ST-150 Stereo Amplifier


Over 150 watts per channel (300 watts of stereo power), this stereo amplifier offers superb musical clarity and plenty of power in one compact chassis. Utilizing the finest quality parts, and entirely hand built by experienced craftsmen, the ST-150 is VTL’s offering of a high value, high power stereo tube amplifier. The noted VTL quick, clean, musical sound and exceptional bass punch is delivered here by the 6550 tubes. Exceptionally well suited to triode operation, yet they are also very dynamic and fast in tetrode mode, these VTL amplifiers are well-suited to smaller electrostatic panels and dynamic speakers not requiring high current. For commanding performances on the midrange and clarity on the top, VTL wins hands down. In triode mode, the amp is best suited to speakers with an efficiency of 92dB/1W/1m or higher.
ST-150 top view
ST-150 back view

Functionality features

  • High energy storage power supply >200 joules
  • VTL proprietary output transformer
  • Very low-noise floor with specially designed grounding scheme
  • Tetrode/Triode Switchable
  • 150 watts per channel in tetrode
  • 70 watts per channel in triode
  • 4 6550 tubes per channel with individual bias setting for each tube
  • Audiophile grade film and foil caps used in the signal path
  • Extruded aluminum front panel with luxurious, modern look — black and silver options available


pdficon_smallS-150 Data Sheet

Technical Specifications

Vacuum Tube Complement 8 x 6550, 2 x 12AT7, 2 x 12BH7
Output power
Tetrode: 120W, Triode: 60W
20Hz – 20kHz <3% THD Into 5Ω
Input sensitivity @ 150W 100V = 0.880V; 120/240 = 1.0V
input impedance 130KΩ
Output Load Range 2Ω – 8Ω
S/N Ratio -95dB, 120Hz
Power Consumption Idle = 240W, Full Power = 800W
Primary Mains Fuse Rating 100V = 15A Ceramic Slo Blo, 120V = 15A Ceramic Slo Blo, 220/240V = 8A Ceramic Slo Blo
B+ Fuse Rating 1A fast acting ceramic 600V
Dimensions W x D x H 19 x 12 x 9 inches (48 x 30 x 23 cm)
Weight 85lbs (38.6Kg), 110lb (50Kg) packed

VTL ST-150 Review | SOUND PLUS

“… one of the rarest tube designs …”

“The power amp continues the VTL tradition, succeeding in the recipe of getting the advantages of the tubes with some of the positive elements of transistors.”

“In tetrode mode the ST-150 has a particular muscular and phantasmagorical sound. We would describe it as Technicolor with shiny timbres, surgical detailing , building a huge soundstage spacing all the musical images with incredible accuracy.”

“Changing the function mode in triode, the sonic character changed. It turned to a pure tube design with all the sweetness and magic we expected from a very good tube having all the dense timbres that enchant us in the triode tube.”

“The tube pair (ST-150 and TL2.5i) from VTL superbly serves the music in every genre, the preamp maximizes all the connected sources and the power amp adjusts to all our needs and tastes with the triode and tetrode function. If you seek excellent tube equipment in this price category do not forget to audition them. They might be exactly what you need.”

Read the full review here…

- Katsen Telema VTL TL2.5i and ST-150 Making Tubes Great Again” SOUND PLUS 02 (Greece,) February 2017

VTL TL-5.5 Series II Signature Preamplifier and ST-150 Power Amplifier Musical Soul

… But beyond this sensation of the musicians’ presence is another kind of harmony created by these designs, the kind that, taken altogether, creates a seamless sense of bottom-to-top tonal coherence, dynamic push, and resolution to create a thrilling sense of aliveness and of the music-making process.

… for these ears (and this heart) VTL’s TL-5.5 Series II Signature preamp and ST-150 power amp are remarkably successful at delivering on all fronts—thrilling in the ways that can arouse the latent audiophile within while drawing him deeply into all spectra of music.

Read the full review here…

- Wayne Garcia, The Absolute Sound, March 2015

VTL ST-150 Test | Tube Heaven

… Plus:
– Sound to remember and which one would wish to own, for those who can afford it
– Atypical tube experience
– Great reproduction of human voice
– Extraordinary bass
– Hand made in the USA …
Read the full review here…

- Zoran Karapandzic, Hi-Files, No.33, Serbia, January 2010

Pre/Power Amplifier | VTL TL5.5 Series II Signature/ST-150

…Every kick, the stretching of the heads, the snap of the sticks – this is indeed visceral sound. VTL has delivered a package that can segue seamlessly from the sweet harmonies of a doo-woop quintet to the in-your-face slam of power rock…

…What matters is the sheer silky naturalness of the sound, matched by the authority one demands of units costing far more. Robust yet refined, well built – this is pure class. Read the full review here…

- Ken Kessler, Hi Fi News, UK, July 2012