Archive for December, 2013

ribbon microphone ribbon

Ever wondered how thin a ribbon microphone ribbon actually is?

Click for full-size

That’s how thin. Edible gold leaf is much thicker than this.

You take aluminium this thin, cut it into strips, then corrugate it with great pressure, with wood, all by hand. It’s not as difficult as it sounds, but once it’s done, it’s like “…wow, that’s… really delicate work!”

I’ve made a couple of viable ribbons at this point and have been testing the completed microphone. This ribbon had a nick on the edge, so was useless, and never made it to the corrugation stage. I threw it out, then fished it back out of the bin for a photo.

You can’t actually touch them; they disintegrate on contact. The toothpicks shown here are for handling the metal.

I’ll make a microphone assembly post probably tomorrow.

eta: I just tried to measure how fast it falls (terminal velocity), and it fell about 60cm before deciding to hover there for a bit. Presumably in an updraft I couldn’t feel, not just out of sheer orneriness. So I’m guessing around 10cm/second? Except when it just doesn’t feel like it.

should have seen this coming

The preamp is sensitive to my personal EM field.


I’ve written the Austin people. Hopefully we’ll get something.

I also been building the ribbon microphone. I think it’s okay! But I can’t be sure yet because I don’t have the right preamp. The mic seems to work fine on the TASCAM – go me! I made ribbon microphone ribbons! – but it lacks adequate gain, so that’s not a workable solution.

Bed now. Work on this tomorrow.

eta: This is still true, but it looks like I can shield around it – it’s in no small part a cable-as-antenna question, and my best cables shield me out – I have successful tests again! n/ Austin Microphones is being super-responsive, too; well done there.

microphone preamp build report

I built an Austin microphone preamp from a kit! It’s for use with ribbon mics, and also dynamics – it doesn’t supply (and cannot be hooked to something which supplies) phantom power, so it’s pretty special-purpose and will never leave the studio. But given that I’m about to have a ribbon microphone, it’s useful! And hopefully fun. Anna made me promise not to blow anything up; when I told her that horse had left the barn, she added “today,” and upon checking the clock I found I could agree.

The kit came in a bunch of components and a few machined parts in an assortment of bags. You also get a PDF with extremely detailed directions. See that printout to the right? You get a bunch of those, along with step-by-step instructions.

Must be Sunday

Building is therefore pretty simple, as long as you know how to solder, can keep your solder under control on a fairly but not screamingly small experimenter’s board – you’ll want a good soldering station, mine certainly earned its keep – and can follow directions carefully.

The supplier even provided all these little jumper wires already cut and stripped! Everything else needed cutting and stripping, though.

Eye recovery makes this a very slow job. Still doable; just… slow.

The supplier said it should take about four hours; it took me rather longer, mostly because of the current limitations in my vision slowing me down. I was also very careful and methodical, for the same reasons. Even with all that, it’s still just a one day project.

Paul asked me right about here whether I was making any headway on that dematerialisation circuit.

No. Stupid time lords.

This is what it looks like when you’ve finished the converter array and have the power rails all set up.

Time to test for magic smoke leaks.

The manual has you do testing at this point, and provides several key warnings. The checkbox-as-you-go system really makes it harder to miss things or to get things wrong, as long as you keep up with their grid system. Thanks to my still-recovering vision, I was checking every solder joint under magnifiers.

First try PASSES!

The kit has two ICs: THAT and OPA chips. I don’t really know why I find that hilarious, but I do.

THAT chip! OPA!

Once the chips have been installed in their sockets, it’s time to start adding I/O ports! This one has balanced microphone input, unbalanced line-level output, and external power connector socket. There’s no power switch; it’s just plugged in to turn it on, and you connect power FIRST – before plugging in to any other hardware like the microphone or the input card – and then remove power LAST, when taking down. This is opposite to my current hardware; I’ll have to add reminder labels.

That, and the whole phantom power thing. It’s an odd beast, for an odd sort of microphone.

I/O ports

Input is boosted enough and output is loud enough that you can test it with headphones; no separate amp required. At the highest power levels, I was honestly kind of astounded at how much gain it had, and quite pleased with the noise levels even at maximum boost. First test of the complete assembly passed just fine.

Yep! That’s a power light!

The printed control panel looks rather smart, I think. It only has the one control – a stepped gain control knob – but it has a good range of boost steps.

All done; all tests passed first try!

I can’t say a whole lot about performance yet – but I can say it’s very low noise at very high gain, and had a nice natural sound on my quick SM-58 tests. The real test will be the ribbon microphone I intend to use with this amp, which is also a kit. Despite fewer pieces, it’s a longer build – there’s materials time, and unfamiliar processes.

But I’ll get there. I’m just hoping my studio is up to gear this shiny. ^_^

This is a related article in the Studio Buildout Series, a collection of posts on building my own recording studio.

second thanksgiving

Second Thanksgiving went well; we had 15 people, as it turned out – a nice size. We were expecting possibly as many as 20, so had a 30 pound bird for the first time in years – but that’s good, because mmmmmmm turkey tacos, mmmmmmm turkey jos, mmmmmmm turkey leftovers on sammiches, etc. 😀

It ran late, into the night, and felt a lot like one of the Homeless Waifs Thanksgivings our housemate Vicka used to throw, before she got her doctorate and moved back to Boston. I don’t know exactly why, honestly; it just did. Good circulation and a crowd large enough to form several groups made up part of that. More new people than usual probably helped too, I suppose.

I imagine the return of the Mystery Science Theatre 3000 Turkey Day Marathon didn’t hurt anything. I missed that – we were singing the “We Gather Together (To Watch Cheesy Movies)” theme over and over again while cooking. We named our turkey Clayton McLargehuge, in honour; Anna told @JoelGHodgson about that on Twitter, who retweeted it. XD

Also, we need more Thanksgiving songs. One isn’t enough.

My long-term undefeated Jenga streak fell this year, I hate to say; that lack of parallax thing really hurts when it comes to tower stability wars. Even when winning the first game, I was telling people, I could feel it – I could be owned, in my current state. And was, alas, the very next round.

We had more music than usual, too, with LasFas and Fred both being around and having more time than usual, and with me and Anna, that made a pretty good bit of jam.

The last people left Saturday, which says a bit about it. We overbought alcohol (darn) and food (like we always do) but it’s all being eaten and much will be frozen or stored.

For real, this is my favourite holiday. How was yours?

Return top

The Music