MB-6582 : A few questions

[renepela]

Last week I received the MB-6582 base en CS pcb's. They look great. Thanks Wilba and SmashTV !

I read all the documents about it but there's a few questions I can't find answers for.

Hopefully someone can help.

1) What's the value of the 4 pots on the back of the case?

2) How do I power the fan in the back? It needs 12V, but 9V should also work (I'm building the A version). It just gets a little slower. Where do I attach the fan to the pcb?

3) What kind of connector is used on the back for the expansion options?

4) Does anyone know where to get the tactile swithes? I can't find them anywhere in Europe and ordering from Mouser is quite expensive from the Netherlands.

Thanks

[nILS]

1) dual-gang 500k pots

2) J25 (~9V-11V DC, for connecting to fan).

3) DB25

4) reichelt, conrad.

Hey, how cool is that - all of the answers are right here: http://www.midibox.org/dokuwiki/wilba_mb_6582_base_pcb_construction_guide

[ping-]

4) http://www.rapidonline.com/  (UK)  part number 78-0626

I think they have the same specs as the switches wilba describes in his guide.. :)

[Wilba]

2) J25 gives ~11V, but you can also use J3 for 5V or J4 for 5V or 9V (or 12V if PSU Option A).

[Wilba]

1) I do mention elsewhere that the pots I used are dual gang 500K log, although linear works too, and also I used 100K pots on the last one with no problems... so anywhere between 100K and 1M will work.

part from JayCar

[Smithy]

1) I do mention elsewhere that the pots I used are dual gang 500K log, although linear works too, and also I used 100K pots on the last one with no problems... so anywhere between 100K and 1M will work.

part from JayCar

Did you notice any difference in the sound?

I guess the linear 100ks arent as strong or something?

Hehe i think we need someone to volunteer to do an audio comparrisson with the different values,

in the style of the site owned by the dude who came up with the idea for using feedback with a sid!

[Wilba]

The pots are just attenuating the SID output on its way into the SID input.

The value of the pot doesn't matter. In my suggested wiring, it's used as a voltage divider so that you can have anything between a grounded input and maximum SID output routed to input.

[renepela]

Thanks for all the answers and help. I''m ready to order those last parts now and finish my MB-6582.

I think the tact switches from rapid are almost right, but the button is not 3.5mm at the base and 3mm at the top. I think it's just 3.5 mm which means it prbably wouldn't fit in the control panel.

[Wilba]

I think the tact switches from rapid are almost right, but the button is not 3.5mm at the base and 3mm at the top. I think it's just 3.5 mm which means it prbably wouldn't fit in the control panel.

http://www.midibox.org/dokuwiki/wilba_mb_6582_control_surface_parts_list

48x ALPS tactile switches, 13mm tall (ALPS part SKHHDTA010). The control surface PCBs and front panel are designed around these switches. They snap into the PCB holes and are thus perfectly aligned with the panel, and poke out 1.5mm from the top of the panel, making for a neat finish. Datasheet here: http://www3.alps.co.jp/WebObjects/catalog.woa/PDF/E/Switch/Tact/SKHH/SKHH.PDF What it doesn’t show is that they taper from 3.5mm diameter at base of shaft to 3.0mm diameter at top of shaft. If you get switches like this from another manufacturer, they should taper the same way, i.e. preferably be 3.0mm at top of shaft so there is a little gap when put in the 3.5mm hole in panel.

I thought I was pretty clear on this topic...  ???

[renepela]

I'm very sorry if I'm asking some stupid questions, but English is not the language I'm used to speak and sometimes I just don't understand 100% what is written.

If I'm interpreting the manual correct the shaft is be 3.5mm at the base and about 3mm at the top. The holes in the control panel are 3.5mm but when I use a button which is 3.5 mm at the top the hole is a very tight fit so that's why 3mm at the top is prefered.

So are the sugested buttens from rapid correct, because I think they are 3.5mm at the top of the shaft?

[strophlex]

What are the other components fitted on the back panel. There is some led and some socket on top of that. Anything special?

[renepela]

The led is just a power led.

The socket above the led is a combined output of the 4 stero channels.

By the way: Is that a stereo output or a mono output?

I guess it's stereo but I'm not 100% sure.

[Wilba]

So are the sugested buttens from rapid correct, because I think they are 3.5mm at the top of the shaft?

I can only say that I expect them to be 3.0mm at the top, if they are made to match the "original" ALPS switch. I can't be 100% certain. I think the reason they make the longer shaft ones smaller at the top is to allow for easier assembly, since the "gap" between the panel hole and the switch base is greater.

The socket above the led is a combined output of the 4 stero channels.

By the way: Is that a stereo output or a mono output?

I guess it's stereo but I'm not 100% sure.

It's up to you... there is a (passive) mixed stereo output at J70 (mixes the 4 stereo channels), which you can connect a stereo "headphone" socket, not intended for headphones though, more for a simple mixed output, say if you wanted to plug it into an amp just to show it off to someone... ideally you should mix the channels using some proper mixer.

[Smithy]

The pots are just attenuating the SID output on its way into the SID input.

The value of the pot doesn't matter. In my suggested wiring, it's used as a voltage divider so that you can have anything between a grounded input and maximum SID output routed to input.

The fact it can be used as a grounded input when its not open is awesome! Thanks for the reply.

What i would love to have for my mb-6582 is have both the 4 stereo feedback pots and 4 stereo (NC) input sockets.

It would need a custom back panel though and could be a very tight squeeze.

I might just be able to get away with it using 1/8" stereo sockets or something. Must fire up the FPD file and see what can be done.

[Smithy]

What i would love to have for my mb-6582 is have both the 4 stereo feedback pots and 4 stereo (NC) input sockets.

It would need a custom back panel though and could be a very tight squeeze.

I might just be able to get away with it using 1/8" stereo sockets or something. Must fire up the FPD file and see what can be done.

Okay after researching this, im thinking about fitting 4 x 3.5mm Stereo sockets into the Expansion port hole,

with the LPT Socket Removed.

The default hole size of the back panel looks too big to be able to tighten the nut of the audio socket around it,

so it looks like the hole would have to be reduced to say the standard hole size you have on the back panel of a Desktop Computer.

I do not have any 3.5mm audio sockets to test this  out yet, but as soon as i get one i shall try to determine what the best size Hole would be.

The advantage of using the existing expansion hole, is that you can always remove the sockets later if you want to put the expansion socket back for other uses, and the fact theres virtually no room elsewhere to do this.

If anyone has any thoughts on this i would appreciate a reply.

[nebula]

The expansion hole fits a standard DB25 perfectly.

If you want to route audio through it, the best thing to do would probably be to make a custom cable that has a DB25 on one end to mate with the expansion connector, which "fans out" to 4 stereo, or 8 mono plugs.

[Smithy]

The expansion hole fits a standard DB25 perfectly.

If you want to route audio through it, the best thing to do would probably be to make a custom cable that has a DB25 on one end to mate with the expansion connector, which "fans out" to 4 stereo, or 8 mono plugs.

Yeah thats a good idea actually, to have a removeable DB25 male to audio connectors!

Cheers.

[Wilba]

The M-Audio Delta 1010LT does this, although it's DB44 and a bucketload of connectors.

[nebula]

So does the Emagic Audiowerk 8.

[stryd_one]

And the Echo Gina/Layla(24/3G), and heaps of stuff with ADAT. It's far from rare ;)