[Captain]

Can anybody advice. I am going to change the Panasonic caps in the output stage of my pre amp for Black gates. There are also two RIFA caps, 630VDC with a value of 0.001uf bridged on each Panasonic cap. First off what do these caps do, and secondly will they benefit upgrading to a better quality cap, for instance a Jensen PIO. I have mentioned the Jensen as Croft who the amp came off, have a very low value Jensen silver foil bridged on the smoothing cap in the power supply(see picture at bottom). When this upgrade was done the sound was improved. Is the RIFA cap function to put it simply purely mechanical as opposed to sound quality improvement?

Power supply

 

[Logistics]

Aren't those 10 nanofarads, which is .01uF? Anyway, electrolytic capacitors are not a good thing to pass audio through. Even Black Gate's are not ideal if you can use a film capacitor instead. However, the design in that amp seems to call for a VERY large cap (2200uF) which you won't find in a film and would be ridiculous to create with multiple films so a Black Gate or a Muse is a reasonable choice, here.

The small .01uF film caps are used in this stage to improve high frequency reproduction on the output, which is something electrolytics are not real good at. Electrolytics tend to hash things together causing a smearing of sound so that instruments are not as discernable and seperation is not very good. The little film caps help to alleviate some of this. In my opinion it is not worth spending big money in this area because no matter how nice the film caps are in this stage, the electrolytics will still harm the sound to a large degree.

However, the PHE426 is a metallized polypropylene so you could try stepping up a bit with a low-cost, non-metallized, polypropylene film & foil capacitor; an actual crossover capacitor.

 

[Captain]

Thanks for the info just what I was looking for. I am sure the PHE426-630 is .001uf check out the LINK or am I reading the date wrong.

 

[Logistics]

Just look at your caps. Capacitance followed by J which should be it's tolerance code. 10nF or .01uF or 10,000pF

Attachment 9769

 

[axiom]

If you spring for the black gate N/NX, most people usually leave out the film bypass capacitor. There are a couple of threads about whether or not to use bypass capacitors. They are not always a good thing.
Some like bypassing all the time, some don't. It is not required though, you should be able to leave them out if you want. As always, trust your ears first! Try it with and without bypassing and keep what you find best.