Art Audio PX25

Behold the Art Audio single ended PX25, a masterpiece of the super exotic, a chrome-polished monument to 6 watts of the very purest audio power ever created, and probably the most vividly spectacular sounding amplifier that I have yet owned.

One of only a very few modern amps based around the rare and expensive PX25 triode, this amp breathes out great bursts of room filling program material and sounds enormous. A strong candidate for being perhaps the most arcane power tube in existence, the PX25 (VR40 in its military designation) is a British tube from the 1930s that is sort of the English answer to the 2A3, and bridges the power gap with the venerable 300B. The original 1930’s-40’s PX25 tubes are very rare and quite pricey now. Thankfully for us all, Riccardo Kron of KR Enterprise in the Czech Republic resurrected this tube from oblivion back in 2000, and now both KR and Sophia Electric/Full Music make new, modern versions of the PX25, so this tube will be around for the foreseeable future.

With super heavy-duty everything, this chrome monster weighs in at 55 pounds and just oozes quality. The oversized volume control is smooth and satisfying. All of the connectors seem to be high quality and everything about his amplifer feels substantial and overbuilt. The tube lineup consists of the PX25 output tubes, with 6922 followed by 12BH7A for the input and Mullard CV378 for the rectifier. Strangely, to me anyway, input tube changes have yielded only slight differences in my room. It seems there may be a few choices in the rectifier position; I’ve used 274B and have seen photos of the amplifier with the Raytheon potato masher 5R4, so it may be possible the tailor the output via the rectifier. Besides the ultra rare NOS Marconi or GEC tubes, there are really only two choices for output tubes in the PX25; globes from KR or ST shaped “mesh plates” from Sophia or Full Music. One note about NOS tubes, they have a British pinout and require a UX4 adapter to work in a modern amplifier like this one. Hopefully one day I’ll be able to sample the differences between some of these fine tubes, but the KR globes seem superb.

So how does it sound? Let me start by saying that when set up in my living room system, this is the only amplifier I’ve owned so far that has inspired both my wife and our teenage daughter to approach me separately and comment about how good the music sounds. There is something happening with this amplifier that is unique, and is very pleasing. The previous owner commented on it, mentioning it was hard to put a finger on, and I agree. I’m not sure yet if its tonality or space or warmth, maybe all of those and more, but its very enjoyable and perhaps defines the ultra-fidelity “big-tube-glow” sound for me so far. This amp just breathes music, with rich textures and realistic layering of performers and instruments. When first evaluating new gear, I often use a set collection of program material as a baseline, and Tom Waits’s Small Change (Got Rained on With His Own .38) is a good example from that list. It's a very sparse but live recording; Tom’s gruff vocal on one side, Saxaphone on the other. Presented by the PX25 both are slightly larger than life but standing in the room right in front of me in a way that is extremely life-like. Closing my eyes I really feel like I could be sitting in the front row of a small, smoky little club looking up at a low stage. Bigger music like Moses Hightower’s Tiu dropar pulse powerfully into the room, smooth and full of mojo. Eddie Berman’s version of Like a Rolling Stone comes through revealing slight nuances between the male and female vocals that I’ve not appreciated before, and placing the two performers so precisely in a remarkably realistic soundscape. These small nuances seem to appear on a lot of material, and while the Art Audio doesn't necessarily feel like it is revealing more details than the Yamamoto 45 or Sean Casper’s AD1, it does seem to give those details a better position in the presentation if that makes sense. Everything has its own aura through the PX25.

So, unbridled praise aside, there are actually a few things that I dislike about the Art Audio PX25. The chrome over-treatment is far too ostentatious for my taste, and being such a large piece this one jumps out and dominates the space around it. The chrome shows every speck of dust and every single fingerprint or blemish. It wants to be cleaned and polished continuously. Compared to the sleek and muted lines of the Yamamoto this one looks like a monster truck at a mudding competition. The amplifier is also physically quite large and very heavy, presenting a challenge to move around, etc. Of course, these are both issues which I fully appreciated before purchase, and can be overlooked easily enough. Other than a vanishingly slight hum at idle on my 96db/wm panels, sonically there is simply nothing for me to complain about here. I don't want to say that the Art Audio’s fidelity is flawless, but I’m just not sure how much better reproduced music can get in my room. The natural and believable rendering from the Art Audio PX25 has just set that bar a bit higher for me, and although there is something beyond fidelity about the Yamamoto that I like more at the end of the day, I do really wonder if I’ll ever own an amplifier that can best the PX25’s level of performance. Super highly recommended, if you can find one.

This is a large amplifer! The butcher block base its sitting on is 18 inches wide.

The chrome might not be to my taste, but this is a very well executed amplifier! The venting under the output transformers and the heat sinks are a somewhat unique feature here.