Tuesday, January 25, 2011

VPO Project : Success

Discovered the problem with running "jorgan-pup"on zombie (Dell Inspiron e1505 without a screen) -- needed more memory. Replaced the 512MB dimms with 1GB dimms. Works with LPK25 keyboard.

Plans now are to build a modern "portative organ", basically a portable pipe organ

  • 2 manuals - 2 octaves each - staggered - I have spacer plates from the Baldwin and Gulbransen.
  • Stop tablets from Baldwin
  • Piston buttons from Gulbransen (or use switches)
  • Dell e1505 as processor
  • Internal audio
  • 15 inch dell display
  • external connections for keyboard and mouse (USB hub)
More details coming soon. Hope to have something working for FOSS faire next month.

Thursday, January 20, 2011

The Problem with Jack

I have been working on two related projects : a virtual pipe organ (vpo) and a guitar effects processor. What they have in common is a PC running Linux. Most audio applications use a program called Jack, which is an "audio connection kit". Jack provides the connections between audio sources (like a virtual synth) and outputs (like the sound card in a computer).

I have been trying for the past two weeks (on and off) to get my computer to make a sound. Any sound. I read the online tutorials. They just didn't click with me. Something was missing. I was using some Sound Blaster Live! cards because they had been recommended for use with the VPO software. I could never get the VPO software (jOrgan) to generate any sound.

I decided to try a different tact with software called Rackarack. I decided to remove all the Sound Blaster cards and used the internal audio. I loaded Ubuntu Studio but could never get the Jack server to run. It would always fail with an error. Via Google, I discovered that Jack didn't work with Ubuntu versions after 10.4 (I was using 10.10).

I loaded a distribution called Puppy Studio, a custom distribution with audio multimedia packages. I booted from the CD. The Jack server started running.

I was reading an article about how to configure the Jack Patchbay and I realized what I had been missing. The Jack Patchbay has "outputs" which come from applications, and "inputs" which interface with hardware. Which seems backwards to me. The audio hardware is managed in Linux by a system called ALSA, which normalizes hardware so Jack can connect to it via the patchbay. The sound hardware was recognized by a system called Pulse Audio, which is used by ALSA to provide the connection to Jack.

I launched Jack, configured the patchbay based on the tutorial, plugged in my guitar and finally....sound.

If you want to use Linux to build an audio appliance, find a distribution with Jack bundled to avoid incompatibility problems.

Wednesday, January 19, 2011

unexpected error?

My work mail is dead. The new GroupWise server is giving me an "An unexpected error has occurred".

So, would an "expected error" be any better?

Wednesday, January 05, 2011

Project : Clavinova

I was recently given a Yamaha Clavinova CVP-87A.

It is a digital electronic piano with 88 weighted keys, rhythm section and recording/playback features. What you would buy if you did not have room for a real piano, but wanted the "feel" of a real piano. Beautiful rosewood cabinet. The piano is non-functional due to a number of defective components on the main sound board that have failed. The solution from Yamaha is to purchase a $500 replacement main board. Apparently, these failures were common, but not common enough to be recognized as a factory defect. Most people make the financial decision to buy a new piano rather than spend $500 to repair a 12 year old piano.

Upon inspecting the main board, the component failures are fortunately obvious, but unfortunately numerous. All are surface mount electrolytic capacitors....which are in some ways easier than replacing through hole parts.

The service manual has been ordered from Yamaha ($16, on CD) and soon another project will begin.

If the piano turns out to be unrepairable, it will serve as an excellent chassis (and keyboard) for a future VPO (Virtual Pipe Organ) project.

Update - 1/6 -: Received confirmation from Yamaha that manual has shipped

Saturday, January 01, 2011

Battery upgrade for 30G iPod - the patient lives

I was getting about 20 minutes on a charge, so the battery obviously needed replacing. Ordered a kit from OWC. Got around to installing it tonight. If I hadn't forgotten to re-install a (non-critical) insulator, it would have been totally done in about 10 minutes. You can see the piece I originally left out in the upper right hand corner.  Doh!

The online video warned about the problems with removing adhesive, but it was no big deal (2 small pieces of double stick tape). Here is the patient on the operating table, about to close up :

Musical electronics @ MakerFaire : NC 2011

I'm working on some other musical projects, mostly involving parts recycled from old electronic organs and vintage computers. Current plans include a MIDI pedalboard as part of a virtual pipe organ, and C-64 related projects.

Flag-O-Matic @ MakerFaire : NC

My dad developed a product called "Flag-O-Matic" in the 1950's. It was a portable traffic light controller for construction sites. He built a working prototype, but it was never produced commercially. I'm planning to open it up and check for potential problems, then have it operating at MakerFaire : NC 2011.

The timing circuits in the Flag-O-Matic are all electromechanical -- mechanical timers and relays. What could be built today with an Arduino and a shield board required much more complex circuitry.

More updates as I progress.