[R+C Termination]

Hi,

 

short question to R+C Termination:

http://www.ucapps.de/midibox_seq/mbseq_v4_dout.pdf

 

 

So i don't have 100 pF (only 220pF instead) ready, but the hint confused me a bit. Should i now take a R 100Ohm + R 220Ohm in serial instead of R 100Ohm + C 100pf in serial?

 

Greets, rio.

 

Disclaimer: I have not built an MBSEQ.

 

The way I read it is you either connect a 100 Ohm resistor and a 100pF capacitor in series, or just a 220 or 330 Ohm resistor without a capacitor if you do not have the capacitors on stock. If you do this you need to do this both on the SC and RC lines, but only if you have flickering LEDs and/or random trigger events.

 

So, first finish your build, then look for flickering LEDs and/or random events, and if you suffer from them then apply this potential fix.

 

 

Not to thread jack but do I need the DOUT module to drive the LED's that populate the control surface from SMASH TV? Hope not or that means i have to order one or make one on perf board...

 

I looked briefly at the CS PCB PDF and saw shift register ICs on the board, so I am convinced that you do not need additional DIN and DOUT boards to make this work in the standard configuration. You can look here for more details: http://www.ucapps.de/midibox_seq_manual_hw.html

[MB6582 - DC Cable]

The cable is about 1 meter long. If you want it just write me a PM or email :wink:

[MB6582 - DC Cable]

I've got some left over 4 core cable from 2 failed C64 PSU's that you can have for free. I only don't know if it's long enough for your liking.

[MBFM 5V option?]

@NorthernLightX, For audiophile powersupply options, the LM317 is a better option then the LM78xx series. But there are better options available.

 

My point was that a complete ready made PSU that delivers +12/-12/+5/GND is as cheap as €25. If you want to DIY something it must be either because you want to do it cheaper or even quieter than a good off-the-shelf switcher. I'm perfectly happy with my MeanWell switchers myself.

 

The LM317 is a good IC, but the 78xx requires less parts. The headphone amp was for my father because he's getting a bit deaf, not for audiophile purposes. He didn't even hear the switching noise from the cheap PSU's  :rofl:, but I wanted to deliver something at least decent. I only hear a little white noise at full volume (with no audio source), more than good enough for this application.

 

Anyway, I'll stop hijacking this thread and let the experts do the talking :wink:

[MBFM 5V option?]

I've seen a charge pump done by simply putting a few electrolytical capacitors and rectifier diodes in the right configuration, that was on a PSU for microphone preamplifiers (those often need +48v for phantom power).

 

I've been working on a headphone amplifier for my father the last 2 weeks and tried 3 different wall warts; all were noisy as hell. Good linear wall warts are hard to get these days. I ended up just using a mains transformer, a few capacitors and an 7812.

 

If you end up building a PSU anyway (because a good off-the shelf 5v PSU cannot be found) it's probably easier to just build a +/- 12v PSU and regulate +5V from the unregulated +12V line; AFAIK the MBFM does not stress the +5v line as much as for example the MB6582.

[SSM2044 MB6582]

There is no way it would fit in the PT-10 case. It can be done in a bigger case, but like Shuriken says your PSU needs to be able to supply the additional voltages and current. AOUT and SSM boards need -12V too, keep that in mind.

[Selling: CNC Engraved Midibox Panels (mbseq/mb6582/etc) & Pactec PT-10 cases (for mb6582)]

Julian has been ill and one of his CNC machines broke down. He has a job for me in the pipeline as well. Do you have his email? I'd send him a mail asking a status update, I'm sure your stuff is fine.

[PIC18F4685 branden rond A'dam?]

Hoi Elektruck, en ander forumlid was je voor, het setje is in principe verkocht, sorry.

[PIC18F4685 branden rond A'dam?]

Mijn oplossing tegen de never ending backlog is alles modulair maken. Het meeste werk gaat toch vaak in het behuizen en bekabelen zitten. Met een modular hoef je alleen een frontplaatje te maken, voeding zit al in je modular behuizing. Voor mij heeft het er voor gezorgd dat ik nu een stuk of 4 modules zo goed als af heb, en de "zin" die dat gaf heeft er meteen voor gezorgd dat wat andere projectjes (standalone 19" behuizingen) ook weer wat aandacht hebben gekregen.

 

Komende week mijn "12v" Ikea Rast rackje (andere rackje is 15v) afmaken, dan kan ik modules gaan testen en calibreren.

 

Ik heb trouwens een PT-10 kastje met (silkscreened) MB6582 frontpaneel over (volgens mij geen achterpaneel), iets voor één van jullie?

[MIDIbox CV V2 Concept]

it's strange, but it's already integrated into the application!

(seems that I forgot to remove it from a basis template, but now where it's in...  :smile: 

 

Best Regards, Thorsten.

 

Awesome! Now this project is definitely going into my synth :) Next to the hacked MIDI keyboard, which I will then be able to route to several modules that have a MIDI input, but also as a CV source.

I started with a webpage which documents the facts: http://www.ucapps.de/midibox_cv_v2.html

 

Best Regards, Thorsten.

 

Just checked the page, and the first line is a bit confusing; V2 is the successor of V1, not the predecessor (then it should be 0,5 or something) :whistle:

[MIDIbox CV V2 Concept]

Maybe it's a strange question, but is it possible to also integrate a MIDI router in the code?

[PIC18F4685 branden rond A'dam?]

Net zo actief als jij ben ik bang; zo nu en dan doe ik weer eens wat en dan verdwijn ik weer een jaar van de radar. :ninja:

 

Ben wel van plan nu echt eens wat dingen af te gaan maken deze winter. Heb gisteren mijn 2e GSSL afgemaakt, nog 1 te gaan, en dan mogen er 2 verkocht. Dan heb ik nog een zieke lijst met andere spullen die afgemaakt moeten worden, dus ik ben nog wel even zoet :angel:

[aout dac chips]

@TK I have 2 spare MCP4822 (the version with the integrated voltage reference) that I can send you for free (I believe I already offered some to you a few years back) if you want to play with them.

[PIC18F4685 branden rond A'dam?]

Misschien kan Shuriken je heklpen, hij woont in Alkmaar en heeft mij laatst ook met wat PICcies geholpen.

[AOUT NG : only half expected voltage in bipolar]

Two comments:

 

1. Do I see correctly that you take the +5v to shift the levels from the power rail? Is that precise enough? Maybe adding a precision reference is a better idea?

2. I would like to see the level shifter as a separate PCB, so MAX AOUT users could also benefit from it.

 

I agree with the usefulness of full scale CV for modulation purposes, like I wrote earlier :thumbsup:

[MIDIbox CV V2 Concept]

 

I actually like this design very much, and also agree completely with TK's remarks; menu encoder on the right, GLCDs on the left.

[MIDIbox CV V2 Concept]

Very nice demo video. For the control surface I have an idea: is it perhaps possible to use the same control panel PCB as for the MB6582? There is already a proven and tested PCB and it has a lot of buttons and encoders on it.

[AOUT NG : only half expected voltage in bipolar]

Last month illogik built my redesigned AOUT module and found some bugs in the PCB. While discussing possible solutions we came to the conclusion that it's probably much easier to have the AOUT only output unipolar 0 to 10 volt, and design a simple -5v level shifter board that can be used as an add-on (or separate module with hands-on access to the level shifting) to shift the output to -5 to +5 volt where needed.

 

Things to consider are:

- not a lot of equipment actually makes use of negative voltages

- equipment that needs bipolar CV input can be retrofitted with a fixed level shifter at the input to make it compatible with your other modules

- negative voltages can be used for CV modulation purposes (modulate one CV source with another) so it's certainly not useless

[Trying to contact the Mike's MIDIshop]

I have had contact with Mike 2 weeks ago on the address Elektronix00 at aol dot com. I don't think the webshop is his day job by the way. What was the block message you received?

[Can you get away with just 1 MAX525 Dac? (AOUT)]

TK has confirmed in the past that the MAX AOUT module will work with 1 DAC. A revised module is in development that would give the option to choose between 2 DACs for 1 Core or 1 DAC per Core for 2 Cores.

[Starting my second SID project]

That depends on all the options you want to include, and is explained in the walkthrough.

 

Better post a list of the functions you want to include and the boards you plan to order, than plainly asking someone else to do that work for you, I guess.

[Sido - simpler than Sammich]

One thing you could improve on is spelling TK's last name right on the PCB :poke:

[need information on the sid chips]

The 6581 and 8580 are the exact same width and have the same pinout. If your 8580 are physically different from the 6581, they are not SID chips. Can you upload a picture?

[need information on the sid chips]

They operate on different voltages. If you just swap the chips out you will destroy the 8580. This info is all over the forums, so please use the search function to find out what you need to change.

[big lcd headache - connection ok - black row]

Well, if another LCD is working it's not your cable and not your core. If all 4 LCD's are not working it's doubtful that they are all broken. So I suspect either a different pinout (don't trust the datasheet in this case! Maybe trace DIL pins to the controller IC?), or you try to run them in 4bit mode when they do not support that (a few OLED have been reported to only run in 8bit).