The Verus motor allows for speed adjustment in 0.16% steps. This means that the worst case speed error will be 0.08% and the average will be 0.04%. The good news is that this figure will not change or drift over time.
The speed accuracy of the Verus motor is roughly 4x more accurate than our Reference II motor. The problem with all DC motors is that the speed is determined by voltage and load. Very small changes in load will cause the speed to change. Our experiments have shown that from a cold start that the uncompensated speed using a DC motor will drift about 3% in the time it takes to play a record side. After that table has been warmed up the drift is less, usually about 1%. So while DC motors have the huge advantage of less cogging, speed accuracy is a challenge. A servo is needed to keep the speed accurate. But this is problematic because making abrupt corrections (hunting) is detrimental to the sound. The Teres belt drive motors use a very slow correction algorithm that largely avoids hunting but the price is speed accuracy. With the algorithm used in our belt drive motors the cold speed accuracy is about 0.25% and when warmed up (1 hour of play) this figure improves to about 0.1%.
We have had 3 Verus motors returned of the 40 that have been shipped to date. One of the returned motors was purchased under false pretense and there was never an intention to keep it. The other return was someone convinced before receiving the motor that he would not like it after having corresponded with Doug. Six customers have upgraded from Reference motors and the feedback has been enthusiastic.
We have listened carefully for the smearing that Doug mentions and simply have not been able to identify anything that resembles his experience. On the contrary myself and virtually every other person that has auditioned the Verus motor find that the belt drive motors have a sound that much more resembles smearing. This discrepancy remains a mystery to me.
We experimented with using a Verus motor with 1/2 mylar tape rather than the o-ring rim drive. We thought that the sound was about in the middle between our Reference motor and the regular Verus motor. There were clear benefits from the lower levels of cogging from the Verus drive. But there were additional, separate benefits from the rim vs. belt drive.
The speed accuracy of the Verus motor is roughly 4x more accurate than our Reference II motor. The problem with all DC motors is that the speed is determined by voltage and load. Very small changes in load will cause the speed to change. Our experiments have shown that from a cold start that the uncompensated speed using a DC motor will drift about 3% in the time it takes to play a record side. After that table has been warmed up the drift is less, usually about 1%. So while DC motors have the huge advantage of less cogging, speed accuracy is a challenge. A servo is needed to keep the speed accurate. But this is problematic because making abrupt corrections (hunting) is detrimental to the sound. The Teres belt drive motors use a very slow correction algorithm that largely avoids hunting but the price is speed accuracy. With the algorithm used in our belt drive motors the cold speed accuracy is about 0.25% and when warmed up (1 hour of play) this figure improves to about 0.1%.
We have had 3 Verus motors returned of the 40 that have been shipped to date. One of the returned motors was purchased under false pretense and there was never an intention to keep it. The other return was someone convinced before receiving the motor that he would not like it after having corresponded with Doug. Six customers have upgraded from Reference motors and the feedback has been enthusiastic.
We have listened carefully for the smearing that Doug mentions and simply have not been able to identify anything that resembles his experience. On the contrary myself and virtually every other person that has auditioned the Verus motor find that the belt drive motors have a sound that much more resembles smearing. This discrepancy remains a mystery to me.
We experimented with using a Verus motor with 1/2 mylar tape rather than the o-ring rim drive. We thought that the sound was about in the middle between our Reference motor and the regular Verus motor. There were clear benefits from the lower levels of cogging from the Verus drive. But there were additional, separate benefits from the rim vs. belt drive.