My….very…dear….Heavens. Especially on the Rickrolling.
He’s got serious servo lag problems and never really gets it to lock — needs a bigger/slower/multi-cylinder prime mover (or just torque-ier. Maybe a steam turbine?) and a more-massive turntable and then some serious, serious work on the PLL. He’s tried with the big flywheel on the engine but even with double-acting valving and the high-ratio transmission, control delta per rev isn’t good.
A massive platter on serious bearings would help a lot; once it is spun up, the motor only has to overcome friction. –The engine flywheel and the turntable platter are actually elements in the loop filter, his tach (unclear in the image — a “flying ball” needle valve might be better than the mystery-driven steam valve, but it’s a job for a watchmaker) does the phase detector job and the steam engine is the VCO.
With enough inertia, the system might actually be able to attain capture, at which point it would sound as good as it could, possibly pretty good. There may still be some “cogging” (every cylinder stroke is a step-function power input to the system; better valve and valve-gear design would help, though the oscillating-sleeve design he is using is limited to port/manifold shaping for improvement; a turbine avoids this) and any imbalance in the mechanicals is gonna stand out, too.
Russco turned out a few low-rumble professional tables that used a synchronous motor on shockmounts that drove a massy flywheel via a live-rubber belt; another belt from it drove the spindle, also on a flywheel, which drove the familiar rubber-edged puck and though it, the inner rim of a conventional turntable. A system like that would help this set-up a lot. (DJ’s didn’t like it: it took at least a half-turn to come up to speed, compared to a quarter-turn or less for simpler versions and essentially zero for better ones like the Sony SP-10)
Roberta, you’re right on the money. If I had enough junk laying around I’d go for a turbine with steam recovery 🙂 double belt drive and massive weight for the turntable and idler, and more magnets on the base of the turntable for better resolution of the RPM.
Now that is a neat one! 🙂
Most elaborate Rick-racking I have ever seen!
Took the Words right out of my mouth, Turk!
My….very…dear….Heavens. Especially on the Rickrolling.
He’s got serious servo lag problems and never really gets it to lock — needs a bigger/slower/multi-cylinder prime mover (or just torque-ier. Maybe a steam turbine?) and a more-massive turntable and then some serious, serious work on the PLL. He’s tried with the big flywheel on the engine but even with double-acting valving and the high-ratio transmission, control delta per rev isn’t good.
A massive platter on serious bearings would help a lot; once it is spun up, the motor only has to overcome friction. –The engine flywheel and the turntable platter are actually elements in the loop filter, his tach (unclear in the image — a “flying ball” needle valve might be better than the mystery-driven steam valve, but it’s a job for a watchmaker) does the phase detector job and the steam engine is the VCO.
With enough inertia, the system might actually be able to attain capture, at which point it would sound as good as it could, possibly pretty good. There may still be some “cogging” (every cylinder stroke is a step-function power input to the system; better valve and valve-gear design would help, though the oscillating-sleeve design he is using is limited to port/manifold shaping for improvement; a turbine avoids this) and any imbalance in the mechanicals is gonna stand out, too.
Russco turned out a few low-rumble professional tables that used a synchronous motor on shockmounts that drove a massy flywheel via a live-rubber belt; another belt from it drove the spindle, also on a flywheel, which drove the familiar rubber-edged puck and though it, the inner rim of a conventional turntable. A system like that would help this set-up a lot. (DJ’s didn’t like it: it took at least a half-turn to come up to speed, compared to a quarter-turn or less for simpler versions and essentially zero for better ones like the Sony SP-10)
…Or am I over-thinking it? 😉
Roberta, you’re right on the money. If I had enough junk laying around I’d go for a turbine with steam recovery 🙂 double belt drive and massive weight for the turntable and idler, and more magnets on the base of the turntable for better resolution of the RPM.