Noise No More

An achilles heel of the Casio CZ-101 (and the electrically identical CZ-1000) is the amount of noise and interference it produces on its headphone port, which is curiously not present on the line out port. In this video I explain why it happens and present a fix that dramatically reduces the noise by just swapping the values of a few passive components.

This fix really improves the usability of this synth, and it's honestly kind of embarrassing that Casio let this system out the door with such a boneheaded design fault.

The Freshening Part 1

This week I have embarked on the final house project of the winter season: adding an ERV to my house. For those of you unfamiliar, an ERV is kind of like an exhaust fan for stale inside air, but it also brings in an equal amount of fresh air and exchanges the heat and humidity between them so you don't waste all your energy by venting nicely conditioned air into the great outdoors.

To start this off, I'm going to do a little prep work before the main event happens a little later this month, starting with making some ductwork accessories. To make those, of course, I'm going to need some sheet metal.

I originally intended to just get a 4ft by 4ft sheet, as I'd managed to lay out everything to fit, but I figured I'd rather not make two trips just in case I messed up, and I'll have another use for the rest later, so I went 4x8.

And by "lay out everything to fit", I really mean "to fit".

So let's get these parts cut out, which starts by getting the sheet marked up. I've tried a number of products that are supposed to mark well on sheet metal, but so far they've all failed miserably. Instead of all that rot, I'm going to scribe the marks using a utility knife.

First, though, I figure out where to scribe it.

Holding a steel ruler down with these welding magnets works surprisingly well.

Then comes the scribing.

This leaves a surprisingly visible and very accurate mark, and as a bonus the shears seem to naturally follow the score line, making cutting straight a breeze.

I do quite enjoy these offset shears.

They make quick work of these cuts, though admittedly at the cost of a bit of a forearm workout. But an hour or two later, everything is chopped up and I didn't need to stray into the other half of the sheet.

In the meantime the ERV showed up, but unfortunately it looks like it was shipped through a war zone.

This corner was bashed in far enough to jam one of the fans, and the collar on the other side was pretty solidly dented.

And oh wait, I guess it was shipped through a war zone.

Well anyway, they're sending out a replacement for free which should be here on Monday, so hopefully this one won't be bombarded by Putin's airstrikes.

In the meantime, let's take a little reservoir break before getting back to work.

Now that's refreshing!

So the first thing on the menu is going to be a ceiling duct boot, 10"x10" nominal (9-7/8" actual so it fits in a 10"x10" hole). The sides are going to be the most complicated part to cut and bend, so I'll call on the services of Bender Bending Rodrigues to help me out.

There's both box bends and some counter-bent flanges to deal with, and luckily a box-and-pan brake has features to accommodate both.

The main 1" flange here is to join to the top of the box, while the 1/4" counter-bent flange is just to stiffen up the edges and seat more nicely against the ceiling. The movable bending teeth give the main flange a place to go when this side bend is folded up, while the notch in the bed and bending leaf gives the counter-bent flange some clearance.

The two side pieces come together like this, and then we put a few break-bends in the top for reinforcement and pop it into place with some clecos to check how things are looking.

And next come the rivets to secure everything together without leaving those stabby sheet metal screw points on the inside.

Fun fact: if you don't deliberately rock the rivet gun backwards after each shot, it can jam up with rivet stems and then you have to pull everything apart to clear out the jam.

Anyway, I need two of these so it's second verse same as the first.

And that's the boots done. I'll cut the 5 inch holes for the collars later when I actually have the collars to verify the measurements. These will be going into my bathroom ceilings to replace the loud and obnoxious exhaust fans, which is why I chose to make them 10"x10". (One of the fans is unfortunately 12"x12" so I'll have to do some drywall work to patch around it, but there was no way to get a 12"x12" boot out of the sheet metal I got without cutting into the remaining 4x4 sheet, so I figured I'd go for consistency).

So that's the first prep week's work done, but there's plenty more to come so stay tuned for that.

Generating Functions

Ok it's not actually generating functions, but instead a function generator.

I picked up an HP 8904A off of FleaBay because I really don't like my cheap Chinese function generator. The latter has a shitty UI, and despite having two channels it's incapable of modulating one with the other. It does have outputs on the front, though, which this one curiously lacks.

But if we peek around back, there they are.

Routing the IO on the back of an instrument is quite common in rack mounted setups where you arrange a bunch of instruments in a fixed configuration, but for more ad-hoc usage it's really a pain. Luckily, the connectors are just routed inside pretty simply with a pair of coax leads.

So it's just a matter of unscrewing them from the back and screwing them in at the front.

And of course we'll transfer the blanking plugs to the rear, though I had to heat them up with my hot air station to get the little plastic catches to stretch back into place after decades of being compressed.

But with everything back together, we get a lovely 1kHz sine wave at 1v peak-to-peak.

Which is, of course, configurable for amplitude, frequency, and so on, as are the many other wave shapes it can generate.

What we don't get, though, is modulation. You see, that's an option that you have to pay HP to enable, and whoever owned this instrument in the past never paid HP to enable it, which means the HP tech never came out and pressed the power button (on), shift, service, shift, f4, 092448, shift, service, next, next, next, f1, 3ffc, f2, ff, f4, f4, power button (off), which would have allowed the instrument to perform amplitude modulation like this.

Or frequency modulation like this.

Or many other types of more complex modulations.

What a shame, I guess I'll have to just live without.

Carbonation

I've had a nonstick Ikea frying pan for ages now, and it's been serving me well. It's quite large though, and this makes things awkward when I want to make myself an omelette since having too much space just lets the egg spread out too thin. So it was about time I bought myself a smaller pan.

Since everyone is freaking out about PFAS these days I decided to go with carbon steel. It's basically identical in function to cast iron, but much thinner and lighter. As such, it needs seasoning.

I decided to use salad-grade olive oil for this task, just to trigger all the seasoning fetishists out there.

After things start to get smoky, the excess is poured off so that the remainder can form a nice thin layer and polymerize onto the surface of the pan. I actually left just a teensy bit too much in here though, which made the seasoning slightly too thick in a few spots.

This lead to the seasoning getting a bit bubbly in these spots, which is not ideal. The thick spots also have a tendency to flake off. It's not a big deal though, and 95% of the seasoning is perfectly solid.

I sanded down some of the lumpy spots and gave it a second blast of seasoning.

And then I cooked myself an omelette.

And the pan came out unscathed, with just a few small spots being a bit sticky.

But those spots will season up over time.

All in all, I'm quite pleased with this pan. It seems to be just the right size for a 2 egg omelette, which is exactly what I intend to use it for.

A Canvas of Sound

This is a Roland SoundCanvas SK-88 Pro.

It belongs to a class of instruments known as "romplers", a portmanteau of "ROM" (for read-only memory) and "sampler", which is quite descriptive of its functioning: it plays back recorded samples from ROM. This is as opposed to synthesizing the sounds from algorithms (either implemented in digital code or expressed as analog circuitry), or being able to record and play back arbitrary samples; what you get in the box is all there is.

Of all the romplers out there, the SK-88 stands alone as the rompliest of romplers. Its sound set conforms to the General MIDI standard, augmented by Roland's own GS extensions. This system was built around the concept of having a uniform list of instruments that a synthesizer could play back when presented with MIDI data, such that any foreseeable genre of music could be accurately reproduced. Its success in achieving that goal was, somewhat predictably, rather limited.

The main beneficiary of this standardization was music playback on computers, and game music in particular. The idea was that you could plug a SoundCanvas (or similar General MIDI device) into the MIDI port on your sound card, and have your ears filled with music that far exceeded the quality that could be generated by the primitive synthesis engines available on the sound cards themselves. The General MIDI standardization ensured that if a piece of music called for a guitar, piano, harp or accordion, the playback device would be able to produce a reasonable rendition thereof.

Of course, most of these playback devices didn't come equipped with a keyboard, but were instead a relatively compact desktop box with just a few controls on the front panel. The SK-88 Pro that I have here is actually identical in its sound engine to the SC-88 Pro sound module, but with the keyboard form factor it was intended to be an all-in-one device for composers of video game music, or just Gemeral MIDI enthusiasts, to compose their sound tracks on.

This peculiar product positioning is why the connectivity provided on the side panel is so peculiar.

The 1/4" jacks for the sustain and expression pedals are straight out of synthesizer-land, while the RCA jacks and 1/8 headphone output were intended to hook up to consumer grade PC speakers or headphones.

And in case you're wondering, the MIDI ports are on the back.

As you might imagine, the overly ambitious aspirations inherent in General MIDI combined with the limitations of the technology of the time did, quite naturally, lead to an instrument with what I will charitably call "character". But, of course, the quirks of the past quickly become the nostalgia of the present, and so that character has come full circle to being desirable somehow, which is the reason behind this particular unit landing in my hands, shipped straight to my door from the far off lands of Japan.

And speaking of desirable, I should mention that it has Tyler's favourite MIDI instrument.

As we all know, this is the perfect instrument to use to play back the theme song for Star Trek: The Next Generation.

Anyway, this shot also introduces us to the first issue that this particular keyboard has, though it's not exactly apparent just from a visual inspection: the volume slider is scratchy as all hell.

Also, just out of frame below this, the pitch/mod wheel has become quite sticky and sluggish.

So, let's crack this thing open and see what's inside.

And what's inside is dust. Lots of dust, and some mysterious, sticky goo, because what piece of vintage electronics would be complete without sticky mystery goo?

So that'll need cleaning, but let's concentrate on fixing the volume slider first, which luckily isn't buried under too many screws.

Giving it a bath in contact cleaner flushes all the gunk out, and then a little bit of friction grease restores its silky smooth action.

Next up is the pitch/mod wheel, which likewise is pretty easy to disassemble. Hitting it with the same contact cleaner loosens it up nicely and gets it back to its original functioning.

We don't want the friction grease here, because that'll just make it sticky and sluggish again.

With that done, everything can get reassembled, taking special note of the screws for the bottom cover of the keyboard: while they all look identical at first glance, the ones that thread into the metal brackets have a much finer thread pitch than the ones that go into the plastic case.

Then with everything cleaned and back together, things are looking fresh and performing perfectly.

Though admittedly the before and after shots aren't especially dramatic, since it wasn't outwardly all that dirty to begin with. But it is cleaner now, which is nice.

Veggie Time

Once again it is time for a new batch of giardiniera as my previous batch is almost gone.

Not too much to report this time. The process went basically as expected and I won't really know how it turned out until a few weeks from now when the last jar of the old batch runs out. I can only assume that it'll taste as good as it looks.

Wacom, Wacoff

Many moons ago I decided to pick up a tablet monitor for my PC. I didn't really fancy the idea of paying the Wacom tax for a Cintiq, so instead I got a Yiynova MVP22U.

Hardware wise it's served me reasonably well, though at one point the power board flaked out on me. I was able to get a replacement from the US distributor of the brand, though, and since then I haven't had any issues.

Well, not any hardware issues, at least. The issue was with the software, in particular the drivers for Windows 10. For whatever reason, every time I rebooted the machine, Windows 10 would disable the pen input drivers for the monitor, and I'd end up with just a regular monitor with no pen functions until I ran the Yiynova installer to remove the driver, reboot, install the driver, reboot, and then it'd work again until the next reboot.

I finally got sick of this dance, so I figured it was time to do something about it.

And wouldn't you know it, but these Wacom Cintiqs are old enough now to be going for pennies on FleaBay. This one in particular is the DTK-2200.

I picked a listing that was missing the stand and power supply but did have the pen and its holder. The pen is still somewhat expensive since people tend to break and/or lose them on a pretty regular basis. Luckily people are much less likely to misplace the power supply, and it's largely a commodity item other than the peculiar connector they decided to use, so finding a substitute was cheap and easy.

And out of the box we can see that it's a bit dirty, but there's no major scratches on the display area of the screen, and just a few minor scuffs on the bezel.

Around back it still has the mounting ring for the original stand, but I won't be needing it since I don't have that stand and I'll be mounting it to a VESA arm.

So I'll need to remove that ring and then also temporarily remove the IO cover panel so I can move the cables to the lower slot.

I have to say this is a pretty decent design. Some other models of Cintiq would, for example, have the USB cable soldered directly to the PCB, meaning that if it got damaged it was quite an involved process to replace it. But here there's just a plain 4-pin extension cable for the power, a regular DVI cable, and a USB-B cable. Very simple and serviceable.

Anyway, back together it goes, and we'll give the backside a cleaning while we're here.

There's still a few scuffs but it cleaned up pretty well. The front cleaned up nicely too.

And mounted up to the arm, it fits nicely in place of the Yiynova, though it is a touch larger thanks to the bigger bezels.

So we just need to install the drivers and...

Real classy, Wacom. I literally installed the drivers linked from the product page for this monitor, but you couldn't be bothered to keep support for this model going in that version.

Luckily the older version isn't too hard to find on their site, and installing it goes pretty smoothly.

Of course you might notice in this photo that everything around the monitor looks rather astonishingly yellow. This is because the white point on the monitor is set wrong, but rather than just switching it I'll go ahead and do a full calibration.

This takes something like an hour and a half, maybe two hours, but when it's done the colours look almost perfect.

The colour is off just ever so slightly in the darkest greys/blacks but I think that's probably due to either ambient light bleed or backlight bleed, and in either case it's not really anything to worry about. What's important is that the colour is basically spot-on, and I now have a tablet monitor that doesn't get its drivers eaten every time I reboot.