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: exactly. Several of our forum mates now find themselves in a very uncomfortable position & empathy for them is the order of the day.

 

@mwjones

At the end of the day, I have yet to see anyone on any forum say the amp does not sound fantastic. While it’s tough to see what may have happened, isn’t that why we do what we do in our spare time?

Two separate issues here. 1, Sound quality (Which many have confirmed). May only be capable of good sound quality into high sensitivity speakers with benign impedance load characteristics.

2, Truthful and accurate specification information (Which is seriously being scrutinize). People shouldn’t be led to believe that they’re purchasing a legitimate 75 watt per channel amplifier if they are not (And possibly getting power far below the specified 75 watts). This is wrong, plain and simple. Frank needs to provide a more thorough explanation with actual verified measurements.

Charles

Charles:

I agree wholeheartedly on both points. That post was an oblique statement which I fleshed out moments late.

 

Mike

If you added $3-400 kin parts ,especially coupling capacitors , Vishay naked resistors , better wiring and Thst cheap Chinese crap has no business in a amp of this cost , rule of thumb as a ex Audii dealer only 25% of the cost actually goes into the build including all components, case , and packaging meaning $2500 including even tubes on a $10 k unit , that leaves very little for high quality transformer and chokes .too much greed for a lousy $300 in parts actually $200 or less dealer cost you could have had at least half way decent coupling caps like Mundorf Evo ,or clarity CSA ,that's just taking a piss in my opinion.