You may also be interested in reading my story on the repair of a Krell KSA250 link below
https://www.diyaudio.com/community/threads/krell-ksa-repair.402617/
After repairing the Krell 250, I proceeded to upgrade the amp which deals with the power supply section. The first one is an easy tweak which all modern audiophile grade amplifier incorporates. This is to bypass the large electrolytic filter capacitors with small value high quality film capacitors. In this case I use 1.0uF 100V polypropylene film cap. Four pieces, one across each of the 68,000uF capacitor.
https://www.diyaudio.com/community/threads/krell-ksa-repair.402617/
After repairing the Krell 250, I proceeded to upgrade the amp which deals with the power supply section. The first one is an easy tweak which all modern audiophile grade amplifier incorporates. This is to bypass the large electrolytic filter capacitors with small value high quality film capacitors. In this case I use 1.0uF 100V polypropylene film cap. Four pieces, one across each of the 68,000uF capacitor.
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The second is slightly more elaborate as it involves adding 4x 120uF motor start 330Vac capacitor. I copy this idea from another fellow DIYAUDIO contributor, ZenMod. He makes many contributions and idea on the Pass Labs forum. It is said make very significant improvements to sound quality. Especially in the high frequencies.
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@KweeSong Lim can you explain the theory behind this upgrade please and what sonic benefit it brings to the table?
Dear Allan, you may read this thread for the reason to add film capacitors in parallel to electrolytic capacitors. Main benefit is high frequencies response improvement. ZenMod also likes to add motor start capacitors too. You can read in the attached link. Hope that helps.
https://www.diyaudio.com/community/threads/film-caps-in-powersupplies.400289/
https://www.diyaudio.com/community/threads/film-caps-in-powersupplies.400289/