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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
fiesta75
1,378 posts
 

The 275 is a disappointment. Why would you modify it and not just sell it?

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jbhiller's avatar
jbhiller OP
1,387 posts
 

@funky54,  I'm curious to read the fire from other cites/posts.  Can you put up some links?  

 

fiesta75,  Can you tell us why you believe the 275 is a disappointment?  Did you/do you own one?  What experience do you have with the amp?  What is it about the amp that let you down?  

 

I have no comment on the unit's power output in watts.  I have 102dB sensitive speakers so I don't need much juice.  

Let it rip folks!  Transparency is a great policy.  

Frank, looks like you have some things to answer!

jbhiller's avatar
jbhiller OP
1,387 posts
 

I read the Audiosciencereview site testing and forum posts on this amp.  A couple of thoughts. 

Folks, especially those who tested it, seem very confident that the amp cannot make spec output, uses Edcor PT and/or OPTs, and is a fraud.  

The original testers of the amp on ASR admit they didn't have units with a serial number on them.  Other posters provided pics from Bob Carver's amp camp, a la Nelson Pass type of thing, where you could build one using Edcors as shown in photos.  

The piling on continues for 13 pages.  Will ASR test a genuine model with serial number?  They promise it's coming and things drop off from there.  Let's see. 

Lest I forget, I own this amp and feel it beat out (in my system) a Primaluna HP integrated weighing 55lbs.  I personally never cared for Bob's marketing. But sound wise, I think this thing sounds great.  

Be careful out there.  As Benjamin Disraeli said, "There are lies, damn lies, and statistics!" 

I'm not sure where this will end up on ASR or any site. I do, however, question how valid, comprehensive or meaningful some of this criticism is on the amp.  

I don't think I care enough to crack my amp open again to look at the transformers.

Keep it coming!

PS. I've heard some of the DAC stuff they love on ASR because "it measures so perfectly."  I tried two of them.  They sounded good--not great, not musical.  Kind of like a stereo in a luxury car.  I also wonder how a Fender Bassman would measure.  I bet gobs of distortion.  Thank goodness ASR doesn't supply bands with amps. :)

 

jbhiller's avatar
jbhiller OP
1,387 posts
 

A little birdie told me that the amps subject of ASR's testing were, in fact, $600 kit amps--differing in quality from actual units sold with serial numbers. 

It doesn't come as a surprise that folks over at ASR believe they've uncovered a fraud.  However, surprise element aside, isn't it ironic that those touting science so heavily in high end audio likely didn't do their testing scientifically? 

For the love of all things sacred....If you're going to test things "scientifically" can you  at least (a) buy the unit from a licensed dealer; (b) note the serial number(s);  (c) make sure you know what you are talking about before posting alleged scientific conclusions.  

What's sad to me is that after reading all 13 pages of the ASR forum thread on their uncovering of "fraud", the confidence in their opinions never budges--even after a reputable dealer chimed in to clear some things up.  

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