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.
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