If you want to see how the pros do it, there’s a video here done by a certified instructor of soldering. It’s more of an advertisement than a tutorial, but if you watch closely you can pick up some pointers.

Having watched all of these, I’ve arrived at the conclusion that I probably need to use less solder and more flux than I have in the past. Eric Brombaugh (who pointed out the instructor’s videos to me) mentioned to me that he often doesn’t use solder at all when soldering ICs to PCBs that have been HASL plated. He finds that there is enough solder left from the plating to attach the leads.

However, it seems that I’m not the only one obsessed with building digital sequencers. Thorsten Klose, owner of the aforementioned site, has put an astonishing amount of time and effort into his MIDIbox system. The pinnacle of his efforts is version 4 of his sequencer, which he calls MIDIbox SEQ V4, appropriately enough. You can find it about halfway down the left-hand navigation column on the uCApps.de website. When I first started thinking about my sequencer project, the MIDIbox system was far less sophisticated and hence I didn’t pay much attention to it. Also, Thorsten based his system on a PIC microcontroller which wasn’t powerful enough to run the software I envisioned. Since then he has switched to a much more powerful STM32 microcontroller and his sequencer design, while not entirely similar to my own, implements almost all of the functional ideas for a digital sequencer that have occurred to me and quite a few more that haven’t occurred to me. Since he’s kind enough to share all of his source code, schematics, and so forth with the rest of the world, I decided to adopt his system as the basis of my own.

This brings me back to the point of this entry. Rather than using his PCB layout for the STM32 core as-is, I decided to design my own PCB from his schematics. I replaced most of the through-hole components with surface-mount packages, dropped the CAN port because I don’t expect to use it, and added headers for almost all of the STM32 I/O pins. The result looks like this:

The components on the board represent the minimum necessary to determine whether the STM32 runs: the STM32 itself and its clock crystal, a USB socket from which +5V can be drawn, a 3.3V regulator, a connector for a JTAG interface, and an LED that demonstrates that the STM32 is able to execute code. It didn’t seem to work at first but after a bit of head-scratching I figured out that one of the JTAG settings in my IDE was set wrong. (I changed the “nTRST Open Drain” property from Yes to No, whatever that means.) I was then able to succesfully install the MIOS32 bootloader. This made the LED blink in a most gratifying manner. I added the components for the USB interface and MIDI ports and was able to use the MIOS Studio to verify that the STM32 was running the bootloader. This was all very pleasing since this is the most complex PCB I’ve laid out and aside from one incorrect footprint for the voltage regulator it seems to have no flaws. (The footprint problem proved to be due to a mistake made by the makers of my PCB software.)

The next step is to finish stuffing the board and hook up an LCD to see whether the LCD interface works. I ground to a halt at that point because I couldn’t find the ribbon cable for the LCD, and the local electronics shop isn’t open on Sundays. I think my Mouser shopping list is now long enough to meet their $25 minimum so I’ll order the necessary connectors this week. I’ll post a photo of the completed PCB next week.

If you’re wondering about the white blob on the resistor SIP near the top of the board, it’s silicone glue. The board needs a 4-resistor 10K SIP for the JTAG, I had only larger SIPs on hand, and the local shop didn’t have any of the right size either. I ended up cutting down a larger package with wire cutters and put the glue on the end to seal it back up. Works fine.

I’ve got a Lexicon PCM-90 reverb that needs a new and understanding home. It has a problem that’s either a show-stopper or insignificant, depending on how one uses it: its analog input does not work. Its S/PDIF digital I/O works fine, and this is how I’ve been using it. Some googling suggests that this problem is not uncommon and is usually attributable to a failed ADC chip. Unfortunately that chip is long out of production. It also has some signs of wear and a few odd-looking bubbles in the plastic in front of the display which are faintly annoying but not actually obstructive.

Not long ago I purchased a PCM-91 and PCM-81 for a friend, and while I’d be entirely happy to have three units of Lexicon PCM goodness, I’m about 4U shy of having enough rack space to accommodate all of my signal processors. (It’s something of an occupational hazard, I guess.) Hence my PCM-90 is up for sale. I paid $450 for it in the same condition that it’s currently in and would be delighted to get $300 for it, but I’ll consider offers.

I have a printed, spiral-bound copy of the manual which I’ll include. Paypal only unless I know you. I’ll pay for UPS Ground shipping within the continental US; anything else you pay for. I’ll ship overseas but you’ll have to pay me way more than $300 for it. (Shipping rack gear out of the country is a royal PITA.) Highly collectible leekspin girl not included.

I got rid of a lot of old computer stuff, including a 2x(!) CD-ROM(! yes, no writing capability) drive dating from the days that CD-ROM drives had those annoying little caddy things and were housed in their own cases. As I threw out dozens of yards of Mac ADB and serial cables (with their funny little mini-DIN-8 connectors) and SCSI cables and adapters (including an infamous “Weird-30″ adapter used by some PowerBooks) I reflected about how much electronics junk Apple had created in the world with their decisions to “think different” and use strange connectors rather than the ones that were already established (such as the DB-9 for serial ports).

In terms of volume, the largest amount of stuff I discarded was 3.5″ Mac floppy discs. I’d had most of these stashed on a shelf for over 10 years, untouched, retained on the “just in case I need them someday” pack-rat mentality. I decided that if that day hadn’t arrived in over a decade, it probably wasn’t going to arrive at all–particularly considering that I no longer have any pre-G4 Macintoshes on hand. I think I filled two grocery bags with the things. Here’s a subset:

They provided little reminders of my computing past. This trio provides a nice representation:

On the left we have the “System Tools” disc from my first Mac. That was from 1986, when you could fit the entire MacOS and some utilities onto one 800K floppy. Next to it is Netscape Navigator, probably from around 1999ish, at a guess. Yes, kids, there was a time in which you could obtain a web browser on a physical medium rather than downloading it from the web. (Why? Well, it’s kind of a long story. Fetch me my Geritol and I’ll tell you.) On the right is MS Word version 6. The label says “Install disc 13″. Remember when you had to stuff a dozen floppies into your machine to install an app? I imagine that version 6 was the last version of Word to ship on floppies rather than CD-ROM.

The discs that I lingered over the longest were the master discs for music software. Many of these were so-called “key discs” which meant that they served as the copy-protection mechanism for the (often fairly expensive) software that was contained on them. They usually permitted you to install the software only a few times, and getting them replaced if they failed could be something of a chore. (Yes, it was my experiences with some of these discs that contributed to my somewhat infamous disdain for PACE. These key discs were the predecessor of the iLok.) Hence their value was disproportionately much larger than that of most 3.5″ floppies, and one tended to keep them in special storage containers on a shelf, safely out of harm’s way. I assembled a small gathering for a final photo:

From left to right, back row first: Master Tracks Pro, my first sequencer and possibly the first commercial music software I ever purchased; the first version of Max published by Opcode (dated 1990); OMS, which I won’t even try to explain–you had to be there; the Digidesign Audio Utilities as published by Opcode, system software for their pre-Pro-Tools DSP hardware; and Galaxy Plus Editors, the patch librarian/editing software for numerous MIDI synths. Next row: a demo disc of M, one of David Zicarelli’s first products and still available from Cycling ‘74 (I think); a demo disc of Turbosynth, Digidesign’s non-real-time but extremely cool software synth; Steinberg’s ReCycle, the genesis of loop slicing written by the guys who went on to form Propellerheads; editing software for a JL Cooper MIDI fader box; and a very early version of Opcode’s Vision sequencer. Bear in mind that none of the sequencers shown here could record or play audio–this was strictly MIDI sequencing we’re talking about. Next row: Music Mouse, a sort of early “intelligent instrument”/software performance thing written by Laurie Spiegel (whom I spoke to on the phone at some point after buying it); Deck, as published by OSC, the first(?) multi-channel recording app for the Mac; the driver software for the MOTU MIDI Timepiece, the first(?) multi-port Mac MIDI interface; a demo version of Cubase (undoubtedly pre-VST, i.e. no audio); and Band in a Box (don’t ask) Front row: a later verson of Master Tracks Pro which still didn’t have audio; Deck, as published by Macromedia after they acquired it from OSC and before someone else acquired them; Bliss Paint, a sort of abstract animation app that involved scripting sequences of patterns–very cool but fatally flawed because the author didn’t tie the timing to any sort of hardware reference so your animations ran completely differently depending on how fast your hardware was; version 2.2 of Turbosynth, now almost real time because it could use an Audiomedia II card for doing the DSP; and UpBeat, another David Z. creation, as published by Dr. T’s who acquired it from Intelligent Music. (I had discs for it from Intelligent music on hand also.)

In other words, my pack-rat stash of floppies represented a lot of history from the music software world. It was kind of hard to let it go. After all, these programs were not only my tools of musical expression (more or less) but also in some sense the inspiration for Audio Damage and its products. Happily, some of them went to a good home: Turbosynth, UpBeat, and a couple other mutual old favorites are on their way to Chris, where they can sit on his shelf near his alphaSyntauri system.

Yes, it’s a Gakken SX-150 Analog Synthesizer, possibly the world’s most famous ultra-cheap synth. Yes, you can get them in the US, with some effort, but somehow that’s not nearly as cool as pulling one off the shelf at the bookstore in Kyoto Station, buying it from the polite young clerk using a mixture of broken English and broken Japanese, and then waltzing back to hotel room, past the smiling and bowing bellhops, bearing it under my arm. Yes, I’m feeling a little bit smug about it all.

Given Dave’s expertise with EQ, I’m betting that this one is going to be a winner. He’s also a heckuva nice guy and has fielded technical questions from Audio Damage on more than one occasion.

Click here to go to his site, read about him and what he does, get a demo version, etc.

Congrats, Dave!

That’s a close-up of one end of the spring tank in my TASCAM RS-20 Spring Reverb. One detail that surprised me a little when I opened it up is that the transducers appear to be symmetric, i.e. the part that feeds audio into the springs appears to be the same as the part that picks up the resulting signal. I’ve never opened up a spring reverb before but somehow I expected the drivers to be different than the receivers.

Actually it’s somewhat pertinent in that I spent part of the weekend happily making insect-like drones with the thing, and this morning have been happily making little filtered-noise whisps and patters. I think I could spend all day doing this, but alas, other duties call.