My new favourite amp for the PF IX and 1601SC is the Pico Power. It is throwing out more raw current than even the powerful Quickstep and this is eking out surprisingly rich bass and an overall full sound. The treble is a bit "organic", not at all sharp, which also suits these headphones well.
This works out great as I actually find that the Pico Power sometimes overwhelms the Heaven VI. It is a fun listen but the bass is leading the music even where it shouldn't. The Quickstep, which I also find to be just a bit faster, is a perfect fit with the Heaven VI. (KAEDE sounds great with both; still not sure which I prefer.) So it is back to the Quickstep as my portable and Pico Power at home.
(Mike, I will be the first to concede that throwing 15 volts into the Quickstep could well close the power gap with the Pico Power. What can I say? I am a 9 volt guy.
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