Carver Crimson 275 Review (Tube Amp)

[AudioTodd]

Even if the poor measured performance might be irrelevant when it comes to "sound quality", how do you justify the high price when such performance can be achieved for a few 10s of $?

I can't and was not trying to, but was pointing out that Amir's listening impressions would not add information. If somebody likes the way this thing sounds and is OK paying for it, that's their business. I have all sorts of amps (too many) that I enjoy, so I'm not going to judge anyone's taste or tolerance for spending!!

My personal opinion, without any regard to the sound, is that this is a vastly overpriced piece of junk that does not meet the specs as you are most likely expected to understand them. I'm not a tube design expert, but I do not see anything in the schematics that would imply any great innovation in design and do see things that contradict the published claims. Having lots of experience with pretty much every amplifier topology ever made, I suspect you can achieve the sound people hear from this unit much safer and likely at much lower cost.

 

[_thelaughingman]

For anybody buying into this BS, I would ask: What magical intelligence does this amp have that separates out the loudspeaker nonlinearities from the effects of the room it's supposedly 'listening' to?

Damn, couldn't have said it any better.

 

[KxDx]

To me the worst ever was that home made DAC full of bad solder and wires hanging, it was beyond words. A shame (or luck?) that I forgot its name to link it here....

Edit: found it! Beware clicking the link below... You have been warned.

Ciúnas Audio ISO DAC Teardown and Failed Review

Someone contacted me to offer a Ciúnas Audio ISO DAC for review which he had purchased used from ebay. I said yes. Well, before he could send it to me the unit failed to operate. He asked me if I could see if it is something simple to fix and I said sure. The ISO DAC costs Euro 400 (US...

www.audiosciencereview.com

In my mind, that was the best review thread this site has ever had.

 

[audioholic63]

They also make medical equipment.

My F&P CPAP ran like a champ and probably saved me from a stroke. Zero issues for the decade I used it until replacing with something smaller and quieter from Phillips. Had no idea they made general consumer appliances.

 

[DSJR]

Other oldies like me will confirm, but valve amps of old (and especially the UK tellies of the 50's to early 60's) used point to point wiring and often a rats-nest of wires underneath. In comparison, the Carver doesn't look so bad on the circuit boards although I'm stunned at the potential lack of chassis-safety here... In the UK, it was common for the signal cables to carry the grounding back to say, the preamp which was usually earthed. Quad allowed a three core mains cable to the mains, but to remove hum loops, it was common to use a two core mains cable to the poweramp and earth the preamp to the mains, the signal interconnect being the power amp 'ground.'

[edit] - Note 'Quad power amp two core plus signal screen for 'ground' and preamp three core to mains...

 

[sergeauckland]

Other oldies like me will confirm, but valve amps of old (and especially the UK tellies of the 50's to early 60's) used point to point wiring and often a rats-nest of wires underneath. In comparison, the Carver doesn't look so bad on the circuit boards although I'm stunned at the potential lack of chassis-safety here... In the UK, it was common for the signal cables to carry the grounding back to say, the preamp which was usually earthed. Quad allowed a three core mains cable to the mains, but to remove hum loops, it was common to use a two core mains cable to the preamp and earth the preamp to the mains, the signal interconnect being the power amp 'ground.'

Which was a pretty lethal arrangement, and I'm surprised at Quad. I had a Quad 22 preamp and FM tuner like that, and the signal earth interconnect, which was cable-formed together with the HT, became disconnected from the Jones multipin plug. The effect was that the case of the Preamp went up to HT volts, and touching the volume control somewhat ruined my day. I suppose at the time, it was common. Leak had an Octal plug and socket arrangement with similar wiring, one return for both power and signal ground, and if that failed, the case went live.

Never liked the arrangement of powering a pre-amp or tuner from the main amp.

S.

 

[bidn]

In my mind, that was the best review thread this site has ever had.

I prefer the TotalDAC DAC review, that was something, the addon units were also a scam, and the guy running the company was posting crazy things here and a lot on a French site. I will never forget that, for building each unit, he would select "by ear" the best sounding items in each batch of components, by listening to them...

 

[Koeitje]

Conceptually dangerous. But less dangerous than going back down into his basement I expect. Or carrying one of the big Genelecs up a flight of stairs.

He's already opened it up, poked around inside and hooked it up to his very expensive analyser.

I think the bigger question is what can be gained by listening to it. It's one of the worst measuring amps he's ever tested and very lower powered. If he says it sounds anything other than bad then where do we go from there?

Just because other things are also dangerous doesn't mean we should accept this. There are safety standards for a reason.

 

[audio2design]

Not here to argue bottledick. See ya.

I see this behavior often on subjective websites and Facebook groups.

Correlation or causation?

 

[tomtoo]

Not here to argue bottledick. See ya.

Give me a argument why i should buy a bad meassuring amp, with less than 30w thats even dangerous for me and for the kids of my friends for 2700$?
The color?

 

[audio2design]

DroOL... That Atma-Sphere gear looks gorgeous and I'm pretty sure that's the brand that I saw in Vegas at the CES displaying huge mono blocks and heating up that section of the hotel.

The owner / designer of Atmasphere is also a class act. He knows his stuff pretty well. I don't agree with everything he says but on balance all good.

 

[sarumbear]

This must be the most conclusive vote on a review.

 

[pkane]

Give me a argument why i should buy a bad meassuring amp, with less than 30w thats even dangerous for me and for the kids of my friends for 2700$?
The color?

If you don’t, Jim-the-dealer will call you names in public, so you better buy it! At least that’s what I got from his sales pitch…

 

[audio2design]

Isn’t “bottledick” kind of a compliment? Sort of like “beer can”?

I don't know what you are trying to say here?

 

[paulbottlehead]

Back EMF itself can be used (and most likely is) but this was not measured.

Here are some quick sweeps I did on a test woofer with the negative speaker terminal floating and the negative speaker terminal connected to audio ground. These are on Carverfest 275s which are alleged to be different amplifiers, but we aren't really able to say why or how.

Above is with the negative terminal earthed.

And a floating negative.

 

[paulbottlehead]

The owner / designer of Atmasphere is also a class act. He knows his stuff pretty well. I don't agree with everything he says but on balance all good.

Ralph is indeed a supportive and helpful guy. I had a pair of M60s come across my bench and he took the time to run down all the changes I needed to make to update them and even sent me some factory correct wire so the amps still looked decent on the inside.

 

[sarumbear]

Practically in every developed country selling an unearthed powered device with a metal case is illegal, that includes the states of USA.

46 CFR § 183.372 - Equipment and conductor grounding.

www.law.cornell.edu

This company must be sued and made a show case of their blatant ignorance to human safety.

 

[teched58]

I am surprised that JimBob didn't use the go-to retort that Stereophile rolls out any time someone criticizes a review praising uber-expensive crap, which is that we "are jealous of our economic betters."

I guess he can't do that here because $2,750 was actually spent to acquire this fraudulently spec'd electrocution hazard.

As for the rude and childish name Mr. Clark called Paul, it seems Jim is sensitive enough about the shortfall in performance of the amplifier that he is displacing measurement envy onto another part of his anatomy.

 

[Spkrdctr]

It is very obvious from the PCB layout the speaker current is being measured as there is a 0.1ohm sensing resistor in series with the output.
For it to 'read the room' as a microphone is bollocks. Bob does seem to use the back EMF but most likely this is to compensate for the high-ish output resistance so the amp output is probably less impedance dependent.
The fact that one can use a speaker as a microphone In this case the speaker must be connected to a high impedance microphone input and not simultaneously to a near 0 ohm amplifier output. Back EMF and 'microphone' signal as well as applied signal can not be 'pulled apart' without complex math and fully characterizing the speaker.

Unfortunately this isn't verified measured as only a resistive load is used. A complex load could shed some more light but this doesn't have back EMF. It should be measured with a speaker and on top of that it should also be measured with no signal and a second speaker with a sweep on it directly in front of the speaker and then measure at the primary of the transformer what the amp does with it.

I voted poor because of safety features. It should have had a different mains socket (without a pin), a double insulated sign on the back and everything mains related should have had some shrink sleeving on it or the ground pin should have been connected.

One thing to keep in mind, given the power remains the same at various impedances, is that while it does not have spades of power available it does output 75W but will sound louder than a 75W SS amp (with any speaker but Maggies).
Most 'power' is needed in the lows for music and the impedance is highest there in speakers.
So a bass note into say 16 ohm will get 75W of power = 34V while at 1kHz (assuming no XO there) will only have 17V (assuming 4 ohm nominal)
A SS amp rated at 4 ohm would need to be rated at 290W in 4 ohm.

This is why a 40W rated tube amp can sound more powerful than a 40W rated SS amp.

Of course, this is cornering it a bit short as there are limits to the max impedance of a speaker where this will work and the speaker would have to peak at the frequencies you want to play louder.

In short... the claim Bob makes has not been verified. The claim of reading the room is bogus. The reflected sounds into speaker will be immensely small compared to the back EMF and the applied signal and cannot be told apart from the back EMF due to the huge level difference of back EMF and 'room reflections'. It simply is physically not possible.

Back EMF itself can be used (and most likely is) but this was not measured.
@amirm could measure it by 'injecting' a signal (using a SS amp output via a dummy-load) into the output of the Crimson and measuring on the speaker out terminals what signal remains. Then do the same thing with the current measurement resistor shorted.
This is a lot of extra work though and he has been quite busy with other (far more important) stuff.

Thank you. My red BS flag is still 100% perfect. I don't throw it often, but when I see someone trying to defy reality with "magic" I feel comfortable throwing the flag! Your answer was way more involved and thought out than I gave it. I just said to myself in two seconds, it is impossible to read the entire room from the speaker position and then compensate for the room so the signals at the listening position (really all listening positions) are corrected. I didn't give it all the thought and explanation you did. Great job! I like our intelligent group of professionals on this site all banding together to keep the snake oil from getting splashed on unsuspecting members and the people who stop by for a quick read. Thanks!

 

[Billy Budapest]

He may also reach out with a cease and desist order to take this thread down.

Good luck with that. There are no DMCA issues on this thread.