Friend-Chip DMX16 Modification

Recently I bought an additional Friend-Chip unit for my studio. It is a DMX16 that I plan to use to convert ADAT into SPDIF back and forth. I needed these extra ports to be able to hook up the digital FX processors that I have that all have SPDIF connections on them and I need to connect those to my RME MADI interface which only has ADAT ports. The unit takes Word Clock from my Big Ben and there something strange occurred. When I correctly terminated the unit it didn't synchronize to the Word Clock, but when I removed one of the 75 ohm terminators it started synchronizing. But then the Big Ben showed a red error led indicating that the impedance on that particular Word Clock bus was not correct. Very strange and I was sure that I had everything connected like it should be.

At first I E-mailed the dealer where I bought it about this and they had no idea and asked me to send them an E-mail in English to explain what happened. I got an E-mail back suggesting that the input voltage on the Word Clock bus was too low and they asked me to measure the Peak-Peak voltage on the Word Clock bus when the unit was connected. I connected my oscilloscope and measured 2 Volts on that. I decided to E-mail the answer to Friend-Chip directly to save some time. I immediately got an answer back saying that the Friend-Chip needed at least 2,5 Volts and that they were going to investigate. Then I got an E-mail that they found a solution with two options. Either to send the modules to them for modification or modify them myself. So I opened the unit and investigated what had to be done.

It turned out that the modification was actually quite simple. On the two MQA modules that have the Word Clock input I had to remove a resistor. They send me this neat picture that clearly showed which resistor had to be removed. Removing it was a bit tricky since it are SMD components that are very very small. But I maned to do this quite quickly actually. After wards I carefully inspected the PCB to make sure I didn't make any short circuits and put the unit back together. I hooked it up with both the terminators attached to the unit and it synchronized perfectly and also the Big Ben found everything to be in perfect working condition :) So the modification was successful. I'm very surprised by the level of support I got from Friend-Chip in Germany and it is great that they came up which such a great solution even trusting me to do this modification myself. Big thumbs up for Friend-Chip!!

Poly 800 Modding (Part 2)

Today I finished the PCB for the Hawk-800 Mod I'm working on for the Korg Poly 800. First thing to do was to make 27 wire connections with the blank wire that was supplied in the kit. You have to be careful here since some of them are quite close together and you have to make sure they don't touch each other. It was quite time consuming but not difficult. Most important is to make sure the wire is as straight as possible.

Also one wire connection has to be made on the bottom of the PCB. The insulated wire for this is supplied in the kit as well. You have to solder this one after all the IC sockets are installed since you have to solder the wire to the pins of two of these sockets. The manual is very clear fortunately on all this. After this I put a drop of glue from a glue gun onto the wire to secure it. I only took the picture before I did this, so you cannot see it here.

Here you see the completed PCB. As you can see not many other components on there than IC's. In the top right corner is a battery holder for the memory backup functionality. This battery is not supplied in the kit. I will have to pick it up from my local electronics shop. The empty sockets will be filled with wire connections to the main PCB of the Poly 800. I will open up the Poly 800 soon to see how I can install it. This will be the first time I open a synthesizer myself. I'll update you soon. Not sure yet when I'm going to do this though. We'll see.

Poly 800 Modding (Part 1)

My friend Hanz tipped me on a very interesting site about a DIY electronics kit do modify the Korg Poly 800. This mod is called HAWK-800 and it turns the Poly 800 into a more sophisticated machine. It seriously updates the midi functionality to start with. You can find a complete list of features on the website here:
http://patrioticduo.tripod.com/hawk800/id15.html. After reading this I decided to order mine. As you can see there is also another kit coming that will be based on this one. And a very nice thing is that the kit holds an EEProm so you can update it when new features come along. Very nice work I think!

The kit arrived last week. And as you can see it is quite complete. It even comes with the necessary blank wire and flat cable. The documentation for construction is on the website I mentioned before. It will be kind of a retro fit kit build in the P0ly 800 itself. The documentation is very precise about where and how to fit it in the Poly 800. But first I will have to build the PCB for this kit. It looks quite easy compared to the other projects I have going on. I guess it will take about one or two hours work at the most. I'll build this one soon and keep you updated on the progress like always.