Acidlab Miami: All Boxed Up And Nowhere To Go....

via MaD:
http://acidlab.de
"The cases of the Acidlab Miami arrived and the prototype has now achieved his final look. The serial devices will become grey and white buttons instead of the red/yellow ones."

Be sure to click on the Acidlab label below for more including video. Click the image for the full size shot.

Oberheim Ob-1

via this auction

DIYing a Roland JX-8P DCO

This came in on the SDIY list via Tom Wiltshire. I thought it would be an interesting post on how these things get started and Tom gave me the ok to put it.

"Hi All,

I've been experimenting with a DCO design based on the Roland JX8P circuit

Broadly speaking, it works, in that I can get a ramp wave out of it if I adjust the 47K pot on the left. This pot and op-amp buffer will be replaced by a DAC when I get it working better. I've got reset pulses generated by a PIC being fed into the base of the transistor at 440Hz for the purposes of the test. That part is fine.

The problem is that the output goes from 0V down to -0.5V and then seems to saturate. What's going on? How can the op-amp output be saturated at only -0.5V when it's running on +/-15V rails? Everything I've read suggests that the output from an integrator ought to carry on as far as the op-amp output can take it, so I was expecting a ramp from 0V down to -15V or thereabouts. I'm sure there's something I'm missing here...

Thanks for any clues,
Tom"

Some clues did come in from members of the list including:
"Looks to me like base-collector parasitic diode starts conducting."
and
"The ramp is negative going, so Vcb is negative. That causes the base collector junction of your reset transistor to forward bias and limit the output voltage. You'll need to rethink the way you've got that reset transistor hooked up, or reverse the direction of the ramp so it's positive going (hint - invert the input to the integrator)."

followed by:
"Thanks both, that's sorted it. I simply swapped the polarity going into the integrator and as if by magic everything became hunkydory.

What I was missing was that Roland were evidently using a negative voltage. That isn't immediately clear from the schematic.

Instant solutions on this list...great suff!"

Why post this? Again, it's and interesting insight for those not involved in the SDIY community to see how some of this happens. Who knows, we might have a very nice Roland JX-8P VCO module or the like available one day. Pretty cool...
The Juno-106 replacement chips immediately come to mind.

Bebot Robot Synth for iPhone and iPod Touch

YouTube via normalware
"Bebot - Robot Synth
Available now in the App Store for $1.99
www.normalware.com "
You can find it on iTunes here:

Synsonics Drums from Mattel Electronics - Features & Demo

YouTube via saulocisneros
"This is a short review of the features of the 1981 Synsonics Drums drummachine/drumsynth from Mattel Electronics. 100% analog"

Electrix Vocoder

YouTube via saulocisneros

NAMM: AX-Synth Shoulder Synthesizer at NAMM 09

YouTube via RolandChannel
"The stylish AX-Synth represents Rolands new generation of remote keyboards, but for the first time, this one has a sound generator onboard. Its self-contained and equipped with powerful, solo-oriented sounds from Rolands latest, greatest synths. Strap on an AX and steal the show."

NAMM: VP-770 Vocal & Ensemble Keyboard at NAMM 09

YouTube via RolandChannel
"With the latest technology onboard, the VP-770 allows a single musician to create realistic backing parts that range from futuristic electronic vocal textures to incredible emulations of large-scale gospel choirs and beyond."

NAMM: FR-1 V-Accordion at NAMM 09

YouTube via RolandChannel. Be sure to watch 1:24 on.
"The V-Accordion is the first instrument of its kind to provide powerful digital modelling technology in a traditional, immediately familiar, accordion design, and with performance functions and authentic sounds that will appeal to a wide range of players. It combines the familiar sounds and nuances of a traditional accordion with the versatility of a modern digital musical instrument. With a V-Accordion you can instantly select and switch between a wide range of sounds and /or types of accordions, or create your own unique timbres and tuning systems. You can plug directly into an external sound system or recording device, while the headphone socket is ideal for silent practice. These digital advantages are featured across the entire V-Accordion range, including on this, the latest addition for young students and stage performers: the FR-1!"

NAMM: VB-99 V-Bass System at NAMM 09

YouTube via RolandChannel
"http://media.roland.com/en/IT/VB-99_IT/
When Roland first introduced the original V-Bass System, serious bass players worldwide took note. This system was like nothing before: it accurately modeled the worlds most popular basses — from classic electrics to upright acoustic bass, fretless bass and more — and combined them with a range of killer bass amps, synth sounds, and polyphonic effects. With COSM® Bass technology and the special GK-3B Divided Pickup for Bass, the V-Bass opened up a world of new sonic possibilities."