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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
jbhiller's avatar
jbhiller OP
1,387 posts
 

After all this dust settles, let's not forget what the late great Ken Ishiwata said, 

"Unfortunately, specifications don’t tell you about sound quality. That’s not just for DACs, it’s for everything. Those specifications are all based on static measurements, but music is dynamic and there are many other parameters that influence performance."

 

 

I'll take Mr. Ishiwata's view over egghead testing alone.  This guy had a dedicated listening space where he tested and tweaked products on sound quality--albeit he did care significantly about specs too.  

mulveling's avatar
mulveling
1,871 posts
 

@jbhiller

Absolutely, I agree listening results come first. This is specifically about whether Carver needs to down-rate its amplifiers, not whether the amp deserves to exist. Likewise, it raises the question: do we have a problem in the high-end 2 channel amp industry right now? Do we need to look at other companies and how they’re rating amps? Maybe we’ve been too comfortable since the HT receiver "peak power" rating debacle in the 90s / 2000s - back then it was easy to say "haha, HT guys - not my Krell!". What about now?

I hate taking sides with the ASR guys because they’re measurement zealots and (mostly) outright anti-audiophile. The overall theme of that forum is listening tests come DEAD last - which to me, means their real hobby is measurements - not music.

jbhiller's avatar
jbhiller OP
1,387 posts
 

@mulveling , You make great points. I agree wholeheartedly.  I didn't mean to suggest that listening excuses any of this!  You also are on to something, I think, about whether there might be a problem in the market right now. 

I had an NAD M22 amp that Stereophile gave a Class A, glowing rec to a few years back.  It was a wonderful product and I'd recommend it. That aside, even with its hundreds upon hundred of crystal clear watts (it tested ridiculously well), it couldn't beat out a nice Creek Evo Integrated of lesser power, driving all sorts of loudspeakers.  Buying on stats alone wouldn't tell me that.  Why ASR's zealot faction (not all of them) refuses to listen at all is beyond me.  

I've got a 9w tiny tube guitar amp that will but a big grin on a guitarist's face.  It hums, has limited power, and is soooo far from state of the art.  I have guys begging me for it. If you tested it you might be scared to even turn it on.  

Tests have a difficult time testing and relaying information about tone, timbre, etc. Those things matter a bunch not just to how we reproduce music but how we make it in the first place. 

 

mulveling's avatar
mulveling
1,871 posts
 

@jbhiller

Totally agree! Haha that reminds me several years ago - I had 400 Watts/ch Parasound JC1 monoblocks, then VAC Auricle 80 Watt KT88 monoblocks - and picked up a pair of 50 year-old 20 Watt Heathkit W4 mono amps (restored buy Gordon) on a whim. The JC1’s were GREAT amps but I’m almost embarrassed to admit how much I enjoyed those little Heathkits - they were just so sweet sounding and enjoyable. NOS Tung-Sol 5881 tubes. 

Soon I learned the limits of that 20 Watts on my (then) 90 dB speakers (Tannoy Dimension TD10), but it really impressed me how amazing even simple tube amps can be.

funky54
20 posts
 

A couple of other forums that are discussing this subject have noticed this thread. Jbhiller’s shared experience about his transformer is now out there to add to this.

 

It’s funny how all the threads go in a circle about “We’ll,…. It sounds good so it’s a great amp… measurements only tell part of the story” All true from my perspective. But that candy coats the turd… we were lied to. It was intentional. The guys with the 97db efficient horns can feel at ease and keep mentioning it’s a nice amp.. what about the rest of us? I’m 3 ohm at 86 db in a 24x40ish 13’ ceiling room.. think it would sound good at 86 db’s for me? It’s just not right. It really burns me up.  

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