Digital PC Scope (Part 3)

The Digital PC Oscilloscope returned from Velleman. And it turned out I was right. They have replaced the AD converter chip. So I didn't make a mistake it turns out and I even detected the right defective component. Well I hooked it up right away and did some tests and everything looks great now. In the picture you can see that I have put it next to the PC Function Generator under the keyboard. Fits quite nicely actually. Now I'm going to play a bit more with this combination and try out the Bode Plot functionality. I'll try to put some results up on my blog when I have them.

Synth.nl in Syndae Christmas Special

Like last year I made a track especially for the Christmas Special from the German electronic music podcast Syndae. My track is called 'SynthCarol' and is my interpretation of the Christmas track 'Carol of the Bells' only with synthesizers in stead of bells. Stefan made a very nice show again of a little over an hour and left me the honor to finish of the show. All music in this Christmas Special is especially made by the artists involved for this show. I think that is quite unique. You can download the show from http://www.syndae.de and as said before my track is the last one at about 1:02:00. Have fun and Merry Christmas!

Yusynth (Part 17)

And this morning I finished another YuSynth module. It is a YuSynth Saw Animator module. As you can see this is a factory produced PCB. I this as a complete kit from Bridechamber including the components. While inspecting the components I found there were 2 resistors missing and there were 1 uF elcos supplied in stead of the polyester capacitors that should be there, but I could easily get them from Farnell. I didn't really bother to contact Bridechamber about it. One nice thing about this PCB is that the component values are on the silkscreen of the PCB. So documentation is close at hand :)

Wiring PCB is becoming standard production work here in my studio the last days :) So I got this one wired very quickly again. Actually this module is a dual module. There are two Saw Animators on the PCB. So you have wiring for module 1 and module 2 being an exact copy. There are also two LFO's standard on the PCB. The LFO's output is normalized to the Mod Input and is disrupted when you insert an external jack. Saw Input 1 is also normalized to Saw Input 2. So if you input a saw on input 1 it is replicated to input 2 automatically.

And here is the completed module. Calibrating is easy. You apply a 10V Peak Peak saw signal and then adjust one trim potmeter to get the output saw aligned and using another trim potmeter you balance the DC offset to get it nicely around the zero. Then you do the same for the output of the other part of the module. If you input other signals than a saw you get some neat output results as well by the way. Also when you don't input a full 10V peak peak signal the output is different. Quite funny what you can do with this fairly simple module.

And here is the finished module from the front. The leds you can see indicate the speed of the internal LFO. As said before you can override those with an external signal. But what does it do then? Well you can 'animate' or 'modulate' a boring saw into an alive one. It thickens up the sound. I heard my PC oscilloscope is back by the way. Maybe I'll grab some signal pictures with it later on so you can see what it does. I hope Gerrit comes back soon with the modified piece for my cabinet so I can finally screw some modules into place and start working with them. For now I'm going to look what is next on my backlog pile :) I'm sure I don't have to be bored the coming days. As always I'll keep you updated on the progress.

Modular Desk Adjustment

Gerrit my Furniture builder was here today to look at the adjustment that needed to be done to my modular desk to fit in the Synthesizers.com modules. So in the morning I cleared everyhing out of the desk to make room for him to work. But he thought it would be better to do it in his workshop, because he has better tools there. So he actually sawed out the upper bar and took it with him. Hopefully I will get it back next week. So still no Q960 sequencers in there unfortunately. Ah well patience will pay out I'm sure Gerrit will make it even nicer than I though. We also discussed a little extension on the desk today. I'm thinking to put some stuff left and right of the desk since there is still space there, but for now it are just ideas. I'll let you know when he has been back here.

Yusynth (Part 16)

Today I finished two YuSynth LFO modules. Again I made everything myself on these modules including etching the PCB's and the front panel designs. I also had these front panels made by Schaeffer. And I used a bridechamber 2 pot bracket as you can see in the picture on the left. I had some more holes to drill on these brackets since the PCB has 6 fastening points in stead of the usual 4. I guess because it is a long PCB and you don't want it to short circuit on the pot bracket when it should bend. I keep having trouble to drill these holes exactly on the right spot. Just clumsiness I guess ;)

And here is a picture of the wiring I did. As you can see there are quite some wires on this PCB. 6 of them already go to the rate selection switch. Which is kind of a cool features because it increases the frequency span a lot. Of course I had the wires correctly the first time on the switch, but doubted that later on and after switching them I found that they had to go back again ;) Ah well this way you learn to test better. The reason I started to fiddled with the wires was actually because it didn't function when I was calibrating the first one.

The first thing I did after that was comparing the PCB's of both LFO modules. And after about 10 minutes of studying and measuring a bit, I found that I had two resistors wrong. On one PCB were two 2k7 resistors and on the other two 8K2 and there were supposed to be one 2K7 and one 8K2 on both of them. I had to remove the PCB's again from the pot brackets to desolder these resistors. Since this is a single layer PCB that is doable with just a desolder pump. I maned to do so even with saving the resistors and just switching from one PCB to the other.

And here are the two finished LFO modules. As you can see in the picture they have another neat feature called Sync. This makes it possible to synchronize two modules to each other of to for example to a sequencer clock or any other signal. Further it has an FM input making it possible to do frequency modulation on an external CV signal. I tested all the features and it works like expected. The only thing I see is a little dip just on the crossing point of the uppper and lower part of the Triangle and Sine wave. I'm not sure if this is normal, but I can't get it away using the trimmers anyway. Actually I don't think it is a big problem either. Well all in all a productive day and two new modules :) More to come soon. I'm on a roll now :) I'll let you know soon.

Modular Backlog Update

I promised to make a blog posting as well about the stuff that I still have to finish. In the picture on the left you see a stack of PCB's. Some are fully populated some not. On the left are some MOTM boards that will be used inside the modular for power distribution. Next to that are some CGS PCB's and on the right are a lot of Yusynth PCB that I made myself. Some of them are also spare. I made a lot of those twice while I will only completely build one. Maybe I will sell the other PCB or maybe keep them for spare for the future. Below the stack of Yusynth PCB's is also some MFOS stuff.

And here is another stack of PCB's. The stuff you see here is mostly populated as well. Most of them are Oakley PCB's but on the left is also a Mega Percussive Synthesizer from Electro-music.com also designed by Thomas Henry. Below is the Snare drum project on the breadboard. I'm saving this to make some video before I put it on a experiment PCB. In the picture on top you see also a front panel laying in the bottom of the picture. That is the Front Panel I designed for my Hip Bass Drum module. That one is quite complete so I can finish that very soon I guess.

There here some stuff I have laying on the floor right now. These are mostly front panels I'm populating. You will recognise the Klee Sequencer panel that I posted about before on the left and behind that is the MFOS Stereo Mixer I'm building. You can also see the VU meter panel on the bottom and some more Yusynth stuff that will come soon. On the far top left are the synthesizers.com Q960 sequencers. Hopefully my furniture builder Gerrit will fix the modular desk on Wednesday so that I can start installing and testing them. I can't wait for that :)

And here the last picture. On the top left is a Bridechamber multiple panel where I already put the jacks in. Then on the bottom next to the roll of black wire is an Oakley MidiDAC that will funtion as a Midi to CV converter in my modular desk. And on the right are three MOTM 300 VCO front panels. All in all quite some stuff I still have to finish, but I nearly got all the parts. Now I'm missing some potmeters that I will get from Mouser soon and I already used up all the jacks so I ordered some more of them too. I thought I had enough. But apparently I didn't ;) Well now you have seen everything, so I hope you can see why I'm a bit busy at the moment :)

Modular Progress Overview 2

I'm working very hard now on finishing some modules for my big modular. So I thought it was a nice moment to post another overview of the current status. I know some of you are following this blog for my DIY stuff and some of you have no idea what it is all about :) So from time to time I will show what it is becoming. In the picture on the left are the modules that I have finished or nearly finished. I'm working at the moment on the YuSynth LFO's and Saw Animator. So you can expect a post on those soon. If you click on the picture and zoom in you can see what it all is. Every module has a text label.

And here is the big overview picture of the hole modular desk. As you can see there is still a lot of empty space, but that will become all filled some time to form one big modular synthesizer. Most stuff will be self build, but there will also be some pre-build modules in there soon like the Synthesizers.com modules I bought recently. On the top left you see the ASM-2 that I'm also still building and in the middle on top is the Elektor Formant that I still need to restore as well. I tried to repair the old power supply that came with it, but it is so damaged that I decided to go for a new power supply for it actually.

And there is lot to some soon. I have been working on a lot of modules the last year that all are missing parts. 95% of the components on the PCB's is very ordinary and cheap stuff that I can find in my local electronics shop, but some parts are very difficult to track down and sometimes quite expensive. So I have a huge backlog of stuff I need to finish right now. I will do a post about that as well later on so you have an idea. I'm still enjoying especially the DIY stuff a lot, but the whole modular is still not in any state to produce music with it. So I'm really eager to create some sounds with it soon, that is why I'm working very hard now to finish enough stuff to be able to hook it all up soon :)

Yusynth (Part 15)

I finished another module today. I had this PCB lying around for a long time. It is a Yusynth VCA module. There is one tricky thing you need to do while building this module and that is to match two BC547C transistors. It is only possible to do this when you have a multimeter that is capable of measuring the HFE (amplification) factor of a transistor. The reason this is necessary is that they will work in pairs.

Building this module even though it is not that complicated was special for me, because it is the first module that both has a PCB that I made myself and a front panel that I designed myself. Again I used a 2 potmeter bracket from Bridechamber. After this it was time to start wiring again. I started as usual with the wiring to connect the front panel components. After that the wires on the PCB. Because there is no silk screen on the PCB, I made sure to use different colored wires to be able to tell what is what later on.

Then it was time to test and calibrate. Yves has a nice calibration procedure on this website, but I misread it. I spend over an hour trying to calibrate it, but it didn't work like I expected. The first thing to do is put the front panel potmeters for the audio and CV input to maximum, but I also put the Gain potmeter to maximum while it should have been on the minimum position. After I found that out calibration was a piece of cake actually :) It is a nice VCA, quite quick actually. I even used the LFO to do audio rate stuff with it.

Here is the finished module in my modular desk. As you can see I still haven't fastened any of them. I have been looking for nice black screws for a long time. I think I found them now. Actually guitar screws for mounting pickups to a guitar body. They have a big head and are not too long. I found them on E-bay somewhere in the UK from a guitar shop. Another thing I'm still thinking about is how I should layout all the modules so that it is kind of logical. Because I'm screwing them directly into the wood of the cabinet I don't want to move them too much since I'm sure that the wood will get damaged and after a couple of times it won't hold anymore. Well next up are the two Yusynth LFO modules you also see in the picture. I'll update you soon.

Resonant Lopass Gate (Buchla 292c Clone)

Today I finished another module. It is called the Resonant Lopass Gate and it is a clone of the Buchla 292c. The PCB is designed by Thomas White with permission of Don Buchla. Construction of the PCB is quite straight forward but there are a few jumpers on the PCB you have to set when you want to use the resonance function. Thomas also added the deep switch mod. Another thing you can chose is to use 3 inputs for both CV and audio inputs through a on board mixer, of you can use direct audio and CV in. The two bbig lack components on the PCB are Vactrols. I got them from Bridechamber. They are not very easy to get anywhere else I think.

Here you see the finished module from the back. I didn't install two potmeters on the PCB but directly on the front panel, because I used a Bridechamber pot bracket. I gambled on the orientation of the switch, but got it right in one time. And this time no potmeters the wrong way around either ;) I'm getting quite handy now in wiring modules to the front panel. It is going faster every time. I only had to fidle a bit with the rotary switch. I never used one before with 4 layers and 3 positions. But with a multimeter I found out quite easily what should go where according to the documentation. I had this front panel made by Schaeffer by the way, but saw later that Bridechamber also has it now. Too bad because that would have been a bit cheaper.

After assembling it was time to test and calibrate again. Everything worked right away. I used the good old LFO again to create a gate signal. This thing is really fun. The resonance adds a great edge to the filter and the Vactrol make the edges smoother. You can create very interesting sounds with this modules just by applying a saw to the audio input and a square on the CV input. I'm sure I'm going to use this module a lot in my future audio productions. I used a similar software tool in the past, but this really beats the crap out of that one :)

Here you see the finished module. I think it looks very nice. As said before I had the front panel made by Schaeffer and you can actually download the Front Panel Design (.fpd) file from Thomas White's website. Here you can find the file and more information about the module. You can also order the PCB from here: http://www.naturalrhythmmusic.com/lopass.html. I can really recommend this one. Thomas White also has some other nice front panel designs on his website that you can download. I'll make some more for sure in the future with his panels. It is great that people share this kind of stuff in the DIY community. As said before if you want any of my panels just let me know. I'd be happy to share them to. Maybe I should put them on my website too in the future.

Magic Smoke Electronics TH-201 Mankato Filter

When I ordered something from E-bay recently I was offered a nearly populated PCB by Magic Smoke Electronics. It is a TH-201 Mankato Filter. This filter is designed by Thomas Henry by the way who also designed the drum modules I'm building currently. When I examined what was missing using the bill of components, I found that the guy I bought it from installed all 5% resistors in stead of the 1% resistors that were recommended. So I mailed Magic Smoke Electronics if that was a problem. They stated that it will probably not track on 1V/Oct but should work fine.

Well actually I don't really care about that. So I finished installing the missing components and started wiring it. I got a front panel and pot bracket from Bridechamber for it. Actually I should be on a 4 pot bracket, but I used that already on another module. With a bit of effort I could just fit it on a 3 pot bracket by drilling the holes on the bracket very close to the edge. I also got a tempco from Bridechamber for it, but I didn't bother installing it since it won't track any way. I'm sure I can use it somewhere else in the future where it will matter.

After wiring I started testing it. I first put an input signal on it from my PC Function Generator. It sounded alright, but I found quickly that I wired the input potmeter the wrong way around. And since I used the same system for all potmeters I figured they would be all wrong. And after checking they were indeed. Luckily I anticipated this and left the outer two wires on the potmeters long enough so that I could swamp them. Not really a problem even though some wires were not so easy to reach anymore. After swapping them I found that the filters didn't auto resonate.

Again not a difficult task to fix this. There are two trimpotmeters on the PCB. One for the resonance and one for the 1V/Oct tracking. I didn't bother the last one but set the resonance potmeter so that it starts auto oscillating on 95% of the resonance potmeter. As you can see this filter has lots of outputs. All with different phases. The frequency scope of this filter is also very wide. So you can use it as an LFO or an oscillator too. When used as an LFO the phase shifted outputs are handy. Well after testing everything I put the knobs on and think it is another successful project and nice addition to my modular setup. Here you can find more information on the TH-201 Mankato if you are interested:

http://magsmoke.com/TH-201-Mankato-Filter-VCF.asp

Synthesizers.com Sequencers Arrived

As you will know by now I'm building a big modular synthesizer myself. But there were some modules I couldn't build buy as a kit, so I bought they assembled. In the picture you see two Synthesizers.com Q960 sequencers and below some utility modules to accompany them. These sequencers are build after the original Moog sequencers that were used by bands like Tangerine Dream in the 70's and are still used by a lot of people these days to make 'Berliner Schule' music. I want to try and use these sequencers next to the sequencers I'm building myself to create some inspiring melodies that I can use in my own music. The only thing I noticed right away is that they don't fit in the modular desk that I had build in my studio. I already contacted Gerrit that build the desk and he will come by next week and see if he can solve it. I'm quite convinced that he can actually :)

Yusynth (Part 14)

Today I visited my old employer Bird Electronics again today to make some more Yusynth PCBs. In the picture you see my former colleague Marcel who did the nasty chemical bits. He put on his special clothes for this, because when you spill the etch material on your clothes the holes will eventually fall in. We made a lot of PCBs together. He helped me with my stuff, but we also created some PCB's for one of their customers. It was great fun to be there again and catch stories up a bit. I think the last time I was there was about a year ago.

My job today was to operate the UV light. The PCB layout is printed on transparent foil that is put on top of the PCB material. That in its turn has a photosensitive layer. So where there is ink on the PCB material the light gets blocked. Later on the unlighted parts will remain in copper while the rest will be etched away. Just leaving the copper lanes. He you see a case with left over PCB material. I can shop for my PCBs from there. All good stuff but only small pieces and big enough for the Yusynth PCBs.

And here are some finished PCBs drying. Next step is to drill the holes in them. I will return there on Monday to start working on that. I guess that will be a days work. I doubted recently by the way to try and make PCBs at home. You can buy all the needed kit online. But after today I'm happy that I didn't. First of all it is always a pleasure to visit Bird Electronics and secondly I wouldn't want these chemicals in my garage with the kids also walking in there and the cars being inside. So that idea is out of my head for good. I'll try to make some pictures on Monday as well.

Bridechamber Package Arrived!

Today finally my package arrived from Bridechamber!! Customs got me again and I had to pay import tax on it. Ah well. That's life :/ As you can see a lot of stuff was in the package. Especially some missing front panels and a lot of jacks! I also got a complete YuSynth Saw Animator kit so that one is complete for sure. I also got some multiple panels. I guess you can never have enough multiples on a modular synthesizer. And I also got a YuSynth CV standards panel with the necessary rotating switches. Well the coming period I don't have to get bored I'm sure :) I can finish up some stuff now :)

PC Function Generator (Part 3)

The PC function generator is all done now. Here you can see a picture of it in its enclosure. Looks nice doesn't it? You wouldn't know I build it myself if you see it like this. I'm very happy with it. All in all this kit only cost me 99 euro's and I think that is very cheap for a complete function generator with all the functionality that comes with this thing. I was almost starting to doubt if it could be something serious for this money, but I assure you it is. It is very complementary to my hardware function generator and now I'm able to chose.

I did some more testing on it. In the back you can see my other function generator that has a build in frequency counter. Or maybe it is more a frequency counter with a build in function generator ;) Well I set the output of the PC function generator at a 1Khz square. And here you see that the frequency counter measures 0.999999 Khz I think that is close enough ;) I did some more tests and funny enough it is every time this same result. Just under, but there is no way to calibrate this and I'm not sure even who is right :) Well it doesn't matter. It seems to do the job.

I found a spot for it under my keyboard. Later on I will place the PC oscilloscope next to it. I don't type much on that keyboard anyway so this way it doesn't take up to much space on my desk. I did some more test with the option to design your own waveforms. There is no graphical interface to do this by the way. You have to punch in values in a table, but here you see the result of a waveform I made. You can see it on the screen in the software and also the upper wave on the oscilloscope. Below that is the output of my other function generator. I used this setup to compare frequency output as well. And it seems that here everything looks good to. So I can close up this project as being succesful :)

MOTM 300 VCO's (Part 1)

I said before that I'm building a lot of PCB's at the moment. Among them are these three MOTM 300 VCO's. I thought since I'm building a MOTM compatible modular synthesizer there needed to be at least some MOTM modules in there. Of course I have build the two power supplies, but that doesn't really count right? They make no sound whatsoever. These VCO's are supposed to be very good. I read that they track over more octaves than a concert piano does. So they are very suitable for musical stuff. In the picture on the left you a start with the resistors on the PCB's.

Next to the PCB's I also ordered the special components kit from MOTM. It comes with some special transistor pairs and tempcos These parts are normally hard to find, so I advise you to get these as well if you are thinking of building the PCB's yourself. There are also some special resistor values on there that I have trouble finding myself. Like the 3M32 1% resistors. I have found them at Mouser, but that will cost me a lot of shipping costs. So I have them in my basket waiting until I need some more stuff from Mouser.

And here are the front panels that I also got in the same order. I still need to order jacks, potmeters, knobs and switches for them, but it is nice to have original MOTM panels. Maybe I'll get the front panel components also from Mouser to complete my order for free shipping. It will only take a lot longer that ordering from Farnell. They usually deliver the next day here. Well I'll keep you updated then I have more news on this project. For now my package from Bridechamber is finally at the post office so I can pick that up tomorrow to finish some other projects :)

The Perfect Apollo Studio Decoration

When I was young (in a galaxy far away) I used to build plastic model kits of cars, planes but also space stuff. My room was full with it. But when I got older I threw or gave them all away. One of the things I enjoyed the most was the big Saturn V rocket from the Apollo space program. And guess what? In celebration of the 40th anniversary of the moon landing Revell decided to reissue those kits. Yeah!! I ordered them all today and can't wait until they arrive. It will be fun to pick up another old hobby and this stuff will be the perfect decoration for my Apollo Studio :) This way I can also get into the mood for the Apollo project that I'm already working on. Hopefully this album will be done in the end of next year or so. I already have some music for it, but still a lot of work. Well I'll update you on the construction of the plastic models as well on this blog :)

AVRSynth 32 (Part 4)

Today I worked a bit more with my daughter on the AVRSynth 32. The next thing to do was to mount all the front panel components. As said before I had to drill the holes for the led holders a bit bigger. 8 mm turned out to be the right size. For the switches I puzzled a bit which ones to use. For the power I decided to go for a double switch so that I can switch both the power and the ground later on. The rest are single on of switches. The midi address selector switches are very close together so I had to leave the mounting ring of there. And because of that I decided to leave them of on the other ones as well.

Here you see a picture of the back of the front panel. I'm quite curious by the way about the material they used to make the front panel. It looks like PCB material but on the front it is black and white. If anyone has info on this stuff I'd like to hear more about it. The only thing I'm not sure about is the orientation of the switches. But I'll see about that when I start wiring and testing. The next thing to do on here is do the inter component wiring. But since my daughter already lost interest during the mounting of the components I wont do that now.

After this I did a little job on my own. Here you see how I'm applying pressure to get the header connector on the flat cable. I used a small bench vice for this since it is quite some pressure you need for this. I made a lot of cables in the past this way, but funny enough I couldn't remember anymore where pin 1 was supposed to go. So I looked up an good old IDE hard disk cable I made in the past to see how it was supposed to be mounted. Good that I save that kind of historic material ;) After this I also made two smaller 10 pin connectors on the left over flat cable.

And here is the end result of the cables and they are already in place on the PCB. The other end will be split up and going to the front panel components later on. I also found two left over components in the case. One resistor that I still have to mount on the bottom of the PCB. And a capacitor that should go on the X2 position (big crystal), but my kit came with a small crystal that is mounted in the X1 position. So now I'm not sure if I need to mount this capacitor or not. I'll have to find out somehow. Well I hope my daughter wants to work on it some more later on. I'd like to finish this project soon. I have enough other stuff laying around as well.

Synth.nl played on Elektroland #96 and #97

In the first two weeks of November music from my OceanoGraphy album was played on the Danish Elektroland Podcast by Bjorn Jeppessen. He has a very nice show with electronic music that is broadcasted on several radio stations in Denmark. His shows are archived online so you can still listen to them online. The reason I bring this to your attention is that he played my song 'Indico' twice. This track is not online on my website or my MySpace page so you probably haven't heard it yet if you don't have the album yet. I think it is a very nice relaxed piece and I think it is worth listening. It is one of my personal favorite tracks of the OceanoGraphy album. You can find Elektroland here: http://www.nattefrost.dk/elektroland

PC Function Generator (Part 2)

I finished the PC Function Generator PCB this afternoon. You can see the finished module in the picture on the left. I was a bit scared it had a serious problem, because when I attached the power supply nothing happened. Not even the power led came on. I quickly checked if any parts were getting hot, but nothing got even warm. So I started looking at the PCB again and found no problems there either. Then I started to measure on the PCB and didn't see power everywhere. I was very confused about this. Then I thought it was time to read the manual. (Who ever does that? ;) ) And it turned out that this module switches itself on when it is activated by the accompanying software :) After this I attached it to the parallel port of my PC and started the software.

And guess what? It switched itself on :) So that mystery was solved. Here you see a picture I took from my screen. The software looks very basic, but there are some nice hidden features in it. But first things first. The function generator needs to be calibrated. Actually that process is quite simple. There is only one trimpotmeter on the PCB that adjusts the DC offset of the output. For this calibration you only have to attach a simple multimeter put on DC Volt measurement mode and adjust the trimmer until it reads exactly 0,00 Volts. So that is what I did.

After that I attached it to my oscilloscope to see the results of my freshly build apparatus :) And look a very nice sine wave! So it actually works :) After this I played a bit around with the software. You can load some freaky sound waves from a library and even design your own. I think this is very cool. You can also program it to cycle through different waves. So lets say 10 seconds of a 10 Volt Peak-Peak Sine wave at 200 Hz and then 10 seconds of a 5 Volt Peak-Peak Triangle etc. And also the Bode plot that I told you about that make a frequency response graph. I will try to show you all this functionality later on. Maybe also in a video.

After this it was time to put it in its enclosure. Here you see what it looks like with the lid of. I'm very happy that this project actually worked the very first time. Gave me my confidence back ;) Now I have to find a spot for this function generator and do some more testing. I want to see how accurate it is and compare it with my other function generator. Another cool thing I forgot to mention by the way is that is has a loop through connector for the parallel port. So the oscilloscope I build can be connected to this unit and operate both at the same time on the same parallel port. Very convinient. I think I'll fiddle around with it a bit more this evening. Well all in all a very productive day today :)