Name:    Steve Kennedy
Email:   steve@pacair.com  
Subject: 112RD 100 watt combo
Thread:  64
Time:    Sun, 20 Jan 2002 06:29:42 UTC

Well, Gosh! Nobody has ever put me and the word "god" in the same sentence before (at least not without some sort of additional expletive)!


Thanks for the praise, I actually have much more GENERAL electronics knowledge (from working in electronics engineering of various disciplines over the last 25 years or so)than I have specific Music Man knowledge.


Most of what I think I know about Music Man amps is a mixture of:


a> What I read from some of the smart guys that hang-out here and other places like it on the web.


b> What I have learned first-hand by being a Music Man owner and enthusiast since 1979 when I got my first Music Man amp (112RD-65).


c> What I can look up in the various catalogs, spec sheets, manuals and ads I have been collecting for the specific purpose of populating the currently empty pages of this site.


Because of all these great resources I can answer a lot of technical questions and look smart as I long as I am willing to put in a little time in research. I learn something from the effort too!


Now, about the reverb tank. This general line of questioning comes up more often than might be seen in the message base, as I get more e-mail messages from people than posts to the message base (although I try to get people to post here instead for the common good).


You will find that, generally, the reverb spring assemblies used in Music Man amps are of the same basic types found in Fender amplifiers.... the long two-spring (17" long x 4.5" wide, including mounting flanges) and the shorter 3-spring unit (9.25" long x 3.5" wide). Both tanks are made by Accutronics and a variety of part numbers can be used, including some other various sizes.


The 2-spring units have a deeper more ambient quality to them but can be more disturb by bumps, shock and sympathetic vibration... especially inside of a combo amp just inches from a speaker or speakers.


The 3-spring units are more immune to the vibrational and shock problems but tend to sound a little less "open", although they are much less "sproingy" (if that makes sense or if its even a real word). If you want 50's science fiction movie sound effects made by hitting the cabinet of your amp stick with the long spring unit!


I have found both types in Music Man amps. Which one is in any particular amp seems to be related to age or size. The older & larger MM amps typically have the long-spring units while the smaller amps made after 1979 (including yours, perhaps) gravitated towards using the smaller 3-spring units.


These usually had a piece of corrugated cardboard taped over the open bottom and slipped into a naugahyde pouch which was screwed down to the cabinet with one screw at each end. This allowed the tank to "float" (increasing its isolation from speaker vibrations and shock) while still being restrained so it wouldn't move.


To install an entire replacement reverb system you will need a stereo phono cable of the appropriate length (3' is usually good), the tank, the cardboard, the bag and the mounting hardware (which includes some "eye-ties" to restrain the cable to the side wall of the cabinet).


I might be able to help in the tank & cable department but the other stuff will have to come from somewhere else. Send me an e-mail if you have any problems locating a tank assembly.


I think you find the 112RD-100 to be a great amp! I have one I restored and it sounds great!


Steve