Kraylix Back From Paint

Not too much to report tonight other than the Kraylix arcade cabinet is back from being painted! As described in previous posts, I had it painted with automotive paint – first a base layer of gloss black, then gloss clear.

Here’s a photo after having assembled the basic cabinet pieces together plus installing the marquee back panel that I painted white myself. Note the artwork on the control panel here is just office printer test prints to see what it will look like.Kraylix-painted 001

From what I heard the painter had to do a bit more sanding and filler (in addition to all the prep I did), but it was well worth it – I’m thrilled with how well it came out. The top arch in particular is totally seamless, as is the control panel. It doesn’t really even look like MDF or wood!

I’ll have to clean up some overspray on the control panel before mounting buttons and joysticks, but other than that it’s pretty much time for final assembly and wiring everything together. This has been a really fun project so far and it’s about to get even better!

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Added Remote Power Buttons to Kraylix PC and TV

With the gaming PC going inside the Kraylix cabinet and the Vizio TV behind a bezel, today I spent some time coming up with a solution to being able to power each on remotely as neither device’s power buttons will be accessible. There’s a couple approaches possible here, like trying to force each device to turn on automatically as soon as power is applied, but I decided against this and favored adding remote buttons instead for a few reasons:

  1. I won’t always be using the gaming PC. The arcade cabinet will sometimes be powered on and playing real arcade boards, not the PC. Therefore it shouldn’t simply turn on when power is applied.
  2. Forcing the TV power on doesn’t solve being able to choose the input (and I will be using multiple). That said, on my television the power button doubles as an input selector! It turns out on my model, a long press on the power button powers the set off, and a short press switches inputs. This means by wiring the button remotely I could control not just the power but also switch inputs. Perfect!

So I went ahead and cracked open the TV first. It took removing just a bunch of screws to remove on the back, and it popped right open. Super easy. Thankfully the power button was wired to the back of the TV with just two wires – it’s very likely a simple passive microswitch, which means I can splice in to that connection and run my own wires to my own button!Kraylix-powerbuttons 001

I went ahead and cut the power button wires, then soldered them back together with my two wires added:Kraylix-powerbuttons 002

I also drilled a small hole in the bottom of the plastic back panel of the TV to feed the wires through. A bit of wire routing and tape later, and the TV is ready to close back up.Kraylix-powerbuttons 003

Finally, the moment of truth – powering on the TV with my own button… It worked!Kraylix-powerbuttons 006

It’s an arcade button, of course, because that’s what will be used on the finished cabinet. I plan to make use of the hidden button slots on the bottom side of the Kraylix control panel for these power buttons.

Next up, my gaming PC. I could have quite easily spliced into the power button’s wiring harness the same way I did above, but I found it just as easy and a bit faster to simply solder my custom power button wires to the cases’s power button solder terminals, pictured below:Kraylix-powerbuttons 004

And bingo, this one worked too!Kraylix-powerbuttons 005

As you might be able to tell, I’m getting as many things done that I can while the Kraylix cabinet is still out to paint. I think when it’s back things should go together fairly quickly now!

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A Few Words on TPA3116D2 Audio Amplifiers

Update – Jan 2, 2020:

This post is years old at this point and the boards pictured below no longer appear to be available – that said there are still plenty of others to choose from on the e-commerce site of your choice. I’ve tried another board design since and have had good results. See also the insightful comments from user “Enlightend” at the end of the post. Thanks!

My plan for sound on the Kraylix arcade cabinet is to use two 4″ JL Audio speakers plus an 8″ woofer for bass. Of course part of having an integrated all-in-one solution for an arcade cabinet means some form of audio amplification is needed – I’m not about to cram a stereo receiver in the cabinet or something along those lines! Thankfully there are tons of decent and cheap audio amplifier boards available these days.

The TPA3116D2 is a popular chip by Texas Instruments used these days in audio amps. It’s very power efficient and hence doesn’t need a large heatsink. Small complete boards using these chips are extremely cheap and readily available on eBay for between 10$ and 20$ including shipping! I did a bit of reading on them online and it seems like results are mixed – but at those prices why not take a gamble and buy a few different ones to test them out? They seem like too good of an option to pass up, especially compared to other options for amps which can easily get in the 100$+ range. I bought three different ones in the “2.1” configuration (two main channels plus a subwoofer channel), each under 20$, hoping for at least one “good” one. I hooked them up to some small speakers plus an 8″ sub for testing. Here are my observations after listening to each for a few hours.

Heres’ the first board I tried:

Kraylix-audioamps 001

It didn’t have screw-down terminals for the speaker wires, so I had to solder the speaker wires in directly. Not a difficult task, but my speaker wire was fairly heavy gauge and the small holes on the board wouldn’t fit all the strands! I cut roughly half the strands away and soldered the speaker wires in. This board has a 1/8″ mini jack for line-in, and three dials – sub volume, main volume, and overall (sub+main) volume. So, how did it sound? Pretty decent, actually! I played a range of music and videos, including bass-heavy songs that would push its power consumption quite hard – no problems at all, and the board didn’t even get hot under prolonged testing. Then I paused the music and noticed a problem – an audible whining noise coming from the speakers. This board seems to have noise problems that are pretty obvious when audio isn’t playing back, no matter what the volume knobs are set to. Bummer. I even tried with two different power supplies (which are not included) but got the exact same results with both.

So, I moved on to board #2 to test, hoping for cleaner audio:Kraylix-audioamps 002

This board has the same volume control configuration, but came with nice knobs to install on the potentiometers. And notice how it also has screw-down terminals for not only the speaker wires, but also for the power supply in case you don’t have one with the right connector. Those are nice features over the first board. So how did it sound? Clean! Good sound at this one, and no audible whining noises! This one would work nicely in the arcade cabinet.

But I had yet another board to try out – here’s board #3:Kraylix-audioamps 003

The nice knobs came pre-installed, it has screw down speaker wire terminals, and it uses RCA jacks vs the 1/8″ mini-jacks on boards #1 and #2. I got nice clean sound out of this one, too! But the biggest difference between #3 and the other two were actually in the configuration of the dials – where as the first two had only volume controls, this board has two volume controls (sub, main) and the third knob is a low-pass filter frequency control for the sub channel. This is a very useful feature for tweaking the sound of the woofer, and for that reason I will most likely use this board in my Kraylix arcade cabinet.

Those were the main differences I found. There were some common points, too, though – they all produced very reasonable volume levels without any clipping, and none of the boards heated up much at all. The bass channel of all three sounded pretty similar, too, and although these boards are advertised as 2.1 channel (where the .1 is a subwoofer channel), I think it’s a bit of a stretch to call it a subwoofer channel. They all sound to me like the output drops off significantly below say 100hz or so. They’re more like a bass channel, which honestly will suit my arcade cabinet build just fine.

For what it’s worth, I have no idea how consistent the quality is on these boards, or why I got a whining sound from the first one but not the other two. It’s possible my board #1 was just a bad copy, but who knows. It’s hard to argue with the price – I think these boards are a tremendous value.

My plan is to install board #3 inside the Kraylix, right next to the coin door – this should allow for easy access to the volume controls while playing.

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Fabricated Kraylix Marquee Holder

With the cabinet off getting painted, I turned my focus to other parts of the build. First off, the artwork! I’ve been working on customizing my control panel and marquee art for a while now, and it’s finally done and off to the print shop. While the marquee will be back-lit and the control panel will not, I decided to do the entire art on backlit film – it makes for just one file to print, and it’s an easy way to assure the colors will be consistent between the control panel and the marquee.

I then started looking at how to mount the artwork to the marquee. The Kraylix kit came with a clear plastic panel for mounting the marquee. It’s presumably acrylic, but I’m not certain about that. The marquee art could mount either in front or in back, but with just four screws to hold it down I’m not sure I like either option – I would prefer to have something that will keep the artwork absolutely flat to the marquee clear panel. I was curious what other builders were doing about this, so after reading some forum posts I found a solution I really liked – sandwiching the artwork between two clear panels! I went to Tap Plastics and bought a sheet of 1/8″ clear acrylic to fabricate my own custom marquee holder.

Tap Plastics cut my acrylic to the proper size, but there are still a few items that need taking care of – rounding the corners and drilling some holes. I clamped some wood blocks to each side to give the material some stiffness and started with the coping saw to cut the rounded corners, using the original panel as a template. Acrylic is a very hard material and it quickly became obvious doing a rounded corner wouldn’t be easy…Kraylix-marqueeholder 002

So, I turned to the Dremel. What an awesome tool. I first used the cutting wheel to do a series of rough cuts right outside my cut line:Kraylix-marqueeholder 003

Then moved over to the sanding barrel tool to smooth out the curve and get right on the desired line. Make sure you wear proper eye protection while doing this, by the way, as hot molten plastic bits will fly!Kraylix-marqueeholder 004

Much easier and faster than the coping saw! All that was left was drilling the holes for the screws that attach it to the cabinet, and I used a purpose-made drill bit for drilling into plastics. Notice how it has a much more acute tip vs a conventional drill bit:Kraylix-marqueeholder 005

Four holes later, all done! Both pieces are clear, by the way, they are simply covered with protective film:

Kraylix-marqueeholder 006

My custom holder (above, bottom) has the same shape as the clear plastic that comes with the kit (above, top)- all for 7$ and about 15 minutes of work. Of course I could have just ordered a second marquee panel with my original order from Kray, which is what I would recommend to anyone ordering in the future… If you didn’t, though, fret not – it’s pretty easy to make your own.

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