Page History

Here starts the Project of a Oberheim OBX Clone

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Projecttime Q4/2013 -Q2/2014 (April 2014)

This build was stopped

pcb sodering was outsourced, this part failed - more than 150hours spends - Return on invest failed.

at last: voice cards dont work correct - some wrong caps and resistors, ic placements

please doublecheck BOM and read all muffwiggler postings about known issues..

SUBPAGES & GALLERY:

COPY from cs.80.com:

Construction Hints

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The host board switches, if using my .fpd panel, need to be dropped into their positions on the board but not yet soldered. The panel is then placed over the switches and each switch is nudged until it seats into its drilled hole. This part is somewhat tricky as there are 17 switches to deal with. When properly seated, all the switches (with a lock washer and lip washer between the switch and panel) can then have a panel nut placed on the bushing but do not tighten them fully until the alignment of each switch in its solder pads is adjusted. I like to choose two switches at opposing corners, such as the LFO wave select and mute, line them up and solder them in then work with the remaining switches. It will take a while.

Powersupply Modification:

The crOwBX requires a +/-19VDC power supply as the boards use local voltage regulators to obtain +/-15V and +5V for the host board. The Power One HAA15-0.8-A linear power supply, which is well-suited to operating the traditional +/-15V modular setup, can be modified to provide +/-19V by simply soldering a 10K 1% resistor across R20 and another 10K 1% resistor across R28 on the power supply board, as shown. The trimmers R21 and R26 are then adjusted such that +19.00V and -19.00V are observed on the DC output pins with respect to common. Be careful not to wire this power supply to +/-15V hardware!

The 4-voice crOwBX draws 420mA at +19V and 380mA at -19V, well within the load range (600mA per rail) of the modified HAA15-0.8-A.