Valve Amplification Company Sigma 170i Integrated Amplifier | REVIEW

Valve Amplification Company Sigma 170i Integrated Amplifier Review by Lee Shelley

(Disclaimer: I’m a photographer by profession and I have many clients in the high end audio industry. I have shot for Valve Amplification Company in the past. My impressions and conclusions in the following Valve Amplification Company Sigma 170i Integrated Amplifier review are unaffected by this, but I felt you should know.) 

At the 2018 Capital Audiofest, there was a huge buzz about the new $150,000 Statement 450iQ integrated amplifier from Valve Amplification Company, and rightly so. It’s an enormous and visually stunning product that looks to redefine the category. However, I was more excited to see and hear the new $14,000 Sigma 170i integrated that was being shown at the same time. Why? The combination of real-world size and real-world price while offering 85w/ch of pure tube goodness. Here was a product the dedicated audiophile can afford and is still worthy of building a system around.

The technical details are as follows:

85w/ch into 4, 8 or 16 ohms

4 line level inputs with an option for one to be an MM/MC phono input

Speaker Taps for 4, 8 and 16 ohms

1 X 12AX7, 5 X 12AU7 and 4 KT88 tubes

A Brief Preview

The first time I listened to the Valve Amplification Company Sigma 170i was in my photography studio while I was shooting the photos for this very review. I happened to have the excellent EgglestonWorks Emma EVOlution speakers on hand and grabbed a few minutes between shoots to listen to the combination.

Streaming Norah Jones’ latest release from Qobuz in this hastily set up environment was magical. She was hovering comfortably between the bright red speakers with an almost palpable presence. It wasn’t all wine and roses though. Switching over to Foo Fighters, I found that the harder driving riffs and baselines in “Learn to Fly” were lacking, It felt slow and a bit fat. I chalked this up to the room (2,700 sq ft with lots of hard surfaces) and lack of time dialing in a proper setup, but it put me on notice that proper setup was going to need to be a focus when I put it into the system at home.

While not as large as the Statement 450iQ, the Sigma 170i is no lightweight. Weighing in at 70+ pounds, it was a two-person job getting it into my room and set up in my system. With dimensions of 18”W x 17.5”D and 8”T, it didn’t fit comfortably into my rack and necessitated putting it onto an amp stand in front of the rack. This is more an indictment of my stand than it is the product, but it’s something to keep in mind when you plan for placement.

I connected the VPI Avenger (Ortofon Cadenza Bronze) to the phono input and Schiit Yggdrasil DAC to input 2. I connected my Joseph Audio Perspective2 Graphene speakers and powered up the amp to let it warm up for an hour before settling into the chair for a first listen.

Listening Impressions

The first listening session with the Valve Amplification Company Sigma was all vinyl. I opened with side one of the very well recorded 1989 eponymous release by Lyle Lovett and his Large Band. All of the magic I heard from the Norah Jones was back in spades. My notes include comments like “great image” and “palpable.” Typically a bit on the bright side, this recording showed no signs of the strident edge I’ve heard on some solid state systems. The track “Here I am” was a particular stunner. The spoken portions never hinted at the throaty undertones I’ve heard in the past and the dynamics of the snare were punchy and crisp.

After this, I moved on to a mainstay of rock for me…Stevie Ray Vaughn’s Couldn’t Stand the Weather. I dropped the needle on “Tin Pan Alley” and right away I noticed an issue. Right from the first drum roll and subsequent bass riff, something seemed off. This recording is notorious for being bassy and needs a tight grip to keep it from sounding bloated. Moving the speakers even further from the wall helped the cause, but the bass control never felt vice-like. I tried adjusting the cartridge loading, but never felt I could get the bass quite right.

Sticking with the same artist, I moved to the outstanding MoFi One-Step pressing of Texas Flood and went straight to my all time fav SRV track, “Lenny.” Here again the VAC showed its strengths. Waves of liquid music washed over me. I had to try more.

Next was the Analogue Productions pressing of SRV’s posthumous release of his homage to Hendrix’s Little Wing. With the lights off and a whiskey in hand, I swear I could smell the tubes on Stevie’s amp burning. I actually got up to see if it was the tubes in the VAC! (It wasn’t.)

My next listening session shifted to digital as the source. I used Roon to access both my local library and Qobuz. I went straight to the HiRes version of “Tin Pan Alley” to see if the issues were the same. Somewhat to my surprise, they were significantly lessened. Again, I never felt like the bass was quite as tight as the best solid state amps I’ve owned, but neither was it as loose as it had been on the vinyl version. This was so much the case, that I returned the Perspectives to their initial position where I felt they imaged better.

Next I went for something completely different; the Chesky release of Macy Gray’s album Stripped. This is a series of covers, including of herself, that is exceptionally well recorded and all acoustic. Through the Valve Amplification Company Sigma 170i, the soundstage was amazing. Both the width and depth were expansive and seemed to make the room seem much larger than it is. The stand-up bass was clearly well outside the confines of the speakers and the space around her voice and each instrument was very clear.

Blues Traveler’s debut album provided the next test. The track “Alone” is a staple for me because it demonstrates great dynamic range, from barely a whisper to full on blow-your-hair-back rocking. The snare punch will reveal the weaknesses of a lesser speaker/amp combination. Happy to report that the Valve Amplification Company Sigma 170i was up to the task. The volume was uncomfortably loud well before I could get any sense of distortion. This is another gritty recording that can sound harsh on some systems, but the warmth of the Gold Lions on the 170i tamed even John Popper’s gravelly vocals and harmonica.

Additional listening over the next few weeks generated the following notes:

Springsteen, Born to Run, vinyl: “Punchy and dynamic. Title track literally giving me goosebumps. ‘Jungleland’ is epic. Sounds great.”

Bill Evans, At the Montreux Jazz Festival, vinyl: “This is what this amp was born to play. Crazy detail. Piano is liquid. Great soundstage depth.”

LV Beethoven, Symphonie No. 5, Carlos Kleiber, vinyl: “Very warm. Never strident. Violins extended, but not steely. Solid image depth. Room feels huge with good ambience.”

The Doors, The Doors, HiRes digital: “Keyboards are magical! Brings out the best in Morrison’s voice. ‘The End’ is immersive.”

Pink Floyd, Wish You Were Here, HiRes digital: “’Shine On’ has me drifting and then snaps back with the vocals. Really nice. WYWH vocals are really crystal. Bass lines in ‘Have a Cigar’ are just right.”

Dvorak Cello Concerto, vinyl: “Nice soundstage. Deep. Every note is distinct, no blurring. Cellos are uber-warm as they should be.”

Christone “Kingfish” Ingram, Kingfish, digital: “Bluesy and guttural. Each guitar note is distinct. Great detail. Rich vocals. Bass is great, if a little ‘round’.”

Talk Talk, Laughing Stock, digital: “Ethereal. Dream-Like. Gear gets out of the way and I feel like I’m floating on the music.”

The Police, Synchronicity, vinyl: “Toes literally tapping. Sting’s bass is great. Drums are punchy.”

Yo Yo Ma, Six Evolutions, vinyl: “Ultra Rich. The textures are amazing. Very nuanced. The simple staging is clear and apparent. Best I’ve heard this sound.”


If you’re looking for the “tube magic,” the Valve Amplification Company Sigma170i has it and then some. Vocals are warm and rich and highs are extended but never strident. The bass is rich and can be a little loose, but that’s the price you pay for that liquid midrange. Careful setup and speaker matching will need to be considered. Outside of that, this amp is a true performer in the world of tube electronics.

In my listening space, I never wanted for more power than those 85w could deliver, even when listening to very dynamic music. While the speaker taps are listed for 4, 8 & 16 ohms, the fairly flat 6ohm impedance curve of the Joseph Perspective2s never seemed to present an issue (I used the 8ohm taps). In the end, I can say that I enjoyed my time with the Valve Amplification Company Sigma 170i very much.


  1. Nice review – left a clear impression of the sound of the VAC amp in your system. I’ve been an admirer of VAC amps since the first time I heard Thiel speakers with tubes, at a CES a long time ago. A pair of Thiel CS6 speakers, powered by VAC amps I believe in the VAC room. It was perhaps the most intoxicating sound of the show. I eventually re-created much of what I heard using CJ Premier 12 140S/side tube monoblocks to drive the Thiel CS6 in my home. But that put VAC on my radar. (And I’ve been interested in the 200 model for a while).

    And BTW, about your system: You finally did it? Bit the bullet and purchase the JA Perspective 2s? Awesome. Do you mind letting us know how long you’ve had them, and what other amps you have been using with the Perspectives? (Love your room set up, and listening chair!).

    (I have the original Perspectives, hope to upgrade them to the 2s at some point. I use my old CJ Premier 12s. The combination is just fantastic. What I’ve always loved about the CJs is how they combine enough of the classic CJ tube sound to give that richness and shine, but they manage bottom end drive and grip on every speaker I’ve tried, even tough to drive speakers. Bass on the Perspectives is among the best I’ve heard. So rich, sound, yet taught and punchy. “chewy” almost…:-)

  2. Warm greetings to all the staff at ‘Part-time Audiophile’, and what an excellent review of the VAC Sigma 170i Integrated Amplifier!

    However, I’m still trying to wrap my head around the idea of what an amp being offered at a “real-world” price of only $14,000 will mean to all of us going forward into the future! I can remember a time (not that long ago, I might add) when spending even $5k to $10k was considered a ‘huge’ amount of money to spend on any piece of audio equipment! Times they have a changed! 😉

    In any event, I’m writing in regards to the tube (valve) compliment of the VAC 170i. The tube compliment, as listed in the article, is given as “1 X 12AX7, 5 X 12AU7 and 4 KT88 tubes”. However, an examination of the photos of the 170i, in the article, reveals 8 small tubes instead of 6, with what appears to be 3 X 12AX7s instead of 1. I can’t really make out all of the nomenclature on the tubes in the photos, so is it possible for someone to confirm this?

    Anyway, a big ‘Thank You’ to all the staff at Part-time Audiophile for making the magazine such an enjoyable read!

  3. Greetings and great review. What are the red speakers in the 4 photo in your article? Looks to be you had used one of Valve’s advertisement photos? Just curious as they are nice looking.

    • Those are the EgglestonWorks Emma EVO loudspeakers that we reviewed in The Occasional last year. Lee Shelley, our reviewer, is a professional photographer and those are his photos, in his listening room.

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