doh -- they stopped the timer for the apgar test!!!! recount!!!! 😁
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.
234 responses Add your response
on the caps in the Carver... Everything is built to a price point. If they charged $500 more for the amp they could use better coupling caps. I am sure it is a very nice amp. I prefer octal tubes in the front end, but anyway, changing the coupling caps to something better will not hurt the amp and will probably sound better. If you don't like it, put the old ones back in. Warranty voided though, you have to take that into account. |
Carver was a transformer genius. Bob carver learned how to wind output transformers from David Hafler. <<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>> Your point is? He learned and then improved as any GREAT student should. He became the "Teacher" vs student.. It happens ALL the time.. A true teachers goal, is to make those they teach BETTER because of the WAY they teach. I sure had some good teachers.. Weather they rubbed off that is a different story.. :-) Carver made some hotrods for sure with LONG valve life.. He always had a hat on too.. Hafler was cult like, still is probably. I did some board changes for a buddy he was a BIG Hafler fan (1995 or so) I was more of a Pass and Mac guy at the time.. Cary wasn’t even on my radar, back then. They have one I fell in love with. V12r gosh what a great amp.. 3 years now. It’s an OLDER amp design BUT a Great idea.. EASY to repair voice too.. 12 to 200 watts. Add or subtract valves and bias.. That simple.. It was made for planars.. 4 EL34s Ruby or GL KT77 or 6V6s, it don’t care.. Put 12 valves in, bias, flip to UL and look out.. The little Carver is no V12r but it's been voiced to please for sure, with LONG valve life.. 1/2 the weight too. Regards |
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! |
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. |
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! |
Guys it’s not the caps that are the biggie. Resistors are where GREAT quality comes from. Good caps Russian PIOs Mundorf MCap and Vishay copper resistors.. AND yes WiMa would have been a heck of a better build... But the guy that voiced that amp is NO DUMMY.. He can really come up with GREAT sound on the cheap.. Carver was a transformer genius. He use to teach classes, 45-50 years ago.. Worked with a few apprenticeship programs to get your requirements.. I did a 3 day class with him. Had a pair of forearms like an APE, from hand winding transformers.. Great guy back then.. SMART very different approach to sound too.. I was a serious Mac guy.. Do you see a problem.. He sure did.. LOL Really though, you should see Carvers Point to Point.. pure art.. The 275 reflects his voicing BUT really NOT his ability to lay out a beautiful valve amp.. Two different things.. Good units.. the 275.. Tinkers delight for the price.. COOL running, lighter.. I like um.. |
I used to own the Black Beauty, It ran very difficult speakers and can handle difficult loads, Unfortunately Bob carver setup Distributors globally and got everyone to buy and market the amps for some time and then dropped all the distributors within an instant. Nice Amps but the people running the company have no idea. If you need allot of power these make sense. |
I don’t see a problem with swapping out capacitors. Listen and evaluate what you hear. The original capacitors can simply be re-installed if no improved sound quality was obtained. In some circumstances the capacitors (Resistors as well) in the signal path may influence the component sound quality as much or more than swapping out tubes. Charles |
If it sounds good to you i would not mess with the caps at all because you can completely change the balance of the amplifier and you may or may not get better sound an easier way would be to swap new old stock tubes into the existing circuit and see if you like the change with different tubes instead of messing with the innards. |
I have heard that amp many times nice little unit but as you already know - cheap parts and circuit boards. Change out the caps and resistors Nichicon and some Amtrans or Audio Notes would be much better options. Neatness does not count but the separation of higher voltage power wires from the lower voltage wires is the way to go. Happy Listening. |
Ha! Yes, I think I can get it back together! The PrimaLuna was difficult to mod Because there was so much going on inside that amp, but I was able to do it. This guy has lots more room yet it’s just going to be difficult to find a place to secure larger caps. I have some ideas. But, most likely, I will remove the cheap caps I want to upgrade and just start with a listening test. If I don’t see a substantial improvement then I’ll just go back to the Suntan caps. I will not be modifying the circuits. |
https://redirect.viglink.com/?format=go&jsonp=vglnk_162576198114510&key=098b477826d9c73180a2... Here's a link. Photo will expire in a few weeks I think. I don't have a good photo sharing account. |