Carver Raven 350 Review (Tube Amp)

[mhardy6647]

Having been gifted with zero aesthetic sense (to a very good approximation), I shall forever be in the road kill pelt camp.
I like that turn of phrase!

 

[DonH56]

Longevity/reliability (real or perceived) is another reason people buy expensive gear. My system cost a fortune but I got it for performance; ain't nobody but me and the family seeing or using it (and usually just me). "Value" is a moving target; a decent $100 speaker to some, a $10k speaker that bests a $50k speaker to another.

 

[IncognitOz]

Longevity/reliability (real or perceived) is another reason people buy expensive gear. My system cost a fortune but I got it for performance; ain't nobody but me and the family seeing or using it (and usually just me). "Value" is a moving target; a decent $100 speaker to some, a $10k speaker that bests a $50k speaker to another.

Loudspeakers are another matter. Loudspeakers are a mechanical acoustic transducer that is very difficult to examine and get an opinion on how it sounds just by looking at measurements.
The claim that expensive equipment breaks down less is also not true, I have seen a lot of high end equipment that breaks down no less and even more than equipment from main stream companies.

A high price has not been a measure of performance for a long time. But what to do, people don't accept it because it doesn't make sense to them.

 

[DonH56]

Loudspeakers are another matter. Loudspeakers are a mechanical acoustic transducer that is very difficult to examine and get an opinion on how it sounds just by looking at measurements.
The claim that expensive equipment breaks down less is also not true, I have seen a lot of high end equipment that breaks down no less and even more than equipment from main stream companies.

A high price has not been a measure of performance for a long time. But what to do, people don't accept it because it doesn't make sense to them.

I am not disagreeing, just pointing out another reason folk buy expensive gear IME/IMO.

One of my most troublesome amplifiers was also the most expensive I have owned, an ARC D-79. OTOH a Bryston amp, not mine but used for a while, was one of the most reliable and expensive (not anymore, Bryston is fairly cheap relative to the stuff available today). It is a mixed bag, like everything else, and price does not necessarily correlate to much of anything.

 

[MaxBuck]

I am not disagreeing, just pointing out another reason folk buy expensive gear IME/IMO.

One of my most troublesome amplifiers was also the most expensive I have owned, an ARC D-79. OTOH a Bryston amp, not mine but used for a while, was one of the most reliable and expensive (not anymore, Bryston is fairly cheap relative to the stuff available today). It is a mixed bag, like everything else, and price does not necessarily correlate to much of anything.

I've come to believe that so many of men's life choices for acquisition are predicated on "What the cool kids have." It manifests itself in cars, bicycles, motorcycles, housing, clothing (WTF is Robert Graham all about, anyway?) and, finally, audio equipment.

I've always felt a bit out of touch with the cool kids, and so my choices have tended to be idiosyncratic and, frankly, based on objective criteria to the extent I was able to ascertain them. Oddly enough, my wife of 44 years was and remains gorgeous, I am well-off without being wealthy, and I love my car, my home and my audio system. And I find that in being overjoyed with my life choices, other people now view me as a "cool kid." Who knew?

ETA: I'm especially pleased with my wife. Just wanted to reiterate that here.

 

[NoxMorbis]

This is a review and detailed measurements of the Carver Raven 350 tube monoblock amplifier. It is on kind loan from a member and (I think) costs US $4,750.
View attachment 225095

The 350 is not a bad looking amp. It has the same "orange peel" paint job of the previous Carver 275 amplifier I reviewed. At 42 pounds, the unit is pretty heavy. With all the weight in the back, the front handle is kind of useless when it comes to lifting it.
View attachment 225100
There is an XLR input but I believe it is for convenience and performs the same as RCA. I measured the DC resistance of the 4 and 8 ohm terminals (after the measurements) and realized they are both the same! Here I was switching back and forth between them. Anyway, measured DC resistance is 0.47 ohm. The 1-2 ohm tap has a lower DC resistance of about 0.3 ohm.

Unlike the 275 amplifier, the fuses did not blow and the amp survived my sweep tests. Bias is to be set at "80" on the front dial and that was the case when I powered on the unit.

There is a gain control but you are advised to set it to max which is what I did for testing.

There is a flip switch in the front which changes the amount of feedback. I tested the amp in both settings.

Here are the specs:
View attachment 225121

Carver 350 Measurements
Let's start with high-feedback performance using XLR input:
View attachment 225102
There is copious amount of distortion causing SINAD to be dominated by it. At 44.1, it ranks as the second worst amplifier ever tested:
View attachment 225104
It even performed worse than the Carver 275 which had a SINAD of 46. Switching to lower feedback doesn't make things that much worse:
View attachment 225106

Note that gain is reduced and therefore, volume will be different. This makes AB testing tricky. Here is a more detailed FFT showing the small difference between low and high feedback:
View attachment 225115
Notice how distortion is made up of both 2nd and 3rd harmonics so you can't make the argument that it is "2nd harmonic goodness."

As noted, RCA performance is the same as XLR:
View attachment 225107

Power supply 60 Hz noise in both cases causes severe intermodulation higher up in frequency. No amount of grounding impacted that so it is endemic tot he design.

Noise performance is decent for type of amp it is:

View attachment 225108

Intermodulation distortion rears its ugly head again in multitone test:
View attachment 225109

I don't know how anyone could hear more "detail" with such an amp where so much of the music signal will get lost in the distortion "grass."

Frequency response should be flat but it is not:
View attachment 225110
It naturally will have load dependency due to output impedance.

Let's see the power situation as we had serious shortfall in the 275 amp:
View attachment 225111

We don't meet the spec there but come closer with 8 ohm:
View attachment 225112

Back to 4 ohm, here is our 1% THD (double the company spec) max and burst power:
View attachment 225113
We seem to get the same shortfall. There is momentary reservoir though allowing the peak output to shoot way up. This was not always consistent though.

I also tested 2 ohm capability:
View attachment 225114

You are still current limited so no more power.

Changing the test frequency gives us the following power curves:
View attachment 225116

There is some instability at 20 Hz and fairly significant power drop. This points to power supply not having enough capacity as the lower frequency taxes it for longer period. Some drop occurs in every amplifier by the way so it is a matter of how much.

Finally, the amplifier warms up quickly and is pretty stable:
View attachment 225117
Testing occurred after this warm up.

Conclusions
What an upside down the world of audio is. Folks want to pay so much more to get dirtier sound. You want dirty? The Carver 350 gives it to you. Even at 5 watts there is copious amount of harmonic distortion. Power supply mixes with that at such high level that it creates its own spread of distortion. A video must come with these amps that hypnotizes you into thinking you are getting great sound....

I can't recommend the Carver 350 monoblock amplifier.
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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

"A video must come with these amps that hypnotizes you into thinking you are getting great sound...." LOL

 

[solderdude]

Walk into any high-end shop or most 'demo rooms' and you will see tubes glowing, anaconda like cables everywhere. Sometimes on risers.
When you want to sell anything 'audiophool' or 'audiophile' no one will take the seller serious when they do not have tubes, huge class-A amps, turntables or exotic looking gear , nice dimmed lighting and comfy seats and they do not sell cables and snake-oil.
Imagine a high end shop with only a few dongles, cheap 100W switching amps and thin generic cables.

This + all the talk on forums changes the perception more than needed. I am quite certain that with the right demo music, good speakers the Carver will sound great in the right setting.

The above is all the hypnotizing the vast majority of audiophiles need and get plenty of.

 

[anmpr1]

"A video must come with these amps that hypnotizes you into thinking you are getting great sound...." LOL

Don't confuse poor measurements, or otherwise less than SOA electrical performance, with someone's possible judgement of 'great' sound. Most of the low-level stuff that is measured can't be heard. And even if (and when) it can, if someone likes the results, that does not mean they are somehow hypnotized, or otherwise fooled. It is just a variance of sonic values. Simply, one person may not like what is heard, while another might enjoy it. Plus, it is possible that someone could like both, for different reasons.

When a person buys a tube amp they are likely not buying in order to obtain the best measured electrical performance they could otherwise get for their money. I think we can agree on that.

[Of course they might be fooling themselves into thinking they are actually hearing what is an 'imaginary' psychological response, not an authentic physiological (aural) one. That happens with SOA solid state gear, too. Or, with stuff that has no 'measure', such as passive cable risers and magic bricks.]

That said, in this case, the specs Carver claims are not quite delivered. So from that standpoint, it's buyer beware.

Historical anecdote: Back in the day, when Bob came out with his monster-sized Phase Linear, judgements were all over the place. Some said it made their loudspeakers sound great, others said it sounded horrible. Who was right?

When Bob 'hypnotized' (in this case the word fits, and is probably closer to the truth than not) the gang at Stereophile into (paraphrasing Peter Aczel) 'screwing up a totally fine SS amp into mimicking a ridiculous tube amp', they thought the SS amp was pretty wonderful. Then, they thought about it for a while, no doubt realized the monetary implications of what Bob did as it related to their business model, and quickly ran another review slamming the actual production amplifiers.

The more I live, the more I think Les Paul was correct when he quipped that most people hear with their eyes.

 

[egellings]

Aczel too no prisoners! Tubes are for boobs according to him. He did write that a competent tube amp could be made, but why bother? Simple; it's amplifier as pet--my little Fi-fi. Nothing's too good for my little Fi-fi. Do you understand? N-n-n-n-nothing! Disclaimer: I have home-brewed tube monoblocks & preamp. The "made it muhself" feel enhances my enjoyment of them. As far as tubes go, if you enjoy them, fine. If not, then simply pass them by.

 

[fpitas]

it's amplifier as pet--my little Fi-fi.

Lol. Warm and takes a lot of TLC.

 

[egellings]

Lol. Warm and takes a lot of TLC.

That's part of the charm.

 

[fpitas]

That's part of the charm.

I understand the DIY part. They were fun when I was a kid, but to me not worth investing much time in now.

 

[sergeauckland]

Aczel too no prisoners! Tubes are for boobs according to him. He did write that a competent tube amp could be made, but why bother? Simple; it's amplifier as pet--my little Fi-fi. Nothing's too good for my little Fi-fi. Do you understand? N-n-n-n-nothing! Disclaimer: I have home-brewed tube monoblocks & preamp. The "made it muhself" feel enhances my enjoyment of them. As far as tubes go, if you enjoy them, fine. If not, then simply pass them by.

I understand the DIY part. They were fun when I was a kid, but to me not worth investing much time in now.

To pass the long winter evenings (and cold, wet days) I built myself a pair of EL84PP amplifiers, and repaired a pair of Quad II amplifiers to use in my study. Listening to Venice Classic as I type. All I need is a couple of watts being as the 'speakers are so close, and the EL84s do fine. The Quads are bridged into a subwoofer under my desk, with a spare Behringer DCX as crossover. Good fun building them, they look good in the dark, and they sound fine giving out a couple of watts at my desk.

Having said that, in my main system, the amps are SS, as valves for me are a bit of fun, not for serious use. I certainly wouldn't pay the prices being charged for classic valve amps (a Leak Stereo 20 (2x10 watts EL84PP) is well over £1000. Utter madness.

Of course having some valve amps means I needed a valve tester, so the last two weeks were spent building a tester for Octal, B9A and B7G bases. It's a rabbit hole I've willingly gone down, anything to get away from the reality of a British winter.

S.