I have an SPL Phonitor XE in the house for review. I've spent a couple of days with it thus far. I wanted to hear what a professional quality high(ish) end solid state amplifier sounded like. First impressions: This is the best string bite I’ve heard from a solid state amplifier. That tends to be a big killer for me; either it’s too subdued, or it’s artificially enhanced. Violins and cellos sound great. Future reference for my comments: Optimized PC -> Sonnet Allegro Pro USB card -> RME ADI-2 DAC -> SPL Phonitor XE -> Sennheiser HD650 w/ PRT and a few mods Cables are customs that I made, but not with anything particularly exotic. Power is cleaned up by an Emotiva CMX-6 for all of my audio devices and PC. I have other headphones and DACs I’ll check it with for review purposes, but that’ll be almost all of my listening right there. Day 2 This is an outstandingly clean amplifier. Excellent blackground, tremendously capable with large power swings, and exceedingly neutral. It’s not explicitly dry or lifeless like some amps described like the above tend to be. The biggest drawback I’ve heard so far is with plucked strings. While bowed strings sound outstanding with a visceral bite to them, plucked strings seem to lack a certain sparkle and shimmer I expect from them. Perhaps the decay is faster than I’d expect? It’s hard to pinpoint at the moment, but I prefer the sound of acoustic guitar (one of my most frequent listens) from the Garage1217 Project Sunrise III, for example. Time to put my above thoughts to the test. I'm comparing the Phonitor XE by itself against the Garage1217 Project Sunrise III as a preamplifier. Those VU Meters really come in handy for auditory comparisons. I engaged DIP Switch 2 to push the RCA inputs to studio levels and connected the RME to the Phonitor via XLR and to the Sunrise via RCA (then the Sunrise to the Phonitor via RCA as well). I’m reversing phase with the RME on the right channel (then it reverses again at the XLR on my headphones). On the Garage1217 Project Sunrise III, the following setup was used: Input capacitors are bypassed Attenuation module is bypassed Electro-Harmonix 12BH7 gold pin (new production) For this first test, I’m not using a linear power supply or @atomicbob Noise Nuke (both of which will improve it sonically) Levels were matched precisely with a sine wave sweep. I first biased the tube in the Sunrise with a multimeter, then matched volume on the right channel to the point that the needle didn’t move on the VU meter when swapping between XLR/RCA, then biased the other tube channel to make the other side’s needle not move. That led to an almost 0.5V difference in the left channel’s bias from the norm, but the volume was right at that point. I vastly prefer the sound of plucked strings using the Sunrise as a preamp. Soundstage depth is notably deeper as well, and bass impact is more pronounced. My favorite acoustic guitar album is Tommy Emmanuel - Live! at the Ryman if you want to go apples to apples with a similar comparison. The RCA cables are better than the XLR, so that might make a small difference. The XLR are Mogami W2534 Neglex with Neutrik NC3MXX (and F) connectors. The RCA are made with Gotham GAC-1UltraPro cable with KLE Copper Harmony connectors. Later today or this weekend, I’ll do the same comparison with an LPSU and/or Noise Nuke and a nicer NOS tube. Edit 1: I double-checked the levels on the VU meters again in case there was some drift in tube bias (there wasn't--the amp has been on for hours). Then I recruited my wife to switch the XLR/RCA while listening. It's 100% clear which is which. The Phonitor XE alone is thicker sounding overall with a slightly compacted stage depth (the front stage is at roughly the same spot, but it doesn't pull as far back... if that makes sense) when compared to the Sunrise preamp. I could tell with 100% accuracy which was which. However, I was far less confident in which was preferable. I said I vastly preferred plucked strings with the Sunrise used as a preamp, but that gulf isn't nearly as wide as yielded by my sighted impressions. Before I knew which was which, I liked the Phonitor better for one song and the Sunrise better for another, despite being confident that I was choosing a different input for each. Ah, the joy of audio testing. I've not yet gone deep into looking for micro stuff yet. My guess is that some of that is lost by using the Sunrise preamp, but we'll see.