Carver Crimson 275 Review (Tube Amp)

[fastfreddy666]

Who cares about efficiency? It's about enjoyment.

Increasing your carbon footprint in the name of hedonism. What about climate change?
You're a monster.

 

[Labjr]

Increasing your carbon footprint in the name of hedonism. What about climate change?
You're a monster.

So quit the forum and go live in a tent. I'm enjoying music.

 

[dougi]

If I wanted an affordable, US made tube power amp I would probably buy the Rogue Audio Atlas Magnum iii. I think US$2400 and measures OK for the eariler model, although Stereophile doesn't measure power capability other than at 1kHz, but the distortion figures suggest power at bass frequencies would be OK. I've owned the Cronus integrated, and that was hefty, but the diode bridge failed and and PS caps buldged badly out of warranty. I did use it as my main amp over Australian summers though.

 

[silverbot01]

Hello, I'm new to this forum and have been following the thread regarding this amp. It's really cool to see the Crimson get properly measured even if the results are disappointing.

As an owner of the Crimson 275 I thought I might capable of adding something to the conversation. For one, odd order harmonics being dominant is normal for push-pull amplifiers. Second, and unrelated to the loose screw I think, is that hole should be a mounting point for one of the output transformers. Sad to see it arrived to you like that. I'll have to check my unit for a lack of ground connection too.

I haven't personally experienced, at least from just listening, the issues I'm seeing here on my speakers. I can get them uncomfortably loud with clean sounding bass without issue. I suppose if 15 watts is enough to do that then I'm not sure what to say but so far I've thoroughly enjoyed my experience with the amp. I've also never had the fuses blow on me which concerns me as to whether newer units are of lesser quality. My unit is Serial# 3 for reference.

I can't provide anything but my subjective experiences with the amplifier, so whether I've actually put enough demand on the amplifier to reach the problems found here is up in the air. Regardless thank you @paulbottlehead and @amirm for taking an objective look at the Crimson. It was a nice surprise to see something like this here. I usually watch this forum without posting.

Silver

 

[paulbottlehead]

It would probably help to know what speakers you have, what you listen to, and how large (approximately) your listening room is. There are huge numbers of people who don't even hit 90dB with their systems and listen to a girl with a guitar in a small room. Under these conditions, 5-10W and 88dB sensitive speakers can do just fine!

 

[silverbot01]

It would probably help to know what speakers you have, what you listen to, and how large (approximately) your listening room is. There are huge numbers of people who don't even hit 90dB with their systems and listen to a girl with a guitar in a small room. Under these conditions, 5-10W and 88dB sensitive speakers can do just fine!

I use a pair of Kingsound Princess IIa hybrid bookshelves. I believe they are 83dB sensitivity and 8 ohm nomimal? I use them relatively near-field however.

Silver

 

[paulbottlehead]

Nearfield listening dramatically reduces power requirements, that's for sure!

 

[silverbot01]

Nearfield listening dramatically reduces power requirements, that's for sure!

My question is what's the difference between running them into an analyzer and running them into a speaker load? Does this change performance? I'm not an engineer but that question has been in my head ever since I saw your initial thread weeks ago.

I ask because the previous owner had no issue with similarly hard to drive speakers in a not so near-field setup. He even managed to power a pair of Magnepans to enjoyable levels. I wasn't there to hear it myself however.

Silver

 

[bidn]

Increasing your carbon footprint in the name of hedonism. What about climate change?

I do not consider myself to be "green" but I do agree with you re. this pure waste of energy.
And it is not only when these very hot tube devices run that they burn way too much energy (compared to solid state devices),
but with such incredibly awful performances, I am sorry but I cannot see them differently than pure pieces of junk: so energy is also wasted in building them.
BTW, I think that in the device polls, the category " poor" is way too good for such devices, would'nt they deserve a category of their own: "piece of junk"?

All the best, Amir, with your house.

 

[paulbottlehead]

When we test the amps into a resistive load, the amp sees a constant impedance at all frequencies (well, close enough to call it flat). This is not particularly realistic, however, as speakers have impedance curves that can wander all over the place. You can use a different load that will simulate a two-way speaker, but all speakers will be different, so figuring out a standardized reactive load is a bit challenging. I have not encountered (yet) an amplifier that performed better with a reactive load compared to a loading resistor.

For an electrostatic speaker, impedance tends to drop as frequency rises and you'd want to see an impedance sweep from the manufacturer to see how low it drops at 20kHz (or have someone help you measure this yourself!).

Here's a sample of the impedance plot of a quad speaker, and for decent high frequency performance, you'd want a 4 ohm tap available to at least try out!

 

[paulbottlehead]

And it is not only when these very hot tube devices run that they burn way too much energy (compared to solid state devices),

There are some solid state devices that chug down lots of power! I have a solid state amp sitting around that consumes 300W at idle when it's on!

 

[silverbot01]

Right, I have the booklet somewhere around here, the impedance was around 2 ohms flat across almost the entire FR above where the electrostatic tweeter takes over on the crossover.

Silver

 

[PoorishDecision]

I understand "Tubes are an acquired taste" but this is terrible from a performance standpoint.

 

[paulbottlehead]

the impedance was around 2 ohms flat across almost the entire FR above where the electrostatic tweeter takes over on the crossover.

To drive a 2 ohm load you'd want to look at high current solid state amps or some specialty tube amps with low taps available. One that I can remember owning a long time ago was a pair of VTL 225 monoblocks that IIRC had 2 ohm taps available.

 

[mhardy6647]

Explaining again, there is only one "set" of measurements there. One line for each channel.

Yes -- sorry about that; I got it on the third try!
(which is not your fault)
... and I, unfortunately, didn't see your first answer until after I posted the second "ask" -- and I do apologize for that!

 

[silverbot01]

To drive a 2 ohm load you'd want to look at high current solid state amps or some specialty tube amps with low taps available. One that I can remember owning a long time ago was a pair of VTL 225 monoblocks that IIRC had 2 ohm taps available.

Well my point is it seems to drive them quite well. I haven't had issues running these speakers in my current setup. I've also run a pair of Sony APM-22ES and a pair of JBL Studio 530. All of them do great off the Crimson. Audible improvement over my Schiit Ragnarok 1 (although I mainly got the Ragnarok for headphones). I probably can't reach 15 watts near-field, however, so take this all with a grain of salt.

Silver

 

[mhardy6647]

The Cayin is not comparable because of its topology (which is what determines that distortion curve). This Carver amp would likely clip in the usual push-pull manner if it didn't blow fuses before its clipping point.

Not to dwell on this -- which I realize is probably imprudent and even impudent! -- but I was just looking at Stereophile's data on the above-mentioned RogueRogue Audio Titan Atlas Magnum (whoa, what a moniker!) amplifier.
This one's PP KT90 (or KT120) with, I presume, a pretty ordinary topology Class AB stereo power amp with reasonable output iron & a reasonable amount of reasonbly well implemented NFB.

To my eye, the distortion behavior looks rather different than the Mac & Sansui ss PP receivers' amps*

Fig.4 Rogue Titan Atlas Magnum, 4 ohm tap, KT90s, distortion (%) vs 1kHz continuous output power into (from bottom to top at 1W): 16, 8, 4, 2 ohms.

source: https://www.stereophile.com/content/rogue-audio-titan-atlas-magnum-power-amplifier-measurements

vs.

" Fig.5 McIntosh MAC7200, 8 ohm tap, distortion (%) vs 1kHz continuous output power into 8 ohms"

source: https://www.stereophile.com/content/mcintosh-mac7200-stereo-receiver-measurements

___________________
* https://www.audiosciencereview.com/...e-gently-than-solid-state.29965/#post-1050377

 

[TunaBug]

Who/what is the current "Bob Carver Corporation"? I'm under the impression that Bob Carver is no longer involved. Trying to throw the guy a bone here...I wonder if he designed a competent amp but failed in who to trust to manufacture and market it?

 

[norcalscott]

Without Jim Clark I wouldn't have dropped $2800 on a new amp to clear all this up, so I suppose in a way we owe him some thanks.

Well the thanks certainly go to you for putting your money where your mouth is. I'll happily donate if you have to pay a restocking fee.

 

[LTig]

My question is what's the difference between running them into an analyzer and running them into a speaker load? Does this change performance? I'm not an engineer but that question has been in my head ever since I saw your initial thread weeks ago.

The analyzer itself is not a load, but the dummy load @amirm uses. Standard dummy loads have a resistance independent of frequency so they are in fact easier to drive than typical speaker loads.

The main difference between measuring and listening is that you drive the amp to max power with the dummy load for a long time (possible because the load makes no sound - that would be unbearable loud) while music has only short peaks so the average wattage of time is much lower. That's the reason why the fuse don't blows when playing music.