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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
1,430 posts
 
Check out the pic in my virtual system (last one) of the original caps.  You'll see I used a Phillips screw driver head from my impact driver to show the scale.  It's shocking. https://systems.audiogon.com/systems/9364
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jjss49
6,612 posts
 
@jbhiller

attempts at morning humor aside, a few points back to you

1 - went through your system pics... just love your room, the guitars hanging... that is a sweet place to be for sure, i can feel the positive vibes just seeing the photos... 👍👍👍

2 - also want to commend you on your spirit of positivity, enthusiasm and passion, and your willingness to tinker to learn and potentially improve already very good gear, ’make it all it can be’ - i don’t trust myself with a soldering iron to save my life, but i am so glad a fellow dedicated enthusiast like you is willing to climb the learning curve and share findings -- for all its faults and garbage, this is the a-gon forum at its very best...

3 - the carver amp is brilliantly conceived, bob carver has more than a little spark of genius, but clearly the crimson amp is built to a price point to make it commercially successful and sell at good volumes, so i can imagine some of the internal components can stand upgrading if the owner seeks a higher level of absolute performance, and is willing to pay for it ... that is no knock on carver (quite the contrary), it takes talent, serious talent to make affordable stuff sound so great, it requires knowing where spending $ makes a real difference, and where $ can be intelligently saved

4 - i know e j sarmento at w4s fairly well, he is a smart, very nice guy, a fellow enthusiast, and he of course builds these units for carver and frank m... i would think he would be very open to trying to incorporate potential mods commercially, but bear in mind he is the contract manufacturer -- bob c and frank m own the brand, and thus the right to ok development changes - no harm in reaching out to them though...

jb, i really look forward to hearing your further observations on how your lightly modded 275 is improved as it has more playing time, and i will likely follow your lead on passive component upgrades... it is a killer app amp at its modest price point in stock form, and the thought of making it even better is exciting!
corelli
999 posts
 
@jbhiller   Thanks much for such a detailed and thoughtful response.  Also enjoyed your comparison to the Elekit.  Your impressions of the PL seemed to parallel mine but you used yours with far more speakers than did I. 

I love elegant solutions--and the 275 surely leans in that direction compared to the PL.  Your caps are only going to sound better in time and I hope this amp is long term keeper for you!

Thanks again.
jbhiller's avatar
jbhiller OP
1,430 posts
 
jjss,  thank you Sir.  You are always doing good on these forums.  I for one have learned much from you.  I also like how you are open minded.  For example, I saw you picked up a Devialet integrated.  I like that you are not diametrically opposed to something just because you typically like lots of tubes.  

I did reach out to Frank.  I keep in touch with him a bit here and there.  I'm going to have lunch with him soon.  He lives in Chicagoland, like me.   I want to be careful not to give them too many opinions--lest they think I'm a charlatan or a know it all.  I do, however, think they could expand their product line.  There's a BIG gap between the $2800 275 and the $10k 350 monos.  

There are pics and a press release out there concerning a slick integrated they might be bringing to market.  
jbhiller's avatar
jbhiller OP
1,430 posts
 
@corelli, I'm happy that my words helped at all.  

The PL is such a great product.  I'd add a big caveat:  Perhaps the PL is just too warm, big and dark for my system.  With the exception of my CD transport (which I rarely even use) I have nary a transistor in my system.  In other words, the PL might be a great fit for folks who have no other tubes in their system.  I'm not sure. 

I've been running the system 12 hours on and then 12 hours off.  The caps are opening up a bit more in the midrange and bass.  The high treble sounds about the same to me.  

I'm hoping the Clarity Caps and the VCap CuTFs mate well. So far so good.  

Quite honestly, I wish I could buy the 275 in a kit form where they sell me the chassis, transformers (power and output), and then I source the rest.  I say this because I cannot help but wonder what $50 of premium resistors and the very few small electrolytic capacitors would do.  

In fact, I'd love it if I could buy a new PCB from Wyred4Sound and mod it up completely, and then compare it to a stock model in A/B.
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