msi Posted June 2, 2003 Report Share Posted June 2, 2003 With the move to the pic18 is it possible for the Midibox to control devices via something like an analog out. Â I'm trying right now to figure out how to build a mixer using something like the Midibox MIOS to control groups and such. Â The dout modual can be used to trigger relays to open/close but controlling something like the level of the channels hasn't come to me. Â I'm going to work on this in levels, starting with a small distortion type box using solidstate components with midi controlled gain/vol/EQ and switching. Â Then move on from there if I succede. Â Anyone have any comments on how this can be done with the current state of the MIOS? Â Thank you.William Quote Link to comment Share on other sites More sharing options...
Frank Posted June 2, 2003 Report Share Posted June 2, 2003 Hi msi,The cheapest solution would be to use VCA's for the analog audio path. And then use MBMF fader control voltage to also drive the VCA's.The easier but more expensive solution is to use motorised audio faders (eg. P&G). They have both a control track and an analog audio track. This is the most preferred method cos the audio does not have to go through another op-amp and the fader just replaces your existing mixer's fader.PeaceFrank Quote Link to comment Share on other sites More sharing options...
pilo Posted June 2, 2003 Report Share Posted June 2, 2003 Another solution : use LDR and Led! this is a better way than relay (LDR and led is use in tube amps such as Mesa Boogie ect...), and if you can control the led intensity, you can control de value of the LDR... without any VCA, you just replace all the pot by LDR, and maybe a little more, to control them with an Analog signal! The midibox as got no Analog out, but I don't think it's a hard thing to implement... (CAN on DOUT?) Quote Link to comment Share on other sites More sharing options...
pay_c Posted June 2, 2003 Report Share Posted June 2, 2003 Nope, no AOUT (yet?). With a digitally out its kinda stupid to realize something like that. You would have to get the DOUTs working as pseudo bits (e.g. 7 Outs as 7 Bits for a solution of 128 steps) having the proper resistors and/or diodes at the outs for regulating the brightness of the LEDs.Another soultion would be to have several MIDI to CV devices and then using a VCA as stated above. Quote Link to comment Share on other sites More sharing options...
Captain_Hastings Posted June 2, 2003 Report Share Posted June 2, 2003 Hmm... i think SmashTV mentioned something about digital potentiometers recently... ::)That would be ideal... Quote Link to comment Share on other sites More sharing options...
TK. Posted June 2, 2003 Report Share Posted June 2, 2003 Possibly SmashTV means the DS1801 from Dallas Semi.; this chip provides two digital potentiometers with logarithmic characteristic which can be controlled via a simple serial protocol. Several DS1801 can be cascaded to a long chain.Datasheet:http://pdfserv.maxim-ic.com/arpdf/DS1801.pdfThe serial protocol (called SPI) is exactly the same like for the SID module. So, no special MIOS extension is required, you just only have to connect the first DS1801 of the chain to J10 of the core module, thereafter you can transfer the command words with the SID_SR_Write routine in sid_sr.inc of the MIDIbox SID application (note that this routine has been optimized for speed and could be written in a less complicated way ;-))Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
Guest Flownezz Posted June 3, 2003 Report Share Posted June 3, 2003 I noticed the DS1802 (http://pdfserv.maxim-ic.com/arpdf/DS1802.pdf) has all the same features plus a manual volume up/down control.... Hmmm - Maybe i could retrofit my behringer with a few if these babies and a motorfader unit... MIOS DIGITAL MIXER!!!It just might work ;D ;D ;D Quote Link to comment Share on other sites More sharing options...
pilo Posted June 3, 2003 Report Share Posted June 3, 2003 Yeah!! this way it's possible every pot of a mixer channel! I've got schématic of analog mixer (with preamp, eq, aux, buses ect...). BUT! I don't think it's a good idea to replace every pot by DS1801 in a mixer : it will be cheaper to use DSP... :-/ Or another solution with a linux box, a good CPU and multiple sound card (for a mixer, we don't care about sync between card) Quote Link to comment Share on other sites More sharing options...
Captain_Hastings Posted June 3, 2003 Report Share Posted June 3, 2003 Hi Thorsten,Can any SPI-compatible digital pot be used with the current MIOS/SID version as you explained?These ones also use the SPI interface:http://www.analog.com/Analog_Root/productPage/productHome/0,2121,AD5206,00.html(Although not logaritmic, you could set the value logaritmically.) Quote Link to comment Share on other sites More sharing options...
smashtv Posted June 3, 2003 Report Share Posted June 3, 2003 (Although not logaritmic, you could set the value logaritmically.)You could also cheat a bit on the log taper without weighting the values from the control side, see http://www.e-insite.net/ednmag/index.asp?layout=article&articleid=CA46509Smash Quote Link to comment Share on other sites More sharing options...
TK. Posted June 5, 2003 Report Share Posted June 5, 2003 Yes, any SPI compatible chip, also the the AD5206Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
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