I'm not that much well know down there on Head-Case. Suscribed a few times ago , I never posted and I'm use to lurk only. @JimL asked me to give some impressions about the srx+ i commissionned to a reputable builder a few month ago and received in last october. So here am I.
First of all , let me give you a few elements about where I come from. I'm a french hobbyst ( that explains my average english and I apologize for that) involved in personal audio since 2012. I began with a Koss Porta pro from my Laptop and now my reference system is a Schitt Yggdrasil , a DNA Stratus , a Sennheiser HD800 (modded with the mod I created last year to make a HD800 sound a bit more like a HD800S : the Superdupont Resonator maybe a few people know here ) and an Old sennheiser HE60 driven by the SRX+ we're talking about in this thread. Actually , even if I'm a HD800 nut , I appreciate a lot Electrostatic headphones i discovered with a classic combo SR303 + SRM323. I owned or listened carefully almost all Stax including vintage ones but despite their excellent sound , I still prefer the HE60 I bought one year ago. My preference usually goes more to brighter/clearer sound sig hence the fact my Favorite Stax is the SR009 followed by the lambda Signature. I'm listening mostly to Jazz ( modern jazz mostly from 90s to nowadays) , Classical and Electronic music. Not much Rock/Pop. You can check my head-fi profile if my whole pedigree matters for you.
so.. SRX+ . here's a pic of mine :
The Builder choosed to insert a Blue Hawai Power Supply , an Antek transformer, an alps RK27 potentiometer and mundorf mcap supreme capacitors . I asked him to respect a size ( especially depth) because i had some rule to respect in my living room. . I'm delighted by the quality of this build and the look and feel offered by this amplifier. I choosed this amplifier because @n3rdling told me it could maybe a great and very valuable choice. I trust Milos so I took the plunge.
I'm not that much a tube roller. I bought a quad or french NOS Laradiotechnique 12AT7 and a pair of NOS GE but replaced it lately by a pair of 6SNGTB Chrome top Sylvanias and they improved the sound ( tighter , clearer , more transparent) significantly .
I had a trip in US in november and went to San Francisco and LA to meet US hobbyists. I brought this SRX+ with me and it seems listeners enjoyed it a lot . I didn't take myself enough time to compare to well known contenders ( Especially n3rdling's BHSE for example) though. We met a few guys from head case. @blubliss I think and another guy I don't remember the name. Sorry.
So... When @JimL asked me to give impressions , i wasn't convinced to be able to provide valuable informations. Fortunately, a meet was organized in France at @Ali-Pacha 's place last week. Ali-pacha already allowed me to listen and measure his huge stable of Stax headphones last year and a BHSE joined his stable recently. It was the perfect opportunity for both of us. We added a SRM-727 (usual feedback mod done) in the shootout to have a more affordable contender.
We used my HE60 and the two Stax Omega (007mkI and 009) to do our listening sessions. During the first sessions i was unable to detect any difference between amplifiers and it was the sign my ears wood... too tired and I had a 2nd sessions during Day 2 of our meet.
Let's go straight to the conclusion : the modded SRM-727 is not in the same league than the two others and the SRX+ is a true bargain in E-stat world.
First Session was with my HE60 I know well and at least much better than the two Staxes. HE60/BHSE is truly a match made in heaven. I love my HE60 but I know well his flaws : it's kinda brightish and sometimes, with a few recordings, it's borderline unbearable. Bass can be punchy but still too diffuse/soft by today standards, mids are wonderful but compared to Milos HE90 clone, they're undoubtly a tad colored (in a good way but still) and overally the HE60 show a bit his age with a kind of slightly "vintage" soft sound. It's really obvious when compared to modern headphones. Nevertheless, it's a superb headphone I love to use for a few genre and when I want a change of pace from my HD800SD.
The BHSE with its kinda cold uber-technical abilities and its slam/power makes the Senn sounds younger that it really is. The low end expecially is clearly improved with much more tightness down low and an overally cleaner, more controlled, more focused sound. The Baby Orpheus gains some 009 qualities but still with the typical Senn Stat sound and still that extremely good staging that offers both a good sense of focus and a lot of air hence the feeling of cohesive but endless staging. In one word, BHSE/HE60 is still HE60 but better everywhere. Think to a hand (the HE60) and its glove (the BHSE).
Considering how BHSE and HE60 works well together, there's no surprise here : my SRX+ (I bought it especially for my HE60) can't compete and the Senn sounds noticeably more blurry and kinda soft/ limp dick on the SRX+. Let's be honest, it's still good enough for me but compared to the BHSE, the loss is significant. No surprise here. For my personal use it's not that bothersome because I use mostly my HE60 when i'm listening to intimate vocals, chamber music and that kind of music. For Orchestral, EDMs I always choose my HD800.
HE60/SRM 727 . No need of long comparison here. the 727 does not play in the same league. The immediate feeling of congestion struck me immediately. Something broken/dead in the sound as well whereas the two other amplifiers let the headphone breath naturally. Maybe something warmish but still steely/grainy in the treble in the tonality was a showstopper as well. I didn't expect so much difference to be honest, even more if we consider I already heard the 727/HE60 combination and it sounded OK to my ears. But compared to the SRX+ and even more the BHSE, the story wasn't the same ...
Summary for HE60 : BHSE >>> SRX+ >>>>>>>>> 727. if the HE60 was my main headphone, I'd order a BHSE right now.
Second session with the SR009.
OK , BHSE/009 is a known association and I won't be long . Sounded really good, clean, a tad cold, very technical to the point of maybe some sharpness but I see how performing is the combo. Seems the Midrange shout that usually bothers me with all Stax headphones is well controlled though. Good pairing but not as special as the HE60/BHSE one to my ears.
Surprise came from the SRX+ there... Honestly I think I'd choose the SRX+ over the BHSE for the 009, especially if I wanted to use a 009 on daily basis as my allrounder. Whereas the SRX+ made the HE60 a bit too blurry, it made the excess of sharpness disappear here and the 009 sounded a tad more rounded , more "human". SRX+ / 009 offered to my ears a very balanced sound with a hint of forwardness/intimacy, a touch of warmth and overally a kinda relaxed yet fun/pleasurable presentation.
Probably a very very good choice for those who listen a lot of modern music with their 009. I liked it a lot and definitely made me think more to add a 009 to my stable. I still think the BHSE is "better" in almost all point but the synergy goes to the SRX+
One more time, the 727 sounded much less good than the two others with the same flaws than with the 009. Both BHSE and SRX+ made the 009 sound more clear and crisp , more focused, tighter in all register. the main issues are congestion and Kinda loose low end I'd say. This and some grain in the treble...
With the 009 I'd see the ranking as this : BHSE>SRX+>>>>>>>>>>>>> 727 . the experience made me want a 009 to associate to my SRX+ ...more than a BHSE
We tried as well the 007 but I'm not familiar with this headphone. Moreover it's not my signature of choice (too mellow for me) so I prefer to let you read what @Ali-Pacha wrote about it.
Overally I Still think the little and kinda cheap SRX+ is a great option for people who want a very competitive amplifier without to spend an arm and a leg. At least, Im' really really happy with my purchase.
Maybe @Ali-Pacha will add some of his own impressions .