since I live in Europe and bought it from the US (the rack version is quite hard to find in Sweden, I’ve been looking out for one for a while), I turned to a guy I know to convert it from 110 V to 230 V.  I read on his blog that the built in PSU can be switched by doing something on the inside. I didn’t ask him exactly what, but for someone that’s good with electronics, doing the mod should be piece of cake. I suspect it’s something simple like repositioning a wire and changing the fuse.

When I got it back I plugged it in and was amazed by it’s sound! Fantastic brass presets, perfect for a brass guy like me. Compared to how I remembered the Matrix 1000, this sounded like something completely different. Maybe it’s the combination of more vintage sounding presets and the fact that the DCOs on the Matrix-6 aren’t controlled by the same clock.

Compared to the Roland MKS-70 that took two rack units, and really deserved them, the Matrix-6R definitely deserves its three rack units! I still have a JX-10 that has exactly the same guts as the MKS-70, but honestly, I think I like the Oberheim sound better! The JX-10/MKS-70 with their 24 DCOs are technically more advanced, but they are flirting too much with the digital trend of that time. I also find the Oberheim snappier and the filter more characteristic. To sum it up:

Roland JX-10 / MKS-70
• 24 DCOs
• Roland chorus

• Filter
• Slow envelopes
• Digital sounding presets
• Broken midi/sysex implementation

Oberheim Matrix-6
• Filter
• Envelopes
• Vintage sounding presets

• 12 DCOs
• 3 rack units (compared to MKS-70 2 or Matrix-1000 1)
• Slow CPU, lots of sysex chokes it


Roland MKS-70 swapped for SCI Six-Trak and cash

I just swapped my Roland MKS-70 for an SCI Six-Trak. I felt that I needed an American VCO poly in my collection. There aren’t many affordable ones available, but the Six-Trak is one. I also have a Roland JX-10 which is the keyboard version of the MKS-70.

Design wise, it’s kind of a strange combination of 80’s high tech and 70’s vintage. While it has the classic Sequential Circuits logo and solid wood sides, it has a “digital” user interface. You select a parameter number on a keypad and set the value with a pot.  This is probably a big reason for why it’s not more expensive, kind of like same thing with the Roland JX:s. However, it’s actually very easy to work with, and there’s a nice template for Ctrlr available. The Six-Trak has a very good midi implementation – each parameter is can be controlled by midi CC (!) and not sysex which was the common and annoying way back then.

The cosmetic condition is very good on this one, I heard it was previously owned by the guy who managed SCI imports to Sweden back then.

Soundwise, it’s not a Prophet 5. Compared to the Roland Juno-6, which also is a one oscillator poly, the Six-Trak sounds very weak. To come alive, some external effects like chorus and reverb is recommended. There are no built in effects.

However, there’s a unison mode that definitely turns the Six-Trak to an monophonic monster! This mode can make it deliver extremely fat leads and basses.

Organix JX-3P MIDI Expansion Kit ordered

I just got added in the waiting list for the Organix JX-3P MIDI Expansion Kit. The JX-3P already has midi, but the Organix kit adds some features. The one I need the most is the ability to use the PG-200 and midi at the same time (this isn’t possible when standard). Another cool feature is that the PG-200 will send midi CC’s, and the JX-3P will receive midi CC’s. This is extra valuable for those who don’t have a PG-200 and want to use a standard midi controller like a Behringer BCR-2000 or Korg nanoKONTROL. Since the JX-3P is from 1983 it can’t even receive midi sysex!

Now I just have to wait… 🙂

Kawai K3 for Akai S900

I just swapped my Kawai K3 for an Akai S900 and a pile of cash. The K3 was one of those synths that are nice, but of some reason never is used. For that reason I decided to sell it.

I’ve also been working on converting Fairlight I/II/IIx disks to other formats. Akai S900 is one of them. So far I’ve used one of my Oberheim DPX-1s to playback the disks, but a lot of the S900 file formats aren’t fully documented. To be able to reverse engineer those formats I needed a real S900 to be able to set parameters. The DPX-1 is a sample player only, no parameter can be changed.

What’s interesting about the S900 and S950 is the fact that they have variable sample rates just like old drum machines like DX/DMX and Linn. This means that the S900  can play back sounds at any speed between 7.5 kHz to 40 kHz, and it does this by changing the clock. This could be described as manually turning a vinyl disk at different speeds. Most newer samplers uses the “drop sample” method instead. What this actually does is to throw away or duplicate samples. If a sound is to be played back at the double speed using the drop sample method, every second sample is discarded and never played back.

Next thing is to temporarily take the HxC SD Floppy Emulator from the Roland S-330 and put it in the S900 for testing my own generated disk images.

JX-3P bought

I’ve been thinking about not renewing, but “reoldering” my synth park lately, since I’ve realized that drum machines and poly synths of the early 80’s is my thing.

Today I went to Denmark and bought a Roland JX-3P with a PG-200 programmer and a case. I got a fairly good deal!

So far, I really like the sound of the JX-3P. It sounds a lot more vintage than the newer JXs and feels a lot more responsive. The programmer is a very nice addition, it should have been built in the synth from the beginning. The presets are mostly hideous, but that’s easily solved with the PG-200. Custom patches can be saved to any of the 32 user slots. This must be one of the most underrated analog synths ever. It can do amazing brass sounds and I really like brass. It’s nice with two DCO:s and faster envelopes, compared to the other JXs.

The JX-3P was released in 1983 and one of the first synths with midi. And it works very well, I noticed that even program change messages work. One thing that doesn’t work though, is using the PG-200 and midi at the same time. There’s a switch on the back where you decide what to use. This is quite annoying if you have a midi sequence running and want to tweak the sound. However, there’s a cheap mod available called the Organix JX-3P MIDI Expansion that fixes this issues and also makes the PG-200 send midi CC! And some other stuff too. I’ll order it ASAP!

Another thing about midi and the JX-3P is that it was made in two revisions, I have an early one and it lacks midi through. Later revisions have it built in.

Changing battery on the TX-816

Sooner or later the battery will go dead on a TF1 module. It has a standard 3V CR2032 Lithium battery that can be found everywhere. When the voltage drops to low, the TF1 will fail to hold it’s memory and all patches and settings will disappear. Unlike the DX7, each TF1 doesn’t have a cartridge reader, but similar to the DX7 there’s no ROM memory. If you lose or edit the patches, the only way to get the factory patches back is to transfer them by sysex from a computer or another DX7.  The TF1 lits the error led and displays a 4 if the battery voltage is too low.

The error led is lit and the alpha numeric display shows a 4. This means error number 4 = low battery. At the top and bottom you can see the hex screws that need to be unscrewed.
The error led is lit and the alpha numeric display shows a 4. This means error number 4 = low battery. At the top and bottom you can see the hex screws that need to be unscrewed.

As with a lot of synths from the early eighties, when patch memory was a novelty, the battery is soldered to the TF1’s circuit board. So it has to be desoldered to be changed. Then the new battery must be soldered back. One alternative is to put a CR2032 battery holder there instead, then next time no soldering will be required. I chose the battery holder path.

First you have to remove the TF1 module and it’s actually very easy to do. Unscrew two Philips screws on the back, and two screws with 2.5mm hex heads (IKEA style, but smaller) at the front. Then push the card from the back so it pops out of the front. Pull it gently towards you without using any force, it should go smooth.

The TF1 module is nearly out.
The TF1 module is nearly out.

I desoldered the old battery and used a solder sucker to remove the old solder. I then measured the distance between the two holes to approximately 16 mm.

Battery is unsoldered.
Battery is unsoldered.
The space between the battery's legs is 16 mm. Unfortunately I could only find battery holders with 19 mm space.
The space between the battery’s legs is 16 mm. Unfortunately I could only find battery holders with 19 mm space.

Unfortunately I couldn’t find a holder with 16 mm distance between it’s pins, 19 mm was all I could find (bought here). Fortunately the pins were quite long, so I managed to bend them inwards enough for them to fit and penetrate the holes.I then soldered the battery holder and put the battery back.

Look closely to see the bent pins (19 -> 16 mm conversion).
Look closely to see the bent pins (19 -> 16 mm conversion).

A quite simple operation. I think it’s worth the extra time and cash ($2) with a battery holder. That time will be spared next time the battery must be changed.

I recommend this site for more info on the TX-816.

Juno-106 sold (feat. some Juno-106 vs Juno-6)

I only had it for three weeks – current record! Blame it on the Juno-6.  It suddenly was for sale one block from where I live for a good price. I can confirm the fact that there’s a sonic difference, the Juno-6 sounds more organic/fatter/analog than the Juno-106.  Not saying that I don’t like Juno-106, George Michael was right, it’s a great synth. But I don’t need both. The Juno-106 was near mint, so I thought I’d share some photos of it.

Juno-6 bought, Juno-106 for sale

I just bought a Juno-6 from someone in the hood. It will replace the Juno-106 I bought less than two weeks ago. So far I’m very impressed by the Juno-6! It doesn’t have midi or polyphonic portamento (is it really useful?) but it does have an arpeggiator! And it sounds fantastic! More on the sonic differences in a later post.

Some quick history:
1982: Roland launches the first Juno ever – the Juno 6 – a six voice single DCO analog
1982: Because of the Korg Polysix and it’s ability to save patches, the Juno-60 is introduced which is a Juno-6 upgraded with patch memory. It also adds DCB (Roland’s own pre-midi standard)
1984: The Juno-106 replaces the Juno-60. The Juno-106 has midi and portamento, but the arpeggiator is gone. Also, some of the chips are now integrated. Time will later tell that these chips are prone to break

The Juno-106 is now for sale.

Roland Juno-106 bought, JX-8P and TX81Z sold

Today I bought a Juno-106 in very good condition. It works perfectly, cosmetically I would say it’s 8/10. Selling the JX-8P was a bit hard for me, but I believe four JX-engines are enough. I can still get the same sounds on the JX-10 and MKS-70. The TX81Z has Lately Bass, but it’s nothing compared to the TX-816. If it wasn’t for the lack of rack space I’d probably kept the TX81Z.

Back to the Juno-106 – my first impression is that it sounds very early 80’s, and that’s something good. My second impressions is how simple it is to program with it’s sliders and simple structure. It’s obvious that the Juno-106 was engineered before the FM boom and that it’s analog and proud of it. Compare this to the JX that has a lot of presets that mimics

DX7 presets like marimba and electric pianos. The JX is like an ashamed analog that wanted to be born digital! All respect to the JX – it is a great analog whether it wanted to be or not back in the mid 80’s! It’s just a matter of programming, and that matter is actually the second problem with the JX. The Juno has very hands on programming, the JX uses buttons and menus, if you want sliders you have to get the overly-expensive PG-800 programmer or a Behringer BCR-2000. The BCR-2000 works great, but it’s still not the same thing.

The reasons explained above are the reasons the Junos are more expensive than JXs. Remember, that when new, the pricing was the other way around! The JX is technically more superior with it’s two oscillators per voice, more high end and more complicated. It’s this complicity that is the problem! I like them both – in different ways!