Pros: Open, liquid sound, reliable, made in USA
Cons: not portable, 2 boxes, needs separate DAC (if desired)
I purchased this from Todd the Vinyl Junkie along with a pair of Audeze LCD-3's. I had already decided to buy the Audeze's, and the Peak/Volcano was the #1 choice on this forum, and Todd offers a great return policy, so I felt confident in my purchase. I was more than satisfied with the result.
My source material comes from my Macbook Pro running Audirvana Plus, feeding into one of two devices I have with high-end DACs. One of those devices is an OPPO BDP 105 that has been upgraded by The Upgrade Company in Michigan. This is a fantastic sounding player with its own headphone jack, but the sound quality was definitely better feeding the analog out from that device into the Peak/Volcano than using the Oppo directly.
As chance would have it, I needed to sell the preamp from my main system. That preamp was a Mark Levinson No. 32, which sells for about 7 times the cost of the Peak / Volcano. However, any port in a storm. I had ordered an integrated amp, but it took many months to arrive, and so I used the Peak / Volcano as my primary preamp for those months, in a system in which the wires were more expensive than that preamp. While I won't pretend that it was as good as the No. 32, it did remarkably well--really, outstanding for its price. It includes three single-ended inputs and single ended line out connecters. There's no remote control--just a volume knob, a standby knob, and an input selector--but I was amazed at how well it did. Compared with the far more expensive gear I was used to, its primary drawback was just a bit of emphasis on the upper bass--a feature that many users will probably appreciate (I tend to go for absolute neutrality).
I have only listed to it with the supplied Sophia Electric 6SN7 tube, although I have enjoyed reading the forums talking about tube rolling. During thie past 6 months, it has been totally reliable and consistent.
Back to its use as a headphone amp: I can't claim a fully accurate comparison, but it has sounded better than any of the headphone amps I have listened to in stores. Given that its sound quality as a system preamp matches that of preamps costing twice its price (although typically with better cosmetics and remotes), I would recommend it wholeheartedly. Adding to that is my appreciation for Todd and his very helpful policies, which take the risk out of auditioning it.