Peeking inside a Carver Crimson 275 Tube Amplifier


So, I just had to pop the hood on the Carver Crimson 275 tube amplifier. I was so curious as to how this little guy weighs so little and sounds so lovely.

  • The layout is simple and clean looking. Unlike the larger monoblocks (that cost $10k), this model uses a PCB.
  • The DC restorer circuit is nicely off to one side and out of the way. It doesn’t look all that complicated but I’m no electrical engineer. Why don’t more designers use this feature? It allows the power tubes to idle around 9.75w. Amazingly efficient.
  • The amp has very good planned out ventilation and spacing. No parts are on top of each other.
  • Most of the parts quality is good. There’s a host of Dale resistors, what look like Takmans, nice RCA jacks, heavy teflon hookup wire, and so on.
  • Some of the parts quality is questionable. There’s some cheap Suntan (Hong Kong mfr.) film caps coupled to the power tubes and some no name caps linked to the gain signal tubes. I was not happy to see those, but I very much understand building stuff to a price point.
Overall, this is a very tidy build and construction by the Wyred4Sound plant in California is A grade. I’m wondering a few things.

Does the sound quality of this amp bear a relationship to the fact that there’s not too much going on in the unit? There are very few caps--from what this humble hobbyist can tell--in the signal chain. And, none of these caps are even what many would consider decent quality--i.e. they aren’t WIMA level, just generic. This amplifier beat out a PrimaLuna Dialogue HP (in my room/to my ears...much love for what PrimaLuna does). When I explored the innards of the PrimaLuna, it was cramped, busy and had so much going on--a way more complicated design.

Is it possible that Bob Carver, who many regard as a wily electronics expert, is able to truly tweak the sound by adding a resistor here or there, etc.? Surely all designers are doing this, but is he just really adroit at this? I wonder this because while some parts quality is very good to excellent, I was shocked to see the Suntan caps. They might be cheaper than some of the Dale resistors in the unit. I should note that Carver reportedly designed this amp and others similar with Tim de Paravicini--no slouch indeed!

I have described the sound of this amp as delicious. It’s that musical and good. But, as our esteemed member jjss [ @jjss ] pointed out in his review, he wondered if the sound quality could be improved further still. He detected a tiny amount of sheen here and there [I cannot recall his exact words.] even though he loved it like I do.

I may extract the two .22uF caps that look to be dealing with signal related to the 12at7 gain tubes and do a quick listening test.
128x128jbhiller

Funky54, I think you are making a big assumption, which may be true or it may not be true.  That assumption is that ASR's testing was accurate and that it actually had a Crimson 275.  

The models ASR tested did not have serial numbers.  The build quality from pictures is not consumer grade or fit for resale.  

Did you know Wyred4Sound makes these amps for the Carver Corporation?  They must be in on the scam too. 

Look, if the Company made material misrepresentations then that is terrible. But don't you, or the numerous folks piling on the ASR forum recognize how absurd this would be?  It would be one thing to miss your specs by a bit.  Here, if ASR is correct then the Crimson 275 only makes 22% of its specified output.  

The Crimson 275 drove Kef Blades at Axpona a few years back with pleasant results.  Maybe they just love 17 watts of power to get them to sing.  I suppose that's possible.  I once had LS50s linked to a 300b SET and they sounded pretty good.  

I did drive Wharfedale Linton Heritage speakers with the Crimson too.  They are reportedly 90dB efficient and 6 ohm nominal impedance.  Had gobs of power for those loudspeakers. Maybe 17 watts is all you need.  

I used to play around with vintage tube amps. Lovely sounding amps, in the range of 20 - 35 Watts. With 90dB speakers, an honest 20 Watts is plenty to drive them quite loud for LOTS of music. It'll even sound very pleasing, too - good to the last Watt, so to speak. In an intimate setting, with a controlled playlist (lots of Krall etc) you may never want for power. The could even play dynamically compressed rock recordings very loud (and they weighed more than the Carver, btw). But it would run out of power in a hurry once you started cranking more dynamic material. 

Modern push/pull amps with KT120 are SUPPOSED to give you all the power and overhead you need, at meaningfully low distortion levels, with a good dose of the tube sound if not the full boat E84/6L6/EL34 "sweetness".

Kinda silly.. doesn’t take an engineer to look up the transformer part number and see it’s only rated for 15 watts. . Doesn’t take an engineer to measure output at only 15 to 17 watts per channel.. pick on science nerds all you want. 

Well, it doesn't take an engineer to throw out all of ASR's testing and your conclusions because the amps in question are not shown to be actual amps built by Wyred4Sound for the Carver Corporation.  The logic above and at ASR is dime store at best.  But, hey, if it turns out Carver puts a 15w OPT from Edcor in its amps and they cannot actually come close to spec, then yes that's a problem. 

It's clear folks are assuming what they seek to prove.  I'm not an engineer--I'm a lawyer.  Such conclusions would never make it into the record from a law perspective (which is a way lower threshold than scientific method).  Think about that.   Hey, this vacuum cleaner is defective Judge and killed my wife.  My expert says its wiring was faulty.  Judge:  But you cannot say the vacuum actually came of the manufacturer's line.  You can't cite to a bona fide serial number on the vacuum. 

I will say, however, Frank Malik should step up and explain this away (if he can) as folks are coming with pitchforks for his brand.