can o worms is right
holy moly
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.
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.
- 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.
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.
Showing 15 responses by jjss49
the amp weighs 19.4 lbs by my scale, with no ac cord attached, tubes in place here is the asr thread, ralph, it is long, jim clark responds on pg 6, and the conversation ensues from there, with photos from carverfest where kits were distributed https://www.audiosciencereview.com/forum/index.php?threads/carver-crimson-275-measurements.29271/ doesn't explain the magic of a 20 lb amp making 75 wpc, but there is the info | ||||||||||||||||||||||||||||||||||||||
i am an owner of your carver 275 amp, actually like it alot, sounds very nice, wrote previously about my experience listening to it, which i enjoyed my speakers are fairly efficient and not a hard load (spendor sp100’s at 89 db.w.m and 8 ohms) so my listening to music does not tax the amp and ask it for big power, even if it makes 15-20 legit watts it could still make good music in my setup that said, i have also been kinda curious as to how the amp with its light weight (and thus small output trannies) would do a legit 75 wpc into real loads (or even an 8 ohm test load) as a point of direct comparison, my audio research reference 75 is also rated at 75 wpc, also runs 4x kt120 power tubes, and it weighs 49 lbs... open the top, the sizable output transformers are right there looking back at you
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quick report i just had my amp in for a check (some tube noise and transformer hum) at wyred 4 sound - w4s is the exclusive contract manufacturer for these crimson amps had a friendly chat with their senior tech who worked on my amp - i know the w4s guys reasonably well, like them, have several pieces of their gear (digital, power supply, class d amps), w4s is a good company, well designed well built, good sounding high value gear, good reputation, and straight shooters in my book i was told that based on their bench experience, the crimson amp can make 75w driving one channel... (didn’t ask for frequency range spec, sorry), can’t in both channels though (’more like 60 thru both channels’), but this isn’t due to the output transformers as limiting factor, but rather, the power transformer, which can’t quite deliver the juice for 75 wpc asked how such a small light tube amp makes that kind of power, was told that the reason is the kt120’s are pretty strong, plus ’the neat feedback circuit employed from the output, holds the distortion in check, other guys don’t do this, we were kinda surprised it can do that through those small output transformers...’ so that is what i learned... perhaps frank m, after consulting with bob carver himself will chime in again, say more for me, i own the amp, bought it used on a lark to try, like it quite alot, drives my spendors and harbeths very nicely, sounds great, runs pretty cool, is small, light, easy to move around... so i’ll be keeping it in my stable of amps - yes, the power output spec may well be overstated by the seller ... oh well, i’ve done a lot worse :) | ||||||||||||||||||||||||||||||||||||||
first i would say this thread is nice in that folks raising issues, and @jbhiller and i as current owners of these amps chiming in with thoughts and info, are keeping it positive and cordial - i think that is important, we can see other threads being much less so, and that can be become awfully unpleasant second, i think to j-b’s comment about pricing of the 275, my own take is that the carver principal(s) were careful to choose their price point, knowing a higher one would considerably reduce their market interest, and i think that is also why they chose to skate on thin ice to write 75 wpc - that was the desired proposition: light amp, kt120’s, $2750 new, 75 wpc, drive most real speakers in real rooms to real volumes - thusly can undercut alot of the competition with a superior value propositon - whether they did this (the power rating specifically) ethically is a fair question -- for me, as an illustration, i bought the amp a touch under $2000 used - had it been a $4000 retail amp, selling for $3000 used, i may well have not gone for it third, i would just reiterate that in my experience and use, i am not using super efficient speakers - spendor sp100 r2 @ 89 dbwm 8 ohms nominal, harbeth monitor 40.3 xd and shl5+ both @ 86 dbwm 6 ohms - in my 19x17 dedicated room, speakers well away from room boundaries - the amp drives all the speakers very well (i listen at low to mid 70’s db average with 80+ db peaks), has terrific bass response... not bass like a pass or a hegel, but roughly as good as much more expensive tube amps such as my audio research ref series -- how it does it, with xyz feedback circuitry, maybe it is managing the distortion, maybe it is playing some nice sounding distortion, but to my ears it works very well for a tube amp, sounds very good - good detail, excellent warmth and imaging, nice drive/prat - just what one would seek from a tube amp last point i would add, and a bit of re-emphasis on what j-b said earlier, bob carver has always been an ’against the conventional grain’ type of character/designer in the audio world, he does things differently, thinks very much out of the box, so to speak... if one understands his long history (as i do, i have been at this as an avid hobbyist since the early ’80’s), he is never been shy to push the envelope -- more often than not, he can back it up... so we shouldn’t be surprised this amp with his name on it follows that tradition - importantly, at least in my case, the amp performs, making very good music to real volumes capably all this said, the stated specs should be honest, and that may well be on bob carver himself, at his current ripe old age, or the folks running the business at present | ||||||||||||||||||||||||||||||||||||||
so what’s it to you? all 15 posts to your credit... below is the sum total of ALL your contributions to this forum so do you own the amp? do you feel better now -- stopping by, leaving your turd here? are you lookin’ out for all the rest of us, with your righteous indignation? --------------------------------------------------------------------------------------------------------------------- funky54Responses from funky54
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@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! | ||||||||||||||||||||||||||||||||||||||
so jbh - would you please write a short post with specifics as to your passive components mod (sorry to make you repeat this), so that i can pass the info to my tech to replicate your successful minor surgery to the unit? i have my parts connexion account locked and loaded to order the caps etc etc!! thanks in advance! 🙏 | ||||||||||||||||||||||||||||||||||||||
