MATRIXSYNTH: Ibanez AD80 repair. Documenting a ghost in the machine.


Tuesday, April 28, 2009

Ibanez AD80 repair. Documenting a ghost in the machine.


YouTube via sounddoctorin. vox continental
"Bob Weigel of Sound Doctorin' ( http://www.sounddoctorin.com ) shows some of the interesting effects attainable from a classic digital delay unit, the AD80 by Ibanez, during a repair attempt. To clarify what I'm saying about the circuitry in the video, this pedal uses two FET's as alternating switches for the bypass or effect signals. A flip flop circuit turns on one of them at a time and toggles of course when the switch is depressed. I've never seen my breath have quite so much conductivity. I must be eating metal flakes in my diet. Because there are 1M resistors coming from the flip flop voltages (which were quite steady at about 10V on the FET that is supposed to be turned on during the cutting out effect you witness in the video) and attaching to .047uF filter capacitors (grounded on the other side) and to the cathode of a diode, the anode of which attaches to the gate of the FET switch. The voltage at the point where the filter cap is is what was collapsing to a few volts. Even at 8.some volts though there is enough current drain from the gate to shut off the FET switch. But I saw the voltage fall to just a volt or two when I was breathing on it. Well the clear cote (a super low conductive paint basically) seems to have done the job at protecting it from ...conductive air :-). If anyone has studied more into this effect let me know."

1 comment:

To reduce spam, comments for posts older than one week are not displayed until approved, usually same day. Do not insult people. For items for sale, do not ask if it is still available. Check the auction link and search for the item. Auctions are from various sellers and expire over time. Posts remain for the pics and historical purposes. This site is meant to be a daily snapshot of some of what was out there in the world of synths.

PREVIOUS PAGE NEXT PAGE HOME


Patch n Tweak
Switched On Make Synthesizer Evolution Vintage Synthesizers Creating Sound Fundlementals of Synthesizer Programming Kraftwerk

© Matrixsynth - All posts are presented here for informative, historical and educative purposes as applicable within fair use.
MATRIXSYNTH is supported by affiliate links that use cookies to track clickthroughs and sales. See the privacy policy for details.
MATRIXSYNTH - EVERYTHING SYNTH