on 5/28/07 7:50 AM, Michael Johnson at [log in to unmask] wrote:
> There are many aspects that need to be considered when debating the design of
> a harpsichord jack, it is not just about the setting of the axle pin, strength
> of the spring or the materials used for it or the need for staples to assist
> escapement, it is about being aware of what needs to happen to get the very
> best result. In my previous posting I mentioned that the tongue must be
> totally still when the plectra collects the string and produces the sound, if
> that in not so, you have lost energy at that most important moment.
> On my early jacks of some thirty years ago that was the case, producing
> flapping tongues on the attack resulting in a nasty clack. Padding the
> bottom of the tongue with thin leather would have quietened it but I chose to
> not do that. Certainly I do not think large axle holes had any part to play
> and indeed, I think it better to be safe there and leave a reasonable
> clearance. The secret is to not have the tongue flapping around at any time
> and the way to achieve that is to have it under the control of the spring
> constantly. Bill mentioned I like to have the spring working just over the
> top of the excel, an observation he has made, and yes I do not like it high
> simply because it then can become too strong. He will also have noticed I do
> create a reasonable angle for the spring to arch which creates energy force
> upwards as well as the direction needed to return the tongue, constant
> control! It is attention to such fine detail that produce the end results
> and the joy is you can always improve and learn if you keep thinking and
This issue is of interest to me because I have always had repetition
problems with the jacks on my de Perticis virginal made by Jerry Prager
(_not_ "Praeger," as some of you seem to insist) back in the '80s. The
difficulty occurs primarily with trills. The jacks are wooden, without any
adjustment screws. They are voiced in Delrin, and the springs appear to be
Delrin as well. Both the top and bottom of the tongue have leather pads,
presumably to minimize noise, and there is a staple at the top, as we have
been discussing. Short of having new jacks made (which would not be
prohibitive, as it's just a virginal), what would you makers suggest?
The instrument is a beauty to look at
(http://harpsichordphoto.org/mccarty/), but very difficult to play compared
to my Dowd, whose original Delrin jacks have never given me the slightest
trouble. I do realize that an Italian virginal action is going to differ
from a French, and that my ability as a player is execrable. I have gotten
suggestions, such as sitting farther from the instrument, playing with less
finger curvature, and playing more toward the ends of the keys, but have no
idea whether these have any merit.
What say you?
P.S. Michael, I really like your description of tongue stability and its
effect on control. That makes a huge amount of sense.
James R. (Jay) McCarty, MD
Fort Worth, TX
"Sine arte, scientia nihil est"