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R/E/P => R/E/P Archives => Dan Lavry => Topic started by: rjd2 on August 11, 2006, 10:56:31 PM

Title: understanding plate reverb pickup output
Post by: rjd2 on August 11, 2006, 10:56:31 PM

hi, i have a homemade plate i inherited that was in disarray. after a complete deconstruction, i was able to rebuild the driver, and got the plate working.  however, i have only been able to make a successful return out of a pzm mic pointed at the plate(i know this is caveman as hell, but what are you gonna do?) here's my question:

there is a pickup installed in the plate, but i when i have tried to wire it as a return, i can only get it to come back dry. it appears the pickup has one wire(signal, right?) coming from the part that is NOT physically connected to the actual plate(looks like a very tiny driver cone, but not wound or anything), and the other wire(ground, right?) is soldered to a sheathing piece that IS physically connected to the plate via screw. i have ran this back as a return on a normal signal/ground cable to a mic pre, or even direct into a channel, but it only seems to come back basically dry. tried switching polarity, same thing.

how do i fix this to actually work as a pickup?  thanks for the help.

Title: Re: understanding plate reverb pickup output
Post by: Ronny on August 12, 2006, 01:18:25 PM

rjd2 wrote on Fri, 11 August 2006 22:56

hi, i have a homemade plate i inherited that was in disarray. after a complete deconstruction, i was able to rebuild the driver, and got the plate working.  however, i have only been able to make a successful return out of a pzm mic pointed at the plate(i know this is caveman as hell, but what are you gonna do?) here's my question: there is a pickup installed in the plate, but i when i have tried to wire it as a return, i can only get it to come back dry. it appears the pickup has one wire(signal, right?) coming from the part that is NOT physically connected to the actual plate(looks like a very tiny driver cone, but not wound or anything), and the other wire(ground, right?) is soldered to a sheathing piece that IS physically connected to the plate via screw. i have ran this back as a return on a normal signal/ground cable to a mic pre, or even direct into a channel, but it only seems to come back basically dry. tried switching polarity, same thing. how do i fix this to actually work as a pickup?  thanks for the help.

POlarity reversal won't stop the plate from vibrating. Generally if their is no reverb noticed, the pickups aren't working or the transducer isn't working, or the torque on the plate tension bolts are too loose, which can happen over time. If you are getting some signal back, that tells me that the pickups and transducer are working but the torque isn't correct. It's been so long since I've worked with a plate verb, do a google for Elektromesstecknik or EMT 140, EMT 150 and see if you can find a schematic that gives you the specs on bolt torque and proper wiring, you could than apply it to your plate accounting for size and thickness differences of the plate.

Title: Re: understanding plate reverb pickup output
Post by: seriousfun on August 14, 2006, 03:19:58 PM

rjd2 wrote on Fri, 11 August 2006 19:56

hi, i have a homemade plate i inherited that was in disarray. after a complete deconstruction, i was able to rebuild the driver, and got the plate working.  however, i have only been able to make a successful return out of a pzm mic pointed at the plate(i know this is caveman as hell, but what are you gonna do?) here's my question: there is a pickup installed in the plate, but i when i have tried to wire it as a return, i can only get it to come back dry. it appears the pickup has one wire(signal, right?) coming from the part that is NOT physically connected to the actual plate(looks like a very tiny driver cone, but not wound or anything), and the other wire(ground, right?) is soldered to a sheathing piece that IS physically connected to the plate via screw. i have ran this back as a return on a normal signal/ground cable to a mic pre, or even direct into a channel, but it only seems to come back basically dry. tried switching polarity, same thing. how do i fix this to actually work as a pickup?  thanks for the help.

Are you describing the driver (which should be like a voicecoil from a speaker, without the cone or dome)? Or are you describing the pickup, which can be a small disc glued to the plate itself?

The voice coil driver gets fed an amplified signal and moves the plate. The pickup, at the other end of the plate, picks-up the delayed/reverberated motion of the plate and sends to back to be preamplified and mixed with the music.

Title: Re: understanding plate reverb pickup output
Post by: Jim Williams on August 16, 2006, 10:01:07 AM

Call Jim Cunningham at Studio Technologies in Stokie, IL. He sells high output piezo discs for a reasonable price.

Title: Re: understanding plate reverb pickup output
Post by: compasspnt on September 04, 2006, 01:45:49 AM

Yeah, sounds like you are talking about the driver.  That signal would be dry!