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
Bob Carver, if you're listening, how about we collaborate on a Signature Edition of the 275?  Woahhhh, where's my humility.  Get back to your day job dude and let Bob work his magic. :)
Blasphemy--I know.... The VCap CuTFs arrived as I was only <12 hours into coupling cap break in, and I just moved forward. I don't want to wait weeks to go back into this amp again. 

The VCaps are in and there is a much bigger improvement swapping out the literally pea sized .22uF caps hooked to the DC phase inverter output to 12AT7 gain tubes (or at least that's how I read the board (again--I'm no pro).  

We are looking at a $500 modification total.  I'd project the Company would have to charge an extra $1500 to do this.  It sounds glorious.  

I hope the VCaps get better not worse.  I know Chris specifies up to 400 hours break in.  I'm not hearing that any is needed. So if it stayed here I'd be happy.  


 'Johnny Hartman's "I Just Dropped by to Say Hello,"' 
@jbhiller,  ahh yes! You have excellent taste. 

 I'm not surprised by your improved sound quality.  Not sure why some are skeptical about capacitor and resistor upgrades. In my experience they can be quite worthwhile if chosen wisely. Congratulations. 
Charles 
Charles, you are a guy that I've always wanted to have a beer or coffee with!

Most of the folks who are skeptical lack experience in doing these things.  I think Don Sach's word is valuable and it is without question he has such experience in spades.  

This little Carver amp is so lovely.  I'm quite pleased.