Melville Clark/Wurlitzer
Apollo Piano Survey

Melville Clark Piano Company Study Project

Introductory Style Notes:

An Invitation to Send Accompanying Photographs

Pictures of the exterior of an instrument often allows us to identify case styles, control knobs, coin slots, art glass details, and other characteristics oftentimes not easily described through text alone. Moreover, snapshots of the interior mechanisms and any nameplates they may bear usually helps us greatly to identify mechanical characteristics that shed light on the mechanical evolution of an instrument, which helps us when developing dating guides. It is no stretch to say that photographs are an invaluable aid in detailing and understanding any instrument for which information has been submitted, and so please do consider sending photographs, albeit separately from the on-line form, but nonetheless augmenting the survey information.

Invitation to e-mail photographs corresponding to a survey submittal.
Please send photographs to:

Apollo Piano Survey Form

All survey submissions to the Mechanical Music Press are given with the provision that the Mechanical Music Press and/or its authors have non-exclusive use of the information, images, or other material submitted for use with this project or in any other part of this web site, and do so without limitation. All contributors of significant, previously unused information will be listed as contributors under general credits in the Registry section. Submission does not guarantee the acceptance of or the use of the whole or any part or segment of any information submitted. Please do not submit information if you cannot abide by the aforementioned stipulations.

Contact Information
  Show owner name in reports.

* Required form fields: Contact information will be kept private, with the exception of owner name if, and only if the "Show owner name on reports" box is checked.

Piano Basic Information

Serial number is stamped on the piano plate between bass & tenor tuning pin sections.

Apollo Master Piano Player; Apolloette Piano-Player (push up models)

Apollo Player Piano, Style G, H, K, L, Louis XV, M, Mission, N, O, Old Dutch, W, etc.

Solo Apollo, Style H, L, R, Grand, etc.

Art Apollo, Solo Art-Apollo (in various styles), and Art Apollo Grand Piano.

Apollophone, Style WP, etc.; Airapollo, Artlectra bench.


The piano action date is often hand written (in red or green crayon type pencil) or die stamped on the bass end of the piano action. Action dates are often accompanied by the personal initials of the final inspector and/or installer.


The keybed date, if present, is usually hand written at the left-hand end of the keybed and on the upper side of the structural cross member. Sometimes there is a handwritten date and initials on the key frame under the piano keys, possibly at the back side of the bass end. Keybed dates are often accompanied by the personal initials of the final inspector and/or installer.

Upright piano.  Grand piano.  Push-up piano player.

If none of the piano type descriptions exactly correspond to what is being reported please describe the component in the comments field at the bottom of this form.

For upright pianos measure the height of the piano case NOT including casters and top lid. Grand pianos are measured by the length from the very front of the keyboard to the farthest end of the piano with the lid closed.

One-piece lid.  Two-piece lid with full length piano hinge running down the middle.

The overall height of the piano measured from the building's floor and including casters and the top lid.

Oak, Golden oak, Mission oak, Mahogany, Walnut, etc.

Piano Plate and Soundboard

The plate number is a 1 or 2-digit number that is cast into the iron plate and located on the bass end about one foot down from the top of the plate.

The plate date code number is cast into the very bottom right hand corner, or for later plates behind the bass strings. Date codes are in the general format of yy-mm-dd, for example: 16 1 26 = 1916-January-26.

The plate height is measured from the bottom edge of the gold painted cast iron plate to the top edge of the plate.

The plate scale consists of the number of musical notes in the bass section, the notes in the tenor section, and the notes in the treble section. For example: 26,27,35.

Piano Soundboard Details:

The soundboard number is stamped into the wood just under the 1 or 2-digit plate number, and usually matches the piano serial number.

The soundboard ribs are glued diagonally across the back side of the soundboard. Some common rib count totals are 12, 14, or 15 ribs.

Accessory Phonograph (Apollophone Model Pianos)
Phonograph installed.
Phonograph missing (but originally installed).
No Phonograph (never installed).

In the Apollophone upright keyboard pianos a wind-up phonograph was cleverly installed above the keyboard and in the space between the piano action and case front.

Principal Pneumatic Stack S/N and Type

Usually die-stamped on the left (bass) side for Melville Clark Piano Company instruments built prior to August, 1919. For pianos built from August, 1919, onward the number is stamped on the top side of the stack, and sometimes covered by the Dynaline pneumatic.

3-tier early stack with pneumatics facing forward, and pushing down on the keys.
4-tier early stack with pneumatics facing forward, and pushing down on the keys.
3-tier common stack with pneumatics facing rearward, and lever system pushing down on the keys.
3-tier late stack with pneumatics facing rearward, and with ordinary pushrods lifting the piano action.

Stack Manufactured by:

Melville Clark Piano Company (prior to August, 1919),
Amphion and/or Wurlitzer (from August, 1919, onward).
Solo Pneumatic Stack Type (Solo Apollo and Solo Art Apollo only)
None (no solo stack originally installed).
Solo stack missing (but originally had one installed).
Solo Stack above the keyboard, with cranks that lift a hook near the rear end of the piano keys.
Solo Stack above the keyboard, with rods that push up on the piano action pushrods.
Solo Stack below the keyboard, with rods that push up on the back of the piano keys.
Roll Frame / Spoolbox

Spoolbox Special Features:

88 to 58-note dropdown feed spool adapters.
88 and 58-note exchangeable take-up spools.
Bass and treble octave coupler control switches for 58-note rolls.
88/58-note tracker bar control switch.
88/65/58-note tracker bar control switch.

Tracker Bar Type:

Wood tracker bar with a single row of 88 duct holes (plays early 88 or 58 note rolls).
Wood tracker bar with two rows of duct holes, 88 at 6/inch in upper and 88 at 9/inch in lower row.
Wood tracker bar with a single row of 128 duct holes at 9/inch (early Solo Apollo only).
Brass tracker bar with 89 duct holes at 9/inch—hole #1 elongated for damper pedal.
Brass tracker bar with 96 duct holes at 9/inch—holes #2, #93, and #94 are elongated (Art Apollo expression system).
Brass tracker bar with 132 duct holes at 9/inch (Solo Apollo only).
Brass tracker bar with 134 duct holes at 9/inch (Solo Art Apollo only).

The tracker bar used in early Apollo player pianos was made of hardwood, with a single row of 88 duct holes spaced at 6 holes per inch, which played both the 88-note 15 ¼” wide rolls and the narrow 58-note rolls.

In later transitional Apollo player pianos the wood tracker bar had two rows, the top or upper row had 88-duct holes with 6 per inch spacing, with a lower or bottom row that had 88-duct holes spaced at 9 holes per inch.

Apollo post-transition player pianos featured a standard brass tracker bar with 89 duct holes spaced at 9 per inch, which could be used to play the common standardized player piano rolls. The Solo Apollo employed a brass tracker bar that was 132 duct holes spaced at 9 per inch, and the Solo Art Apollo used a tracker bar with 134 duct holes, both of which played a music roll 15 ¼” wide.

Roll Frame/Spoolbox Power Source:

Spring-motor powered roll frame.
Air/wind-motor powered roll frame.

Spring motors were probably standard in the early Apollo pianos, and optional in some later model pianos, with the more modern airmotor system becoming more prevalent.

Dynaline pointing device:

Dynaline installed.
Dynaline missing (but originally installed).
No Dynaline (never installed).

The Dynaline device consists of a movable pointer that slides back and forth above the music roll with its exact position dependent upon the vacuum level, which, in turn, represents the player volume. And so all that one has to do to secure correct expression with the Apollo is to pedal to the extent that the Dynaline indicator follows the "blue volume line" printed on the music roll.

Sliding glass door over roll frame/spoolbox:

Sliding glass door over spoolbox installed.
Sliding glass door missing (but originally installed.
No sliding glass door over spoolbox (never installed).

For some upright keyboard models there is often a sliding glass door in front of the spoolbox, which slides in a pair of felt lined grooves.

Pump Type Foot pedal pumped only.
Foot pedal and electric motor combination pump setup.
Electric motor operated pump only.

Is the player piano manually foot pumped only, or is it capable of being both foot pumped and operated by an electric motor, or is it electrically operated with no manual foot pedal capability?

Electric Motor Information (only if Installed and original to Piano)  Motor Model:  Motor S/N:  Motor RPM:
Art Case Description (omit if not an art case)
Date and Notations Written on Case or Mechanisms

Oftentimes dates and notations are written on the case and/or on various player components.

Comments, History, and Explanations

Please include any additional information about the piano that might be pertinent, such as its history, i.e., various locations and owners. If you find a date (or style number), such as on a paper sticker inside or on the backside of the case, or on a pneumatic component, notice an early tuning date written by hand on the piano plate, find an original sales invoice, etc., please describe any such items.