External PSUs and optimal voltage for 301's

[Wakefield Turntables]

Guy's. As you know many external PSU's allow you to drop the votage down and then experiment with your 301. I'd just like a general consensus of opinion as to what the optimal voltage seems to be to get the best performance. I've been using using my PS Audio P10 regenerator to power the 301 and must say that the deck does seem to perform better with a nice clean regenerated 50hz. I can also drop the voltage with the P10 so I wondered if further improvements could be had by messing with the input voltage??? Currently use 238V's, what about you lot :D?

[Light Dependant Resistor]

Hi
To conveniently alter AC voltage, a variac provides proper ability to
do this. Their construction uses a form of high current and of course voltage
potentiometer to alter voltage. The one I had used a big toroidal transformer
and element to wipe across the winding, providing lower voltages as needed.

Cheers / Chris



.

[struth]

I found 230 to be bang right with 50hz. tried taking it down with a variac but felt 230 was optimum for my thorens. Depends what the motor is rated at tbh.

[lurcher]

Their construction uses a form of high current and of course voltage
potentiometer to alter voltage.

They are always a autoformer, never a potentiometer.

Being inductive, they can produce more than the input voltage, you will often see them calibrated as 240v in, 0 - 270v out. The origin of the name is (to quote wiki)

"Variac Trademark

From 1934 to 2002, Variac was a U.S. trademark of General Radio for a variable autotransformer intended to conveniently vary the output voltage for a steady AC input voltage. In 2004, Instrument Service Equipment applied for and obtained the Variac trademark for the same type of product.[7] This word has become generic for hand-variable autotransformers in general."

The power version of a potentiometer is called a rheostat. Much less efficient, but unlike a variac can be used with DC as well as AC

http://www.steadresistors.com/images/products/wire-wound-rheostats-004.jpg

[Moko]

On my 401 I run it with around 190v - 200v using the Nigel Speed Controller developed over on the Lenco Heaven site which works perfectly with Garrards

[Wakefield Turntables]

Yeah I have the NSC PCB and it'll probably be a 2016 DIY project. There are some pretty low voltages especially 190 - 200V not that there is anything wrong with that, I just thought that it might be a smidge higher ;)

[Cotlake]

I experimented with voltage drop on my 401 and concluded it spoils the sound with an overall loss of dynamics. It just went all soft and floppy. To the best of my knowledge, no (and there have been several) PSU's designed for the 301/401 have ever been successful. Remember the original design concept. A motor that is magnetically braked to hold it to speed, thus not losing the original torque of the motor. I believe this is fudamentale in why a 301/401 sounds so good.

[A.Grail]

There are several differences between 301 motors over the course of production. Torque is one of the differences, the highest torque is from the Hammertone motors (Although the very first hammertone motors ran on a sintered thrust and are noisy as a result as opposed to all other 301 motors which use ball bearings) In general I found Grease bearing motors run well between 195-210v and Oil bearing motors at approx 210v