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

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. 
 

Why does the manual say the transformers are made from fictional steel from Greek mythology or Wolverine’s claws… no kidding right out of the manual. FROM CARVER, there it’s verified.

Two points, 

If you're going to test a component,  ensure you have the authentic model.

At the end of the day the sound quality is the most important parameter for an audio component. It's being purchased to reproduce music, so presumably you care how it sounds, No?

Charles 

I agree listening enjoyment is most important to our hobby. I’m no fan of ASR - they put listening dead last. But outright false claims by manufacturers can also damage the hobby. And I don’t see how these particular amps come close to hitting their power specifications, unless they can break the laws of physics or have a hidden plate amp under those transformer covers. I’m not a stickler for 1% THD being the "clipping" cutoff for power measurement, but it shouldn’t be pushed much more than a few %.

Sure, I’m biased - I had a Sunfire Sig II amp a while ago and hated its sound. Too many aspects of Carver, and these tube amps, set off my BS alarms. Aren’t the tube fuses on these amps even advertised as a tube HEALING feature somewhere? LOL

These amps might well sound good, but it’s looking more and more like they should have been spec’d at a much, MUCH lower power. Now where’s the value? Plenty of low power vintage amps that sound wonderful. EL84, 6L6, and EL34 tubes are hard to make sound bad.

yep, sonics matter..but so does ability to drive a speaker… so no speaker, no music. The specs are useful in assessing current and future suitability to drive various speakers….

Having said that, i am guessing the Music Reference RM-10 , also a lightweight gives the Carver a run for the sonic money…..Modjeski like Carver a genius…

@mulveling

These amps might well sound good, but it’s looking more and more like they should have been spec’d at a much, MUCH lower power. Now where’s the value? Plenty of low power vintage amps that sound wonderful. EL84, 6L6, and EL34 tubes are hard to make sound bad.

I’m not disagreeing with you, perhaps the specs are inflated and I do not support that. The OP and others posting here say it’s a very good sounding amplifier, to me that means something. ASR seems to care little (If any) about how a product sounds. What do you hear? That’s the essential question.