sparx

Not going to build one of these, but can you provide a link to the LPC17 output buffers schematic please?

I have had this on DIY MIDI circuits, what opto is the TR-9090 using? At a guess the opto is not as sensitive as others. Assuming it is the same issue, three choices: 1) Replace the opto circuit with a 6N139 circuit. Will require a bit of work to get it right. 2) Connect the Out via a MIDI Thru/Merge unit to as you say, "amplify" the signal. 3) Change the resistor in the TR-9090, I wouldn't but its up to you. Best choice is number 2, but these are just thoughts and I may be writing rubbish! S

is the double NAND necessary I don't know for sure but would have thought so. Looking at other designs, they all use a 7400 in this part of the circuit and most use the LS version. What I can tell you is that one device I wish to add to this setup won't work with the Core MIDI output, but does with the NAND output, makes sense to use something that will work rather than something that may work? S

Double post.

Martijn, using an op amp is not the way to go here, all that is needed is a couple of inverters. Take a good look at the design of the GM voice, this uses two NAND gates with inputs tied together. I am in the process of uploading all my stuff on this so far, if you can't wait, google "sparx plays up the junction". Give me a day or so and I'll post it all. Regards S

This is all really interesting stuff and has appeared just at the right time. I've been playing with a DB60XG clone and LPC17 core for a few months and am just about to revisit the project with ideas as to the end result. Hopefully this will be a starting point, at last, for everyone in uapps land. Take a look at the GM Voice here: GM Voice This circuit works, I have built and tested it. In the next couple of days and if there is any interest, I will post more stuff in probably a new thread as to what I have been doing and what I want to do with the board. In the meantime, have a think about what you want to do with yours and post back here. Regards S

The breadbins sometimes had soldered in SIDs, so 6581. Don't think I've ever had to do that with an 8580, they've always been socketed. But yes you are right, cost cutting and they told us at college to always use an IC socket. To answer the original question, unless the C64 is functioning, your pretty much stuck at trying to test the SID. If the rest is in poor shape, then you have nothing to lose really.

OK, the way I have desoldered SIDs is to get Mrs Sparx wearing a glove and holding an IC extracter. I then use a regular Blowtorch (Butane/Propane mix) and heat the solder side until its out. She loves it and has become quite the expert! She even looks forward to it..... Haven't damaged a SID yet but be as quick as you can. Oddly enough they didn't teach me this method at college. Needless to say the C64 board is damaged beyond repair after this.

Hi Marcelo I can understand the challenge, but out of interest, how much would a weighted keyboard be in Argentina? Just a keyboard, not any housing or commercial product? I have, in front of me, an LPC core hooked up to the GM Voice which in turn is hooked up to a Yamaha daughterboard. I'm using MIDI cables to connect everything, this was to make initial testing easier. So, my keyboard feeds the MIDI In of the core board, the Core board MIDI output feeds the Daughterboard via the GM Voice PCB. The way I thought about it was, the optos are safety devices, they stop unwanted signals and are cheap. Also my core board was already built and I'd put MIDI sockets on there. The Core PCB does have places I could have just put a connector and wired them together without the MIDI cables and sockets. This might happen in the "finished version". From what I have understand, the daughterboard requires MIDI at TTL level, hence the 74HC00. I'm actually usuing an LS version. Can report it all works very well! Regards Sparx

Seems a lot of work to make your own keyboard but if you're happy doing that.... Have a look at the GM Voice at: GM Voice It might be easier to follow. Good luck! S

Why not develop one for him and your band? If you look at the pinout of the SID and the YM2612 you should see they are similar, you'll need to write the software, but thats half the fun, so they tell say! More noise makers are always welcome with me!

Might the LCD be faulty? Do you have a known good one you can try in its place, just to see if you get anything displayed?

If you were paying into their bank they would be able to do it for free!

Ah, remember a lot of European countries use the same currency (at the moment!), which should make cross border trade easier. Paying any kind of fee to a bank seems wrong to me, but to transfer funds from one account to another must be easy for them.

Paypal seems to be the easiest way to do things like this. Yes they take a cut and charge a fee but its less than a bank. What about one of those money transfer places? I've never understood why the cost is so great, surely its only tapping a few buttons on a computer?

You can indeed see me on the video, I am at 5.57 in the blue T-shirt, sort of upper right, back row of audience. The gent with the black hair and pale face on the same row is Dave Vanian, lead singer with Punk legends The Damned. Re: Big boobed woman playing Theremin, there was a photo floating around the net showing just that. It's actually a fairly common reaction when someone sees a Theremin, they will often try to make a noise with some other part of their body. As you can see from the video and others on the net, the instrument does attract arty experimental and "wanna be" types, while there is nothing wrong with that, sometimes the end result isn't always very pleasant to listen to. Slow clasical string pieces seem to be the norm, although the guy playing Video killed the radio star at the beginning also belted out Should I stay or should I go and a couple of Ramones tunes, very different and very entertaining! S

Ah OK, there are plenty of things like that on the net, here are two: Jaycar MIDI Theremin Arduino based I have the Jaycar MIDI Theremin, don't use it much, but from memory, it was fun for a while. If you've never played a Theremin, the cheaper ones especially, its like trying to play a concert on a rubber band, its difficult and only a few can do it: Some of the performers at this concert were very good, others not quite so hot. I know because I was there! Generally, something like you are describing would use light dependent resistors or infra red sensors. The Jaycar uses a more "traditional" Theremin approach, but that might explain the high price. HTH S

Is the idea to get a Theremin MIDI controller or to build a Theremin with a micro controller? Some say only a unit using valves can be considered a Theremin. Think you are probably better off asking at Theremin World.

I'm getting an XML error when I try to downoad the PCB file, is it working for anyone else?

I'm back to playing around with the MIDIO128 V3 again. Spent quite a long time looking for details of the additional MIDI inputs and outputs, can find the schematics but no other details, can someone put a link for me? Other thing I have been thinking about, is it possible to have a push button turn off (or on) a channel on one one of the outputs? Setting the volume to zero won't work here, no data has to go to one particular output. All of this has to go into he MIDIO128 program. Its been a long day and an even longer week (which isn't over yet!), so if anyone can help it would be appreciated. Thanks all S

Great work! I'm not getting noise from the output of an NEC card, its driving TL072 opamps and seems fine. As for the inputs, from what I've read, they take line level. There seems to be a lot these cards can do.....

Have just hooked one of these up with a small interface board and a PSU, the sound is great! Where it goes from here and if it makes it to the MIDIbox family is another matter. Is anyone else looking at building something around this?

Here: Key Parts UK £24.50. HTH S

Tried 3 differemt PSU's since posting that, final one is 15VA, so am feeding it 9V, should be plenty of current to spare if it was needed. What is really throwing me is that the LCD doesn't dim, the control surface still works, just no output after a few minutes of use. As I said it was working fine, been away for a month or so, now poorly :-(.

Heres one which I am having trouble tracking down, SammichFM was working fine, now it seems to shut down, ie produce no sound after about three minutes, display is fine, voltage regulator is +5V, anyone got any ideas? Thanks S