I’m not going to do a full-on nuts review like I usually do on the Liquid Plat, mostly because I don’t own and don’t have much experience with any other amps in this $500-800 tier. I will give a few thoughts though, and do the best comparison I can with the Asgard 3. These thoughts will be based on the LP with stock tubes (Electro Harmonix 6922). I haven’t tube rolled yet, but I’m sure that’s an itch I will need to scratch before too long. Also, because I’m sure you’re curious, I’ve used balanced-modded DT-880 600 ohm, Focal Elegia, HiFiMan Edition X V2, and Massdrop + Fostex TH-X00 Purpleheart both before and after a full Lawton mod to Lawton’s purpleheart cups on the Liquid Plat. I’ve used the SMSL SU-8 and iFi Zen as DACs, mostly with both connected balanced.
The Liquid Plat strikes me as a really good amp. It is warm, wide, and relaxed without seemingly sacrificing much in the way of detail. The spatial performance is really good; wide soundstage, good imaging, solid separation, depth, and layering. But to me the standout sonic feature is the timbre. Vocals and instruments, and well basically everything, sound very natural and organic. In other words, voices sound more like voices, pianos sound more like pianos, horns sound more like horns, and so on, than any other amp I’ve tried. I can’t detect any real grain or noise either. And for being a tube-hybrid, it is dead silent. Even cranking the pot when nothing is playing, it’s very quiet. I should also note that these comments apply to the balanced headphone output. The single ended output really is not so great. Don’t buy this amp if your primary headphones are single-ended only. It will disappoint. This amp is and needs to used as a balanced amp. However, there is a minimal performance hit from using the RCA inputs instead of the XLR. It’s not zero, but it’s perfectly useable and still very high-performing using RCA inputs and balanced headphone output. I also don’t pick up any obvious “tubey-ness” to the sound either, like I did when I had a Darkvoice (however I’ll put in the disclaimer that tube amps don’t inherently sound thick and gooey; some are very clean).
There is more than enough power. There is no gain control, but it does not struggle to drive high impedance dynamic loads or high-current demanding planars. The bass is deep, powerful, and controlled. However, this power that feels unlimited and lack of gain control does have an annoying catch: the loudness takes a HUGE jump when the potentiometer gets to somewhere in the 10:00-11:00 range. The best way I can describe it is like this: the pot goes 8:00-9:00-10:00-DEATH. This loudness jump can be mitigated to varying degrees if you use a DAC or preamp with a volume control. That does give you more precise control and decreases the magnitude of the volume jump in that 10-11 range, but that jump is still always there, and annoying.
The LP also runs hot. Some of that is its tube preamp stage, but also it’s just a warm running amp. It’s noticeably warmer to the touch than even the Asgard 3, but never reaches a temperature where burns are a concern. Still, it’s probably wise to make sure that it’s in a well-ventilated shelf/rack space.
I’ll do a quick comparison with the Asgard 3, as that’s the jump I made. The A3 was my workhorse for several months until the LP came along. The A3 still has a place in one of my systems because it’s flatout the better single ended amp and in terms of peak performance is really not all that far behind. Truthfully, most of the differences are subtle. The LP is slightly wider in staging with slightly better imaging and separation. The LP provides just a dash more overall detail. The A3 doesn’t suffer from that potentiometer issue, though. However, I think the LP separates itself from the A3 the most with its timbre. The LP sounds more natural and closer to real life in that way. That really is saying something, because for my money timbre is one of the Asgard 3’s greatest strengths too, especially for its asking price, and even more especially when it’s compared to THX and other op-amp based amplifiers that are its current primary competition. However, voices just sound more like voices - and so forth - through the LP than the A3.
I’ve heard others with more listening experience say that the Liquid Platinum is a good deal even at its original $799 asking price. Monoprice is currently selling it for $484 [EDIT - As of 9 Sept. 2020 the price is 516.09USD] . IMO, that’s a steal. It’s going to be locking down my primary amp duties for awhile. If you’re looking around for amps in the ~$500 range, be sure to check this one out too.