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Carver Raven 350 Review (Tube Amp)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 262 82.9%
  • 2. Not terrible (postman panther)

    Votes: 29 9.2%
  • 3. Fine (happy panther)

    Votes: 15 4.7%
  • 4. Great (golfing panther)

    Votes: 10 3.2%

  • Total voters
    316

vkvedam

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My brain's SINAD dropped to the lowest after looking at these measurements o_O

giphy.gif
 

solderdude

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@amirm ... a strange question. Seeing that there are no listening impressions and this amp can actually change the sound (probably not for the better :)) is it possible to record some music played through this amp (into a dummy load) and the original and post that. A short excerpt may be all that is required.
Not many people get the chance to listen to such 'amplifier effect devices' and could be interested to hear what it does to the sound and or AB it.
 
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I rated this #2 instead of #1, "broken". Clearly it is WYSIWYG and not broken. Prodigious amounts of power should result in healthy dynamics; the distortion levels are at the edge of audibility and buyers over 50 can’t hear much anyway (me included). I’d never even consider this let alone have it in my system at any price, but at least it’s not a $20,000 USB cable.
That's a very good point, actually.
 

Jim Shaw

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Now this is 1958 technology. Nostalgiacs should wallow in it. These were the measurements we battled back then; it brings a tear to see them back again -- from the mud in my eyes and ears. By the way, the DC resistances of the output windings of a tube amp are almost meaningless.

Expensive as a good used car, and for that you get boatloads of harmonic and intermodulation, a gaggle of glowing tubes, and a space heater. It may even make a flute sound more like an oboe. A Bourdon more like a Posaune.

This is like stick shift and 4 carburetors on a straight 8, but in an amplifier. Nostalgic! 1958 muscle.
 
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tomtoo

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@amirm ... a strange question. Seeing that there are no listening impressions and this amp can actually change the sound (probably not for the better :)) is it possible to record some music played through this amp (into a dummy load) and the original and post that. A short excerpt may be all that is required.
Not many people get the chance to listen to such 'amplifier effect devices' and could be interested to hear what it does to the sound and or AB it.

I realy would be interested.
 

AudioSceptic

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IP law actually would be engaged there - Carver wouldn't be able to use the name of the reference amp in the model number, and would have to be very careful about the way he used the name in advertising materials, or he could run afoul of trademark laws. Easier to just be cagey.
So, even if he didn't mention C-J, he would have been on shaky ground? I wonder if even C-J knew that their amp was the reference?
 

tomtoo

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Now this is 1958 technology. Nostalgiacs should wallow in it. These were the measurements we battled back then; it brings a tear to see them back again -- from the mud in my eyes and ears. By the way, the DC resistances of the output windings of a tube amp are almost meaningless.

Expensive as a good used car, and for that you get boatloads of harmonic and intermodulation, a gaggle of glowing tubes, and a space heater. It may even make a flute sound more like an oboe.

This is like stick shift and 4 carburetors on a straight 8, but in an amplifier. Nostalgic! 1958 muscle.

YES!!

Even i would never buy a thing like this, it has some fascination to me. 300W raw tube power.
 

nyxnyxnyx

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well at least this one is indeed audibly different from many others.
maybe if we exclude personal preference aside, it was more understandable that someone who purchased this amplifier in the past did it because a lack of information available at the time. also I don't think many people were expecting ultra clean sound from a tube design from a somewhat prestige, boutique brand.
 

lc6

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I think you've taken the wrong lesson from this Stereophile story.

What it goes to show is that the writers of Stereophile are lunatics.

I particularly liked this bit:

"The possibility of Carver's manufacturing his modified amplifier raises some very knotty questions concerning morality and legality. Does an amplifier manufacturer who designs something from scratch, coming up with a sound unique to that product, have the exclusive right to that sound? In other words, is it dishonest or even illegal for someone to use a technique such as Carver's transfer function analysis to duplicate that "unique" sound, without having done all the usual homework involved in designing an amplifier from scratch?"

No, this does not raise any "knotty questions" around legality. There is nothing in law that would give you any intellectual property over a "sound". The only way you're running afoul of IP law is if you literally reverse engineer and directly copy the circuits.

Not that I want to defend them here, but subsequently in that article the writers came to the same conclusion, citing functional cloning of VisiCalc as an analogy:
"Thus, it is likely that Carver, or anyone else with his technical smarts, would be legally free to duplicate the sound of any amplifier, as long as different circuitry was used to do it."

Also, a technical implication of the accomplished "transfer function matching" is that Carver's amp had distortion characteristics similar or superior to those of the reference amp. That is because the passive components Carver used to achieve a null difference signal would not have been able to correct such deficiencies in his amp (otherwise, the correction would already be done in product development). So, it is sad to see such poor performance of the Raven 350.
 

DSJR

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Someone mentioned ARC (Audio Research) amps and included them in a list of other tube amps. The insinuation is that ARC is the same as the poor tube products mentioned in these reviews, and geez, they are pretty terrible. I have an old Counterpoint hybrid that is still plugging away and has specifications that still surpass any tube amp mentioned on this site. The ARC equipment, that I do not have and have not owned since the seventies, is superb. Its specs, using the standard test equipment at that time, equaled or surpassed all but a few solid state pieces... and it certainly sounded just as good. I listened to a Wilson Alexxa driven by new ARC equipment last year over a period of a few days and can say it sounded better then the McIntosh equipment that it was compared to. Unfortunately, I am no longer working in that industry and have no access to todays test equipment. Last words: I hate tubes! If you can equal or better sound quality using solid state, why would you bother with all the nonsense that goes along with tubes... unless you have some crazy load that needs transformers. Even then, you can add one!
I'll do some scans as evidence. Nice sound is one thing, -40dB distortion is quite another and believe me, some of the expensive tube based preamps they did were effects-generators/sonic processors if compared to a straight-through source... The Reference 2 preamp I remember was awfully coloured, as was an LS25 and lord knows how they measured. Early ARC power amps didn't care for UK voltages either and VERY EXPENSIVE blow-ups were common at one time if not now. Seriously, a collection of WonderCaps or whatever they use these days is no substitute for proper design, but audiophiles aren't so interested in the latter as long as it's a conversation piece to show off to their pals. I admit I went off the brand and now regard them as male jewellery, the same as a lot sold by Absolute Sounds in the UK.
 
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SuicideSquid

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Not that I want to defend them here, but subsequently in that article the writers came to the same conclusion, citing functional cloning of VisiCalc as an analogy:
"Thus, it is likely that Carver, or anyone else with his technical smarts, would be legally free to duplicate the sound of any amplifier, as long as different circuitry was used to do it."

Also, a technical implication of the accomplished "transfer function matching" is that Carver's amp had distortion characteristics similar or superior to those of the reference amp. That is because the passive components Carver used to achieve a null difference signal would not have been able to correct such deficiencies in his amp (otherwise, the correction would already be done in product development). So, it is sad to see such poor performance of the Raven 350.

My issue is that it was even raised - it's a completely absurd assertion, and it's not "likely" that Carver could legally duplicate a sound, it's an absolute guarantee.
 

FeddyLost

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Weird device.
Ok, if one needs znf and short trail of harmonics, I assume only 2-3-4 harmonics.
If one needs more high harmonics, he'd better buy exciter.
But this ...
Let's just wait until some tricky designer put tubes into DSP exciter followed with purifi amp module...
 

fpitas

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Weird device.
Ok, if one needs znf and short trail of harmonics, I assume only 2-3-4 harmonics.
If one needs more high harmonics, he'd better buy exciter.
But this ...
Let's just wait until some tricky designer put tubes into DSP exciter followed with purifi amp module...
You know they will :confused:
 

Thomas savage

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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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Great work my old friend, poor performance, widely liked.

Humans , its why its best to leave the meat sacks out of recommendations.

We know what keeps true to source.
 

AudioSceptic

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I'll do some scans as evidence. Nice sound is one thing, -40dB distortion is quite another and believe me, some of the expensive tube based preamps they did were effects-generators/sonic processors if compared to a straight-through source... The Reference 2 preamp I remember was awfully coloured, as was an LS25 and lord knows how they measured. Early ARC power amps didn't care for UK voltages either and VERY EXPENSIVE blow-ups were common at one time if not now. Seriously, a collection of WonderCaps or whatever they use these days is no substitute for proper design, but audiophiles aren't so interested in the latter as long as it's a conversation piece to show off to their pals. I admit I went off the brand and now regard them as male jewellery, the same as a lot sold by Absolute Sounds in the UK.
HFN also got onto the US High End bandwagon in the 80s. I might even have some of those issues somewhere.
 

fpitas

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But they're so pretty... :facepalm: At one time I wanted a pair.
Yeah, if you DIY and can get one cheap, maybe you can re-design it to be worth owning.
 

SIY

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Not that I want to defend them here, but subsequently in that article the writers came to the same conclusion, citing functional cloning of VisiCalc as an analogy:
"Thus, it is likely that Carver, or anyone else with his technical smarts, would be legally free to duplicate the sound of any amplifier, as long as different circuitry was used to do it."
So they know just as little about IP law as they do about technology.
 
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