Thread resurrection! (Hey, it's a good thread) I just want to have a bit of a discussion about the cutoff frequency formula used in the first post. For completeness: OK so for those of us who aren't using headphones with massive impedance, it would seem that 22uF won't quite cut it. I'll use 2 popular headphones as examples; Koss PortaPro: 60ohm impedance With the AV710 default caps (10uF) 1 / (2*Pi*60*0.00001) = ~265Hz With the original mod caps (22uF) 1 / (2*Pi*60*0.000022) = ~120Hz I chose these mainly because i have a set but also because they are considered possibly the best sounding headphones in their price range. They're very popular and everyone should own a set. Audio Technica ATH-AD900: 35ohm impedance With the AV710 default caps (10uF) 1 / (2*Pi*35*0.00001) = ~454Hz With the original mod caps (22uF) 1 / (2*Pi*35*0.000022) = ~206Hz Chosen because they're known for having an excellent sound without an amplifier. Now i know my portapros seem to lack a bit of bass but 265hz cutoff is pretty huge. Can someone confirm/deny what i'm doing here? Are there any dangers associated with putting in capacitors as big as 220uF?