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
Hello jbhiller!  Bob Carver is a superb designer. He sells his company every ten years or so and starts another one to keep from getting bored. The man is an audio genius. If you replace those "iffy" capacitors, don't use anything less than Mundorfs with the appropriate rating. Since there are only two, go for the fanciest ones. Be sure they will fit. The Duelands for that rating are HUGE. Enjoy!
You ever look inside a First Watt? Chock-a-block full to the top with WiMa and Vishay.. Heck yes they are good.. Accurate and really ZERO coloring via a cap anyways. LOL They give the sound to the new Mac. Just full and Vishay copper resistors and WiMa.
Carver was a transformer genius.


Bob carver learned how to wind output transformers from David Hafler.
Guys, great comments above are making this thread!  

Yes, I fully realize that swapping out coupling caps can change things for the better, not at all, or for the worse. I would, however, like to do the experiment.  

I'll likely test two types--WIMA and ClarityCap CMRs.  I've used Audyn, Mundorf, VCap, Auricap, MultiCap, ClarityCap, and others in the past. 

I'm very tempted to call up Bob the man himself and ask him if I could visit him for an afternoon.  I bet I'd learn more in 3-4 hours than I have tinkering, reading, and assessing on my own.  

I'm very, very curious to see inside the 350 monos.  
From above..."Go ahead and chase your tail. Knock yourself out! Placebos and sugar pills will make it sound “sublime!""

Hmmm.... Not only is this not a very fun spirit you cast on this experiment, but I cannot agree. Why is it do you think Bob himself says the 275 gets about 75% of the sound of the 350 monos, which cost $5k each?

I think it’s because he worked really hard to keep cost down.

Take Don Sach’s post about upgrading the crossover in the Klipsch Cornwall IV. Roy Delgado likely knows a bit more than Don about speaker design. That doesn’t mean Don is wrong. It means Don can be right that better caps and resistors can improve the speaker. It also, arguably, means that Don’s upgraded crossover parts come to $900 retail, and if Klipsch bought those parts the build cost would certainly elevate and perhaps drive down demand.

I see this being the situation here. Bob Carver--the madman designer--put the 275 together with an eye on budget and end user price.

And finally, I have real confidence in my ears and listening. I’ll even admit that something expensive or "better" doesn’t sound better when it doesn’t. When I put VCap CUTFs in my Primaluna at the gain and phase split area they helped and it sounded better. When I added in Audyn True Coppers and some better Mundorfs in as coupling the power tube section and filtering power they didn’t do much if anything--but cost me money!  Wanting something to be better and actually making it better are different pieces.  

To each his own.  Thanks for dropping by!