The ALO Audio Studio Six Headphone Amp Review

As I sit in my office, in my listening chair with some Senheisser HD800’s on my head, the needle on my new VPI Scout 1.1 turntable drops onto some vinyl. The amp and phono stage powering these HD800’s is the ALO Audio all tube Studio Six amp and Phono Stage. It is incredible. Really. 

Record after record..I am simply sucked in..addicted to the lovely sound that is in and out of my head. But it gets better…as I take off the HD800 and look at my desk I have several headphones to test on this rig, so I pull out my HiFiMan HE-1000’s (See review here) and wow, vinyl, Studio 6 and the HE-1000 is a match made in Heaven. Digital, even with high end sources, does not sound like this. This is rich, fat, detailed but oh so nice.

How did I ever get so lucky as to own this amp, the phono stage, a VPI Scout 1.1 and the amazing HE-1000 headphones? Well, not so sure it is luck or me…draining my bank account… but either way I have what I feel is the best dedicated headphone setup ever created with the Studio 6 and HE-1000. At least for me and my ears.


ALO Audio is where the amp and phono stage came from, and Ken Ball, head honcho at ALO Audio in Portland OR sold me the setup. I was recently at ALO Audio and picked up some headphones and an Astell & Kern AK 120II high res player. When I was there I eyeballed the Studio Six, not even knowing what it is. To be honest, most of my HIFi Experience has been with 2 channel speakers and amps, not so much hi end headphones and amps. Even so, I was fascinated by the six tubes atop the amp, and the fact that they believed in this amp so much that they created an all tube phono stage that ONLY works with the Studio 6 Amp! It is THAT good.

Over the past few weeks I have been able to hear many high end headphones from Audeze (LCD-X, LCD-3), Sennheiser (HD-800), HIFiMan (HE-1000), Grado (PS-500 and PS-1000), Ultrasone (Edition 9) and Oppo (PM-1).

Without question, without doubt..the best setup of that group of headphones is the HE-1000 with Studio 6. My 2nd fave was the HD-800, which as some great synergy with the Studio 6 amp. The setup that I disliked the most was the Oppo PM-1 with the Studio 6 (and other amps I have here). They sounded muffled and lacking in details, almost broken when you do a side by side with the other sets of headphones. MUCH too full sounding, which resulted in a loss of magic or soundstage. The Oppo’s sound direct in my head with pleasing full sound, but that was all I got from them.



I love magical audio listening sessions and they are rare. Magic happens when you have amazing synergy between componets, speakers, headphones, amps, DAC’s or whatever is in the signal chain. Some systems sound dry and lifeless as they have NO synergy. Some systems sound gorgeous and amazingly beautiful, and that is when you have some synergy going on.

In my 45 years of life I have had systems with amazing Synergy TWICE and have had many without synergy, maybe 7-8 systems that sucked but cost me tons of cash. With the ALO Audio Studio 6, just about any headphone I plugged in meant that it was being driven to the best that it can be. I mean, the is an end game headphone amp. One that will last you a lifetime and btw, is built to last several lifetimes so this is something you could hand down to your kids. It’s that solid.

This Studio 6 amp is built to a level that is rarely seen today, and to top it off it is made in the USA which tells me the $3900 price tag is in line with what it is worth as USA made amps are NOT cheap. This is all tube, built to last 100 years, sounds delicious with ANY headphone and will drive ANY headphone and allow you to tube roll (try all kinds of tubes) to tweak the sound signature. My Studio 6 has been tried out with new tubes and NOS tubes. Either way it sounds glorious but the sound does change with different tubes. It’s pretty cool and like owning several amps in one. If you ever want a different flavor of sound, change out a few tubes. Easy as that.


My Month so far with the ALO Studio Six and Phono Pre Amp

So Ken Ball, the head guy at ALO Audio decided he would send me some of his personal headphones to test out with his amp. HOW COOL WAS THAT?!? He sent over the HD800, Ultrasone 9, Grado PS500, Oppo PM-1 and I already own the HE-1000.

He told me I could run them all through the Studio 6 at once with no loss of power or signal. Up to four at a time. I plugged in the HD800, the HE-1000 (both of which are tough to drive), Ultrasone’s and Oppo’s, all at once. All sounded fantastic and there was NO LOSS of power, just as Ken said. What an amazing feat as the amp was powering ALL of them at the same time. PERFECT for parties, meets or listening with a friend or four. What it did for me was allow me to easily and quickly switch between headphones which is how I discovered that none of those could touch my HE-1000 for sound quality or comfort. 🙂


Many say the HD800 are the best all around headphones available to mere mortals (as in, not going over $5k) and over the years many have tried finding an amp for them that made them sing without being to harsh or trebly or too thin and bright. Not an easy feat. The Studio 6 with the HD800’s gave me an experience I never heard before while using the HD800. Bass, and a taming of the harshness that many find with this headphone. I will list below each listening experience with the Studio 6 to make it easier to understand. I will describe each headphone and its character with the S6 Amp, at least in my experience and with my ears. As with anything audio, it is always about personal preference more than anything.

I will list the headphones starting with what I liked the best going to what I liked the least…

The HiFiMan HE-1000 and Studio 6

Wow. Just wow. This headphone, to me, is the best in the world. There may be more expensive headphones (Stax) or headphones that are said to be just as good (HD800) but neither of these give me what the HE-1000 gives me, especially with the Studio 6 amp and phono stage. (See my review of the HE-1000 HERE)

When plugged in to the Studio 6 the HE1000 becomes an ultra organic and very special headphone. Notice I said “organic” and not “orgasmic” though in reality I could have said “Orgasmic” as this setup is responsible for more than one “Eargasm” I had 😉


Once you log in a few hours with this setup, it will be very very hard to go back to anything else. I am warning you now. I also have a McIntosh MHA100 here that powers the HE-1000 slightly better as it pours 1 watt into them where the Studio 6 puts less power to them. Even so, the Studio 6 has something special going on with the HE-1000. Delicacy, huge soundstage width and depth, liquid… all words I wrote down while listening (With the MHA-100 I wrote “slam” “power” and “BALLS). Even more qualities with the Studio 6? Intimate. Real. AMAZING. I have never heard anything better than this in the headphone world, ever. I remember having a serious sit down session with the Sony Qualia 010’s when they were launched a long long time ago yet nothing comes close to what I hear with the HE-1000 and the Studio 6. The McIntosh amp in some ways is better but loses out on soundstage and delicacy as that amp just goes for bite power and drive and pushes out more treble out of the HE-1000.

With the combo of Studio 6 and HE-1000 I can sit in the dark and feel as if the performer is right in the room with me, NOT in my head. Impressive, very impressive. The only niggle I have is I can tell the phones need more power than the Studio 6 will give them. I can max out the volume and they will not have the drive and power that the McIntosh gives them at 60% volume. Even so, I prefer the Studio 6 with these as they are out of this world and they do have the “Magic” sound I love.

The HD800 and the Studio 6

The HD800 has long been regarded as one of the best headphones available (unless you step up to a $5k and up price bracket) but so many get frustrated with it as it is is VERY finicky when it comes to choosing an amp to pair with it. I have tested it with an older Musical Fidelity and now the Studio Six (and MHA100). The best I have ever heard the HD800 comes from the Studio Six. When listening to digital or vinyl I am rewarded with a big sound, details, and even some warmth which takes the HD800 up a notch for me. I waste of those who had this set long ago and sold them as they become tough to listen to for more than an hour. They would give me a headache with the excited upper energy present and lack of mid bass. This time around on the Studio 6 the HD800 took on a new life and while they still fell short of term HE-1000 by quite a large margin, they sounded incredible and have I not just sat with the HE-1000 for 2 hours I would never have noticed the weaknesses of this headphone.


The HE-1000 offers up a HUGE tonal pallette that leans ever so slightly to the warm rich side of neutral but it offers this while giving more detail than the HD800, giving a more impressive soundstage width and height and somehow manages to keep it all fluid and coherent, making music. The HD800 to me, sounds a little disjointed. But since this is not a headphone review I will state that I never heard the HD800 sound better than I did on the S6 and S6 Phono Stage. If you own an HD800 and love it, you owe it to yourself to try them with the ALO Studio 6.

The Audeze LCD-X with the Studio 6


This is my 3rd fave headphone on the Studio 6 (That I have tested) and it offers up a HUGE visceral experience on the S6. These cans are big, plush and offer a sound that matches the looks. HUGE bass here guys, almost too much though it is NEVER EVER boomy or “beats’ like. It is an audiophile quality headphone but the sound character runs on the dark side of neutral. They are warm and dark and have no treble excitement to speak of but they again, PLAY MUSIC with a natural flow that is tough to get from a headphone. The HD800 could not match the LCD-X’s flow of music but it did beat it on resolution, imaging, details and soundstage. The LCD-X sounded amazing on the S6 but I had  to sell mine to afford the HE-1000. In a perfect world I would have kept them for those times I wanted to REALLT ROCK OUT. These headphones on the S6 with some rock or metal will have your head banging all night. Maybe I will save for these again soon. I sort of miss them. Reminds me of what systems sound like in the late 70’s and 80’s. Lots of BEEF DRIVE AND RYTHYM.

The Ultrasone Edition 9

These were loaned to me by Ken Ball of ALO Audio along with a few others here. This headphone is now discontinued but to me it felt cheap and plasticky and I found it hardtop believe this was sold as a premium money headphone. BUT when I put them on my head I was treated to a nice firm grip, but not too tight. When I dropped the needle on the “Simon & Garfunkel Live In Central Park” and a HUGE sound hit me with details flying all around me. The acoustic guitars rang out with authority and slam and they were very EXCITABLE headphones but not harsh, they were beautiful actually and had me researching this brand for a closed back set. While I am out of funds to buy anything else, I will keep this brand on my Radar as they sounded phenomenal on the Studio 6 and especially yummy with Vinyl. The phono stage for the S6 is magical, and to me sounds better than most $3k phono pre amps. These Ultrasone’s are great though I feel the build could be much nicer for the money. These also were EASY to drive as they went CRAZY loud with a short twist of the massive volume dial on the S6 (studio 6). The only thing that may get to me with these over time would be the treble which is sort of up there at times.


So goes to show this amp can power hard rot drive headphones as well as uber sensitive ones. Never do I hear any hum, buzz or noises when I have the amp on though the Phono stage can put out some noise on sensitive headphones, until you drop the needle.

Grado PS-500


I love the PS500 and the PS1000 from Grado. The PS500 used to be my #1 headphone! I experienced some build quality issues with my old set that literally fell apart after 10 months. So I am not sold on Grado for longevity but the sound is fantastic and again, easy to drive so the Studio Six powers these to another level that I am used to hearing them. I used to power mine with the wooden Grado cheap-ie amp and they sounded good. On the Studio 6 they are taken to a new level of resolution. Live recordings sound AMAZING on these little guys. Like you are there as they can push the volume and ambience of a live event. This is one area where I love Grado…reproducing live performances. Throw on some PS1000’s and a great live recording and be prepared to be blown away. While not offering the refinement and soundstage of the HE-1000 and HD-800, this little Grado can rock the house and sound amazing doing it and it can kick you in the chest at times as well. I was starting to see a pattern..no matter what headphone I plugged in to the Studio Six it sounded incredible and to the best of its ability (or so it seemed). Up next, the Oppo PM-1

Oppo PM-1


It’s funny as I almost ordered these as the price is right for a Planar headphone. The style is nice, and they feel great. When I put them on I thought something was broken when I played digital or vinyl as the sound was VERY distant and dark, almost muffled to me. I decided to give my ears a break and the next day I went into my listening room and put the PM-1’s on my head again to give it a serious listen. Again, very dark sound..not much detail and the soundstage was absent. The sound was not up to the quality of any of the above headphones for me, and while I could live with these if I never heard the others, when you compare them side by side these come up the weakest of the bunch. By far. Now, these do have a nice fat fluid sound, just more direct and dark. Like a baby brother of the LCD-X with less drive, refinement and without the organic music flow of the LCD-X. Still, they were powered VERY easily by the S6. To make sure it was not the amp I plugged these into the McIntosh MHA 100 I have here and it was the same with a little more drive. More on the muffled side of neutral 😉


FIRST CONCLUSION on the Studio 6

So there you have it. The Studio 6 from ALO audio along with the Phono Stage for the Studio 6 is the best dedicated Headphone amp I have ever had the pleasure of listening to. I have heard some exotic amps, some cheap amps and some mainstream popular amps. None  – zero – zilch have compared to the Studio 6 when it comes to sound and the ability to tweak the sound to your liking by rolling in some new or old tubes. The Phono stage is quite special and beats out my Jolida and Lehman stages quite handily. The Phono stage works with nearly all cartridges, just not low output MC’s.

Even though this is the best setup I have heard from Headphones, it is still quite expensive at $3900 for the amp, and yes, this is just a Headphone amp. It will not and does not power speakers, so it is a one trick pony but that one trick it does, well, it does it better than any other amp that I have experienced.


If you are 100% dedicated to Headphone listening or even like to attend meets, this is your amp. It’s an end game, It’s beautiful, built to a standard that will have it working longer than you will and it offers some versatility in Tube Rolling. This is what the hobby is all about IMO. An “interactive” amp that you can tweak to you hearts content with a simple tube swap. Enough power to drive all headphones that come along and while it doesn’t offer the last word in punch, drive and slam it offers the best of everything else.

Huge soundstage, rich intimate vocals that appear at times to be in your room, details without any harshness and a bass quality that goes DEEP and has some power. With the Studio 6 I am never ever wanting for details or midrange magic. I am never missing out on an organic presentation of the music more do I miss out on “magic”. I feel it has a lot to do with the Tubes as my MHA100 from McIntosh is even more versatile with the ability to power speakers as well as having a great DAC built in, but it loses out on the delicacy, the magic and the sound of tubes. While the Studio 6 is never mushy or slow like many feel tubes are, it offers up that magic tube sound mixed with a modern sound. So its just about perfect IMO.

I told Ken Ball at ALO he created a work of art here. At $3900 you will need some cash to plunk down for a dedicated head amp but I went ahead and purchased mine with the Phono stage. I feel the Phono stage and a decent vinyl rig will reward you with probably the most amazing listening sessions you will ever have. I have discovered that THIS is the way t o listen to vinyl. I prefer it to speakers  – so analog, so real and so takes me back to my days as a teen when I was obsessed with Vinyl and had a HUGE collection. I love it.

FINAL CONCLUSION on the Studio 6

As I said, if you are serious about your Headphone listening, the ALO Studio 6 is a heirloom piece that will last forever and provide some of the best amplification for any headphone you may own. Past, present or future. I highly recommend this along with the Phono stage if you want to take it to the next level. The setup I have here for this review of S6, Phono stage, VPI Scout and HE-1000’s are simply incredible. I could listen all night long (and have during this evaluation).

Even so, I will not be keeping the Studio Six as I realized that I much prefer listening  to speakers for my preferences. I was getting much too “lost” in the music and sitting in my room listening for HOURS..which is no good for family life 😉 So I will stick with my speakers and amps but if I were a tried and true headphone guy, my amp search would end here. It truly is one of the best out there.

You can check out more on the Studio 6 and Phono Stage at ALO Audio HERE.  If you love tubes, if you love build quality and if you treasure sound quality, it’s a must hear.

QUICK COMPARE: Compared to the McIntosh MHA 100


The S6 amp is $3900. The McIntosh is $4500 but offers more power, a built in DAC and the ability to dial in your headphone sensitivity and ohm’s for the best matching and power for your specific headphones. It also has a pre amp out where you can drive an amp or a subwoofer. The coolest feature is the Speaker taps with a genuine McIntosh 50 WPC Power Amp for  the speakers. This way you can listen to headphones or speakers and utilize the built in DAC.

But how does it sound in comparison to the Studio 6? Very good, but loses out in soundstage width and depth as well as those intimate moments. The S6 midrange is beautiful, the MHA100 is more sterile. While you gain features and power and kick and drive (the MHA100 excels at this) you lose the immediacy and flow of the Studio 6. It’s a trade off. For rock or metal, go with the MHA. For everything else, the S6 excels and is a notch above the McIntosh. For convenience go McIntosh. For the true love of music, you can not beat the Studio 6.

For this evaluation I used the following equipment:

VPI Scout 1.1 with Clearaudio Virtuoso II Ebony (amazing with the S6 Phono Stage..wow)

Yamaha CD2100 SACD & DAC (This is a fantastic player and DAC that many will overlook)

Astell & Kern 120II (crazy good portable but also sounds great piped into the S6)

Nordost Heimdall II Interconnects (My fave brand of IC)

Stock power cords