strophlex Posted January 8, 2010 Report Share Posted January 8, 2010 Great that you got a working EQ! Quote Link to comment Share on other sites More sharing options...
freddy Posted January 8, 2010 Report Share Posted January 8, 2010 I've abandoned the single-connector design in order to shorten audio paths and avoid parallel tracks. The current design is as shown in the attachment, I'll print it tomorrow and try building a prototype if no significant comments appear. Tried it today, but whatever I do the output still looks the same. Regardless of which PCB design I use there is always 400kHz sine wave generated on inverting pin of IC1 (see attached schematics). The 400kHz frequency is determined by the oscilloscope. The sine wave and it's frequency stays the same regardless of input signal frequency and shape (using function generator, 50Hz-20kHz input wave, sine, triangle or square). This "noise wave" is then mixed into output, obviously, and causing noise as shown on previous photos. Since the frequency stays the same regardless what I do I'd expect it to be some "environment" noise or error (though of unknown origin). I ran out of 100nF filter caps at the moment, so I'll finish building the gyrators later this week. Meanwhile I'll solder one AD5206 and depending ICs and start modifying MBMixer code to work with AD5206. If anyone op-amp skilled looks at the schematics and an obvious reason for the noise occurs to him, please let me know as well :rolleyes: The up-to-date EQ PCB design is attached for reference as well. Quote Link to comment Share on other sites More sharing options...
lylehaze Posted January 15, 2010 Author Report Share Posted January 15, 2010 Tried it today, but whatever I do the output still looks the same. Regardless of which PCB design I use there is always 400kHz sine wave generated on inverting pin of IC1 (see attached schematics). The 400kHz frequency is determined by the oscilloscope. The sine wave and it's frequency stays the same regardless of input signal frequency and shape (using function generator, 50Hz-20kHz input wave, sine, triangle or square). This "noise wave" is then mixed into output, obviously, and causing noise as shown on previous photos. Since the frequency stays the same regardless what I do I'd expect it to be some "environment" noise or error (though of unknown origin). I ran out of 100nF filter caps at the moment, so I'll finish building the gyrators later this week. Meanwhile I'll solder one AD5206 and depending ICs and start modifying MBMixer code to work with AD5206. If anyone op-amp skilled looks at the schematics and an obvious reason for the noise occurs to him, please let me know as well :rolleyes: The up-to-date EQ PCB design is attached for reference as well. I think I may have a clue... A resistor, a capacitor, and feedback are all that's required for a "R-C timer" or free-running oscillator.. so somewhere in your circuit you have a feedback problem. There are a LOT of resistors and caps in a EQ.. but finding the offending circuit might be as easy as jumping an extra resistor across each one in your circuit.. as the resulting resistance will be less, the pitch of the oscillation will change when you hit the right one. It's worth a try, anyway. Good Luck, LyleHaze Quote Link to comment Share on other sites More sharing options...
matoz Posted March 10, 2010 Report Share Posted March 10, 2010 (edited) HI LyleHaze, have you got some news for Mb-Mixer (hardware)? Is it still actual? regards Matoz Edited March 10, 2010 by matoz Quote Link to comment Share on other sites More sharing options...
lylehaze Posted March 10, 2010 Author Report Share Posted March 10, 2010 HI LyleHaze, have you got some news for Mb-Mixer (hardware)? Is it still actual? regards Matoz I don't know what the current status is.. We have talked about a re-design to make it all easier to build and more affordable, as the "stackpins" that I used in the last revision turned out to be a problem. The new design will look more like a normal board, but it will fit more PGAs per board, and use standard connectors. At least, that's the last I heard. It is still "actual", just not yet. I can tell you it works well, mine has been running every day for a long time.. it's the center of my entertainment system right now. And just in case you missed it, there's a java program for controlling a MIDI mixer over will control a MB-Mixer, or any Midi mixer, or most other midi gear if you take a few minutes to write an XML file that describes what you want. Thanks for your interest! LyleHaze Quote Link to comment Share on other sites More sharing options...
matoz Posted August 11, 2010 Report Share Posted August 11, 2010 Hello, old topic! Some news about this awesome project? I' ve nearly finished many projects and now, i can' t use all the stuff i built the 3 last years because my mixer is too small... I plan to build 7 mixers of 8 mono full boards, and i will mix these 7 mixers into another stereo one, so i would have 56 inputs. I want to control them with 2 modified mb64. I will gather all my machines with mixer, to do only a big one. But i can't make the final front panel because i' m not sure about the mbmixer final design. regards Loic Quote Link to comment Share on other sites More sharing options...
matoz Posted August 12, 2010 Report Share Posted August 12, 2010 I tried to redo the concept, and tried to remake the layout of boards, but after spending about 20hours of trying to make a mono board i told me it is a pity to spend time to try to remake something which already was reflects and quite advanced, than to advance the project which is in study...And i havn't the electronic level to redo the concept alone... So,if you need some help for something or testing, i have time and possibility to make some PCB. Don' t hesitate... best regards Loic Quote Link to comment Share on other sites More sharing options...
matoz Posted August 23, 2010 Report Share Posted August 23, 2010 i read another time my messages, and i think they coud be misunderstanding. Sorry for that... English is not my native language, and i think i didn't speak correctly... i don' t want to speed anyone, but, like i need a lot of boards stacking together for my project, i propose to make some tests with 8 and/ or 16 boards stacked together to see the limits of the concept, and try to find some solutions with all midiboxers. I hope it is more correct now... Best regards Loic Quote Link to comment Share on other sites More sharing options...
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