Disc Graphophone runs unevenly...
Posted: Wed Oct 15, 2014 9:41 am
I am trying to sort-out my "new" Graphophone "Imperial" model BJ.
Last night I re-rubbered the Analyzing soundbox, it sounds great ! ( Thanks for the tips, Harvey !
)
But the motor runs unsteady.
Here's the symptoms:
Wind it fully, it plays through 3 sides of ten inch discs, but no more.
As it plays the speed fluctuates... slows-down slightly, speeds-up slightly. I've been trying to quantify it, but the best I can do is in musical terms...
Playing a 12" Columbia Disc, Waltzes from "The Count of Luxembourg" ( Franz Lehar ), the tempo is approximately quarter-note = 192 beats / minute or dotted half-note = 84 beats / minute ( "one beat to the bar" ). While the disc is playing, the music will slow-down slightly for about 3 bars, then gradually speed-up for about 4 bars, and repeat the cycle, through the entire disc. The cycle is pretty consistent.
The behavior is similar with other discs ( mostly 10-inch Victor and Regal this morning ). Even as the spring is running-down, this cycling still occurs, though the time to complete the cycle may be a little longer as the spring loses its oomph.
As for "how much" speed variation, I would say slightly less than ½-step in pitch variation between the high and low ends of cycle. ( the distance between adjacent black key and white keys on a piano or organ ). Enough to be noticeable and a bit frustrating.
This particular machine seems to be a very early example of the BJ: the winding crank is on the left-side, the speed-control / brake plunger is in the back. The reproducer is the Columbia Analyzing, but with a thumbscrew instead of the spring-loaded clamp. ( Latest patent-date behind the mica is Jul, 25, 05 ). The motor is a two-spring with a two-weight governor ( lead "lozenge" weights ).
Based on what I've been able to decipher from Baumbach's Columbia Phonograph Companion Vol II [ disc machines ], this motor is likely the same as the second-style AH front-mount machine, introduced in 1904.
It almost seems to me that there is a "binding" or "tightness" somewhere in the power train, as opposed to a governor issue ?
Has anyone run-into this with early Disc Graphophones ? This is my first experience with one, and I'd rather ask a lot of questions before plunging-into it with tools and invective...
Would appreciate any thoughts / suggestions from Disc Graphophone veterans...
Thanks !
Frank
Last night I re-rubbered the Analyzing soundbox, it sounds great ! ( Thanks for the tips, Harvey !
But the motor runs unsteady.
Here's the symptoms:
Wind it fully, it plays through 3 sides of ten inch discs, but no more.
As it plays the speed fluctuates... slows-down slightly, speeds-up slightly. I've been trying to quantify it, but the best I can do is in musical terms...
Playing a 12" Columbia Disc, Waltzes from "The Count of Luxembourg" ( Franz Lehar ), the tempo is approximately quarter-note = 192 beats / minute or dotted half-note = 84 beats / minute ( "one beat to the bar" ). While the disc is playing, the music will slow-down slightly for about 3 bars, then gradually speed-up for about 4 bars, and repeat the cycle, through the entire disc. The cycle is pretty consistent.
The behavior is similar with other discs ( mostly 10-inch Victor and Regal this morning ). Even as the spring is running-down, this cycling still occurs, though the time to complete the cycle may be a little longer as the spring loses its oomph.
As for "how much" speed variation, I would say slightly less than ½-step in pitch variation between the high and low ends of cycle. ( the distance between adjacent black key and white keys on a piano or organ ). Enough to be noticeable and a bit frustrating.
This particular machine seems to be a very early example of the BJ: the winding crank is on the left-side, the speed-control / brake plunger is in the back. The reproducer is the Columbia Analyzing, but with a thumbscrew instead of the spring-loaded clamp. ( Latest patent-date behind the mica is Jul, 25, 05 ). The motor is a two-spring with a two-weight governor ( lead "lozenge" weights ).
Based on what I've been able to decipher from Baumbach's Columbia Phonograph Companion Vol II [ disc machines ], this motor is likely the same as the second-style AH front-mount machine, introduced in 1904.
It almost seems to me that there is a "binding" or "tightness" somewhere in the power train, as opposed to a governor issue ?
Has anyone run-into this with early Disc Graphophones ? This is my first experience with one, and I'd rather ask a lot of questions before plunging-into it with tools and invective...
Would appreciate any thoughts / suggestions from Disc Graphophone veterans...
Thanks !
Frank