Midibox with AOUT + SHX8?

[Synthhead]

Hi.

I'm planning my first midibox, hopefully to include an AOUT and SHX8. At the moment, only the MB64 supports the extension.

I couldn't find any posts mentioning this combination in the forum. Has anyone built such a midibox?

Any ideas welcomed.

cheers,

Dave

[illogik]

Hi,

I'm also building a shx8 module to use with midibox cv.

The midibox_cv is quite a new application and the shx8 an even newer module; it's working like you said in mb64 but still has to be implemented in the other applications for more possibilities.

at the moment however, TK is in the middle of designing the midibox fm-synth ( ;D ;D); which leaves i guess not so much time for doing anything else...

for me this means i'm going to build the shx8 module when i get the parts and just be patient.. (well, patient; from my experience i'm slower in building pcb's then TK is in making complete applications so it will be fine   ;) )

Just figure out what you want to make exactly (sequencer, midicontroller , midi interface) by reading about the possibilities(+planned features) of the applications and thinking about what you plan to do with your machine; and if there are things you want wich aren't implemented yet; read around a lot on the forum to look for news, and again, patience...

good luck, marcel

[Synthhead]

Hi.

The plan is to build a multi-output midi-CV converter to control an analogue synth that I'm building. The MB CV would be the best for this job (low latency) when the SHX8 is supported, but as you pointed out, TK is busy with a little FM project..... :)

The MB64 would be an interim solution for now, as it would be a control surface, as well as having the ability to generate lots of CV outputs. If only the MAX525 chips weren't quite so expensive - about £24 each + tax! On the other hand, the nearest rival is a ready made Doepfer unit with only 24 CV outputs that costs about £350 + tax.

( everything is expensive in the U.K. :(

Once the MB CV gets SHX8 support, I think a lot of analogue synth DIY guys are going to be very interested.

I'll probably go for an MB64 now, as I'm keen to get stuck in to building the 1st midibox. I guess I can always upgrade later as changes happen.

Cheers

Dave

[TK.]

Hi,

a short note to the AOUT board: I'm also not happy with this high-cost solution, especially because of the bad availablility of the MAX525. Currently I'm using only one AOUT board for myself for different purposes (MBSID/MBSEQ, later also with MBFM), a friend uses one AOUT driven by MIDIbox CV and one AOUT/SHX8 driven by MIDIbox64 to control his modular RSF kobol expanders.

We both need more CV outs - therefore next year I will possibly build a cheaper version. The only problem I have is to find a DAC which suits perfectly:

• 1) best availability
  
• 2) best resolution
  
• 3) most channels
  
• 4) serial interface
  
• 5) best price
  

To 1) the DAC should be available at a mailorder company which delivers worldwide to hobbyists (small quantities)

To 2) 8bit is ok for most projects! 9-12bit are better, more than 12bit not required

To 3) if 4 single channel DAC are available for less money than a 4-channel DAC, then I would prefer the single channel DAC

To 4) a serial interface (SPI) with a chip select input, a clock and a serial in/output is preferable, otherwise the devices cannot be chained

To 5) we want to save money :)

So, if anybody has some tips, please inform me and I will try it out.

Best Regards, Thorsten.

[AndrewMartens]

• 1) best availability
  
• 2) best resolution
  
• 3) most channels
  
• 4) serial interface
  
• 5) best price
  

TK, I've been looking a bit at DACs for my other project I've told you a bit about - it's especially important given that I need 8 CVs per voice.  One possibility would be TI's TLV5620 - http://focus.ti.com/lit/ds/slas110b/slas110b.pdf:  a quad, 8-bit DAC with serial input.  The serial interface is rather odd, and the chip select/latching method involves some LOAD and LDAC pins, which I haven't figured out yet - it may mean that the device cannot be selected separately from other DACs (and is therefore useless).  

It's only $3.85 CAD at Digikey, which means that it's pretty available, at least in my books, and also reasonably affordable.

[moebius]

Hi,

I've been looking into this matter too with no success. Multichannel DACs with chaining options are hard to come by.. (Is this Maxims specialty?)

TI also has Octal 8-bit DACs (DIP), SPI but no serial output.

To 2) 8bit is ok for most projects! 9-12bit are better, more than 12bit not required

I'm a bit worried about future expansibility in projects like Andrews.. That is If PIC is directly used to generate control information, say, like mixing note and pitch bend data to be used directly to control VCO.

Bye, Moebius

[AndrewMartens]

I'm a bit worried about future expansibility in projects like Andrews.. That is If PIC is directly used to generate control information, say, like mixing note and pitch bend data to be used directly to control VCO.

I'm a bit worried about trying to implement projects like mine  ;)

I'll start a new thread which will cover more of the specifics of it, instead of trampling all over the place (it's a bad habit of mine...).

[DrBunsen]

Is it possible a dedicated PIC could do service as a DAC, using the existing analog out pins?  Perhaps a different (cheaper?) model?

[TK.]

The PIC doesn't provide an integrated DAC.

Sometime people are using the PWM outputs to generate different voltage levels, but there are only two sources, the voltages are not adequate enough and a cheap(er) DAC would do a better job

Best Regards, Thorsten.