try some known brands for output caps- Mundorf, Ampohm and such - MKP or PIO or paper etc.

I had a very nice experience with an MKP with polystyrene bypass. give it a try, the one I used was a 1uF Mundorf Mcap with a .001 bypass.

I'm using it in an arcam alpha 5+ and will experiment soon with a better MKP from them and even some paper ones. Will post results