Maintenance – Regulation

by admin on April 29, 2015

Regulation is not only relatively simple to do, but also something that is very necessary for harpsichordists to learn!

Regulation is not only relatively simple to do, but also something that is very necessary for harpsichordists to learn!

There are two important details that need consideration to give a good harpsichord final action regulation, the attack (pluck) and the escapement (jack return).

The attack requires that there is a positive pickup of plectra to string so the plectra is allowed to go through a controlled arch as you depress the key and on releasing the string the tongue is still in a solid firm position. Failure of the tongue to maintain that results in a loss of energy given to the speech of the string. On my jacks this is achieved by a design that requires a minimum of retention from the bristle or peek spring. On many jacks the spring tension has to be strong to retain control for that final plucking of the string and that can and often does result in hangers. The jack is not returning simply because the spring is so strong it does not allow the jack tongue to release and fall by its own weight. When you get this design factor right it will give the player much greater control of how sound is focused, and that is so important. Also when this detail is right there is a minimum of ictus because ictus comes from that very stage of the pluck and even a slight movement at the time of string release will be heard as ictus.

Now we come to escapement. The plectra on the jack return is bound to come into contact with a vibrating string and that will always be heard to a small extent, more so by the player at the keyboard but it will be lost once away from the instrument, certainly by an audience. However we can offer some control here by the use of a weak return spring. If the spring is strong the plectra will bounce on the string until the damper has taken effect resulting in rather nasty buzzes. It is also important to have the damper as close to the plectra plucking point and the string node as possible as dampers work ideally just behind the point of pluck. You will notice I always make my jacks so that detail of design is taken care of, this means my short 8ft rank of jacks plucking to the right are made left handed to accommodate that positional damper detail. You are bound to get kick back on the return of the jack from the plectra contact on the vibrating string but we can control that as well. This of course becomes more of a progressive problem down towards the bass as the longer string becomes more difficult to control. The cotton tie I use controls the distance the tongue travels back and though not essential will most certain help the player gain better repetition. However the clearance position of that tie has to be subtle and just right or the plectra will not clear properly and that will result in the string not being cleanly damped and the plectra buzzing on the string. This process does demand that plectra length has been accurately cut so that good control of the distance the plectra has been allowed to advance under the string is consistent and accurate. If you have a variation of plectra length under the string, the escapement cotton will need to be given excessive clearance and that defeats the object. Should that be the case and your plectra have been allowed too far under the string you would be better off without the cotton tie!

Finally keep a careful eye on the tension given by the hand stop screws. They do tend to work loose with use and need to be kept as tight as is comfortable to work the register. There is a tendency of damper drag to move the register off if the hand stop screws are not kept as tight as is possible for good working.

Stagger is also something that should always be personalised to your desire. The 4ft, because plectra are just a tad shorter than 8fts in order to make them faster, pluck first and their separation to the lower 8ft can be a little closer than that of the two 8ft ranks. The stagger between the 8fts should be as close as is comfortable for you the player and always adjusted through the coupler on a double manual in order to have the right comfort feel with the upper manual key dip.

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