FPE Panels for MB-6582

[nILS]

mmmmmorange!

[m00dawg]

What LCD are you using? Seems to have nice contrast (and I'm shopping around atm)...

Agreed. I think it will look awesome with the rest of the look!

As for the LEDs, it's a little hard to tell from your photo how orange or yellow they are. Looks like the white-balance might be a bit off? Either way, I think I know what you are talking about. My Virus appears to have yellow LEDs, but they look much more amber to me than yellow when lit. I hadn't thought of the cause being due to the LED matrix stuff (I think the Virus uses something similar too) but that would make sense.

Even so, I think it would still be a damn good look!

[strophlex]

There are some pinctures of my build here http://www.midibox.org/forum/index.php/topic,13432.msg115675.html#msg115675 if you are interested.

[fussylizard]

@strophlex - Looks good!  I didn't see your post earlier since it wasn't in the MIDIBox SID forum.  Thanks for the link!

@wilba - the display is a CrystalFontz CFAH2004A-YTI-JT - https://www.crystalfontz.com/product/CFAH2004AYTIJT.html

I used a 2x20 version on something else and really liked it, so I decided to get the 4x20 version.  You can get cheaper displays elsewhere, but I've been happy with the CF ones so I've stuck with them.

@m00dawg - yeah, the lighting is off, sorry!  At full power the LEDs are similar to the yellow display, but as part of the CS they are much more orange.

I'm not sure if reducing the resistors used to ground the LED matrices would change the color or not.  The resistors are only 220 ohm IIRC, so there's not much to reduce.  It's probably the 1/8 duty cycle that's the issue, but I'd have to test to find out for sure.

[fussylizard]

My post count hit 50 so I became a "MIDIBox Member" and got a second star by my name...

<proudly wipes tear from eye>

I love you guys.

[Wilba]

@wilba - the display is a CrystalFontz CFAH2004A-YTI-JT - https://www.crystalfontz.com/product/CFAH2004AYTIJT.html

I used a 2x20 version on something else and really liked it, so I decided to get the 4x20 version.  You can get cheaper displays elsewhere, but I've been happy with the CF ones so I've stuck with them.

Ahh... FTSN Negative... this is basically a green version of the red one I've used. Nice. Cheaper than Optrex STEP displays, almost as good.

It's been fun watching you guys build and blog about it... I may have to send you some tinted grey 3mm acrylic windows to go between the panel and LCD... fills the gap nicely and you don't notice it anymore. Black sharpie on the panel cutout edge finishes the job nicely. You see people? Pics get rewards!

P.S. 2000 posts :)

[fussylizard]

@Wilba - Well I'm having tons of fun with it.  This truly is a great community.  I've kept a few notes along the way so hopefully I can contribute some pics and improved documentation.

So what do you get at 2000 posts? :-)

Quick update: I indeed still had the testtone app on cores 2 and 3, so after uploading the MB-SID app all four cores are working.  I also enlarged the passive audio out hole to fit my jack w/ a size O drill bit (.316") - see pic below.  I have a small milling machine so it was super easy.

I also installed the fan I bought from Mouser.  It's super quiet so I'm pretty happy w/ it.

I played about w/ the CS and I think my LEDs are too bright.  Pity since I'll have to de-solder the resistors I put in the other day.  I may just solder in sockets so I can try different resistors to find the ideal brightness.  Glad I kept that assortment bag of resistors I bought from Radio Shack back in, oh, 1985.  Better sand those leads a bit to remove any oxidation before I use them...

NB #1 - the encoders are a bit difficult to turn w/out knobs.  Can't wait for those to arrive from Goblinz's bulk order.

NB #2 - it's also hard to use the softkeys below the display when the display is not mounted and sitting off to the side. :-)  I should get my LCD mounting bolts tomorrow, woohoo!

I've been surprised at how the pins for the headers to my CS have not managed to short themselves despite not having the black female sockets yet.  I was a bit concerned about it, but they seem to have stayed fairly well aligned despite opening and closing the case dozens of times.  See pic.

Also, my SIDs get way hotter than I'd like.  There was a recent thread about heat that I'll have to re-read, but mine are NOT comfortable to touch for more than a few seconds.  Hopefully this is normal, but I'll probably look into getting some sort of heat sinks if possible, esp. since replacements will be scarce since Wilba haz no moar SIDz (though I did get two spares just to be safe).

Hmm, 3mm acrylic windows might work well.  Where would one get such a thing?  A plastic supply store?

[strophlex]

Hmm, 3mm acrylic windows might work well.  Where would one get such a thing?  A plastic supply store?

I cut a piece of CD jewel case. Judging by how jewel cases usually behave, it might be a bit fragile, but it is pretty well protected and looks good.

[fussylizard]

I cut a piece of CD jewel case. Judging by how jewel cases usually behave, it might be a bit fragile, but it is pretty well protected and looks good.

Good idea!  I guess 2-3 layers are required (not sure of the thickness) to close the gap?

[fussylizard]

FWIW My screws stick great to the FPE panel I got.  Those things are never coming off.  I think the threaded shaft would break off before the head came unstuck.

I take it all back.  I got my LCD installed to the board and was screwing the case together with the bottom screws when one of the corner screws detached from the back of my front panel.  Once I figured out what was going on I discovered another one (opposite corner) was loose, and I yanked a bit on another and it came off also.  The fourth one is still solid.  So...I guess I'll have to try sanding the panel and using more JB-Weld.

One downside to using right-angle headers is the wires get pretty bunched up and can make it a little hard to close the case.  The wires have to be long enough to allow you to open it up flat, so I don't know that there is much to be done about it.  But I can't imagine not being able to detach the boards from each other without desoldering, so I'm still glad I did it.

One step forward and two steps back tonight... :-(

[m00dawg]

One downside to using right-angle headers is the wires get pretty bunched up and can make it a little hard to close the case.  The wires have to be long enough to allow you to open it up flat, so I don't know that there is much to be done about it.  But I can't imagine not being able to detach the boards from each other without desoldering, so I'm still glad I did it.

So, to clarify, you used right-angles on both panels? That was my plan, though I forgot about putting the right-angles on the bottom of the main-board. Seems like that makes a lot more sense :)

I started soldering diodes yesterday. I don't have any pictures (not much to speak of yet) but it's coming along. I haven't had my screws come off although I am a bit worried about them myself. I was messy about my JB Welds for the spacers too. I opted just using my screwdriver method. That worked well initially but, as the JB started to turn in to putty, it got interesting. There are a few places I would have liked a bit more JB but, for the most part, everything looks good.

I did have to hollow out the screw holes in the PT case quite a bit, though. But other than that not too bad.

I also thought I had ordered yellow LEDs but, apparently, I didn't :) So I had to order those. And my LCD is green since I originally thought green would be fine. I'm going to go ahead and wire it up for now but will eventually need to replace it with an orange one.

[fussylizard]

I only used RA headers on the top of the CS PCB.  I soldered the cable to the baseboard as shown in the pics here: http://www.midibox.org/forum/index.php/topic,13492.msg116408.html#msg116408

There really isn't much space in the bottom part of the case for RA headers on the baseboard (they *might* fit, but it would be tight) but ultimately you really only need one side detachable so I just put the RA headers on the CS.

I'm going to have to re-glue the corner screws sometime this weekend, and this time I'll use a lot more JB Weld.  I didn't have to hollow out the holes before, but this time I definitely will. :-)

[strophlex]

Good idea!  I guess 2-3 layers are required (not sure of the thickness) to close the gap?

I used only one layer but glued it right to the panel with cyan acrylate glue.

[fussylizard]

@strophlex - Cool, I'll have to give that a shot.

Project update: I finally got some more time to work on stuff last night, so here's where things are:

- I fiddled about with new resistor values for the CS LEDs and determined that 2200 Ohms are what the doctor ordered (instead of the stock 220 Ohm with SmashTV's kit).  I tested with the original 220 Ohm resistors and thought they would be fine (and, let's be honest here, I was perhaps just the slightest bit impatient and wanted to see the pretty lights working), but once things were closer to finished they were way too bright.  The new resistors make the LEDs almost dim, but I compared the brightness to other equipment I have and tried to match that.  I can now read the text legends easily even with several lights on nearby.  So my advice on LED brightness is to compare to other equipment if possible since the best brightness will probably be way less than you initially think.  Way less.

- Desoldering the old resistors was a barrel of fun.  I tried to salvage the old resistors by cutting one leg from the top side and pulling them out from the top while heating the bottom.  Unfortunately I ripped up a trace (!) on one of them.  I got lucky in that it didn't detach from the pad at the other end, so I was able to just solder the other end back down with the new resistor and it works fine (you can barely tell it was messed up).  So for the rest of the resistors I followed Wilba's instructions exactly and cut each one in half, heated the bottom while pulling the part off from top of board, and then used a solder sucker from the bottom while heating from top.  A solder braid helped with a few problematic holes, but it went pretty smoothly after I cut the parts in half.  Thanks Wilba for the recommendations!

- Turned out I had 15 2.2K resistors in my scrap box, one short of the 16 needed.  I popped by Radio Shack earlier today and they had 2.2K 1/8 watt resistors.  The others are 1/4 watt, but by my calculations the 1/8 watt will be fine so I can live with having one physically smaller resistor.

- I re-glued the corner bolts using way more JB-Weld than last time.  Hopefully that will hold better now.

- I soldered wires and crimped headers for the feedback pots.  I have two 500k audio taper and two 100k linear taper pots.  I'll try them and see which I prefer.  I also discovered that the rear panel holes are too small for my pots, so I'll have to drill them out like I did for the power LED.  (I guess parts in Australia are smaller, Wilba? :-)

- I need to figure out how to attach the power LED.  My plan is to just glue it to the back of the hole, but if anyone else has a better idea feel free to pipe up.

I'll upload some pics later.

Regards,

C

[Wilba]

- I soldered wires and crimped headers for the feedback pots.  I have two 500k audio taper and two 100k linear taper pots.  I'll try them and see which I prefer.  I also discovered that the rear panel holes are too small for my pots, so I'll have to drill them out like I did for the power LED.  (I guess parts in Australia are smaller, Wilba? :-)

I'm pretty sure it's a standard 16mm pot.

- I need to figure out how to attach the power LED.  My plan is to just glue it to the back of the hole, but if anyone else has a better idea feel free to pipe up.

I don't have a better idea. I use Super Glue (Cyanoacrylate), and wires/two-pin connector.

[fussylizard]

@Wilba- thx for the info.  I ended up getting 24mm pots, which probably explains it.  Nothing a drill bit can't fix though!

BTW did your pots have little metal posts that stick out the same direction as the shaft (see pic), presumably for going into a second hole in a panel to keep the pot from rotating when you turn it?  If so, did you leave it on or grind it off?

[fussylizard]

Scratch that last part about the pots.  I drilled out the feedback pot holes to .316" and was test fitting the first one when I realized that the pots are too big for the rear-panel hole spacing (back part of pots are too wide) so I can't fit adjacent pots on the back panel.  Duh.  So I'll have to order new pots.  I'll probably just put in two temporarily to see which I prefer (500k or 100k; audio vs. linear).  Not a big deal, but a bit irritating.

At any rate, I only have a few things remaining and I'm at that dangerous point where things are functional and motivation to finish off the last details wanes rapidly. :-)  My biggest concern at this point is the heat that the SIDs generate, so I'll at a minimum cut some ventilation slots similar to Wilba (or maybe just drill holes, that would be much easier) to increase airflow.  If I can find suitable heat sinks I'll use those as well just to be safe or I could try making some on my milling machine (that might be fun!).

I need to post pics of the way I mounted the front panel to the case.  After my copious amounts of JB Weld on my corner bolts it seemed unlikely that "countersinking" the mounting holes in the case would leave much plastic left.  I ended up cutting the corner mounts out completely with a hobby saw.  I then put the panel in the front part of the case and then used large-ish washers to hold the front panel to the backside of the case.  I still had to file down part of the ledge that supports the front panel near a couple corners due to JB Weld, but everything seems solid so far.  I'll probably JB Weld the washers in place to preclude slipping just in case, but it's probably fine w/out it.  I used two nuts with a lock washer in between them to hold the washer in place without putting undue pressure on the front panel.  Pity I didn't take pic of the final assembly, but I'll do so when/if I mount a clear window in front of the LCD.

So here's a pic of where things stand.  I'm pretty happy w/ the LED brightness, though they barely show up in the pic.  It is a huge improvement.   Can't wait for the knobs from the bulk order...

[m00dawg]

Looking good! That LCD display looks pretty how with everything too!

It's a bit hard to tell from the photo, but are your LEDs showing up as yellow or amber? I know you wanted yellow - I'm actually trying to see about making mine look more orangish.

[fussylizard]

Looking good! That LCD display looks pretty how with everything too!

It's a bit hard to tell from the photo, but are your LEDs showing up as yellow or amber? I know you wanted yellow - I'm actually trying to see about making mine look more orangish.

These definitely turned out more amber than yellow.  I'll see if I can get a pic to accurately portray it.

I have some extra LEDs, so I can post you some if you want to try some out (PM me).

[fussylizard]

BTW I started spending a little time trying to learn the synth engine this evening (since things are in a usable state now), and all I can say is *wow*.  This is one serious synth.  Props to everyone who brought this little beast to life.  I've spent the last hour just playing with the "fat pulse" preset in the intro page, adding modulation, portamento, filtering, etc.  I just kept laughing it sounds so good.  Fat and digital but in a very, very good way.  That fat pulse sound uses six SID oscillators and man you can sure hear it!  And this is with just one patch, woohoo!

[m00dawg]

Good to know about the LED colors.. I'll have to play around with some resistor values too, I think. As for the extra LEDs, I've already got some yellow LEDs from Smash in the mail :) But thanks just the same!

As for the synth itself, indeed it is one awesome beast. I believe it is the best SID based synth on the planet - even better than those you can buy. And I've done quite a bit of research on the matter over the years. It's fantastic!

[fussylizard]

It was pretty amusing last night playing the the MB.  I grew up listening to SID tunes on my '64 instead of listening to the radio or tapes much.  I've played a few SID songs for my wife who graciously puts up with it (though she has heard a few she has liked, I think C-64 music is somewhat of an acquired taste).  So I was playing the MB and my wife came by and said (with what sounded suspiciously like relief) "that doesn't sound like SID music".  Which in a lot of ways sums up a lot of people's misconceptions about the MB SID synth.  It uses SID chips as a foundation, but provides a very powerful and expressive modern synth engine.  The hour or two I spent last night with it suggests to me that the power of the synth is in (1) having lots of oscillators per sound (which does limit the overall polyphony of course) and (2) (more interestingly) the amount of control one has over individual parameters.  I mean, being able to control the porta rate of each oscillator individually?  Awesome (try it!).  I've not really even begun to scratch the surface of the beast yet, but it's looking to be LOTS of fun, and hugely inspiring.

On the resistor values for LEDs I would wait as long as possible to solder them in until you are sure.  I was able to test the LEDs without soldering in the resistors and they initially looked fine, but they turned out way too bright.  You might try inserting the resistors without soldering them and seeing if you can bend/clip the leads so you can get the case partly closed and try to use the synth a bit before deciding.  Actually using it made the difference for me in finding the correct LED brightness.

[m00dawg]

Yeah Wilba mentioned that in the guide. I've debated about using the machine hole strips but the last time I used those, they didn't hold as well as I would have liked. So I think I will try your method of bending the leads. Taping them down with electrical tape should work just for a quick test so no biggie.

I'm going to start with 1k I think and go from there. Unfortunately, I don't think I have any 1k's so that's a trip to Radio Shack...

As for the synth itself, I agree. It's quite expansive. In some cases, it even rivals my Virus. I'm pretty excited about the control surface, too, as that was sort of a limiting factor with my first design.

[fussylizard]

Pity the hole spacing won't support just a 16-pin DIP socket for the LEDs.  I ended up just fitting them in the holes without really bending the leads much and they had decent contact so it should be fine for you as long as you avoid shorts.

You can probably use the brightness of your Virus lights as a gauge of brightness.  I used the lights on my Mackie Big Knob as a ref, and they were surprising dim when I gave it a critical look, but they are plenty bright to see comfortably.

I'm curious how yellow your LEDs turn out.  I'm not about to resolder 100+ LEDs, but it might be useful for future reference.

If I can find the time I'd really like to look into LED ring support for MIDIBox.  I have a MIDIBox CV project to build (right after the "Where's the Party At" 8-bit sampler - http://www.narrat1ve.com/) and was considering trying LED rings on that.  I have a Nord Lead 3 rack that has the LED rings and it is a thing of beauty.  I hate programming soft synths since it's just too tedious to move the mouse about.  Most hardware synths are also irritating since the knobs never match the settings so there is no visual reference to what is going on.  Admittedly I'm a *very* novice synth programmer, but the Nord is the only synth I've had the patience to program at all.  So it would be great to have LED rings for the CV project (mostly as a proof-of-concept for other projects).  I don't think it would be practical on a MB-6582 since there are just so many controls.  You never know, I suppose.

At any rate, I've been spending my extremely limited free time of late building the MB-6582, so it will be good to get back to actually making music again.  I've often debated with myself if this should all be an electronics hobby vs. a music hobby, but I'm still trying to stay in the "actually make music" camp.  But I have to say I do love all the electronics stuff, so it's a tough call sometimes. :-)

Oh BTW I had some knobs sitting around from another project so I temporarily attached them to the MB.  Made a huge difference since twisting the bare encoder shafts was incredibly tedious.  Can't wait for the real knobs though (though I have considered machining some just for the heck of it...I've never tried knurling anything though, but one has to start somewhere..).  Funny how much difference that really made to the usability.

[m00dawg]

Hah me too! In fact, I stopped doing music altogether so I could concentrate on my synth. After I finish the MB-6582, I've gotta then upgrade a few parts of my "studio" but hope to get back to music soon. Using the LEDs on my Virus is indeed a good idea! I was hoping to get the LEDs today, but, alas, they were not in the mail. Oh well.

And yeah, LED rings are hot. Maybe on my next MidiBox project (probably will do a MB64 type of thing at some point).