Category Archives: Synth

PPG Wave 2

PPG wave 2 – cassette interface pinout & factory program dumps

The PPGs’ program storage depends on the battery having enough juice. My PPG wave 2’s battery started to shown signs of a small leak, even though it was supposedly replaced only a few years ago by the previous owner. After the battery was replaced I wanted to reload the factory programs. I had some luck following the instructions in my own video that I published four years ago (yes, I partially have this blog to compensate for my bad memory). Read the post here. Below is the cable I got from the previous owner, that actually works, and is used in the video. Please do continue read, a neater solution is presented later in the post!

The other day I got contacted by a fellow PPG owner that still had struggles reloading the programs, even though he carefully followed the video instructions. We had some FaceTime discussions and those are the questions that arose, that we both thought would be nice to have answers to:

  1. What is the pinout of the cassette interface? The one that came with my PPG is a home made, spliced together thing.
  2. Which dump of the ones that are floating around is the factory dump, and why are they so hard to restore?

CASSETTE interface pinout

The PPGs use a DIN connector for the CASSETTE interface. The DIN connector was very common, and there are loads of variants with different amount of pins and varying uses of them. There’s a standard numbering for the five pin DIN connector, the type that is used on the PPG for cassette, MIDI cables etc. Note that the numbering is not in the physical order they appear! Also note that the numbering could be mirrored, depending if you’re looking at a female or male connector.

For modern use, we need to have an adapter to RCA or 1/4″ jacks. Unfortunately there’s a plethora of different adapters for different purposes. You can find two adapters from DIN to white and red RCAs, but they could be differently patched depending on if they’re made for a tape recorder or an amplifier. I found both variants in my old-crap-that-might-be-useful-some-day-pile. The only thing that you can probably be sure about is pin 2 being the signal ground. I found an adapter that has all four RCAs in that same pile, which made investigating the pinout easier.

I first tried the CASSETTE➡2 to see which pins the program data was outputted on. I then tried to reload the dumps in the PPG using the other two pins. This is my conclusion, I have double checked this a dozen of times:

In the PPG 2.2 service manual I found this, which caused a lot of confusion in the beginning of my investigation. Once I figured out that the image is the male side of a cable and not the actual female DIN connector on the PPG, it all made sense. Otherwise they would have switched “sides” on all pins requiring a different cable for a 2.2, which seems like a pointless thing to do. Yes, it’s me who added the red text!

Program dumps

When you dump to tape from the PPG by using the CASSETTE➡2 function, you first get a calibration tone that is followed by the data itself. Some kind of checksums are also in this audio, so that the PPG can discover if the data is corrupted or the if the transfer is too unstable. The PPG will respond with a  CASSETTE➡9 when an error occurs, or a  CASSETTE➡0 if everything went well.

Old dumps

In my collection I have two dumps, one called w20_fact.wav that supposedly is the factory programs. That one I’ve never managed to load into the PPG. It’s 8-bit and sounds a bit distorted. This has no calibration tone, the data starts directly.

With the purchase of the PPG I got an MP3 file PPG Wave 2 – 3.mp3 which is the one that I’ve managed to load to the PPG and the one used in the video. It has a calibration tone, but someone seems to adjust the recording level up and down, just before the data starts. I found out that starting at the end of the calibration tone where no volume changes are resulted in far more successful loads. I don’t know if it’s stereo because it was recorded from both pins 1 & 4, or if it became stereo when converted to mp3. No one probably knows.

New dumps – a.k.a. the “REDUMPS”

As I had more knowledge about the pinouts, I could now make a successful and audibly cleaner dump out of  my PPG  that was loaded with PPG Wave 2 – 3.mp3. It was recorded with no gain applied using my spare Focusrite 2i2 in 24/44.1. I got a nice steady data stream peaking at -18 db. I did two recordings, one for each pin (1 & 4), and got similar results.

The PPG has a  CASSETTE➡4 function that let’s you compare the contents in the PPG’s memory with the content from the cassette input to validate that the dump is correct. It’s similar to  CASSETTE➡1, but doesn’t actually store the data in the PPG.

I tested to play back both recordings to both input pins (3 & 5) in all possible combinations, and all of them were successful. I played them back both from the MacBook’s internal sound card and from an Antelope Orion 32 output.

Next question was, could I modify the w20_fact.wav so that the PPG would accept it? By normalising the data to -18 db and adding the calibration tone from one of my new dumps at the beginning, I kept my fingers crossed. And amazingly, it worked, for the first time ever! I then immediately made a dump of it. Playing some of my favourite programs, I really couldn’t hear any difference to the PPG Wave 2 – 3.mp3 programs I had loaded before.

This made me wonder, are PPG Wave 2 – 3.mp3 and w20_fact.wav the same? By using the CASSETTE➡4 function to compare the PPG’s programs with all of my new dumps, I had “proof” (given that the PPG is accurate enough), that they are the same. The PPG wave 2 manual I have states the following in German:

Die auf der Kassette aufgespielten Daten werden mit dem Speicherinhalt verglichen. Bei Fehlern die beim Aufnahmen entstanden sind erscheint eine “9” auf dem Display.

that translates to:

The data recorded on the cassette are compared with the contents of the memory. A “9” appears on the display for errors that occurred during the recording.

Download REDUMPED factory programs

This is w20_fact.wav loaded into my PPG wave 2 and then directly dumped from pin 5. There’s no point adding the other dumps since their contents are the same!

w20_fact factory programs “redumped” in and out of my PPG Wave 2

Findings

  1. Both of the dumps I had had the same contents and are probably the factory programs.
  2. A clean dump is much easier for the PPG to load, than the low quality ones I had (doh).
  3. A stable calibration tone at the beginning is important, the overall volume not so much (as long as it’s stable).
PPG Wave 2.2, Synth, Uncategorized

Racking a PPG Wave 2.2 – part 3 – battery change, v8.3 upgrade, service, measurements

Time flies, it’s been one and a half year since I started this project and progress is slow. Though there is progress!

Battery change, service V8.3 upgrade

In March I discovered a battery leak in the PPG Wave 2 and decided to send that board to Virtual Music for repair. I also did the same with corresponding 2.2 board. Since the V8.3 firmware upgrade goes on the same board I sent the chips as well. Besides the battery change, the 2.2 also got a little service.

Today, nine months later, I decided to put the card back in the 2.2 and it started right up! Great success on that and I feel that the hardware is now serviced. Focus will now be on the racking process.

Rack measurement

A year ago I also purchased a rack chassis. I bought a 6U rack with the widest inner width I could find. The inner width is 434 mm and the outer width is 436 mm.

I’ve also done a lot of measurements of the PPG and rack, and right now I’m feeling very hopeful. There were two main obstacles, both having to do with the width.

The first one was the fact that the original LCD and the “button board” simply wouldn’t fit. With the newer LCD, that will not be a problem. The board is around 240 mm and the lcd is 182 mm. That means more than 10 mm margin.

The second one, and this still needs to be solved, is the 2.2 motherboard. The width is 435 mm which is 1 mm wider than the inner width. I see two ways of solving this:

  1. Use  washers or some other kind of spacer on each side to move the side panels a few millimeter outwards. According to my measurements I could probably gain 6-8 mm by doing this
  2. Shave off the motherboards right edge – from what I can tell it’s probably possible to shave off around 2-4 mm of the motherboard. In a way, I feel this is kind of risky, but on the other hand the rack case will be properly assembled.

No matter what route I take, there’s one thing that also has to be modified. On the motherboard’s other edge, there are two pin headers that have a 90 degree angle. They need to be desoldered and straightened up, otherwise the connectors will hit the side panel. They can’t be bent when soldered to the board since they’re very thick.

I think the best thing to do next is to simply test fit the board in the case and actually see how many mm that are missing!

PPG Wave 2, Synth

PPG wave 2 – loading programs from CASSETTE

UPDATE! Read more about the cables needed and get a clean factory program dump here!

I just put a video up on YouTube, showing how to load programs using the CASSETTE port at the back of the PPG wave 2.

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

This PPG wave 2 probably has a weak battery and loses its programs after a few months if it’s not turned on. The battery will eventually be replaced with a modern, non-rechargeable lithium battery and a diode.
Instead of using a cassette tape, I’m playing the data from my MacBook. The MacBook is set at 100% volume, the PPG seems to be very sensitive about the levels. The program audio that you hear in this video from 0:50 should theoretically work to restore the programs in you PPG. That’s why I chose to keep it at the right level, -5 dB, in this clip.
PPG Wave 2.2

Racking a PPG Wave 2.2 – part 2 – display change

Display change

Yesterday I got my new display and digital board back from Alexander at Virtual Music in Vienna. The old display had to be changed to a newer one for two reasons, even though the old one still worked.

First of all, the old one would never fit a 19″ rack since it’s too wide. The new one is 182 mm, so it will fit.

Secondly the old one was very hard to read, especially if you were not straight in front of it. Since the PPG Wave 2.2 is supposed to sit in a rack, sideways visibility is crucial.

As you can see on the pictures it’s not just a matter of swapping the old display for a new one – serious modifications must be made to the so called digital board. The digital board contains the driver for the display and the two keypads. All work was very professionally done by Alexander! I plugged it in and it worked instantly!

The encoder for the contrast was also replaced since the old one was kind of intermittent.

V8.3 firmware

Virtual Music also happens to be the reseller of the newer V8.3 firmware that adds a lot of sysex and fixes bugs. V8.3 was ordered as well as new battery kit. I tried to change the eproms, but the old ones were really stuck and impossible to remove without using brutal force, which I didn’t want to. I will have to install V8.3 when the board is removed from the chassis.

The next step is to order a new 6U 19″ rack chassis.

 

PPG Wave 2.2

Racking a PPG Wave 2.2 – part 1 – intro

Intro

I recently got this “racked” PPG Wave 2.2. The history of it is quite unknown, but this brutal treatment was done in Germany by someone else than me. I’m innocent!

Someone has cut this Wave in half, removed the keyboard and put the right side  on top of the left side using standard screws and standoffs from a hardware store. It’s a shame since it looks as though the panel was in great condition – most Waves suffer from the graphics peeling of, especially in the area near the logo close to the push buttons.

Software wise it’s running OS V6 and has MIDI. MIDI is the way to control it since it has no keyboard. Since it’s a PPG Wave 2.2, it’s compatible with the Waveterm A – which I don’t have. There’s however an upgraded OS, V8.3, which makes the PPG Wave 2.2 compatible with Waveterm C, a software version of the Waveterm A and B.

Unfortunately, the serial is unknown as on most PPG Waves. It was hand written on a label on the back with a permanent pen that wasn’t as permanent as it was supposed to. It is probably an early/mid PPG Wave 2.2 as it has the same display as the Wave 2 but is equipped with factory midi.

I asked myself – what have I done – buying an expensive piece of junk like this that could electrocute me. And the racking procedure won’t be cheap and will take a lot of man hours. However, I’m running out of space in the studio and PPG Wave 2.2s don’t grow on trees, especially if they’re not upgraded with 2.3 voice cards. So I decided to take on this challenge and make myself a one of a kind rare PPG Wave 2.2 rack. I guess my metal skills from working with cars will be needed…

The width problem

The problem with the current “racking” is that it won’t fit in a standard 19″ rack – it’s simply too wide! A standard 19″ rack case has a panel width of 19″ (483 mm) , but the case width is often closer to about  17.5″. I’ve found a rack case supplier that has a model with an external width of 435 mm and inside width of 432 mm. This means that 432 mm is what I have to deal with.

The mainboard with all voice cards that is on the lower section is luckily enough around 430 mm. There’s also possibility to shave off a couple of mms at the far ends. The pots are placed on a board that is around 400 mm. The “Basis” and “Master Volume” pots to the far left are not on the board and can be placed anywhere.

The upper section has the power supply and MIDI and audio outputs at the back. They can easily fit within in the width. The biggest problem is the so called digital board that has the keypads and the LCD display. Together they have a total width of 460 mm so they can impossibly fit. One solution is to cut boards so one end is in a 90 degree angle (like this racked 2.3). I have  chosen a different path – changing the display to a more modern and narrower one that also has backlight.

The original display must have cost a fortune back then, and it’s not directly compatible with modern displays. Therefore the digital board and display will be sent to Virtual Music in Austria to be modified.

I won’t reuse the original panel metal since a few things will have to be modified and moved around. Instead I will create new original looking graphics for the faceplate so it looks factory.

The plan summarized

  1. Make a plan
  2. Change the display to a narrower modern one with backlight
  3. Upgrade the OS to V8.3
  4. Put everything in a rack case
  5. Create new graphics
Roland MKS-80

Replacing the backlight of a Roland MKS-80 rev 5

Today I changed the backlight on a Roland MKS-80 rev 5. If the backlight is very weak, the electro-luminescent foil it’s probably worn out. They simply have a limited lifetime. When this happens you have three choices;

  1. Ignore the problem and use a flashlight
  2. Replace the whole LCD
  3. Replace the foil

I think the missing backlight is really annoying and makes the synth harder to use, so not doing anything was not an option.

Replacing the LCD would probably not be too hard, it has standard dimensions of 80×36 mm and are cheap. If you’re lucky a new LCD would just work, but in the worst case there could be compatibility problems. I’m not saying there will be problems since I haven’t tried it, but there’s an obvious risk. For example, changing the LCD on an EII to modern LCD also required changing a chip, otherwise the LCD just displayed strange characters.

I went for the third option, namely just replacing the foil. There are some companies providing replacement foils cut to the right size in various colors. However, I thought I’d give Roland a try since they seem to have a lot of old stuff left in stock. So I emailed Roland Scandinavia asking for a foil for a Roland MKS-80 rev 5. Since they didn’t know exactly what part was, they emailed me the service manual for me to look up the part number.

After browsing the manual I finally found what I suspected was the correct part, namely “15029181 EL-101 (electro luminescence)”. Roland said it’d be around €20 and recommended me to visit my local Roland retailer to order it, so I did…

Replacing the foil is quite straight ahead. Most of the work is getting to the LCD. To do this you of course have to remove the lid, and then the front panel. Then you have to undo three screws and three standoffs so you can fold the two voice boards upwards to finally reach the CPU-board at the bottom which the LCD is connected to in three places. Two of the connectors are snapped in place, so use a small, flat screwdriver to fold the latches away. Then you finally remove the four screws holding the LCD in place, remove the LCD and heat up your soldering iron.

I used desoldering wick to remove the old solder. Then it’s just a matter of sliding the old foil out of the LCD. The “new” one I got from Roland is probably NOS, because it looked exactly the same as the original one. I slid it into the LCD and soldered it’s two legs to the circuit board. I actually cut away about two mm of each leg since they were a bit too long. I powered the MKS-80 up, and the backlight was really bright – success! However, it seems that I should have placed it a little more to the right.

Then it was just a matter of reassembling the MKS-80. However, this was not as easy as disassembling it. The tricky part is the front panel that has three rectangular holes for the OMNI, POLY, MONO leds. The leds have to go straight in their holes, otherwise the front panel won’t sit where it should. There’s also a similar led for MIDI MESSAGE to the right which makes it even more trickier… Do not try to force the front panel, just take it easy and align the leds, and do try not to get too annoyed.

I put the MKS-80 back in the rack and fired up my DAW to realise that the MKS-80 sounds great and the backlight is strong – but – the MIDI MESSAGE led doesn’t work… I will replace it some other time.

Roland JX-3P

Roland JX-3P sold

The JX-3P was sold today to finance the Prophet 5. I really liked it, it had character. For a while it has been the only affordable vintage sounding Roland poly, but I’m certain the prices will rise! It’s so much better than the later JXs and Alpha Junos.

SCI Prophet 5

SCI Prophet 5 bought! (and reloaded with patches!)

Today I bought an SCI Prophet 5 rev 3.0! This is cheapest one of the three editions made. That doesn’t mean it came cheap, I’ll have to sell at least 3-4 synthesizers to make up for the loss.

Rev 3.x is the last and most common main revision. 3.3 is the last sub revision and came with support for SCI’s midi kit, but it also got 120 patch memory slots. The 3.2 can easily be upgraded to 3.3, but 3.0 and 3.1 can’t without lot’s of hardware modification. Not having the capability to be upgraded to 120 memory slots or getting the official midi make 3.0 and 3.1 the cheapest ones. Kenton does however offer a midi kit, but it’s a bit expensive, so I think I’ll pass. The P5 has CV/gate for one voice if you need to sequence.

The seller said the P5 had the original patches loaded, but clearly it didn’t. On non-midi P5s patches can be saved to and loaded from cassette. Of course any audio recorder better than a tape recorder will do.  The patch data can be downloaded from analog.no as 8-bit wavs.

I downloaded bank 1 as it contains the first 40 factory patches. To be able to import it in Logic I had to convert it to 24-bit audio. I followed the instructions below taken from Prophet 5 Resources

  1. Look at the Prophet’s rear panel and set the Data Record slide switch to ENABLED.
  2. Set the tape to the position that holds your program. Listen for the announcement.
  3. Set playback level play at 0db.
  4. Hold the Prophet’s orange RECORD switch down while pressing the grey LOAD FROM TAPE switch.
  5. The Prophet front panel will go dark, except for the LOAD FROM TAPE switch indicator will be lit.
  6. The L.E.D. will go out after about 40 seconds, now Stop the tape.
  7. If the LOAD FROM TAPE light blinks, an something has gone wrong. Adjust your playback level and try again.

Unfortunately, this didn’t work. And the instruction doesn’t mention how to try again, or describes the confirmation you get if the loading was successful.

I read somewhere that some poly Oberheim from the same era needed quite a hot signal for it to work, and therefore the headphone jack was recommended instead of the ordinary outputs. Before testing the headphone jack I tried all output settings on my RME Fireface: -10 dBv, +4 dBu and Hi Gain – but it didn’t make any difference. Except on Hi Gain where I once actually got the blinking led, which means error. Maybe the signal was hot enough at least at some point?

I connected the cable to the headphone jack instead and restarted the load procedure. In the first run I had the headphone volume encoder on very low volume, and it actually gave an error – some success! I tried again by pressing the “Load from tape” button. This time I set the headphone volume encoder to point to a quarter to, and believe it or not, the patch data was loaded and it was confirmed by the P5 rebooting.

I shot a quick video of it, first showing a failure, then success:

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

Here are my additions to the standard instructions:

  • The LOAD FROM TAPE light will stay on until it gets something loud enough
  • The P5 will reboot after a successful load (you’ll notice the TUNE button light up for a couple of seconds)
  • I don’t know how to cancel a load, but if someone knows, please tell me
  • The P5 wants a hot signal. Start low and gradually increase the output level
Waldorf Microwave rev A

Waldorf Microwave rev A bought

Today I found a Microwave rev A locally on Vend. As always, I discovered the ad a couple of hours too late, it was already “sold”. After almost two days the ad was still there and I contacted the seller who said the buyer had backed out because he’d bought a guitar instead. Sounds a bit strange going from a Microwave to a guitar, they’re on totally opposite sides of the spectrum…

I convinced the seller I could get there quick and pay more than the price he’d put in the ad. So I went there and bought it. Apart from a small scratch on the front and a couple of scratches on top (not noticeable when it’s racked), the cosmetic condition was very good. The “alpha” wheel was a bit loose though.

The rev A is cosmetically different with a green bottom LCD display and blue anodized aluminium. The rev B is painted with a paint that peels of and has a black bottom LCD display. The biggest difference though is that they use different filters, the rev A has CEM3389s and rev B has CEM3387s. The rev A is valued higher than the B.
Read more about the differences here!

Sometime in the future when I’ve time I’ll be doing a A/B test, literally speaking.

Roland Juno-60

Roland Juno-60 midi kit

Last night I upgraded my Juno-60 with the MDCB60 midi kit from D-tronics. Even though I prefer not to use midi, there are situations where midi is nice to have, for example when doing quick sketches that you want to save, or try different sounds without manually having to play the same sequence over and over.

The DCB port

The Juno-60 was an upgraded version of the Juno-6, with the main difference that it had memory section, just like it’s main competitor Polysix. Another addition was the DCB port, which was Rolands predecessor to midi. Remember, this was back in 1982 and midi was first introduced in 1983. Before midi, Roland had DCB, Oberheim had it’s own proprietary protocol etc. Too my knowledge, only the Juno-60 and some of the Jupiter 8s had DCB . The JX-3P was the first Roland synth with midi, so DCB didn’t live more than a year or two. We should be thankful that the manufacturers actually managed to agree on the midi standard, that still lives 32 years later, even though it has its flaws.

Luckily, DCB is quite primitive and therefore simple to convert to midi. The MDCB60 only adds note on/note off, so there’s no pitch bend, program change, arpeggiator sync etc.

Installation

The installation was very straight forward:

  1. Open the Juno
  2. Remove the DCB-connector from the back
  3. Cut one zip tie so the DCB-connector reaches outside the synth
  4. Unsolder all wires
  5. Insulate the green and purple wires
  6. Solder the wires to the MDCB60
  7. Screw it to the back of the Juno-60
  8. Add a new zip tie
  9. Solder the wire from the MDCB60 to the gate pin on the Juno-60 board for 5V power

There’s a video here describing the installation, however, they seem to take the 5V power from another place than the gate pin.

The installation took less than an hour in total, and it worked straight away! I recommend this kit if you need basic midi on your Juno-60.