The Legend of the Dyno Hammer Tip Modification

Contrary to popular belief, the Dyno-My-Rhodes modifications did not include replacing all of the rubber hammer tips with wood-core versions (a.k.a. the treble hammer tips). Chuck Monte explains how the Rhodes hammers were modified and adjusted....

What we did is:

• Set all the tone bars at exact equal height (3/8") high at the front screw closest to the keyboard), and by the art of the trained ear, adjust the tone and volume (back tone bar screw and pickup distance) at an optimum position as is anticipated by the engineering specification of both the factory AND the Dyno My Piano Equalizer circuit. (This also changes the striking line.) In effect, we "blueprinted" the electromechanical interrelationships of every aspect of the piano and it's interoperability with the EQ filters. Rhodes pianos were never set at this "optimum" from the factory.
• Replace every bad tine that did not tune or produce long lasting sustain.
• Replace all hammer tips with a new factory set, and by ear, determined the best note location where the tips transition from each section hardness to the next, (custom tip voicing). Mounting all the new tips consistently in the exact position requires skill, knowledge, and the correct tools and adhesives - not a job for the amateur.
• Physically adjust (bend) every damper so they are pulled away from the tine at the exact minimum distance (further in the bass section, closer in the treble sections) when pressing a key, and in a way so all the dampers come down exactly at the same time when depressing the sustain pedal. This is extremely difficult (if not impossible) without the formal Dyno training.
• Executed many additional adjustments and modification depending on the year and model of Rhodes, but never violating the engineering design rules of the piano as was intended by Harold Rhodes. (However we did add back checks and modified the key pedestal to change the feel of the action according to the keyboard players preferences. We also sometimes replaced all the bridal straps if they were worn or incorrectly assembled at the factory.)

The result of this sophisticated procedure was an incredibly even playing and sounding Rhodes with substantially enhanced dynamic range, and fundamental and overtone content without any visible "modifications" or additions (except as noted above). Most importantly, we ONLY did complete work to the maximum level of quality. We never sacrificed quality for price. It was all about completeness and quality.

For the record, I do not recommend replacing the hammer tips with all treble [wood-core] assemblies. Dyno NEVER replaced all the hammers with the treble hammer tips. This would radically change the interrelationships between the hammer "striking line" (where they impact the tines), and throw the Rhodes out of specification in a few ways.

Because the hammers are a cam and follower arrangement that travel about a pivot point in an arc, the height of the tips (each section from bass to treble are different heights) effect the striking line. The shorter tips will strike the tine towards the free end, and the taller tips will strike the tine towards the base (if the piano is set up properly). This is anticipated by the mounted placement (height and horizontal position) of the harp assembly above the hammer action from the factory. Replacing all the tips with a consistent height tip will require "re-voicing" the harp. This is done by removing the mounting screws and pivot arms located on each side of the harp, and slightly sliding the harp forward and backwards on each side while continually playing notes in each keyboard register until the sweet spot (fullest sound) is realized. Then remounting the harp by drilling new mounting holes in the support blocks (that suspend the harp above the action) as well as the pivot arms where they mount to the sides of the support blocks. (You have to completely remove the action assembly from the box.) Also, while using all treble tips may make create more overtones, it also increases the volume of the percussive sound that occurs when the tips strike the tines. Not good!

Despite the inherent problems Chuck mentions, there exist some Rhodes pianos with all wood-core tips. This is not a Dyno mod, as Chuck explains....

I reversed a lot of these mods myself over the years. They were mostly done by players and technicians that didn't have a handle on the engineering and physics of the Rhodes. I suppose the tip mod could increase the brightness, depending on how muddy the specific piano was set up to begin with.

It's really a problematic procedure that is a poor Band-Aid at best. I shudder to think of all the "hammer kludges" there are out there (damaging the pianos) from people experimenting around with something they should leave alone - or to a qualified technician.

Our advice: don't try this at home!!!

More Info

• Dyno-My-Piano
• Chapter 2: The RHODES Modular Action
• Chapter 8: Early Design RHODES Pianos - Action (Prior to September 1975)