Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Don Kuenz Newsgroups: sci.electronics.design Subject: Re: How do those Spring Reverbs work in guitar amps? Date: Tue, 21 Mar 2017 17:22:18 -0000 (UTC) Organization: A noiseless patient Spider Lines: 48 Distribution: world Message-ID: <20170321a@crcomp.net> References: <50a79d86-0efd-4aa4-a5ac-2d26f4bedff8@googlegroups.com> <20170318b@crcomp.net> Injection-Date: Tue, 21 Mar 2017 17:22:18 -0000 (UTC) Injection-Info: mx02.eternal-september.org; posting-host="9f8afc6d5f81b7567cf077f2acb46136"; logging-data="1600"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18GmOiPqmnUi6lXYiP3X70e" Cancel-Lock: sha1:CPy2nGlozSFp9+QWZP7y/j31IkQ= Xref: csiph.com sci.electronics.design:452906 oldschool@tubes.com wrote: > On Sun, 19 Mar 2017 22:49:52 -0500, "Dave M" > wrote: > >>> >>> This site seems like a good source of information: >>> >>> https://www.amplifiedparts.com/tech-corner/spring-reverb-tanks-explained-and-compared >>> > > That is exactly the info I was looking for. The PDF file includes > pictures too, and is very useful. Thanks for the link. > You're welcome. AmplifiedParts personnel kindly sent me Document 126-00005, which was written in 1978. It appears that only the two spring variety of tank was manufactured at that time. Document 126-00005 is now available at: http://crcomp.net/electronic/reverb/accutronics_document_126-00005.pdf Here's what it says about the mechanical physics of the tank: Accutronics' electromechanical reverberation devices consist of input and output transducers and a set of transmission springs. These components are mounted on an aluminum channel, which is usually supported by four springs to an outer case or channel. Briefly, the device operates as follows: An electrical signal applied to the input transducer is translated by the magnetic circuit to a torsional force on two small cylindrical magnets. The magnets are mechanically coupled to a pair of transmission springs and the torsional motion is propagated slowly along the spring path. At the output, a replica of the original input signal is produced by the action of magnets again coupled to the transmission springs. The signal has now been delayed by some period, determined by the diameter, wire gauge, and length of the transmission springs. Additionally, most of the torsional energy is reflected back to the input transducer. The result is a multitude of reflections each smaller in amplitude than the last. The delay time of each additional reflection is 2T since the torsional motion must travel the spring path twice to reach the output transducer. Thank you, -- Don Kuenz KB7RPU