Amp/Preamp Asylum: REVIEW: Audio Research, Inc. Classic 150 Amplifier (Tube) by scousepasty

Model:	Classic 150
Category:	Amplifier (Tube)
Suggested Retail Price:	$10,000
Description:	Hybrid Monoblock Amplifiers
Manufacturer URL:	Audio Research, Inc.
Manufacturer URL:	Audio Research, Inc.

Review by scousepasty ( A ) on April 26, 2007 at 05:20:14
IP Address: 163.121.179.183

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for the Classic 150

I have owned 2 x ARC Classic 150's for more than 8 years. I had them modified and upgraded with Pabst motoren,Germany, type 4840n fans, hard wired mains cables & NOS G.E. 6550A valves by Anthony Matthews of Tube Distinctions in Wales, UK. He achieved a large reduction in the noise floor of these amps, most notably by changing the cooling fans, the originals were sourced from Taiwan by ARC and I see that their new amps are now fitted with Pabst fans, so enough said about quality issues there!
I use the amps in my second system which is bi-amped through powered cross-over. ARC Classic 120's feed Gradient SW63 subwoofers, and the Classic 150's feed Quad ELS 63 electrostatic panels. Beware that these amps are heavy and have heavy mass power transformers and develop a lot of heat, so they need good ventilation fans and air circulation.
They can be a little tempremental at times and will mute if surface noise, musical transients / sibillance is high on the vinyl being played.
I have tried different valves - mostly Sovtech, etc, but have always come back to the G.E. 6550A's. They have an edge on bass and speed. Biasing the valves regularly is critical to amp performance and is not the easiest thing, considering weight of the amps to lift to a position were it is safe to access the adjustments and needs you to have a Fluke digital meter or similar quality.
I play mostly Opera, Classical and Jazz on this system, with occassional Country music and prefer that little warmth that these amps add to the music over S/S. They need a warm-up period of about 1 hour before sounding at their best but then produce a astonishing depth and width to the musical stage. Vocals are flowing and instruments are all placed as recorded, with good channel seperation.

Product Weakness: OEM fans were noisy and OEM power cable can be improved upon.
Weight and fragility of front panel flick switches.
Product Strengths: Build Quality.

Associated Equipment for this Review:
Amplifier:	ARC Classic 120 used with electronic cross-over
Preamplifier (or None if Integrated):	ARC Ref
Sources (CDP/Turntable):	VPI HRX
Speakers:	Quad ELS 63 / Gradient subs.
Cables/Interconnects:	Nordost Power cables. Van den Hul Interconnects.
Music Used (Genre/Selections):	Vinyl - Opera, Jazz, Classical
Room Size (LxWxH):	30 x 24 x 8
Room Comments/Treatments:	Heavy furnishings and carpet.
Time Period/Length of Audition:	5 years.
Other (Power Conditioner etc.):	Russ Andrews wall sockets, earth cable.
Type of Audition/Review:	Product Owner
Your System (if other than home audition):	See inmates systems.

Product Weakness:	OEM fans were noisy and OEM power cable can be improved upon. Weight and fragility of front panel flick switches.
Product Strengths:	Build Quality.