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AndrewMartens

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About AndrewMartens

  • Birthday 01/01/1

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  1. I think I might have a spare (ie, I have two total) in the batch I ordered a few years back. Let me take a look for it. Whereabouts would I be shipping to?
  2. Assuming that down the road you plan to provide PCBs for people, one option would be to have the 28- and 40-pin layouts side-by-side (ie; one row of 28 pins, one of 40, space, one of 28, one of 40) so that the user could simply solder in a socket for whichever size they had - without needing to built their own adapter board, or using point-to-point "dead bug" wiring. The downside is that (assuming you have a 28-pin device), you're paying for 40 useless holes per board. Looking at the datasheet, the footprint difference between the AY-3-8910 and -8912 is somewhat compatible, though not perfect. This approach might work with only a few jumpers required on a single-sided board.
  3. This is correct. Several years ago I picked up a bunch of old audio ICs from VintageFunWorld (now closed), including this assortment of chips (plus a SID and a few POKEYs). At the time I was looking at the YM2149 / AY-3-8910/12, and they are all essentially the same thing. You'll need to make a 40PDIP to 28PDIP adapter board if you want to use the YM2149 / AY-3-8910 in a board designed for the AY-3-8912, though.
  4. Great work! I must say, I'm so impressed with everyone pulling together all of these MIDIbox user projects for all the classic chip synths. I had acquired some AY-3-8912s and POKEYs several years ago, but never had the time to do anything interesting with them. Kudos, and I look forward to seeing the final project! :D
  5. The rat can make some pretty sweet sounds, that's for sure. The circuit is also very simple and runs happily off of +9V. Built it on a breadboard, worked great; moved it to a stripboard, and it still worked great ;D I was definitely tempted to build it into my SID, but it will most likely end up as a piece of outboard gear once I package it up.
  6. I looked at building the Wasp filter a while back, since IIRC it runs off of +9V happily. Alas, mine never worked properly, whether due to a cheap breadboard or cheap capacitors, I'm not entirely sure.
  7. I've had issues with 7912s as well. IIRC the problems I was experiencing were with ST's 79xx regulators. From a bit of Googling, I believe it had something due to them locking up (?) when there was no current draw on the output. Supposedly it could be fixed by adding a resistor to ensure a constant current draw during power-on, but that didn't seem to resolve the issue that I was having, either. Recently I picked up some 7912s from two other sources... and both of those sent me ST units as well. ARGH. I think I'm going to be reduced to using a MAX660 or an SI7661, etc. as a voltage inverter for my bipolar supplies.
  8. Fantastic! Now, I just have to figure out what box to put one into! I foresee a MIDImerger with an 8x output driver in my future ;D
  9. I remember those times. Creamware had launched Scope, and with a whole lot of Sharcs on board it was an amazing (and amazingly expensive) product. It was a shame Pulsar only came out later, as I had already exhausted my computer budget by then, and never had a chance to play with their products.
  10. Awwwwwwesome! I just acquired a Juno-6 a while back and haven't used it as much as I would like simply due to not being able to sync the arp on it. Now I have something I can fit into the extra space inside my 1U rack SID project :-)
  11. Just taking a quick look at the circuit, I noticed one problem... in the middle of the schematic, R42 (20k) should be connected between pin 8 and -9VDC. Pin 9 should also have a 20k resistor R43 connected to -9VDC. On your PCB layout, I believe these correspond to E$14 and E$15, except that you have them connected to +9VDC instead. This might cause it to be maxing the resonance value, hence why all it does is oscillate. Fingers crossed! [uPDATE]: On a slightly longer glance, you seem to have V+ connected to pin 6, and V- connected to pin 11. From the schematic, V+ should be on pin 11, and according to the LM13700 datasheet, V- should be on pin 6. ... aaaaaaaand all that really means is that on your PCB layout, the + and - labels are reversed. But assuming that you hooked it up with red = V+, then you at least have connected it correctly.
  12. That's a nice, easy-looking layout there. Should even be pretty simple to put on a veroboard. Bipolar power supply, I assume? Regarding ceramic vs. styroflex caps, of course the conventional wisdom is to use better caps in filters, but... meh, you don't really *need* to. Sometimes it's easier to just use whatever you have on hand. ;)
  13. This project isn't really on my radar, but I thought of one possible alternative to keeping panel sizes down: bi-colour LEDs. One instrument on a shared 'track' of LEDs would be green, the other red. It wouldn't help with DOUT or wiring complexity, but would keep the panel a bit smaller. Awesome idea! Just promise me that you'll find some good (free) Windows drivers for MIDI-over-IP :-) Are you thinking of the ENC28J60, or of one of the PICs that has a built-in MAC for Ethernet (which iirc there is one or more out by now)? I remember looking at the ENC28J60 a while back for a different project, and one issue I had with it is that essentially the PIC is a slave of the 'J60 when it comes to accepting packets on the SPI bus. There are a number of nice features, though - the 'J60 has a lot of capabilities for pattern-matching and filtering in the packet, which should make it a lot easier to reduce the amount of traffic that the PIC has to deal with.
  14. I've always been a fan of threaded rails, myself...
  15. I'm sure that we've all misapplied power at one time or another. I managed to swap Vcc and Ground to my LCD! IIRC my 6581 gets warm, but not too hot to touch. If you're concerned (and your SID isn't going to be moving around much), you could always attach a heatsink to the top of the chip with a bit of thermal paste. I had more heat issues from dropping 12VDC into my 7805 at 250mA, though - that one got the heatsink.
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