@halcro
I thought it was a fun exrcise. I'm pretty relaxed sbout the outcome, happy that I got the first comparision correct. As I said I found the second a little harder to pick.
I am a little surprised on the second - I listened to the bottom end extension and definition and on my "reference" standard issue earbuds TT4 was a little imprecise. I am more surprised given the Dynavector arm, which I've had for years, is very tight in the bottom end. The astringency of the of Palladian in the mid to top end was also a little surprising because I remember the comaprison when you switched it from the Dynavector arm to the Cobra unipivot, most of this went away.
DD vs Belt Drive
The most interesting thing here is that for over 30 years my reference has been the thread drive Final Audio VTT1. To summarise - it has a 26kg platter, inverted bearing, huge by most standards AC motor driven directly off an Onix OA60 power amplifier controlled by precision independent sine and cosine generators for the motor. There is no speed correction - it relies on huge inertia and a large AC motor independent of mains fluctuations. The recommended "belt" which I use is a chalked silk thread. This is important.
HP had it in house briefly at Seacliffe in the late 70's/early 80's and he described the Final Audio VTT1 as sounding more like a direct drive TT than a belt drive.
Qualitatively he compared it favourably to his Goldmund Reference, but in typical HP review he mentioned "midbass hump". Unfortunately the US importer had set the Final up on a crude air bag platform which destroyed the whole intent of the design. The whole design is premised upon sinking all unwanted energy to ground. There are no lossy materials used, materials used are processively from stylus to ground - chromium copper, aluminium, gunmetal ( leaded bronze ), SPZ ( superplastic Zinc alloy ). Additionally I use Final's recommended platform which is a constrained and compressed stone plinth using the same materials and principles that support the Shinkansen bullet train cement sleepers. This all sits on a custom steel table.
So from this reference and having had many top end TT's in my system, what I have found is -
All belt drives that use a lossy belt ( rubber the worst ) lterally sound rubbery in the bottom end. Leading transients are diffuse. I concur with @edgewear when he says
A few years ago I wanted a second TT and bought a Platine Verdier.
Even with it's high inertia, I could not achieve anything like the pitch stability on the Final - converting it to thread improved the stability, removing the rubber bellows feet and replacing them with rigid footers, improved the stability, modifying the motor mounting helped, but unfortunately still a dog.
Now for Direct Drives.
I have heard the Technics SP10mk3 and Kenwood LO7D on inumerable occasions, had them in house. Although they are quite good, I always hear a grey wash, the LO7D less so. The SP10mk3 appears more pitch stable than the LO7D, if you look at the error correction systems the Technics uses fast recovery. The LO7D allows a much larger speed error before correction.
Your Victor measures and spreads the error correction over a longer period of time, smoothing out what I call jitter induced by the error correction systems.
Some folk on this forum are sceptible as to the connection between error correction and sound. however look at the evolution of the GP Monaco direct drive - it entered the market with "state of the current art" error correction algorithms, streets ahead of what was technically possible in the 70's/80's when the SP10mk3 & LO7D were built, and yet the GP Monaco is now on its 3rd or 4th upgrade path, and all owners describe massive improvements with each upgrade.
That does not mean i am against DD in principle, as with any TT it comes back to the quality of the design as much as the Technology chosen.
If I were to build a DD turntable I would use a very high inertia platter ( 25kg ), and no error correction.
Some folk refer to the fact that some cutting lathes use direct drive motors, but what they ignore are 2 important facts -
1. The load on a motor when cutting records is far far different that the load on a motor when playing records. This means that the motor when used in cutting is being driven considerably harder, and in most instances the motor will be operating at a level at which it produces higher torque. This is the same principle as the eddy brakes used in some idler turntables - for example on the Garrard301/401 the eddy bake is designed to make the motor work harder, at an operating point where it produces more torque. Putting drag on a motor can also assist speed stability - some belt drive TT's are designed with "bearing drag" so force the motor work harder.
2. Cutting lathes use flywheels to add intertia. Even one of the most powerful cutting lathe motors ever produced - the Technics SP02 - which dwarfs the motor used in the SP10mk3 was designed specifically for the Neumann lathe, and more specifically for the Neumann lathe when used with an additional 70lb flywheel.
Idler Drives
Funnily enough after the disaster with the Platine Verdier, I rebuilt an old 60's Pioneer idler drive I had lying around. I wanted a 2nd deck with 78rpm capability. This demonstrated far better pitch stability than the Verdier, when compared directly with same arm and cartridge ( I used multiple FR64S I had to compare decks. It did lack some resolution, but given the bearing was stuffed and I had made a crude replacement this was not surprising.
And so I picked up a Garrard 301 and rebuilt it. Mine has been considerably refined, full motor rebuild including new bearings and blueprinting and hand tuning for minimum noise, elimination of metal to metal contact in the linkages under the chassis by replacing all rivet/pivot joints with nylon bushes/teflonwashers/nautical grease to eliminate noise, modified bearing/thrustpad, but standard platter. The standard platter was precision ground to ensure the surface is flat - the original is concave.
This is the nearest I've got to the Final. From listening to other idlers including the massive Denon RP52 I think that it is the big AC motors used in idlers as much the idler drive per se that provides the drive.
I have 2 friends with SME 20's and 30's - the Garrard 301 slaughters them, and no loss of transparency despite the "idler noise".
Ultimately I think in reality folk have to make the best of what they can afford or have, and what really happens is that folk buy arms/cartridges that work to mask the deficiences in their TT , complementary colourations - no TT is perfect.
I thought it was a fun exrcise. I'm pretty relaxed sbout the outcome, happy that I got the first comparision correct. As I said I found the second a little harder to pick.
I am a little surprised on the second - I listened to the bottom end extension and definition and on my "reference" standard issue earbuds TT4 was a little imprecise. I am more surprised given the Dynavector arm, which I've had for years, is very tight in the bottom end. The astringency of the of Palladian in the mid to top end was also a little surprising because I remember the comaprison when you switched it from the Dynavector arm to the Cobra unipivot, most of this went away.
DD vs Belt Drive
The most interesting thing here is that for over 30 years my reference has been the thread drive Final Audio VTT1. To summarise - it has a 26kg platter, inverted bearing, huge by most standards AC motor driven directly off an Onix OA60 power amplifier controlled by precision independent sine and cosine generators for the motor. There is no speed correction - it relies on huge inertia and a large AC motor independent of mains fluctuations. The recommended "belt" which I use is a chalked silk thread. This is important.
HP had it in house briefly at Seacliffe in the late 70's/early 80's and he described the Final Audio VTT1 as sounding more like a direct drive TT than a belt drive.
Qualitatively he compared it favourably to his Goldmund Reference, but in typical HP review he mentioned "midbass hump". Unfortunately the US importer had set the Final up on a crude air bag platform which destroyed the whole intent of the design. The whole design is premised upon sinking all unwanted energy to ground. There are no lossy materials used, materials used are processively from stylus to ground - chromium copper, aluminium, gunmetal ( leaded bronze ), SPZ ( superplastic Zinc alloy ). Additionally I use Final's recommended platform which is a constrained and compressed stone plinth using the same materials and principles that support the Shinkansen bullet train cement sleepers. This all sits on a custom steel table.
So from this reference and having had many top end TT's in my system, what I have found is -
All belt drives that use a lossy belt ( rubber the worst ) lterally sound rubbery in the bottom end. Leading transients are diffuse. I concur with @edgewear when he says
My old Micro RX1500 (with separated motor unit, stainless steel plateau, copper mat and brass stabilizer ring) uses the non compliant SF-1 kevlar belt. This is a massive improvement over a rubber belt and largely closes the gap with DD in terms of pitch stability,
A few years ago I wanted a second TT and bought a Platine Verdier.
Even with it's high inertia, I could not achieve anything like the pitch stability on the Final - converting it to thread improved the stability, removing the rubber bellows feet and replacing them with rigid footers, improved the stability, modifying the motor mounting helped, but unfortunately still a dog.
Now for Direct Drives.
I have heard the Technics SP10mk3 and Kenwood LO7D on inumerable occasions, had them in house. Although they are quite good, I always hear a grey wash, the LO7D less so. The SP10mk3 appears more pitch stable than the LO7D, if you look at the error correction systems the Technics uses fast recovery. The LO7D allows a much larger speed error before correction.
Your Victor measures and spreads the error correction over a longer period of time, smoothing out what I call jitter induced by the error correction systems.
Some folk on this forum are sceptible as to the connection between error correction and sound. however look at the evolution of the GP Monaco direct drive - it entered the market with "state of the current art" error correction algorithms, streets ahead of what was technically possible in the 70's/80's when the SP10mk3 & LO7D were built, and yet the GP Monaco is now on its 3rd or 4th upgrade path, and all owners describe massive improvements with each upgrade.
That does not mean i am against DD in principle, as with any TT it comes back to the quality of the design as much as the Technology chosen.
If I were to build a DD turntable I would use a very high inertia platter ( 25kg ), and no error correction.
Some folk refer to the fact that some cutting lathes use direct drive motors, but what they ignore are 2 important facts -
1. The load on a motor when cutting records is far far different that the load on a motor when playing records. This means that the motor when used in cutting is being driven considerably harder, and in most instances the motor will be operating at a level at which it produces higher torque. This is the same principle as the eddy brakes used in some idler turntables - for example on the Garrard301/401 the eddy bake is designed to make the motor work harder, at an operating point where it produces more torque. Putting drag on a motor can also assist speed stability - some belt drive TT's are designed with "bearing drag" so force the motor work harder.
2. Cutting lathes use flywheels to add intertia. Even one of the most powerful cutting lathe motors ever produced - the Technics SP02 - which dwarfs the motor used in the SP10mk3 was designed specifically for the Neumann lathe, and more specifically for the Neumann lathe when used with an additional 70lb flywheel.
Idler Drives
Funnily enough after the disaster with the Platine Verdier, I rebuilt an old 60's Pioneer idler drive I had lying around. I wanted a 2nd deck with 78rpm capability. This demonstrated far better pitch stability than the Verdier, when compared directly with same arm and cartridge ( I used multiple FR64S I had to compare decks. It did lack some resolution, but given the bearing was stuffed and I had made a crude replacement this was not surprising.
And so I picked up a Garrard 301 and rebuilt it. Mine has been considerably refined, full motor rebuild including new bearings and blueprinting and hand tuning for minimum noise, elimination of metal to metal contact in the linkages under the chassis by replacing all rivet/pivot joints with nylon bushes/teflonwashers/nautical grease to eliminate noise, modified bearing/thrustpad, but standard platter. The standard platter was precision ground to ensure the surface is flat - the original is concave.
This is the nearest I've got to the Final. From listening to other idlers including the massive Denon RP52 I think that it is the big AC motors used in idlers as much the idler drive per se that provides the drive.
I have 2 friends with SME 20's and 30's - the Garrard 301 slaughters them, and no loss of transparency despite the "idler noise".
Ultimately I think in reality folk have to make the best of what they can afford or have, and what really happens is that folk buy arms/cartridges that work to mask the deficiences in their TT , complementary colourations - no TT is perfect.