Audio Research Classic 150 tube hybrid mono blocks with silver face plates. They have a tube power output. These have balanced inputs only and can only take a balanced input.
I tried using an adapter with a single ended output preamp and these amps weren't having it. No damage done, the relays just flicker on and off. I've been told that is the case with some Audio Research amps and these apparently act the same way.It isn't a flaw, it is just how they are designed. These amps take 8 6550 tubes each. You could also use KT88s or KT120s. The sound output is extremely dark, and the tubes themselves look worn, so they need tubes. All switches and lights on the front do what they are supposed to do. There are some scratches and wear to these.
The tube cages show some minor bends and paint chipping. Some screws missing from the cages. One of the four total fans does not work.I believe these are the 3rd version of these amps because the fans are the German ones. Otherwise, these seem to be working fine.
I have not had these serviced nor do I know of the history. I decided not to have them checked out by a tech, replace the tubes and keep them because they are too big for the small bedroom I rent. I bought them because I saw Audio Research tube monoblocks for sale for less than 2k and jumped on them, figuring I could somehow cram them into my bedroom.
That turned out to be impossible. I can't stress that enough. They are 110 lbs each and I have no ability to lift them myself. I wish I was that strong, but oh well. I can't box them, put them on a pallet, or in anyway move them from where they are without you physically being here to help carry them.
I can barely carry them with another person, so hopefully you are strong. 140 watts minimum continuous at 8 ohms from 10Hz to 20kHz with less than 0.8% total harmonic distortion typically below. Approximate actual power available at "clipping"; 150 watts (1kHz).
Note that actual RMS power output is dependent upon both line voltage and condition i. If power line has high distortion, maximum power will be affected adversely, although from a listening standpoint this is not very critical.
(-3dB points) 7Hz to 100kHz. 6V RMS for rated output. Approximately 0.3dB, 8 ohm load to open circuit.
Less than 2mV RMS 90dB below rated output (broad-bandwidth unweighted, inputs shorted). 105-125 VAC 60Hz (210-250 VAC 50Hz) 650 watts at rated output, 440 watts at "idle". (4 matched pairs) 6550 power output.
19" (48 cm) W (standard rack panel) x 10½" (27 cm) H x 16 (41 cm) D (front panel back). Handles extend 1 (4.1 cm) forward of the front panel. Output connector extends 1 behind rear panel.
(50 kg) Net; 126 lbs. The item "Audio Research Classic 150 Tube Hybrid Mono Block Amplifiers, Pickup Only Please" is in sale since Sunday, July 4, 2021. This item is in the category "Consumer Electronics\TV, Video & Home Audio\Home Audio\Receivers & Amplifiers\Amplifiers & Preamps". The seller is "stuff371" and is located in Newton, Massachusetts.This item can't be shipped, the buyer must pick up the item.