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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
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.

jbhiller's avatar
jbhiller OP
1,403 posts
 

@grovergardner , You are the voice of reason and a wealth of knowledge.  Many folks hop in to spew diarrhea of the mind with no point, or only to criticize.  This is, after all, a passionate hobby for most of us!  Thank you!

I'll take you up on that bet--just for fun.  I'd love to hear and nice W2, 3, or 4.  My 300 B (Elekit) sounds great on the Cornwalls, but at 8 watts it could use a bit more in my room--and I don't listen that loud.  While the C-Walls are super efficient, I do think they like a bit more wattage than flea or minimal SET to get moving---that's only based on listening. 

Yes, the Crimson does sound very good with the C-Walls. It's just sad that they did what they did with it.  Maybe I'lll fix the problems: add a chassis ground, install a backlit meter, and upgrade a few other things, including isolating the transformers a bit.  

And finally, I do own a Doge DAC 7.  People don't believe me how good it sounds.  It is stellar. The build quality on it crushes things people pay $5k for and then some.  I've mated it with all sorts of preamps and integrated. It plays well, always.  

I also own the Doge Clarity preamp.  All Clarity caps throughout the signal side of things.  Doge sources parts from all over the world and surprisingly few are Chinese.  Most are German, Swiss, British, Japanese, and US.  The build quality here is stellar too.  There's a few nits to pick but at $2k it can play with preamps costing twofold its ask.  

I think my real woe with the Crimson is (a) not likely being able to pair it with less efficient speakers; and (b) a sadness that Bob Carver's swan song is a bit blemished.  I feel sorry for him, but more sorry for the folks that made the actual misrepresentations.  They played the short game.  

 

Thank you Grovergardner!  You pass the audiophile "beer test" and then some!

 

charles1dad's avatar
charles1dad
10,250 posts
 

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.

I suspect this is  the result of a robust power supply  and very good quality output transformers. Always seems the common denominator for well performing SET/tube amplifiers. 

Charles 

jbhiller's avatar
jbhiller OP
1,403 posts
 

Yes @charles1dad you are correct.   My 300 b uses Lundahl PT and OPT and I think it makes a big difference. 
 

 

jbhiller's avatar
jbhiller OP
1,403 posts
 

@grovergardner , In the Doge I really like NOS Brimar 12AT7sbut the reissue Mullards 12AX7s (when from a good source) are very quiet.  Reissue Gold Lions are fantastic yet I have had them grow noisier overtime.  
 

The Doge experience is really first rate. Wooden crate and boxing. Shipped to me inChicagoland in just a few days via DHL. 
 

Customer service abs communication is really responsive. 
 

Doge is a legitimate company owned and operated by its chief engineer.  This is not stuff you get on Alibaba or eBay.  

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