Sundryundies

I decided

2011-07-25T21:29:00.009-05:00

not to build any more time machines. Instead I decided to try my hand at a project involving electronics mixed with furniture. I found an old tube stereo housed in a big console on Craigslist for $25. There isn't even a modern equivalent to these. I guess it's kind of an early entertainment center. It's a Zenith from the 60's.

I've had this idea for a while but couldn't find the right piece. My idea is to gut the inside and replace the old tuner, amplifier, and turntable with a modern tuner/preamp/amp, CD player, and turntable. So the exterior is all 60's cool, but the interior is all mod cons. And the sound should be a whole hell of a lot better. Tube stereos can sound good but this one wasn't particularly high end.

So that's one half of the project. The other half is to take the newly removed power amp and turn it into a guitar amp. I attempted this once before using a Magnavox power amp that a friend gave me. The problem was, I wasn't there when he removed it from the console and so when I got it it had a bunch of unlabeled wires hanging off of it. I didn't know what they were for and with no schematic I finally gave up on getting it to work. This time it should be a snap. Plus I know a little bit more about tube technology than I did then.

So here's a pic of the console:

And here's a pic with the lid up, showing the original stereo:

With the stereo components removed:

And here's a pic of the speaker array (rear cover removed):

Some of the basic stuff I plan on doing:

1) Remove the latticework speaker grilles for a bit cleaner look. (When I took the pics I had already removed one.)

2) Replace the black speaker grill cloth. The original stuff is faded and shows where the lattice was. I also would prefer brown.

3) Remove the section of the upper deck where the original stereo was. I'll be stacking my component stereo inside on the "floor" of the console with my turntable on top of the other components.

4) Remove the original speakers. I'm really, really hoping I can pull the speaker drivers from my Technics speakers and put them where the original speakers were. The original speakers have absolutely puny magnets and no umph. Plus the entire setup was open-backed. With any luck I can just screw the Technics speaker frames right where the old ones were, then add a rear sealed baffle giving it the same cubic footage as the Technics boxes. It's a big if, but if it works it'll be really cool. I love my Technics speakers and if they don't fit, I'll keep them as they are and just have them outside the console.

5) Currently, the console only opens on top. That gave access to all the original vertically-mounted components. I need access through the front too so I can get to my tuner and CD changer . The front doors you see in the pics are false doors. With some careful planning and cutting, I'm hoping to make them into real doors. Hopefully not impossible.

6) Refinishing. This is something I have no experience with. The exterior has some nicks and stuff that I could probably just touch up with a furniture pen. But because of the major modifications (lots of cutting) I'm doing to the interior, I'll need to finish/refinish it when I'm done.

7) Fix one of the legs. The legs are just screwed into the bottom piece of plywood. The wood is pretty dry and the screws on one of the legs have stripped the wood. I need to come up with a way to strengthen all four legs so it can tolerate being moved. I need to be able to slide it out to get to the back occasionally.

That's it for now. I think I'll figure out more things that need to be done as I move along.

Hello Earth!

2011-07-25T21:27:00.003-05:00

I finally finished my time machine. It was fun meeting my future self and my past self and all that, but the damn thing broke and luckily I got stuck here in the present. But during my visit to the 1960's it seems I developed at taste for mid-century decor.

Resistors and diodes...

2009-06-16T22:11:00.002-05:00

2009-06-13T04:04:00.004-05:00

So the other day I mentioned that the man in brown brought me some gifts. Some as in plural. Well the gift I didn't mention is an oscilloscope. I've had it on my wishlist for a while, but never wanted to spend the $$. New ones are in the range of $400+ and who wants to spend that kind of money on something that doesn't even make any noise?

I've kept my eye on used scopes on Ebay, but those are either $200 or they are sold as-is and untested. Well I finally took the plunge on an as-is untested scope.

I opened the box and powered it up and at first I couldn't get it to do anything but crackle and smell funny. After a little fooling around I realized I was going to need a manual. So I bought one of those on Ebay too. Using the manual I got a little closer, but it was not working nearly correctly. I did some troubleshooting and replaced a couple of parts and it finally came to life.

This is what it looks like right now when I feed it a sine wave:

Obviously, that's not a good sine, but at least I'm in the ball park now. I should be able to figure some things out and get it where it needs to be.

Note the stack of Post-its under the front left corner. Without it in place, the screen goes blank and the crackling sound comes back. I spent an hour or so trying to figure out what's causing it, but no luck.

2009-06-05T00:08:00.000-05:00

Drilled all the holes. Took about an hour, nonstop. So now what?

Ain't she luvly?

2009-06-04T00:09:00.007-05:00

Got a visit from the man in brown today. He brought me some gifts. One of them was an order from one of my favorite places to shop online: MOUSER. They sent me my 12V AC wall wart and blank PCB stock.

TO THE BATGARAGE, ROBIN!

First up was testing out the power supply I built. After switching a diode around that I had put in backwards, I fired it up.... -12.0V/+11.97V. YEAH!!

So then I got to work on the making the PCB. Now THAT was a bitch! Double-sided PCBs are my arch-nemesis. I've only somewhat successfully made one double-sided board in the past and I didn't even end up populating it. And there were many scrapped attempts. In fact, that power supply PCB was supposed to be double-sided and I ended up trying and failing. Fortunately, it was easy to make it single-sided with just one jumper. That would not have worked with this PCB. So I used ALL my powers of PCBing and came out a winnar!

You can see in the pic, the holes on each side of the board lined up perfectly. This is no mean feat! Props to Mouser for stocking translucent PCBs. It doesn't help with lining up the holes, but it makes for much cooler pics! So I'm glad to be finished with that stage. I did have to clean up a lot of bridged traces with an X-acto. The traces on this board are pretty close together. Next step... drilling about a million tiny holes!

I didn't order any of the components. Gotta put that off till payday.

You are now about to enter.... the THIRD dimension!!

2009-06-02T12:55:00.006-05:00

I found a cool application online. It's Google's Sketchup. It's basically an entry-level 3D CAD program made simple and pretty for everyday folks. You don't have to be an engineer to use it. I'm already thinking of all the trouble I could get into with this program. And it's FREE!!

Last night I did a model of the case for the MFOSSU. Wasn't too tough, but there is a (very) little learning curve. Not nearly as hard to learn as a vector-based graphics program.

Gonna make the case out of some nice hardwood--maybe walnut. The white space on the right is where the expander panel will go (it has some extra functionality: ring mod, ADSR, and some other stuff that the main unit doesn't have). The panel is posted on the MFOS site, but I don't think it's finalized yet. So I'm gonna wait before I do anything with it.

The big black rectangle is a tray. It's basically just a nice convenient spot to put all the patch cables when they're not being used. I may end up using that space for some small modules, more like guitar effects... delay, chorus, phaser, etc. that I'll be able to patch into.

Look at all the colors!!

2009-05-30T23:24:00.012-05:00

With DIY electronics, decorating the enclosure is one of the more difficult parts. Doing stompboxes over the years has been fun, but coming up with a durable, legible, cost-effective, feasible way to paint or plate or whatever has been an exercise in frustration.

I didn't know how I was going to do the panel for the MFOSSU. I had found several transparent label-type products online, but they were either too small or too expensive or both. So yesterday I was babbling my troubles to my wonderful wife while we were out driving and we drove by a sign shop. She asked why I didn't have them print it for me. Of course! The panel (which I bought at a hardware store) is 1/16" thick aluminum sheet--pretty much the same stuff street signs are made of! I'm glad one of has half a brain. So I'm thinking they can do lots of colors including white, which is really tough to do with laser printers. Up till now I was thinking I was stuck with black print on raw aluminum or something like that.

Most modular or vintage synths are pretty plain graphics-wise. I figured hell, if I'm making this I can do whatever colors I want. That way it won't get confused with everyone else's MFOS synths at a gig, right?!

Here's my scheme:

I lost some of the crosshairs for the holes. Oh well, I can do them later by hand. It's because I suck at graphics. If I was good, I'd do a layout from scratch. I was pushing my abilities just adding the colors to MFOS' layout!

I HAVE THE POWER!!!!!!!!!!11

2009-05-29T13:40:00.024-05:00

First, a little correction. The MFOS Synth Ultimate is not modular. It is a patchable synthesizer. It has all the jacks and cables of a modular but is built into a single panel. So you can't add or remove modules, but you can patch around them. My plan is to get this thing built and use it as the heart of a bigger truly modular system eventually.

Here's the panel silkscreen from the MFOS website:

So it's got 3 VCOs, 1 VCF, 1 AR generator, 1 VCA, 2 LFOs, a mixer with white noise and external in, and Sample & Hold.

MFOS is currently developing an expander which I'm also planning to build. I'll house it in the same cabinet. It's slated to have an ASDR generator, another VCA, a state variable VCF, a ring mod, and a mixer. So that's 14+ (there are also attenuators) modules for a couple hundred bucks. If I were to buy all that from, say Doepfer or Synthesizers.com it would be at least $1,200.

So without further ado...

The heart of a modular/patchable synth is the power supply. No power = no worky. So I built the one MFOS recommends. It's a wall wart based deal. The wall wart is an off-the-shelf 12v AC/AC adapter... basically just a transformer that plugs into the wall and steps down mains voltage from 120VAC to 12VAC. It connects to the circuit I built (pictured below) which half-wave rectifies it, splitting it into +12VDC and -12VDC, more or less. The ripply DC waves are smoothed courtesy of the six capacitors in the pic below (never used caps that big before!), then they get regulated to a steady +/- 12V by the two voltage regulators.

Pretty straightforward build. The original PCB was double-sided, but I opted to make it single-sided. Way easier. I just used a jumper on the bottom of the board because the top of the board only had 1 trace. Saved me a lot of agony because making 2-sided PCBs is a PAIN! I haven't tested it yet because I forgot to order the wall wart. I'll get that with my next order which will also include double-sided blank PCB stock for the main board and all the resistors. Yeah, I etch my own PCBs 'cuz I'm a cheap bastard and a glutton for punishment. I don't get flawless results as you can see in the pic, but it's good enough for me to get down.

Humble beginnings...

2009-05-24T21:04:00.004-05:00

I've been tossing around in my head the idea to build a modular synth. I've been doing guitar stompboxes for a while but since I hardly play guitar, something keyboard-based makes a lot more sense. But I'm on a budget so a huge monstrosity is out of the question. And dropping a whole lot of $$ at one time won't work either. This has to be something I can do a bit at a time.

I was originally planning to do something module-by-module, designing my own panels, but that's a lot of work and expense. So I was really happy when Music From Outer Space released the DIY Soundlab Ultimate. I like that it tracks notes accurately. The lack of that function is what turned me off from his earlier projects. You couldn't really play them with a keyboard without serious modifications. They were basically noisemakers. The MFOSSU is an instrument.