33 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

Still waiting on those EDCORs hmm but I have been playing with the on I do have and I've grown more impressed at the noise rejection abilities of the thing. It doesn't look like much, but here is basically an ugly prototype before the prototype:

The board at the top is my ShieldBoy and the yellow protoboard is the noise rejection circuit. That's basically all there would be to the StageBox. The aluminum enclosure came in along with some samples of the audio jacks I will likely use. Waiting to have the board fabbed until I can measure the EDCORs just to make sure. Still am pondering the LED situation as well.

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34 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

egr wrote:

Nicely done!  The PISSbox "mixer" does indeed have some odd behavior, will try to address this in future revisions.  Just how big is this transformer you're using?

I think a different type/rating on the resistors may help? The mixer I setup while testing the EDCOR had the same problem, though I couldn't really hear a noticeable problem when using my GB test song.

The EDCOR I'm looking at is perhaps as big as the whole PISSBox smile I plan on using the 1455K1201 from HammondMFG (http://www.hammondmfg.com/1455.htm), which should fit both the PC and PCW line of transformers from EDCOR. Specifically this one is the one I'll likely go with, though I may try a 2:1 or 4:1 so see if that fixes the speaker funkiness on the GB. Since I'm having to send both channels to the tranny, I needed something a bigger to keep that bass response up. For the price, the EDCOR I tested (the 600:600:600) did an amazing job so I think it should be good to go.

I should probably setup some sort of test to verify the balanced circuit works well for longer cable runs. Don't have great means to do that, but I guess I can connect all the XLR cabling I have and make the longest cable possible and measure that high frequency rolloff with an unbalanced and balanced output and compare.

I may also change the design a bit for how the LEDs work on the ArduinoBoy side. I'm trying to avoid using extra boards which means all my I/O has to be on the bottom board in the enclosure and there isn't enough room for 6 LEDs. I'm thinking 2 tri-colors or perhaps 3 standard colors and doing sort of a binary count kinda thing to determine the modes. Smaller detail though (I plan on having headers on the board itself for folks wanting to do something else).

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35 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

As another update, I got the EDCOR tranny. It didn't work quite as I thought it would, but in the process, I think I found a better way - hook the L and R signals as the outer taps of the input side and use the center-tap as ground. This creates a difference signal. As with the PISSBox, play all the content on one channel and, BAM, noise reduction. It has the added benefit of not needing a passive mixer which seemed to be causing some harmonics from what I could tell. The EDCOR transformers are much larger than the one used on the PISS but, as a result, they sound pretty good - only a very marginal loss in bass from what I could tell. The output side is also balanced so two birds, meet one stone.

The caveat is that the speaker volume on the GB is noticeably attenuated. I rarely use it when hooked up to a mixer or my sound-card so no big, but I think that indicates an impedance mismatch in the GB and input side of the transformer. I was using a 600:600 Ohm transformer. But since the output seems unaffected, so long as it's not a risk to the GB itself, it's a non-issue. I'm just not sure if it is indeed a risk or not.

Any thoughts there? Apart from that, the box is coming together nicely and, if this works, it's basically ready to be prototyped.

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36 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

EDCOR came back and suggested this as a means to accomplish the both goals using a single transformer. In practice, I'm not sure how well it will work, so I am going to buy one and give it a go before changing the above design.

I am cautiously optimistic, however! The only downside is that using a single transformer like this means that it cannot be bypassed like the current design (so as not to color the sound more than the noise rejection). So it'll have to sound good, but the spec sheet indicates 20Hz-20kHz and I've read good things about EDCOR so I think it's worth a shot.

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37 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

As an update, EDCOR makes a combination summing and balancing transformer so I'm checking with them to see if inverting one of the inputs is possible. If so, it means those two tranny's turn into one. EDCOR also has much better specs and for way cheaper. The downside is availability is sometimes an issue, but is probably worth it.

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38 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

Well here is what I came up with. For now, I am calling it the GigBoy:

Note that air wire is intentional as there are two ground planes. I did it this way because both sides are grounded to the GameBoy and I haven't figured out how best to do that to avoid a ground loop.

Still a work in progress as things need to be tested, measured, etc. I need to make a simple control surface board for the LEDs and button for instance. I am fairly happy with it so far. I do wish I could have figured out a way to house a 9V battery in the thing, but a bigger enclosure would be needed and the cost increase didn't seem worth it. Similarly, an active circuit for the balanced out would have likely provided better sound but the power solution just didn't seem worth it.

On that note, though, I suspect the transformer will still attenuate some bass (still need to test that), so for cases where that cannot be compensated for and balanced output isn't needed, I added jumpers to switch it to an unbalanced out and avoid the output transformer entirely.

Feedback certainly welcome! I haven't decided on which open hardware license to use, but I plan on using one with it and, like my other designs, will make the board layouts and schematics available.

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39 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

Hmm so I really like the active approach. One problem is I don't know what the output impedance is for the Pro-Sound mod and that could be one reason why there is a big bass drop-off when using a tranny. If I go active, I think I can do both the inversion (noise rejection) and balancing without needing a tranny at all for anything (though the output won't be isolated, obviously).

The problem is, I don't think a voltage divider is gonna cut it since there is too much draw on the positive rail. I could simply require dual power supplies, but that seems kinda dumb. I want the box to be as integrated as possible.

The plan is to try one of the tranny's from HammondMFG, which seem a bit larger, to see if they end up offering more low end. Since I don't know what the impedance is from the GameBoy, I'm going to just get a 1:1 and hope that'll do the trick. Open to suggestions if anyone has ideas on a bipolar PSU that can tolerate higher load on the positive side.

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40 Reply by m00dawg

(20 replies, posted in Nintendo Handhelds)

@egr

Yes, in fact I was seeing if I even had enough room for a bipolar supply and a line driver. The seems to be the case so far, though I'm not done routing just yet. The GB won't be the only thing I would need to isolate in cases where isolation was really necessary, so for that, using a rackmount Ebtech would probably be good enough. Of course, along those same lines, I guess I could argue as to whether I needed a balanced output at all.

@basspuddle

A balun is a circuit the converts an unbalanced signal to balanced or visa-versa. So basically on the output side, there would be an XLR or 1/4" TRS jack you could plug into a mixer. It's not really required, but makes the box more stage friendly and would allow running longer cabling without near as much loss in signal quality.

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41 Topic by m00dawg

(20 replies, posted in Nintendo Handhelds)

I'm back at it again working on yet another ArduinoBoy design. After realizing that a rackmount ArduinoBoy doesn't work well in live applications, I've decided to try making a stomp-box style ruggized thing while also adding some features to reduce all the crap I have to take to a live show.

So the plan is to combine an ArduinoBoy, PISS BOX-like design, and a Balun into one box. The schematic is basically done, though untested. But one problem I've run into is whether or not to use a transformer for the balun and what type. The PISS uses what appears to be something close to the Xicon 42T series. Seems to work well, but it does attenuate the bass and requires more EQ. For noise rejection, that's not a big deal since you'd just run the empty channel through the tranny. For a balun, however, that's a problem. I looked at using bigger tranny's from Hammond MFG, but their working range is from 200Hz - 15kHz which represents a cut in bass that would have to be brought back in with EQ. Anything larger and both the cost and complexity go up to the point it's not practical (from what I found so far).

An active balun would offer much better frequency repsonse, but it wouldn't be isolated. That means ground loops could become a problem if the box is powered by an external wall supply requiring an isolation transformer anyway. Likewise, using a 9V battery may get tricky because an active driver needs a balanced circuit (so +/- 4.5V) and the Arduino needs +5V.

Yet another option I have read about but don't now quite so much about is to effectively do something of both by driving the tranny with more power, boosting the input side to help keep a more flat response. That fixes the isolation issues, but still requires an external power supply.

So I said all that to say, both, if anyone had thoughts on the above considerations (say if isolation is really an issue for most applications) and if there was anything else that might be convenient to have in a box like this?

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42 Reply by m00dawg

(12 replies, posted in Other Hardware)

Just throwing it out there, but I made a shield that is specifically for the ArduinoBoy if you wanted to go that route instead:

http://victimcache.com/hardware/shieldboy/

You have to build it, but the schematics are there for the taking and you can have the board fabbed at oshpark.com for a reasonable price. If there was enough interest, doing a bulk order would drop the price even more.

I also made a rackmount version that does away with needing an Uno board, but it doesn't work as well for live shows as I wanted. So instead I'm going to make a stomp box style thing that has an ArduinoBoy, a PISS Box style noise filter, and probably a balun (active or passive, not sure which yet) for balanced output. Haven't started on that just yet beyond some loose schematics, but when I'm done I plan on sharing all that work just as I do for all the other stuff I make.

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43 Reply by m00dawg

(7 replies, posted in Nintendo Handhelds)

Downstate wrote:

mine is still fucked. i gave up. any one want to buy my arduinoboy ? lol

Did you put it together yourself? If so, you may want to check things like solder joints along various paths (like MIDI and GB Link if not the whole board). A bad solder joint won't always just be a full short, but could be a noisy connection and could be what is causing the sync issues perhaps?

If you want to simplify things a bit, you can always route a board and get it printed (if you're wiring everything to a protoboard or something). I've got two different designs here and here. The latter is more for all-in-one rackmount so it's not especially simple, but it is small and works great.

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44 Reply by m00dawg

(7 replies, posted in Nintendo Handhelds)

By the way, we had band practice today and used MIDI mode for all the songs. No discernible problems whatsoever with sync on both fast and slow songs, so looks like that did it! Thanks again for the help!

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45 Reply by m00dawg

(7 replies, posted in Nintendo Handhelds)

Oh, heh, derp - I actually didn't think there was a significant difference between SLAVE and MIDI. I actually thought MIDI was for outputting note-data FROM LSDJ? Just did a quick test between SLAVE and MIDI and, yeah, the sync actually seems much improved but I'll have to test again tomorrow. Was packing it in for the evening and turned my other synths off so just had the metronome to test.

Seems to make some sense since I always did feel the GB was more on beat when the BPM was faster - it's only our slow songs that I seem to complain. Would be lovely if it's as simple a fix as to setup MIDI mode tongue

Thanks for the insight!

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46 Topic by m00dawg

(7 replies, posted in Nintendo Handhelds)

Has anyone else noticed a bit of a MIDI sync delay with ArduinoBoy and/or LSDJ (not sure which one), especially at lower BPMs? Working on a song at 100bpm and had to put in about -16ms pre-delay in Ableton Live on the MIDI interface hooked to the GB. The other synths don't seem to have an issue. Not a big deal, was more so wanting to make sure it wasn't something with my config.

If there is a delay, anyone have any suggestions on the ms to put in to compensate? I just picked -16ms by random guess and ear for that one song.

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47 Reply by m00dawg

(26 replies, posted in Nintendo Consoles)

Would this basically allow me to play an NSF (say via PowerPak) sync'd to a MIDI clock (ala LSDJ)? If so, that'd be HUGE!

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48 Reply by m00dawg

(83 replies, posted in Nintendo Consoles)

derekb wrote:

honestly thats a big problem with kickstarter, thereve been other projects where the dudes bailed bigtime after they got the cash and theres no real balance for kickstarter to help them

That's the risk, and Kickstarter has been pretty clear about it. That is why terms like "Pledge" and "Back" are used. Simply put, if you don't trust the project, you shouldn't put your money behind it. Or, if you do, be mindful of the consequences.

I choose my projects very carefully and there are tons of good projects that are coming to fruition. But when I do pledge, I expect the consequence to be that I might not get something back. For what it's worth, had I found the Kickstarter for Chip Maestro I would have definitely backed it too.

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