Awesome post Don! I can see a whole Institute class on repetition springs! Thanks for the detailed description - I feel like a little light bulb just went on. Now if it will just keep going... Ryan Sowers, RPT PTG Institute Team - Las Vegas 2010 Success. Guaranteed. On Tue, Jun 22, 2010 at 7:51 PM, Don Mannino <donmannino at ca.rr.com> wrote: > John, > > I thought I would pull this out of the previous thread, as it's a different > topic. > > There are other issues with the adjustable screw for the "butterfly" style > repetition springs. Not issues that make them bad or unusable, but they do > affect the feel and the performance of the action. > > In the original system, the repetition spring normally slides out the > groove > on the repetition lever. This changes the point of contact of the spring > on > the lever, moving away from the lever center and towards the knuckle, while > gradually increasing the spring resistance. > > In the screw-adjustable system, the contact point of the spring on the > lever > remains the same, but the spring length becomes shorter as the spring is > compressed. This changes the rate at which the spring stiffness increases, > and also does not "soften" the affect of the spring's stiffening by sliding > the contact point closer to the knuckle. > > Finally, the spring force ratio between the repetition lever / knuckle and > the jack is also affected. This is of less consequence than the rate of > spring tension increase, but has an impact on the overall force which the > spring applies to the capstan during repetition. > > The end result of all this is that the touch is affected in a small way. I > installed 3 sets of these wippens in the 80s when they were first offered > by > Renner, and went back to the normal design because I didn't care for the > touch, and felt that the repetition was not as good unless the springs were > regulated strong enough to make the hammer rise quite fast. The hammer lift > was then bothersome during soft playing at times, detectable by the player. > > So, for these reasons, many people (and piano companies) prefer to use the > old "PITA" style of wippens, even though the new design is certainly much > simpler to regulate. > > Don Mannino > > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On > Behalf > Of John Delacour > Sent: Tuesday, June 22, 2010 9:58 AM > To: pianotech at ptg.org > Subject: Re: [pianotech] WNG Parts Question > > > I met Bruce Clark in England a few weeks ago and had a long chat with > him. . . . . . . I was also critical of his decision to stick with the > most > primitive > and PITA type of repetition spring, and the reason he gave me was > that an adjusting screw would add weight. Yeah, and a fat lot of > weight it would add compared with the added convenience of an > adjustment such as used by Ibach, Grotrian, Schimmel etc. for > donkeys' years. > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100623/d439315c/attachment.htm>
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