Just to preface, but this is my first time really reviewing a pair of headphones, but I felt that these warranted me typing up some of my thoughts.
Electrostats, I'd always been interested in picking some up, but had heard a ton about how expensive and finicky they could be. Needing a specialized amplifier to drive them, issues with dust and moisture, and the price kept me from taking the plunge for the longest time. Despite these concerns however, I finally chose to dive headfirst into the world of estats, grabbing a used SR-Λ Pro and SRM-006t off yahoo.jp.
Not going to go too far into the shipping and unboxing for these, since these were bought used and it'll be different for everyone, but both units arrived incredibly well padded and quickly. I used Buyee as my forwarder, and had a good overall experience.
https://i.imgur.com/xPKoJl1.jpg
The first thing to arrive was the 006t. This is an old Stax tube amplifier from the late 90's, and it's pretty long, so finding a spot on my desk for it was a bit of a hassle. It has 2 RCA inputs, 1 balanced XLR input, 2 580V pro bias outputs, and 1 230V normal bias output.
My first order of business was to get the thing working properly on 120V AC. This was a JP model, and so from the factory it only supported 100V AC. Luckily, it's old enough that Stax had not yet started to cut the windings on their power transformers, so all I had to do was remove the stock voltage jumpers and solder new ones on the blue and purple wires. I made no other adjustments to the amp, although I might install a CCS mod at some point to increase headroom.
https://i.imgur.com/wRU3mEM.jpg
Onto the headphones themselves, they arrived in very good condition. The SR-Λ Pros were initially released in the early 80's, and are 580V pro biased. I had heard a ton about the poor build quality of the Lambdas, and these definitely don't have the same bulletproof feeling of my DT1990s for instance, but they don't feel like they'll fall apart if you look at them wrong either. As long as you're careful taking them on and off, I don't imagine that durability is a major concern with them. Putting them on, they immediately felt very comfortable, with very little clamp force, and deep enough earcups for my ears to not touch the drivers. The headphones themselves are quite light, and the cable, despite all I had read about the weight, is quite manageable, particularly when you can rest the majority of it on a desk or table. Sound isolation is completely nonexistent, it's as if there's nothing there.
The first time I listened with these, I smiled more than I think any other pair of headphones or IEMs had ever made me smile before. The detail retrieval on these blows anything I've ever listened to out of the water, and it does it without needing to sacrifice tonality by boosting the treble (ahem Beyerdynamic). I've mainly been listening to a mix of rock, metal, and electronic music through these, and no matter what I throw at them they just sound fantastic.
The bass probably won't satisfy true bassheads, but extension is decent and what it lacks in pure punchiness it more than makes up for in control. Electronic music in particular sounds crisp and tight in the bass, and works quite well with these headphones.
Mids and treble are where these truly shine in my opinion. The midrange is very natural sounding, and the treble has all the detail and sparkle that I tend to prefer, without being harsh and fatiguing. Coming from my 1990s, these immediately sounded far more natural, while also managing to be more detailed. Other than a bit of a bump in the 1-2k range, they sound pretty flat, and even that slight bump doesn't sound unnatural, it just sounds slightly more forward compared to the rest of the midrange. Going back to the 1990s after a couple weeks with the Λ's just sounds muddy and unrefined. However, these do lack the bass impact which the 1990s have, which could prove a dealbreaker for those into more bass quantity. Songs which on my 1990s either ended up sounding like a wall of sound, or which had a tad too much spice in the highs, sounded much more natural, and were much easier to pick apart and hear individual instruments.
Soundstage and imaging are both very good as well. Playing games with these, there were some times where I heard quiet ambient sounds in the background and physically turned my head to look for the source of the sound, thinking that they were coming from something in my room. Coupled with the extremely good detail retrieval these have, I imagine that these would be quite good for more competitive gaming if you were so inclined to use them for such. I mostly play rhythm games and Genshin though, so I can't really speak much to that. For most music though, I would compare the soundstage to that of a well treated recording studio. It's certainly much more intimate than proper speakers, but instruments still clearly sound like they are coming from outside your head, and the separation is very good as previously stated.
One thing I noticed immediately was that this setup with the Λ's and the 006t requires about an hour to really warm up and start sounding its best. Whether that's mainly due to the diaphragm on the headphones needing time to charge fully, the tubes needing time to warm up, or a mix of both, I am not sure, but before these are fully warmed up the sound is much thinner and more airy.
Overall I'm extremely impressed with this setup. It's honestly somewhat ruined my other headphones for me, since none of them can really match these in terms of both detail retrieval and tone. If you can live with some of the tradeoffs which come with electrostats, I would wholeheartedly recommend that you go and try to put together even a "cheap" used setup. These truly do knock the doors off of anything else I've listened to, and now that I've gotten my foot in the door with estats, I do kind of want to try my hand at DIYing an amp, or even headphones if I ever decide to really read through that one HeadFi thread to learn how to make the drivers. There's no way that you could make these your only headphones, but they certainly have become my main headphones.
