1. Rotate the Crimson/Raven/Silver Seven volume control counter-clockwise to fully turn down the volume. 2. Make sure that your output source (preamplifier, DAC. etc.) is operating correctly and playing. This may require plugging in headphones, ear buds or routing the input device's output to a different amplifier/speaker combination (still have that '90's boom box?). 3. Check the connections between your output device and your amplifier(s). Even pricey connection cables can fail. 4. Check the connections between your amplifier(s) and your loudspeakers. 5. Carefully rotate the Crimson/Raven/Silver Seven volume control clockwise. 6. Call us! This shouldn't happen and we're eager to get you back up and running.

The owners' manuals deal with this. All Bob Carver Corp amplifiers can repair defective tubes if the failure is due to an impurity within the glass bottle--by far, the most common cause of failure. There are two fuses on the back panel. Your "tube" fuse blew to protect the tube and supporting circuitry. No other brand can do this. Replace the fuse and the tube is now "healed" and you may resume your enjoyment with no degradation in perfomance at all!

No, our warranties apply to the original purchaser only. The inherent risk of damage from shipping between owners limits this warranty to the original purchaser.

We do not list damping factor becase, simply put, much of the general population of audio enthusiasts do not understand the lack of importance. The great majority of world-class tube amps, all have an output impedence between one and two ohms. Ours is between 1.5 and 1.8 resuling in a damping factor below 15 for all of these, depending on the brand. We suggest this improves the listening experience. It's important that you realize that the very circuit designs optimizing certain specifications may actully degrade the sound while posting better (meaningless) numbers. Listen to the product and you'll see. In the casse of the Crimson 275, compare it to any amplifier up to around $10,000 and you'll be convinced!

All Bob Carver Corporation products are designed by Bob Carver and built and tested in Illinois, California from domestic and imported parts. Some products use automated assembly process equipment located in Shenzhen.

Bob Carver prefers 80ma which would provide a slightiy larger soundstage and a bit more depth (he's really intro that aspect). We ship at 100ma for a bit more detail and a lttle less of the spacial aspects metioned above. If you change output tubes, check the bias. Note that once adjusted, the bias stays stable and may never need an adustment until the tubes age a bit. You'll not damge the amp no matter the setting.

When playing music, the meter is responding (quite slowly in comparison) to the DC Restorer (a type of dynamic bias supply) preventing DC voltage sag in response to the reactive, dynamic conditions of reproducing music and driving complex variable loudspeaker loads. The DC Restorer is one of the reasons our products drive loudspeakers so well, enabling Bob to create designs that run cool, save weight, reduce cost, and improve performance.

Yes you can. We have updated our business model to internet direct for the greatest customer value. Our Carver Amplifier Challenge, money back guarantee, lets you compare our products to others multiple times our price, in your home making music through your loudspeakers. See The Carver Store above. Challenge our products. The customer always wins!

Yes we can. Bob Carver vacuum tube products are faithfully supported by Bob Carver LLC.. Phase Linear, Carver and Sunfire products are fully supported by our authorized service centers with direct links found on the service page. Bob Carver designs from the early 1970s are still being serviced and proudly serving our customers today.

If they do, they are unknown to us and likely to be accidental. Dr. Carver has a background in physiology, as well as electronic design and engineering and his doctorate is in physics. He developed monoclonal antibodies to fight cancer and infections and established a facility to manufacture the antibodies as well. Every product we make takes the ear-brain interface into consideration. For example, without providing proprietary details, Bob's research is consistent with that of Frank McIntosh, Stu Hegeman, the BBC, the Crown Corporation and Seigfried Linkwitz despite minor differences in application, but Bob has made more products following those precepts than all other companies combined. The goal is the reduction of listener fatigue, imprecise imaging and a small tight soundstage lacking envelopment, depth and openness. All our amplifiers use this technology as did the loudspeakers he's manufactured in the past. For more details, contact Call us at

Bob Carver and his family own Bob Carver today. Bob started this company in Feb 2022 after a company that had been building Bob designs under license, closed during the COVID pandemic late in 2021. Bob came back with some special designs he had made several years earlier that he was anxious to build. Bob is back.

Yes he is. Bob Carver is owner and chief design engineer. Bob's signature is required from concept sketches to CAD models, from prototype to production. Jim Clark is Director of Operations and works directly with Bob and manufacturing.