A spring type reverb device contains an electronic driver, and electronic receiver (preamp) and a electromechanical spring device.
The reverb "tank" consists of two transducers with springs mounted between them. The springs have varying delay but common are in the 28-31ms range. The transducer on one end excites the spring (or in most reverbs there are two or three springs each with a different time delay) it delays the signal and the spring mechanical action tends to sustain the delay and then the transducer on the other end converts it back to an electronic signal.
This should help you in determining how to build a mechanical reverb. You can probably go to a repair facility that repairs guitar amplifiers and they may have a reverb unit that you can buy.
If not, years ago I built a crude reverb tank using a small speaker with the voice coil as the "exciter" transducer connected to a small screen door spring, and the other end connected to a phonograph needle cartridge for the receiver transducer.
I worked, but did not have much fidelity.
Your on your own from this point. Good luck
<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Jack Stoner on 23 January 2000 at 06:28 AM.]</p></FONT>
Reverb
Moderator: Dave Mudgett
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Terry Downs
- Posts: 491
- Joined: 8 Jun 1999 12:01 am
- Location: Wylie, TX US
Nice explanation Jack! In addition, the reverb spring exitation is torsonal. In other words, the spring twists with the audio. This gives you a lot of isolation to ambient vibrations. You will notice you have to shock you tank so hard that the spring clangs against the tank before you get noise. Longitudinal exitation would be suseptable to all general movement around the tank.
Higher quality reverb transducer drivers are constant current drivers. This overcomes the impedance change in the transducer over frequency due to its high inductance.
Also, since the movement at the receiving transducer is very small, the output signal is very small. Good shielding is a must. I had a Peavey Mace back in the 70's that had some hum when the reverb was turned up. All of them did that. I designed a preamp that resided in the tank that gets the signal level up and the impedance down so the flux leakage from the power transformer can't be perceived.
------------------
Terry Downs
http://nightshift.net
terry@nightshift.net
Higher quality reverb transducer drivers are constant current drivers. This overcomes the impedance change in the transducer over frequency due to its high inductance.
Also, since the movement at the receiving transducer is very small, the output signal is very small. Good shielding is a must. I had a Peavey Mace back in the 70's that had some hum when the reverb was turned up. All of them did that. I designed a preamp that resided in the tank that gets the signal level up and the impedance down so the flux leakage from the power transformer can't be perceived.
------------------
Terry Downs
http://nightshift.net
terry@nightshift.net