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Bob Carver Crimson 275 Tube Power Amp *Manual *Box

Bob Carver Crimson 275 Tube Power Amp *Manual *Box

Regular price $2,500.00 USD
Regular price Sale price $2,500.00 USD
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In design for over one year, the white knuckles screaming amp, outperforms amps priced at 5 times the cost of the Bob Carver Crimson 275! Very closely the Crimson 275 performs next to our 350 series monoblocks which sell for $9,500 pair!

Bob Carver holds more audio patents than 31 Flavors Ice Creamery.

Bob’s unique DC restorer circuit offers much lower distortion – extended tube and amplifier life.

Bob Carver 275 Stereo Amplifier Logo

Totally seriously cool!

Bob’s amplifiers run really cool. Heat Kills the electronics, not the Crimson 275 – 75+75 Watts Per Channel. Realiable, robust, amazing sonic performance.

There is a meter on the front of the amplifier which indicates the health of the tubes — get a bad reading, get free tubes! Aside from the extended circuit and tube life, it’s the sonics that blew us away. One of the reasons for this is our proprietary use of two separate feedback loops. One, typical of what you’ll find in many fine amplifiers, ensures stability and linearity. But the other is quite fascinating.

An amplifier that actually listens to the room.

All loudspeakers generate voltage as they play. It’s generated from the driver movement necessary to reproduce music but also all loudspeakers technically “listen” to the room. 

Loudspeakers are electric motors. Electric motors all kick voltage back to the power source whether it’s a loudspeaker, a refrigerator or an electric drill.  Manufacturers of line conditioners have a point. Your refrigerator motor not only adds noise to the AC line, they actually send electricity back through the wall outlet. We call this Back-EMF.

With a tube type amplifier, when back EMF appears at the output terminals, to the loudspeaker the output transformer’s secondary becomes a primary! The back EMF enters the amplifier through the transformer and affects frequency response downstream. With ordinary tube type amplifiers, speaker matching becomes critical. Our amplifiers are load-invariant. Through decades of experimentation and some pretty heavy mathematics, Bob Carver has been able to use the Back-EMF to increase efficiency in the mighty SunFire subwoofers, and to improve the soundstage and openness of his full range amplifiers.

This is done in a unique fashion, and, as in the case of our extended tube life, unique to our products. The amplifiers listen to the room through the loudspeakers and preserve a large soundstage. It took literally decades to get the circuit right without creating artificial coloration. If you’re concerned about naturalness, consider that Harry Pearson, the founder of Absolute Sound Magazine, noticed this phenomenon, pointed out to Bob (who already knew about it) and kept our Silver Seven amplifiers as his personal reference for years. Dick Olsher from Stereophile Magazine called this series the most important tube amplifiers in decades.

Crimson 275 Stereo Tube Power Amplifier


  • 75 x 75 watts into 8 ohms

  • Under 2-ohm capability

  • Tubes

    • 12AX7 x 2

    • 12AT7 x 1 (part of DC Restorer circuit)

    • Tung-Sol KT120 x 4

  • Output Transformer

    • Proprietary design with hand-wound, interleaved windings of copper and silver on a steel core; low leakage inductance, super wide band

  • Four-function meter

    • Bias setting (in conjunction with rear panel control)

    • Tube Tester (tests at actual voltage and current conditions)

    • Tube Matcher (cool, but not really necessary)

    • VU Meter

  • Rear Panel

    • Power Switch

    • IEC AC Input Socket

    • Line Fuse

    • Tube Fuse

    • Recessed Tube Bias Control

    • 5-way binding post outputs

    • Gold-plated 5-way binding posts

    • XLR Input and gold-plated RCA Input

    • 40Hz crossover switch

  • Crimson hand-rubbed finish

  • Convection cooling

  • Individually hand-signed by Bob Carver


Rated Power:
More than 75 Watts Per Channel, both channels driven at eight ohms, from 20Hz to 20kHz with no more than 1% total harmonic distortion. Distortion decreases at lower levels.

4Ω       75 Watts Per Channel

8Ω       75 Watts Per Channel

16Ω     60 Watts Per Channel

Frequency Response:
+0, -3dB from 16Hz to 35kHz.; Flat 20Hz – 20kHz ±0.25dB

Less than 1.0%

Power Bandwidth:
24 Hz to 28 kHz without filters

Line Inputs:
Left/Right gold-plated RCAs

Speaker Outputs

Gold-plated 5-way binding posts

Input Impedance:
100 Kohms (RCA)

29 dB (8 ohms)

Tube Complement:

One 12AX7, two 12AT7’s, four KT120’s (optional: KT88 or 6550)

Hum and Noise:
Better than 100 dB below 75 Watts, A-weighted.

Rear panel potentiometer adjust,  front panel meter

Output Transformers:
Interleaved windings, super wide-band, low leakage inductance, proprietary design

Source Impedance:
1.7 ohms

Crossover Roll-Off

Optional —3dB @ 40Hz, 6 dB per octave

Sparkle Burgundy Red


14″ x 7″ x 9.5″ (W x H x D) / 19 lbs

Country of Origin:
United States of America

Chassis and Tube Warranty:
5 years

Specifications subject to change without notice.

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