Phono II advice Please!

[Greg.]

I recall that back in the day when upgrading PSU II, several of us used ceramic caps on the PCB underside to bypass all the large PSU caps.

[bob orbell]

Thanks' for correction John, I should have read all the chapter on ceramic capacitors. Bob

[Lyndon Johnson]

Thanks everyone for your responses. So in summary I have learned that I may hear an improvement if I fit a 10nF capacitor in parallel with each of the four diodes in the HT rectifier bridge, as this will help suppress any switching spikes from the diodes.
Also, 10nF capacitors in parallel with C1,2 and 4 will further reduce the ESR and so help reduce ripple in the DC.
In both cases these can be ceramic.

I will go ahead and let you know how I get on.
Lyndon.

[John Caswell]

Hi Lyndon,
You wrote "In both cases these can be ceramic."
Ideally they should be ceramic disc types min 1kV rating, which are now becoming difficult to source, as Murata have ceased manufacture.
I bought a batch from eBay suppliers.

John

[Lyndon Johnson]

I have ordered Vishay 300V ac ceramics RS part number 183-7414.
There were higher voltage alternatives at higher prices.
Lyndon

[John Caswell]

Hi Lyndon,
They'll be fine.

John

[Chris]

A very interesting post. Something that could have been included in the original design?

I have included some links:

http://www.hagtech.com/pdf/snubber.pdf

https://www.diyaudio.com/forums/powe...-test-jig.html

Chris.

[Greg.]

Good source for high voltage ceramic caps.

http://www.banzaimusic.com/High-Voltage/