Restoration Report

Copyright © 2015 CBH

on the
1951 John Challis Double-manual Harpsichord
now owned by the Honolulu Museum of Art

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1951 John Challis harpsichord, Honolulu 71K jpeg
Challis Harpsichord #51-125 on first inspection, June 2010

Historical background

The work of John Challis (1907–1974) is discussed on pp92–99 of Wolfgang Zuckermann’s 1969 classic The Modern Harpsichord. Following four years of study with early music pioneer Arnold Dolmetsch, Challis returned to the United States in 1930 and established himself as the first American harpsichord maker, predating the Hubbard/Dowd partnership by almost two decades. (Dowd eventually trained with Challis.) Unashamedly modern in his approach, Challis abandoned traditional materials in favor of metal framing, pierced metal bridges and soundboards, although wooden casework was often attached to the substantial metal structure of his instruments to make them look more like the harpsichords of his day.

One of his pedal harpsichords from 1967 was recently exhibited in the Musical Instrument Gallery at The Metropolitan Museum of Art as an important example of American craftsmanship. His work was carefully considered and well-crafted. There has been a small resurgence of interest in harpsichords of this twentieth-century type, but they are not presently held in great favor by many musicians because of the direction towards historic principles of construction and performance during the past four or five decades.

Challis instrument #51-125 was commissioned by the Honolulu musician Gertrud Künzel Roberts (1906–1995). While it wasn’t the first harpsichord in the Hawaiian Islands—that distinction probably goes to a German-made single-manual instrument which accompanied the Roberts family when they first moved to Hawaii in 1947—it was the first harpsichord specifically commissioned for the Islands. For more than forty years, the Challis was frequently played by its owner in concert. It made a remarkable sight because of the mural in naïve Mexican style painted on its lid interior by the famous artist and family friend Jean Charlot (1898–1979), resident in Honolulu for the last thirty years of his life. His artwork adds considerable value to the musical instrument, and the item has obvious important cultural and social connections to Hawaii. It is therefore fitting that it has now found a home in the Honolulu Museum of Art.

Gertrud Roberts was also active as a composer. Several of her solo and chamber music works are listed in Adel Heinrich’s Organ and Harpsichord Music by Women Composers: An Annotated Catalog, and she recorded several of her own compositions on her Challis. The Ho’okani Enterprises label released an LP in 1979 (#781219) including a piece from 1955 titled Charlot suite. Each movement in this work was a portrait of a different member of the Charlot family, all of which—with the exception of their speaking pet mynah bird—were present at the first performance of the work at the Honolulu Academy of Arts in 1956.

Pacific map: Honolulu 8K jpeg
Introduction to the instrument

My late colleague Floyd Cammack told me of the legendary status of the Challis harpsichord during my first visit through Honolulu to meet him in 1991. Almost two decades passed until June 2010 when I was to see the instrument for the first time, having been invited by the late Gertrud Robert’s daughter Marcia Roberts-Deutsch to inspect and report on her harpsichord.

It appeared in good structural condition, but after so many years of exposure to the constant high humidity on the windward side of Oahu, it was quite unplayable. The case interior, including the Charlot mural, was affected by white mould and there were signs of insect occupation.

Under the strings, the aluminium soundboard was very dirty, and some areas of its finish were bubbling and beginning to lift. The finish of the top of the metal framing under the soundboard was corroding where dust had been able to settle and attract moisture. The color-coded zither tuning pins were affected by surface rust, although the majority of steel strings seemed clean. There were several broken brass bass strings in the unison choirs, with remnants in the instrument. The overspun strings for the bass of the 16⁠´ were intact. The mahogany keylevers were bushed like a piano, the upper keys balanced with cast lead weights screwed to the rear of the upper surface of each key: These weights had not corroded. The keys were generally in good condition, although their playing surfaces were covered in mould. Many of the keys were found to be stuck down or sluggish with very tight mortises, but it was possible to quickly free several of them without removal of the upper keyboard.

There was sufficient clearance in the gap with no tension problems evident. The pedals operating the register mechanism were badly corroded, but all the registers were movable with the exception of the 16⁠´ which was able to be temporarily engaged by levering the end of the register.

The black vulcanized rubber Challis jacks were in good condition, and at some stage in the instrument’s past, every choir had had its tongues carefully replaced and plectra converted to Delrin. The tongues appeared to be pivoting freely and the plectra quite usable. Most of the chrome-plated steel end pins of the jacks were heavily corroded, and the jacks held captive in the lower guide as a result. Several of these jacks were able to be quickly eased. Other jacks were tight in the upper guide, although again able to be eased. The felts were judged quite usable.

Was it possible to help this harpsichord to play once again, without unnecessary over-restoration which its musical value alone may not justify?

The prognosis was good.

It was obvious that a collaboration would result in the best outcome for the instrument, so I recommended my colleague Steve Premo of Premo’s Piano Shop become involved. The work the Challis required was not dissimilar to that for pianos which have suffered in the tropics. Steve was well-equipped to handle that so there was no need for the harpsichord to leave Honolulu. My involvement would then commence in the final stages of the restoration, reinstalling the action and considering the regulation to have the instrument playing its best. The mural required specialist attention, and Laurence Pace of Pace Art Conservation was engaged by the museum to deal with that.

1951 John Challis harpsichord bass end of wrestplank 81K jpeg 1951 John Challis harpsichord keywell 75K jpeg
Bass end of wrestplank Keywell and nameboard

The work proceeds

In June 2012, the Museum was ready to allow the restoration to commence. The harpsichord was moved to Premo’s Piano Shop for thorough cleaning and attention to the mould. The lid was removed from the harpsichord, its metal hinges dismantled, and the lid exterior finish revived along with the rest of the mahogany casework. The lid was then collected by Laurence Pace for his conservation work on the mural.

Steve removed the harpsichord action without damaging the jacks. Every jack endpin had to individually cleaned and polished before each jack could be placed in order in a custom-made jig. He then paid careful attention to the cleaning and easing of the felt-bushed mahogany key levers. The corroded pedal work was cleaned, lubricated and adjusted. The especially complex string layout of this type of harpsichord obstructed access to the soundboard, so cleaning of the sprayed finish on the aluminium could only be carried out using compressed air.

In August 2012, the Challis was ready for my work. While the harpsichord was still in the Piano Shop, I examined the bushed keyboards with Steve and did a final check of tilt, level and spacing. The action was ready to be reinstalled, easing each jack from bass to treble of each choir in turn. The broken strings were replaced and the tuning checked. It was a testimony to the ingenuity of the maker that most of the instrument was in amazing tune and spot on A440 pitch despite not being tuned in probably fifteen years! We were then able to attend to some niceties of regulation and quite soon, the harpsichord was playing again.

1951 John Challis harpsichord upper keyboard 52K jpeg 1951 John Challis harpsichord lower keyboard 47K jpeg
Upper keyboard completed Lower keyboard completed

1951 John Challis harpsichord pedals 41K jpeg 1951 John Challis harpsichord jacks in jig 53K jpeg
Seven pedals Seven registers of jacks in Steve Premo’s jig

1951 John Challis harpsichord registers at spine 61K jpeg 1951 John Challis harpsichord wrestpalnk in treble 68K jpeg
Registers at the spine Wrestplank in the treble

1951 John Challis harpsichord seven registers of jacks 69K jpeg 1951 John Challis harpsichord action installed 77K jpeg
Seven registers of jacks Action installed and instrument playing once more

Descriptive notes for players

John Challis Double-manual Harpsichord #51-125, 1951

61 notes: FF–f''' reverse keyboards with gilded front mouldings, bushed mahogany keylevers, front guiderail for lower manual. Aluminium soundboard and bridges, strung in yellow brass and steel with overspun strings to bottom half of 16⁠´ register, A440. Jacks in black vulcanized rubber with white Delrin tongues and Delrin plectra for all choirs, working in machined brass registers. Jack height adjustment endpins, front-facing tongue advancement screws, separate damper jacks (except for 16⁠´ choir and extreme treble of 4⁠´ choir).

Mahogany casework with beveled cheeks, keyed corner joints and gilded bottom moulding. Mural on lid interior by Jean Charlot (1989–1979). Simple demountable square leg stand with casters, the front assembly containing the mechanism to operate the registration by seven pedals.

There is no manual coupler: The front 8⁠´ choir has two sets of jacks, the front-most working from the upper keyboard and a second plucking the same set of strings further back, playable from the lower.

There is a single buff batten which originally could operate on either the front 8⁠´ or back 8⁠´ set of strings.1

The Challis has seven registers, from front to back:

  1. Upper manual front 8⁠´ ←
  2. Dogleg damper jack for both 8⁠´ choirs ←→
  3. Lower manual front 8⁠´ ←
  4. Lower manual 16⁠´ →
  5. Lower manual 4⁠´ →
  6. Lower manual back 8⁠´ →
  7. Shared damper jack for 4⁠´ choir with secondary damping of back 8⁠´ → [up to note #50 from where 4⁠´ dampers are attached to the back 8⁠´ jacks]

There are no handstops: The registration is controlled by seven pedals, from left to right:

  1. Lower manual 16⁠´
  2. Lower manual back 8⁠´
  3. Lower manual 4⁠´
  4. Buff to lower manual back 8⁠´ 1
  5. Buff to upper manual front 8⁠´
  6. Lower manual front 8⁠´
  7. Upper manual front 8⁠´ piano & forte 2

1 The single buff batten was originally intended to service either the front 8⁠´ choir (playable from either keyboard) or the back 8⁠´ register (lower keyboard only). From the grooves worn in the bass side of the original buff pads and some odd thin leathers glued there, it appears that the buff stop was greatly used on the front 8⁠´ strings, and the pedal trapwork adjusted accordingly over the years to provide sufficient and even buffing only on that set of strings as the pads wore. There is insufficient adjustment available in the trapwork to allow the other side of the existing original red felt buff pads to work against the back 8⁠´ strings. This is only a minor limitation as the front 8⁠´ strings can be played from either manual, and the buffed front 8⁠´ choir played from the upper keyboard can be dialoged against the other choirs on the lower. Access to the buff batten is limited and the original pads were probably fitted before the 16⁠´ choir was strung. Therefore, pedal 4 is not operational at this time.

2 From the geometry of the instrument, it is apparent that the upper manual front 8⁠´ pedal OFF position provided a piano substitute to the normal fully ON position: The front register cannot be retracted sufficiently without interfering with other strings and as there is no other register on that keyboard, there is no real musical requirement to turn it completely OFF. The difference between piano & forte would have been more remarkable with the leather plectra the harpsichord was probably delivered with.

pdf icon 2K pngThese notes for players are available for download as a pdf.

1951 John Challis harpsichord bridges and soundboard 59K jpeg 1951 John Challis harpsichord underside of soundboard 41K jpeg
Pierced aluminium bridges suspended above soundboard, 16⁠´ in front Underside of soundboard at spine, showing honeycomb layer

1951 John Challis harpsichord metal framing 33K jpeg 1951 John Challis harpsichord rose 57K jpeg
Metal frame Pierced metal soundboard rose


This was a fascinating project to be involved with, and provided an opportunity to closely examine the work of one of the great modern American harpsichord makers. The revolutionary aluminium soundboard used by Challis is in fact not a single layer, but a sandwich of two layers separated by honeycomb. To allow greater flexibility, only the top soundboard layer is actually attached to the frame: The lower layer stops short of the perimeter by at least an inch, the honeycomb originally secreted by masking tape but now visible as the tape adhesive has failed. The upper keys were heavily weighted because they only supported two choirs of jacks including the dogleg unison damper jack. Most of the lower keys were front heavy to avoid excessive touch weight with so many jacks resting on them. There are no nuts: Instead, the strings pass through holes in right-angled brass attached to the wrestplank, not unlike the concept of the modern piano agraffe. String replacement is somewhat tedious because of poor access. The unison and 4⁠´ tuning pins work smoothly in phenol bushings, the 16⁠´ pins quite tight in a solid phenol block running the full width of the wrestplank. The scaling is compromized in the extreme treble because of the width of the gap, and the 8⁠´ and 4⁠´ “nuts” run straight for the top four notes.

The Charlot lid mural was successfully restored by Laurence Pace, and the Challis was included in the “Now Hear This” exhibit which ran at Spalding House from June 18 2013 to January 5 2014. A picture of me tuning the harpsichord for the exhibit appeared in an article titled “Harpsichord strikes warm notes” in the Sept Oct Nov 2013 issue of the Honolulu Museum of Art Members’ Magazine (vol. 85 no.4). The instrument was opened in November by harpsichordist Thomas Yee and Tresemble, performing works for Chamber Music Hawaii including the de Falla Concerto and a new composition by Daniel Morse (grandson of the original owner Gertrud Roberts), titled Variations on “Bist du bei mir”.

1951 John Challis harpsichord, Honolulu 69K jpeg
1951 Challis Harpsichord on display,
Honolulu Museum of Art, Spalding House, June 2013

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