Valley of the Nerds

[MylesBAstor]

Thought it might be good to spin off these posts into their own thread dealing with the effect of power cords and power supplies on the sound of turntables.

Just a brief synopsis:

1) For whatever the reason, power cord choice can improve the sound of your turntable.
2) Power supplies and the type of wave fed to the motor makes a difference (AC v. DC motors).
3) What about after market PS for turntables like Peter Noerbeck's?

Just to throw one experience out there. Years ago, I found that the VPI SDS improved the sound of my Linn table.

[MylesBAstor]

Bigger nerd alert. What power cords are members using on the turntables?

[Albert Porter]

Bigger nerd alert. What power cords are members using on the turntables?

Purist 25th Anniversary AC

[Guest]

Bigger nerd alert. What power cords are members using on the turntables?

I'll follow up to ask: What difference does your choice in TT PC make?

(This topic may deserve its own thread.)

[david k]

You gotta be kidding guys ! There was a review of active active platforms and the difference audiophile cords make in their performance, maybe that should be included in this topic too. While at it let's make a chart of possible combinations of $5k+ cords on motors and active platforms like Herzan, the best and worst $10K combos and why!

david

[banditcat200]

I use isolating transformers + light AC filtering for my vintage AC motor based turntables and diy. shielded power cables directly mounted into the motor.
I found this to give the best sound in my system.
But what works in my system, might not work in other systems and therefore a number of options have to be tried before settling on the solution for your turntable.
On DC based motors, I know the PSU is very important for the final result, the same is true for the phono or line stages.
I think there is no easy or cheap solutions here, its trial and error in most cases and then settling on the best sounding solution, which may not always be the most expensive solution

[Rust]

Looking at it from the electrical engineering standpoint, a properly designed AC power supply allows for a unity power factor and better inductive coupling of the rotor and stator which results in a 5-10% increase in motor efficiency which decreases the amount of motor slip for a non-synchronous motor and gives better speed control. More evident with a motor barely powerful enough to turn the platter in the first place. If it works in a 2,000 HP motor it works in a 1/10 HP motor, just a matter of scale.

Household current has less than a unity power factor simply because the electrical grid does not have a unity power factor. It varies throughout the day depending on how many motors attached to the overall grid are operating. Thinking about it, if a power cord had a capacitive factor built in, it might slightly improve the power factor seen by a turntable. Hmmmm. Might be the same for some power conditioners, correcting power factor. But then the manufacturers aren't letting on which magic pixie dust is actually working.

I'm always amused by the advertising copy, which is much like a politicians speech, lot's of unsubstantiated words saying nothing.

[MylesBAstor]

Looking at it from the electrical engineering standpoint, a properly designed AC power supply allows for a unity power factor and better inductive coupling of the rotor and stator which results in a 5-10% increase in motor efficiency which decreases the amount of motor slip for a non-synchronous motor and gives better speed control. More evident with a motor barely powerful enough to turn the platter in the first place. If it works in a 2,000 HP motor it works in a 1/10 HP motor, just a matter of scale.

Household current has less than a unity power factor simply because the electrical grid does not have a unity power factor. It varies throughout the day depending on how many motors attached to the overall grid are operating. Thinking about it, if a power cord had a capacitive factor built in, it might slightly improve the power factor seen by a turntable. Hmmmm. Might be the same for some power conditioners, correcting power factor. But then the manufacturers aren't letting on which magic pixie dust is actually working.

I'm always amused by the advertising copy, which is much like a politicians speech, lot's of unsubstantiated words saying nothing.

Yes but if you look at the specs recommend driving for most AC motors used in tables with a square wave. So many turntable power supplies (for instance the VPI PLC) convert the sine wave to either a square or hybrid waves to drive the AC motor. So why should an AC cord make a difference if you are converting the sine wave? But it does and the effect is far from subtle. And no turntable manufacturer pushes it; in fact, I don't know of any table manufacturer that pushes ac cords. Most of us found it experimenting on our own. When I found it years ago using my HW-19 table, I called HW and he agreed he heard the same thing. But he had never mentioned it before.

Also, consider what the Power supply is adding to the line -- not to mention equipment around it. I never keep digital or turntable power supplies on the same line as my equipment nor near equipment.

Power factor is nothing new either. I discussed power factor back in the early '90s when I reviewed the original Tice Power Block/Titan and George attempted to correct for power factor there.

[Rust]

Myles - If a power cord is not contributing by way of power factor correction, then that pretty much leaves its contribution due to acting as a filter. There isn't really anything else it can do be it a twisted pair balanced or star quad or any multiple of star quad.

Inexpensive combination Programmable Logic Control/Power Supply units are not especially sophisticated and the output tends to be quite noisy across a broad spectrum. Unless heavily shielded and filtered ,impulse noise, such as would be produced generating square waves would be transmissible back across a transformer.

It would be interesting to see the noise spectra of the AC into a turntable drive and the power output with various power cords. That would pretty much tell what is in fact happening.

[MylesBAstor]

Whatever they are doing, it makes a difference.

[Rust]

That part I don't argue with, they do.