Synergistic SR20 Fuses In PWD Question


#1

Has anyone installed these fuses in their PWD???

If you did did you find a direction that sounded better?


#2

Yes, I did some time back.

The way I figured it, based upon trying them both ways, the ‘proper’ orientation was the power flow moves from left to right as you look at the writing on the fuse

Put another way the left side of the fuse, again as you read the label, is the source (ac mains) side, and the right side of the fuse is the power supply side (the transformer etc.).

I have (I think) seen where others have noted the reversal of this ‘polarity’.

According to Synergistic Research there supposedly is no polarity to their fuses, but that doesn’t match up with most of the reports I’ve read.

JJ


#3

Ok JohnJen I think I got it… So on the PWD it looks as if the power moves from the back of the unit where the AC inlet is towards the front of the unit… So the SR end of the fuses would be pointed at the back or like this 20 SR < arrow is the back of the unit…power flows from the inlet forward…


#4

@johnjen So to clarify… After looking closely at the power supply board, power on the DS or PWD flows from the back of the unit to the front. Back of the unit is the IEC inlet…

So what you are saying is that based on your experience the correct orientation of the fuse would be with the writing on the fuse SR 20 reading from the back to front i.e. Front < 20 SR < Back/IEC inlet or basically the writing is going from back of unit towards the Front, am I correct?


#5

Yep! :thumb:

JJ


#6

Yeah! I did it right…

So for future reference here’s a picture of a PWD power supply board ( the topology is similar to a DS) the board sits in the chassis as it’s shown in the picture with the transformer and caps at the front of the Dac (display)(top of the picture) and the fuse holders at the rear of the unit (IEC or back side)

Power flow is from back to the front. One can see in front of the black fuse holders a tab that says “TB1 Line” the power start here and goes directly to the fuses and then on to the rest power supply/transformers etc…

So the correct way that has been found to orient the fuses for best sound quality is for the writing on the fuses ( SR20) to read in reverse of the power flow… or simply put the fuse is oriented with the “20” end at the point that power enters the unit, this would be with the writing backwards or right to left, since we read “SR20” as left to right. We could even say that the 20 side of the fuse is down and the SR side is up.

photo-5.JPG