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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
1,386 posts
 

Sad results.  The machine Amir at ASR reviewed had worse build quality than mine, in the form of super high gauge wire going to the speaker output terminals, a missing bolt, and so on.  Disgraceful. 

Mine also has no chassis grounding, which is a touch scary given the voltages in the unit. 

Mine has the slots on the PCB, C4 and C19 (going by memory), missing the actual caps.  The ASR review sample has caps in those slots, but they are mounted on the other side of the board.  ??????? 

Whatever wattage this thing makes sounds good into super sensitive speakers. But thanks to the teardown, we can see the OPTs are just 15W Edcors.  

What is going on with the differences in build quality? 

Why is Music Direct (and other retailers) no longer selling the product? Hmmm...

Why is Jim Clark, a dealer, defending the product, but there are circuitous and scant responses from Frank Malitz, Wyred4Sound, and even Bob Carver?  

I questioned the build quality on certain areas, as a hobbyist.  Now, it is more than confirmed that there are multiple more questionable things going on, and the marketing of the product is totally wrong and misleading. 

 

charles1dad's avatar
charles1dad
10,250 posts
 

@jbhiller 

Why is Jim Clark, a dealer, defending the product, but there are circuitous and scant responses from Frank Malitz, Wyred4Sound, and even Bob Carver?  

I questioned the build quality on certain areas, as a hobbyist.  Now, it is more than confirmed that there are multiple more questionable things going on, and the marketing of the product is totally wrong and misleading. 

Absolutely +1.

Charles 

jbhiller's avatar
jbhiller OP
1,386 posts
 

I'm off to Discogs to do some "retail therapy", and buy some nice pressing that will make me smile and stop thinking about what a mess Bob Carver's amp appears to be. 

grovergardner
6 posts
 

I'll suggest some evaluation at this point.  IMO, the amp is cleverly designed to provide 17wpc continuous across the bandwidth at low distortion, with some pretty fair peak power into 8 ohms.  It's a "concept" amp, and as such it succeeds, IMO--a clever design, light weight, large under-biased output tubes that will last for years, current feedback to adjust for low-frequency speaker impedance swings.  Many people say it sounds great--and it probably does in many circumstances.  My old ProAc Response 2's only need 15 wpc to sound really nice in my room.  With the peak reserve, they'd probably be very happy with the Crimson (now Raven, apparently).

The problem is that the amp is sold at 75wpc 20Hz-20kHz at less than 1% distortion.  The amp clearly cannot meet those specs.  Jim Clark claims that only the sound matters--and he's right in some respects, but audiophiles aren't stupid.   Sound matters, but so do honest specs.  So Jim is in a terrible position.  An example of honest marketing from the days of yore was posted above, with an eye on the intelligent buyer (and he had to have some deep pockets back then) who valued technical competence as well as sound.

jbhiller, the only answer is, does the amp work for you at the price you paid?  

Many years ago, I built a pair of single-ended 845 monoblocks for a friend.  He uses them with some old Gallo towers (remember those?)  By any technical measure they shouldn't have worked--but they do, and he still uses them with great pleasure.  No less than David Berning actually paid me a compliment on the amps.  So there are anomalies in this world of audio.

 

grovergardner
6 posts
 

OMG!  I just noticed you have a Doge DAC 7!  I LOVE mine.  I only know one other person who has one.  What tubes are you using in it?

But regarding the Crimson, I'll bet a case of nice Oregon wine that a classic Williamson--like the Heathkit W2, W3 or W4--would beat that Carver hands down on your Cornwalls.

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