It seems tube amps, power amps, and headphone amps are back in the ‘almost’ mainstream. I haven’t heard a high-quality tube power amp in many years, but my ears feasted on this new amp from LSA, an 80 watts per channel behemoth that puts out glorious-sounding music for not a lot of money. In fact, it’s competitive in price with high-quality solid-state designs.

LSA VT-150 80 WPC Power Amplifier

At $2995.00 this tube amp compares in specs and in sound quality with higher priced tube amps, some selling for 2 to 3 times the price. Currently, as the amp is being introduced, it is selling for $2499.00 making it an even better deal. I heard the amp driving different sets of speakers, on a variety of program material. It’s dead silent when it is not playing anything, and when it is playing music, it is silky smooth with an excellent low end. The mid-range is engaging, and while I was pretty neutral on tube amps before I auditioned this amp, you’ll now find me enthusiastic. I’ll get into details about the sound later in this review.

Highlights

LSA VT-150 80 WPC Power Amplifier Highlights

  • The LSA VT-150 has a smooth frequency response and low distortion.
  • It can drive most speakers to very loud volumes.
  • The build quality of the VT-150 is excellent.
  • A bargain for this audio and construction quality at a low comparative price.
  • The amp is very heavy at 80 pounds.
  • A black faceplate would be a nice option for those who don’t want silver.
  • Meters are small.
  • No trigger functionality.
Introduction

The LSA VT-150 should get a lot of attention from audiophiles. A bit about the company that has produced it. LSA (Living Sounds Audio) is part of Underwood HiFi. Their products are designed in the USA, then made in China to LSA’s specifications, and sold directly to customers. This amp, however, was designed by the ex-Chief Engineer of Line Magnetic, in China. Their varied products, including power amps, turntables, speakers, and phono stages have been very well reviewed and are pleasing customers for their physical and audio quality. The company is run by and was founded by Walter Liederman, a 50-year veteran of high-end audio, who consulted in the past for companies like Infinity and Acoustic Research.

I go way back with tubes, having, in the dim past, built a few Dynaco Amps, and listened to hand-me-down tubed components from my grandfather and dad from Fisher and Sherwood.

I liked the sound of tubes back then, but there wasn’t anything else to hear. It was tubes or nothing. When solid-state amps came out they quickly became all the rage, but audio engineers I knew whom I considered knowledgeable stayed away from the early solid-state stuff saying it sounded brittle and wasn’t all that reliable.

It was like the early days of the CD. They were very convenient and had an extended frequency range, and no pops and clicks, but the early releases sounded terrible. The industry learned how to improve CDs, and solid-state amps, but over the last several years a significant percentage of audio enthusiasts were turning away from CDs and moving back to vinyl, and the same thing is happening with amplification. Tubes are having a surprising renaissance.

Listening to the LSA VT-150, I thought, was a good way for me to hear a tube amp in my system, and hear for myself the differences, if any.

LSA VT-150 80 WPC Power Amplifier Tubes

LSA VT-150 80 WPC Power Amplifier Specifications
Inputs:

RCA and XLR balanced inputs

Power Output with KT88Tubes:

55W +55W Stereo 110W Mono

Power Output High Bias:

80W +80W Stereo

Power Output with KT150Tubes:

100W +100W Stereo, 200W Mono

Distortion:

1% @ 1kHz

Frequency Response:

20Hz-40kHz

Input Sensitivity:

1000mV

Input Impedance:

100kΩ

Output Impedance:

4Ω and 8Ωtaps

S/N Ratio:

88dB

Standard Tubes used in the Amplifier:

12AU7×2, 6SN7×2, KT88×4, KT150 tubes are optional.

Switches:

Front-mounted volume control – Can be used as an integrated amp.
Front-mounted RCA/XLR switch.
Power meters that also do bias

Outputs:

4- & 8-ohm outputs

Voltage:

Switchable voltage

Weight:

80 pounds

Size:

17” w x 14″d x 9”h with removable tube cage in place

Shipping size:

22″w x 20″d x 14″h

Warranty:

2-year warranty/ 6 months on tubes

MSRP:

$2999.00 but $2499.00 during an introductory period

Company:

Underwood HIFI

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Design and Features of the LSA VT-150

LSA VT-150 80 WPC Power Amplifier Backpanel Inputs

As mentioned, this is a lovely amp to look at. It is built solidly, with a silver faceplate and 2 VU meters used to monitor audio output and for biasing the tubes. There is a piano black cage to protect the delicate tubes, and on the backside, there are RCA and XLR inputs for your preamp or other sources. A switch lets you choose between the two. The speaker connectors offer 4- or 8-ohm taps to best match your speakers.

LSA VT-150 80 WPC Power Amplifier Backpanel Speakers

Front panel switches include power and a switch to illuminate the meters or turn them off. There’s a switch to choose meter mode or bias mode, and on the top plate, there are openings for a screwdriver to do the bias adjustments.

LSA VT-150 80 WPC Power Amplifier Power

LSA recommends bias be adjusted out of the box, so after listening for a few minutes first, I checked the bias and the tubes seemed fine without adjustment.

LSA VT-150 80 WPC Power Amplifier bias

The tube biasing is going to be an extra step for listeners used to solid-state gear, but it’s not difficult. If you replace tubes (they don’t last forever, and run quite hot), you’ll need to run the bias setup again. And it’s probably a good idea to check the bias as the tubes age.

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The power output of the amp varies with the tubes used. The LSA VT-150 ships with KT88 tubes which offer up to 80 watts per channel. With optional KT150 tubes (not offered by LSA), you can get 100 watts per channel. I did my listening with the stock tubes.

The front panel of the amp sports a volume control, allowing you to use the amp without a pre-amp. It’s always in circuit, even when the VT-150 is used as a straight power amp.

LSA VT-150 80 WPC Power Amplifier volume

Other than the bias adjustments, connecting the LSA VT-150 is no different than connecting a solid-state amp.

Setup

The amp was packed very well. But buyers will be surprised to learn that this is one heavy amplifier. I expected to simply lift the amp out of the box, but I could tell from the resistance my old back was getting I was going to need help. I called a friend, who mocked me because I could not get the amp out on my own. He tried and had the same result. The amp was not simply going to easily come out of that box.

We were able to get it out together (still no easy task) made a bit more complex because most of the weight of the amp is in the back half where the transformers are, giving the amp a heavy list toward the rear.

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We were able to get it on my stereo cabinet, and after affirming the connections were good, I replaced my trusty Emotiva XPA-2 amp with the LSA VT-150. The Emotiva amp was wired with XLR connectors, so it was an easy matter to plug those into the VT-150, and since my speakers were wired with banana plugs, it was an easy switch between the two amps.

LSA VT-150 80 WPC Power Amplifier rear view

Listening Tests

My audiophile friend and I listened for about 15 minutes, but something did not smell right. I removed the tube cage and realized the tubes were wrapped in plastic styrofoam covers to protect them. That’s what smelled. Silly me, but a note in the manual might have been nice to tip me to the covers. It was then (after the amp cooled down) that I did the bias check, and it was fine.

Most of my listening tests were done on Ohm Walsh 2000 speakers. Normally I listen with surround speakers engaged, but I turned on the stereo mode so all I was hearing was the VT-150. It sounded really good. A full and musical midrange, sparkling highs (a bit of a surprise), and solid deep bass. The highs surprised me because the conventional wisdom was the solid-state amps excelled at high frequencies, but the VT-150 was clear as a bell.

There was a clear difference in sound between the VT-150 and my solid-state amp. The tube amp was not ‘better’ than the solid-state amp to state it objectively, but it sounded different, and the difference was pleasing.

I’d liken it to the differences between two violins made by different companies, or a brass instrument, or even a kick drum. Each instrument, while on the surface is the same, but each reflects a different approach to the sound, and that’s what we have with the VT-150.

My solid-state amp is more analytical, and to some, that’s a plus. To others, the detail offered is not as musical.

My own extended listening to the VT-150 left me feeling the amp was very good. It was very, very musical, and if I had to abandon my solid-state amp, I would not feel I’d lost anything, and perhaps gained something that let me hear more of the inner beauty of the recorded sound.

I listened to a lot of digital sources, but also played some analog tapes back on my vintage Teac reel-to-reel. It seemed a fitting way to feed the VT-150: analog in and analog out.

The results were pleasing and took me back many years to my listening to reel-to-reel tapes in my college years on my Dynaco tube amp and KLH speakers.

In general, I liked acoustic music the best on these speakers. Rock and roll not so much. That’s not to say rock and roll sounded bad, it’s just that I thought the VT-150 was excellent on acoustic music, vocals, and live concerts.

Symphonies, small ensembles, and choral music recorded in large venues sounded just great. So did folk music and jazz, instrumental or with vocals.

Here’s a quick sample of my listening experience.

Original Soundtrack

Original Soundtrack “How The West Was Won”

A reel-to-reel recording on analog tape. Sounded wonderful on this amp and speaker combination. Orchestra, a large chorus, and percussion sounded visceral and real even in this 1962 recording.

Alexander Desplat

Alexander Desplat “Isle of Dogs”

A powerful soundtrack recording. Lots of deep percussion here, and I thought the dynamics might trip up the VT-150, but it didn’t. I was struck by this recording, and others, how after a loud drum hit, you could easily hear the realistic decay just as you would in a live performance.

Simon and Garfunkel

Simon and Garfunkel “Sounds of Silence”

A recording from Columbia’s heyday in the 60s. This recording of voices and acoustic instruments sounded palpably live. The VT-150 gave no ground to my modern solid-state amp and to my ear bested it.

Rebecca Pidgeon

Rebecca Pidgeon “The Raven”

A great jazz vocalist recording I often use for testing. Again, the female voice sounded very real here with excellent imaging of the accompanying instruments.

Flint Juventino Beppe

Flint Juventino Beppe “Remote Galaxy”

A large-scale classical recording. It sounded big, with solid dynamics and nice imaging. Was the good imaging a function of my excellent speakers or the amp? I think it was both, working in tandem.

Conclusions

LSA VT-150 80 WPC Power Amplifier above view

I think this is a very high-value amp at an attractive price when you consider the competition. Tube amps are very expensive; with similar specs and features to the VTA-150 expect to pay a lot more. The VT-150 will be beaten in price by excellent lower-priced power amps from companies like NAD with similar power, but if you step up to more esoteric solid-state ultra-high-end amps the prices will be similar or higher than the VT-150 without necessarily better sound.

Likes
  • The sound is excellent, especially on acoustic music.
  • For the sound quality and build quality, the amp is a bargain that will please audiophiles.
  • It’s easy to set up, even with the addition of bias adjustments.
Would Like To See
  • A trigger feature so the amp can be switched on, like most solid-state amps, with a trigger cable.
  • A black or darker face plate
  • Better looking, larger meters

I wasn’t sure what to expect when I started this review. In the back of my mind, I figured my modern solid-state amp would be preferable, but with extended listening, I came to like the sound of the VT-150. It may be that the slight loss of detail to my analytical solid-state amp gave the VT-150 a smoother more relaxed sound. It’s truly hard to express why the VT-150 sounded so good.

I’ve begun to understand what tube fans like about these components. While ultimately choosing this amp over a solid-state amp may come down to a matter of taste rather than specs. For example, on paper, the VT-150 has a bit more distortion than my solid-state amp. It’s 1% at 1000 Hz, but I could not hear it, and music emerged from my speakers with no colorations I could detect from the amp. Another bonus is that it was silent when nothing was playing. My old tube amps were pretty noisy, with some hiss and low-level hum.

The VT-150 can warm up a room, as all tube amps can, so new owners should be aware of the heat. Don’t put this amp in an unventilated cabinet.

Given those warnings, the VT-150 is musical, never seemed to strain or garble complicated passages of music, and did not cause me any listening fatigue.

I found the silver front panel attractive but would have liked to see a version in flat black. The meters are nondescript. I think something more stylish, and easier to see from a distance would be an improvement. The meters feel a bit tacked on and utilitarian.

LSA VT-150 80 WPC Power Amplifier VU

Potential buyers should be aware that tubes fail eventually, and replacement tubes can be expensive, so replacing them should factor into your equation about costs. Solid-state amps do not need the care that tube amps can require. An advantage of this design is that you don’t need matched sets of tubes because using the bias control, output tubes can be biased individually.

Having said all that, I give the LSA VT-150 a very high recommendation.