Don't recycle electronics, repair them

Don't recycle, repair. My wife is now using two 20 inch Samsung LCD displays that I repaired with a well documented fix found on the internet. Spent about $4 in parts and an hour of my own labor. They were about a week away from being in the landfill. If your late model Samsung or Phillips LCD display/flat screen TV has recently stopped working (my Samsung LCD TV died about 4 years after its' purchase), it is probably easily fixed. --tom

Java is a 4 letter word

Got this today from a friend : Java users beware : Exploit circulating for just patched critical flaw So, Oracle just patched Java (again) and almost immediately that patch is being patched. If we were to sum up the cumulative misery (lost time, lost work, endless patching) that Java has inflicted on humanity, it would be a big number. The whole concept of "the same code runs everywhere" NEVER really worked. Whose time are we saving? --tom

I found an Optigan!

This past weekend, I found something from my musical "Holy Grail" list....an Optigan! The Optigan was built in the 1970's by Mattel Corp. (yes, that Mattel) in Compton, California (yes, that Compton). Wikipedia has a pretty good overview : http://en.wikipedia.org/wiki/Optigan The Optigan used samples recorded on circular film stock that looks like a vinyl LP, but you can see through it. Each key on the keyboard was mapped to a separate track on the optical disk. There were also tracks for the chord buttons and 5 special effects buttons. The Optigan was built by a toy company, thus the dodgy build quality. Some internal parts would disintegrate, the rubber idler wheel would get hard and the disk would slip. Nonetheless, the Optigan and its' low-tech sampling capablity has appeared in many commercial recordings (and still does to this day...check out the Optigan Facebook page). My main interest is historical. Here is my Picasa album of the teardown. When I brought it home and plugged it in, for the most part, it worked (this is unusual for Optigans). The special effects buttons were intermittent so I had to take off the top to access the buttons. To remove the top, the sides must be removed because they cover the screws that hold down the top. Yay. The pictures show the state of the internals. Not so bad. While reassembling, a small wire which moves the disk assembly fell out. In order to reinstall the part, I had to pry out an internal panel, replace the part (with forceps) and screw it back together. Another common problem is the idler wheel. The rubber has turned hard and slips on the disk. It can be resurfaced, but requires major disassembly to remove the part. Once I have a service manual (or at least a procedure), I may attempt this.

Raspberry Pi, Puredata and MIDI

My initial test with the Raspberry Pi running Puredata did not go as well as I had hoped. Noticeable noise in the output audio. In my MUS306 class today, MIDI was the topic of discussion. Why not MIDI? Connected my $5 no name MIDI interface to the Pi and started Puredata. Changed the configuration to turn off the audio output and set the MIDI ports. Used my Yamaha QY-10 as the MIDI tone generator. Everything worked perfectly. Now I'd like to see if I can attach controls directly to the GPIO port. This would save me from having to attach another MIDI device.

Hammond Tone Generator - Part 3 - FInding the usable tonewheels

I have tested the outputs of the tone generator...there will be about 60 usable outputs. The other 31 outputs consist of the lower frequencies..the windings on the tonewheel cores include resistance wire which drops the levels significantly. I will have to further dismantle the TG to see if the resistance wire can be bypassed. I don't think that further dismantling is worth the potential of damaging the TG. I know that at least 2 or 3 of the tonewheels are stuck and will be looking at those to see if I can get them working. Fortunately, there appears to be a correlation between the color of the wire from the tonewheel and whether I am seeing usable output. For example, none of the red wires produce usable output. Most of the orange wires provide usable output. If I'm not getting output from an orange wire, something is probably stuck or broken. I have documented all the wire colors and whether I am seeing output. Next step is to recheck the outputs that should be working.

Hammond Tone Generator - Part 2

I have tested all the outputs of the Hammond tone generator. Some of the levels are lower than others, but all are generating output. The levels are too low to be switched by anything other than physical switches, so they must be amplified. Many of the tone generator (TG) outputs are filtered through a LC filter to suppress harmonics and reinforce the fundamental. If I were to bypass this filter, I would have higher levels from each of the TG outputs. Unfortunately, the harmonics are clearly audible without the filter, so the filters must be retained. The lowest 42 tones have resistance wire wound into the coils, which is required when the TG outputs are connected to the various busbars in the organ, but not necessary if I were to replicate the Hammond wiring scheme (61 keys x 9 wires per key = 549 wires per manual). I plan to use the TG in a more novel way, which has yet to be determined. The TG output levels can be increased by moving the core closer to the tone wheel, but external amplification will probably be required.

The amazing Deacy amp

Was listening to Queen's Greatest Hits and was looking up the band members on the internet. Turns out the bassist, John Deacon, was an electrical engineer. In the early days of the band, he FOUND a amplifier circuit board on the street and decided to try and make it useful. He put the amp in a spare speaker cabinet and the Deacy amp was born. http://www.brianmay.com/brian/briannews/briannewsjun05.html In combination with May's Red Special guitar and a treble booster pedal, the classic Queen guitar sound was born. Expensive replicas have been built : http://www.astrings.co.uk/deacy_amp that achieve 85% of the sound. :-)

Hammond Tone Generator Project - Part 1

Early this year, I acquired a tonewheel generator (TWG) from a Hammond series H organ. The H series was rushed into production to compete with offerings from other organ companies, and suffered reliability problems as a result. Here are some photos :

The Tonewheel Chronicles

This TWG had already been removed from the organ and was headed for the dumpster when I picked it up. I have bolted it to a wooden frame to prevent flexing. The Hammond tonewheels organs were produced from 1935 until 1975. Tones were generated by spinning a toothed steel wheel next to an electromagnet. The wheels rotated at a fixed rate, locked to the speed of the synchronous motor. When operating properly, the TWG never went out of tune. This was an improvement over electronic oscillators, where at least 12 oscillators must be tuned to their appropriate pitches. Here is a more extensive description : http://en.wikipedia.org/wiki/Tonewheel So, what can you do with a TWG from a Hammond organ? First, I needed to test the TWG to make sure that it was operating properly.

Synthesis on the Parallax Propeller

Have been experimenting with audio synthesis on the Parallax Propeller chip. The Propeller is a 8 core multiprocessor chip that can be purchased for $7. It is remarkably capable...the processors share the I/O bus on a time slice basis, so each processor knows when it has access to the I/O bus. Anyway... There is discussion on the forums about a SID Synth project. It runs an emulation of the Commodore 64 SID chip in 4 of the 8 cogs (processors). The processor accepts MIDI input and passes the note commands to the various cogs. Here is a link to the forum discussion : http://forums.parallax.com/showthread.php?133075-Polyphonic-SIDcog-synth-WIP Even more interesting, the circuit is capable of digital audio output via a simple RCA connector, using the S/PDIF protocol. I am using it with a $20 S/PDIF to Analog audio converter. I have the digital audio working, unfortunately not yet with the SID emulation. WIll be working on this. While this is nothing like having real SID chips, it is pretty impressive for what it can do.

Microsoft Family Security. Useful? Not Really.

I'm trying out Microsoft Family Security on our Windows 7 box. Following is the list of software that my son is "using". Completely accurate, but pretty useless. There are 3 real programs in here : Google Chrome, Nero and Snagit Most of this stuff runs in the background all the time. Apparently there is no way to exclude this background nonsense from the report. I don't want to disallow it, because then everything breaks :

Citrix online plug-in Connection Center 4 hours 8 minutes

Event Monitor User Notification Tool 4 hours 8 minutes

Google Chrome 4 hours 8 minutes

HP QuickPlay Resident Program 4 hours 8 minutes

HPWAMain Module 4 hours 8 minutes

hpwuSchd Application 4 hours 8 minutes

Internet Low-Mic Utility Tool 4 hours 8 minutes

Politics : Don't like the facts? Legislate them away

Our legislature in action : Climate change may be illegal So, if you don't like the science, make it illegal. This is the legislative equivalent of putting your fingers in your ears and saying "La La La, I can't hear you.

Project : Clavinova - where to go from here?

My attempt at repairing the Clavinova CVP-87A did not help (the audio output still sounds terrible), but there was a silver lining. It turns out that the MIDI out still works. I am currently using a Yamaha external MIDI sound module as the sound source. I disconnected the audio output of the mainboard, and connected the audio output of the MIDI module to the external input of the Clavinova. Unfortunately, there is no volume control of the external input -- the volume controls on the Clavinova do not work.

So, it is a perfectly good learning piano. I take my piano lessons on it. I love the way it plays. However, I can only control program changes. The first 10 are on their own buttons, the other 50 are available through more keystrokes. None of the other controls work, including the floppy disk interface. Every key has a corresponding LED, which is used to indicate the position of keyboard splits, among other things.

So my options are :

• Purchase a new mainboard for about $500, which leaves me with a Clavinova and its' 1993 era voicings. Next year it will be 20 years old.
• Do nothing and continue to use it as a piano controller with a bunch of non-functional controls. This is practical, but somehow dissapointing.
• Replace the electronics with something more modern. I have looked at commercially available MIDI controllers. Almost none of them provide for velocity sensing and very few provide for control of 88 keys.

I have thought of building a computer inside the Clavinova. There is plenty of space. I could probably salvage the amplifier boards, but not much else.

Logitech Orbit AF - Only in Ubuntu :-)

Grabbed an old Logitech Orbit AF cam to do some video conferencing. Logitech does not support this device under Windows 7, and Mac OS X does not recognize it. Finally tried Ubuntu 11.10 and the camera WORKS, though the audio does not. Amusing.

It's been awhile : new HP laptop series naming?

It's been a while since I posted. HP has just come out with a new line of laptops -- The HP Spectre. Looked up the definition of spectre on the Free Dictionary : spectre US, specter [ˈspɛktə] n 1. (Spirituality, New Age, Astrology & Self-help / Alternative Belief Systems) a ghost; phantom; apparition 2. a mental image of something unpleasant or menacing the spectre of redundancy Hmmm.

Success : Auto update of Ubuntu 11.04 to 11.10

Did the "click the button" update from Ubuntu 11.04 to 11.10. Zero problems. I did have to ask Mr. Google how to get the old Gnome desktop back. This is the 2nd time I have done a hands off (mostly) Ubuntu upgrade...previously from 10.10 to 11.04. That upgrade was also flawless, but I did have to answer a few questions about keeping files that were to be replaced. I have been using Ubuntu as my primary desktop for the last 3 months, and have been very impressed. The biggest problem with using Ubuntu at NCSU is the problem with configuring the VPN. Which is totally a Cisco problem....their client assumes that Firefox is installed and tries to save the certificate in a .firefox directory. If that directory does not exist, the VPN client fails with a generic message. Why this dependency even exists is puzzling.

Roland - Why such cheap connectors on expensive gear?

I just finished repairing the 2nd piece of Roland music gear in the past two months. Earlier, I removed the audio output jacks from a Roland SPD-S Sampling Pad and replaced them with a cable to an external breakout box. The 1/4 in output jacks are used more than any other connector on the device, but the parts are of poor quality, and mounted in such a way that guarantees their failure. No strain relief is provided -- all the stress of plugging and unplugging audio connectors is absorbed by the connector and its' solder joints. While the connectors are threaded for a mounting nut, the design does not allow them to be added. Original retail on this device was between $500 and $800. Earlier this week, I repaired a Roland RD-700SX Stage Piano. Original retail was likely between $1000 and $2000. The contacts of the power connector were totally mangled. Rather than use a replacement part that would likely fail again, I used a connector from an old piece of test gear.

Open letter to HP

Guys,

I know you are having a hard time right now (and by the way, my HP stock is way down), but this is not the time to be running from the hardware business. My opinions vary on your consumer products, but my ongoing good experiences with your server class hardware tells me that you should keep doing that. Your background in instrumentation and testing gives you a good perspective on how to develop systems that can be monitored and maintained effectively. Keep it up.

--tom

Hammond T-595

From Hammond T-595

My new, old Hammond T-595. The previous owner got as far as painting the organ to match the room. Has a built in Leslie. From the symptoms (hum, very low sound), I'm guessing bad capacitors or a bad output transistor.

The Hammond T-500's were the last of the tonewheel organs that Hammond produced. Tonewheels generate sound via spinning metal discs and electromagnets. The drawbar controls allow a specific mix of harmonics in the output.

Amusingly, the T-500 Hammond incorporates circuitry to eliminate the uniqueness, classic, Hammond B3 sound. Forutunately, The modifications to reverse these "improvements" are well documented.

Project KOW : Console design

The jOrgan software uses "dispositions" as configurations for how a virtual organ will look and sound. When these dispositions are very complex, the control scheme is also complex. Generally, the player will choose combinations of stops and apply them to "pistons" which are basically presets. These pistons are physical controls and are generally located below the manuals, though pistons can be displayed on the computer screen and selected with the mouse, or via a touch screen.

During the performance, the pistons allow rapid changes of stop combinations that could not be achieved by manually changing the stop tabs. My first "proof of concept" organ used a ELO touchscreen, which allowed me to tap the screen to make changes.

So, now to console design. A touchscreen allows access to many stop tabs and pistons, but lacks the tactile feel of real switches. One can glance at physical switches to check and change configurations, but this is much more difficult with touchscreens.

I did extensive research online to help me decide on a design for my console. I have narrowed this down to Schlicker and Holtkamp consoles, as they often used a very minimalist design (some call it ugly) The console that most approximates what I am planning is this Schlicker practice organ :

http://mysite.verizon.net/dalderdi/organ/

Reducing the number of controls allows all controls to be "real" and eliminates the need for a computer display. This will allow me to concentrate more on playing, and less time fiddling. There will be likely fewer than 30 physical control elements, which also makes the console project much more "doable". The thought of wiring even 100 different controls is daunting.

Hardman Wurlitzer in Virginia

The theatre organ that Cameron Carpenter uses on his "Cameron Live!" DVD/CD is located in Great Falls, Virginia near Washington, DC :

http://theatreorgans.com/wurlitzer/

The reconstruction story is very detailed.

An entire building was built for the organ console and pipes. My understanding is that the local zoning board would not allow the owner to build a new structure that was bigger than his house, so the organ "barn" was built as an addition (connected by an enclosed corridor) to his existing house.