Tube Power Amp Reviews

Audio Research VT-150 monoblock power amplifier Specifications

Sidebar 3: Specifications

Description: Vacuum-tube monoblock power amplifier. Tube complement: two matched 6550 pairs (output), two 6550 regulators, one 12AX7 regulator, four 12BH7A driver, two 6922 input. Power output: 130W continuous into 16 ohms (24.2dBW), 20Hz–20kHz, with <1% THD (typically !x0.05% at 1W). Approximate power available at clipping: 145W at 1kHz (24.6dBW). Power bandwidth (–3dB): 12Hz–80kHz. Input sensitivity: 2.3V RMS balanced for rated output. Input impedance: 200k ohms. Hum and noise: <0.5mV RMS (98dB below rated output, IHF weighted, input shorted). Power-supply energy storage: approximately 420 Joules. Power requirements: 470W at rated output, 600W maximum, 290W at idle.
Dimensions: 14.5" by 12" H by 22" D (knobs extend 5/8" forward, output connectors extend 1" to the rear). Weight: 62 lbs net, 82 lbs shipping.
Price: $11,990/pair (1994); no longer available (2020). Approximate number of dealers: 65. Warranty: 3 years limited (90 days on tubes).
Manufacturer: Audio Research Corp., Minnetonka, MN 55343-4424 (1994); Audio Research Corporation, 6655 Wedgwood Road N., Suite 115, Maple Grove, MN 55311. Tel: (763) 577-9700. Fax: (763) 577-0323. Web: www.audioresearch.com (2020).

COMPANY INFO
Audio Research Corporation
6655 Wedgwood Road N., Suite 115
Maple Grove, MN 55311
(763) 577-9700
www.audioresearch.com
ARTICLE CONTENTS

COMMENTS
Ortofan's picture
Submitted by Ortofan on January 10, 2020 - 4:20pm

... 40dB below the fundamental, one has to wonder whether you're listening to the music or to the distortion?
Is it those relatively high levels of both harmonic and inter-modulation distortion that contribute to the allegedly "magic" sound quality?

Did RH ever compare the VT-150 with the Threshold S/550e?

Bogolu Haranath's picture
Submitted by Bogolu Haranath on January 10, 2020 - 6:38pm

These ARC VT-150 mesurements are somewhat similar to recently reviewed ARC Ref.160M and ARC Ref.160S (reviewed in Feb. 2020 issue) :-) ........

Bogolu Haranath's picture
Submitted by Bogolu Haranath on January 10, 2020 - 7:18pm

BTW .... A rose by any other name still sounds (smells) the same :-) .........

Bogolu Haranath's picture
Submitted by Bogolu Haranath on January 11, 2020 - 7:54am

Sound to die for (S2D4) :-) ........

JRT's picture
Submitted by JRT on January 11, 2020 - 5:04pm

Not sure how that VT-150 SE differs from the VT-150, but it's interesting regardless.

More commonly the output transformer of an "ultralinear" configured amplifier (eg Dynaco MkIV) simply includes taps on the primary to connect to the screen grids, so those taps share the same B+ power supply voltage with the anodes, which requires suboptimal voltage on the anodes to prevent too much at the screen grids, and that compromise often results in lower than optimal voltage at the anode and higher than optimal voltage at the screen grids with shortened life and degraded performance. This amplifier (at least the SE edition of this amplifier) takes the better approach of providing a separate center tapped winding for the screen grids, allowing those to be operated at reduced power supply voltage than the anodes, which significantly reduces nonlinear distortion and lengthens usable life of the output tubes. Also there are four separate cathode feedback tapes, one for each output tube. For an unchanged level of global feedback, utilizing cathode feedback tapes further reduces nonlinear distortion and reduces output impedance by including the transformer in a local degenerative feedback loop with the output tubes' cathodes.

Lorton's picture
Submitted by Lorton on January 18, 2020 - 3:25pm

I had this amp, worked well on my watt puppies, wounder how it would sound today and if it will hold against current ARC.

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