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Two questions about the MB-6582


renepela
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Since a few months I enjoy having a MB-6582. It works great but there's two things I still have to do.

First the LCD display. On wilba's photo's The LCD screen is almost in line with the Control surface. It's just a little bit lower.

My LCD screen however is a lot lower than the panel. That's because I had to put several plastic rings between my CS and the LCD for isolation.

Is there a better way to get the LCD screen higher?

The second question probably is asked before, but I still don't get it.

I want to use the expansion port. At the moment I didn't wire it because I don't know how to do it.

I don't know which pins of the expansion port to which pins on the MB-6582 main board.

Do I have to wire all core's to the expansion port or only the first core?

Kind regards,

Rene

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First the LCD: Ignore photos of the prototype - this used a PLED display that was thin enough to fit between PCB and panel. The Mk II (TK's gift) was using the production run PCBs, with cutout in the PCB. I'm not sure why you needed "several plastic rings"... if you solder the wires to the back of the LCD, you only need something as thin as business card to insulate between the LCD and the CS PCB. Even minimizing this spacing, the top of the LCD will be approx. 2.5mm - 3mm lower than the back of the panel. I filled this gap with a piece of clear acrylic (in this case, slightly tinted grey). It doesn't go through the panel cutout, it is just glued behind the panel and so the edges can be rough, they won't be seen anyway.

I have considered doing a bulk order for pieces exactly the right size, made from clear 2.5mm acrylic... they would be so cheap to make and post that I could probably sell them for US$2 plus US$2 shipping anywhere, that is assuming I had a minimum of 25 orders.... however, it's the sort of thing I'd prefer someone else manage, I'll make them and send them in bulk to the US and Germany and let someone else with more time do all the packing and posting :)

The expansion port wiring is completely up to the user - the idea was it gives the user the ability to connect AOUT modules or analog inputs (like a joystick or SoftPot) or maybe one day it will connect to a Core32 daughterboard for MB-SID V3... i.e. a substitute for a USB port. If you don't have anything to connect to your MB-6582, you don't need to worry about wiring it! ;)  (It's also an homage to the original C64's expansion port).

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Thanks Wilba. It's probably a very stupid question, but what exactly can i do wit the aout board. Is it to control external filters? So will i be able to use the midibox OS to control external filters?

If I want to connect an aout module, Do I need to wire it to the first core only?

Another thing i don't understand fully is the combination of the auout module and the 2044 dual filter VCF.

I understand the AOUT module Control Voltages control the filter. But where does the audio go?

Can I use the expansion port to route the audio output to the VCF? Can I route the Audio output of the VCF back to the MB-6582 (again using the expansion port) and send the filtered output to the main outputs of the midibox sid?

That way i would only need one cable to the aout/vcf expansion and no extra audio connections.

Last question: Can I power the aoout module and the 2044 dual filter VCF from the expansion port or do I need an external power supply?

Kind regards,

Rene

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Yes, AOUTs generally control stuff like external filters. You'd need to power them separately, as they typically need bipolar PSUs. You can connect them to each Core, i.e. if you want to have all four SID engines have their own external filters, you'll need (for example) 4x AOUT_NG and 4x SSM modules.

The audio would typically come out of the audio sockets and through cables to the external filters. The SSM module has a bypass switch which means you could have it always connected and get the Core to use/bypass the filter. The other ideas you suggest don't work well, and would involve cutting tracks and wiring SID outputs through the expansion port, and then if you weren't using external filters (i.e. it wasn't present at all), you'd need some some kind of loopback plug. All very messy. You're better off with the flexibility of cables between MB-6582 and external filters.

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It's all becoming clear to me now. Last questions (I promise).

The aout_ng has 8 CV outputs. I probably need 2 CV's for a filter module (one CV for cutoff and one fro resonance).

So can I use 4 x 2 CV's for 4 filters? That would mean I only need 1 AOUT_NG module to control 4 filters.

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each core can only control parameters of its own SID pair. that also is true for the connected AOUT(NG/LC). so you'll need one AOUT for each Core/SID pair. but as there are two SIDs on one core, that also means you need to control cutoff/resonance for two channels/SIDs, so you'll use 4 CV outs on each AOUT. The other four are free to use for something else (e.g. a final VCA per channel etc, whatever you might want to add to the box).

S

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How stupid of me ! I completely forgot it's stereo. Now I also understand why you designed a dual VCF.

So I need an aout_ng module for each core and 4 dual VCF boards.

Are there pcb's available with 4 x aout_ng and 4 x dual filter on it? A one pcb solution would be nice and a great addon for the mb-6582.

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Are there pcb's available with 4 x aout_ng and 4 x dual filter on it? A one pcb solution would be nice and a great addon for the mb-6582.

no, such a PCB doesn't exist. At first I thought about doing something like that - or at least one NG + stereo filter on one pcb. But aside from complete projects like the mb6582, the original modular approach of midibox does make sense. If you offer such a pcb, some people will say "but I've got mono, I need only one filter", some others "but why only 1 NG/2 SSM, 4/8 are better", some people have already bought their NGs in advance and couldn't make use of half of the pcb etc. so for something like the SSM filter that is clearly an addition for more adventurous/advanced builders (who in my opinion CAN be bothered to do a bit of extra wiring ;)), you can't ever make everyone happy by doing such a combined board - btw, for a MB FM, a pcb with one NG and 4 SSMs would be best...

S

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I use an AOUT_NG connected to the expansion port for CORE 1 in my MB-6582.  There are a few pictures here:

  http://picasaweb.google.com/fussylizard/MB6582?authkey=Gv1sRgCM7npqbPgvbfYA&feat=directlink#

I just wired J6_CORE1 to the first few pins on the expansion port.  No major planning, I just picked what was easiest to solder. :-)

I ended up putting the +/1 12VDC power supply board and the AOUT_NG board in a cheap plastic box as described here:

  http://www.midibox.org/forum/index.php/topic,13845.0.html

In my setup I connect the audio out from CORE 1 to audio in on a Moogerfooger lowpass filter guitar pedal (one channel only since it's a mono pedal), and audio out from the pedal to my soundcard input (which then goes out to the speakers, etc.).  Channels 1 and 2 on the AOUT_NG are routed to the filter cutoff and resonance CV inputs on the Moogerfooger.  Then I can play sounds on the SID and have the SID filter envelope control the Moogerfooger cutoff, etc.  It's lots of fun.  I'm actually thinking about getting some modular synth filters and trying those out just for fun.

I also just got one of Seppoman's SSM filter boards (rosch had an extra one he let me "borrow") but I've not tried it yet.

Have fun!

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