Carver Raven 350 Review (Tube Amp)

[Bob from Florida]

I looked up the operators manual and the bias instructions call for an optimum bias of 80 milliamps. This is the total for all 6 tubes - 13.33 milliamps each tube at 720 plate volts with 360 screen grid volts. Bias percentage is 16 % - clearly class B Pentode operation. The low screen voltage combined with low bias should make the output tubes last. The Class B operation accounts for the high peak power and the crossover distortion perhaps has some responsibility for the measured distortion. Should play very dynamically - especially with 8 ohm speakers without dips in impedance.

 

[AudioSceptic]

I don´t know

Is this bass doubling (2H higher than fundamental) or something else?

 

[Billy Budapest]

Any indication that the chassis ground issue present in the Carver 275 is present in this amp as well? I know that at least one previous version of the Carver 350 did not have a ground pin receptacle and were emblazoned with the Type-2 wiring symbol. They might have even had ETL or UL certification. Wondering what the case is with the ground in this iteration.

 

[lc6]

Just to jog memories...

The Carver Challenge

Is it possible to make a $700 "mainstream-audio" power amplifier sound exactly like a high-priced perfectionist amplifier? Bob Carver, of Carver Corporation, seemed to think he could, so we challenged him to prove it.

www.stereophile.com

A fascinating story! It goes to show that (a) the SOTA amps at that time were not "audio-modulated power supplies" they were supposed to be (instead, they had specific "sound" to them); (b) mains voltage and current does matter (so get a dedicated circuit to the distribution panel if you can, instead of employing some "stabilizer" or "power conditioner"); (c) there is a need for massive caps in a traditional linear PS to overcome the voltage sag between consecutive peaks of the rectified mains sine wave (a problem largely overcome in a SMPS), which we see to this day with some amps exceeding 1 F of such capacitance to produce powerful bass.

 

[avidedtr]

So that's what the warm of tube sound looks like - YIKES!

 

[RammisFrammis]

Wow that thing distorts! I like tube power amplifiers as long as they are reasonably clean.

 

[Mulder]

Is this bass doubling (2H higher than fundamental) or something else?

I think it follows from the very design of tube amps, ie the output transformers. They simply do not have the same grip on the bass range of the speakers as a modern transistor amplifier.

 

[Shadrach]

A fascinating story! It goes to show that (a) the SOTA amps at that time were not "audio-modulated power supplies" they were supposed to be (instead, they had specific "sound" to them); (b) mains voltage and current does matter (so get a dedicated circuit to the distribution panel if you can, instead of employing some "stabilizer" or "power conditioner"); (c) there is a need for massive caps in a traditional linear PS to overcome the voltage sag between consecutive peaks of the rectified mains sine wave (a problem largely overcome in a SMPS), which we see to this day with some amps exceeding 1 F of such capacitance to produce powerful bass.

Then add this and all those this is complete rubbish votes start to look a bit silly.

Richard Clark Amplifier Challenge FAQ

True it doesn't measure well but I very much doubt anyone would notice through listening.

 

[AudioSceptic]

When Carver meets an APx555 for the very first time.

I think it follows from the very design of tube amps, ie the output transformers. They simply do not have the same grip on the bass range of the speakers as a modern transistor amplifier.

So how would that appear in measurements?

 

[KxDx]

Yo, unless you haul them around the"hood" with you, how you gonna get street cred?

It would actually be interesting to see a pair of tube amps mounted on the deck by the rear windshield in a car. Until the inevitable fire, of course.

 

[strummr]

Well I'm a guitarist, and always on the lookout for the best 'dirty' tube sound.

 

[Mojo Warrior]

and Bob Carver is laughing all the way to the bank

 

[lhimelfarb]

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!

 

[YSC]

well, at least for this one, it have the dominant 2nd harmonic where tube lovers chase after?

 

[GXAlan]

I learned that JAN tubes tend to have reliably lower noise and microphonics. Otherwise, most tubes sound pretty much the same, although they have different distortion profiles (the much debated "hardness" measure) from tube to tube, model to model, and brand to brand.

I also think there is greater longevity with JAN tubes. I don’t think a consumer GE 6550a is necessarily different than a JAN GE 6550a in sound, but I think you are more likely to find JAN tubes in more consistent condition due to how they were stored before surplused.

Are you saying that you think the EL34 and 6550a sound the same? Since they can be biased differently I do think there's a difference in sound. I do think there is a difference in sound depending how you bias the tubes even if you didn't change it.

I don't have a good way to test amplifiers, but am willing to measure my SFS-80 with JAN GE 6550a and JAN Sylvania 6DJ8's since any digital ADC should be more than adequate to show that it's better than this amp (if it is indeed better) at the 1 to 5W range

 

[tomtoo]

At least they can give a good punch.

 

[SuicideSquid]

A fascinating story! It goes to show that (a) the SOTA amps at that time were not "audio-modulated power supplies" they were supposed to be (instead, they had specific "sound" to them); (b) mains voltage and current does matter (so get a dedicated circuit to the distribution panel if you can, instead of employing some "stabilizer" or "power conditioner"); (c) there is a need for massive caps in a traditional linear PS to overcome the voltage sag between consecutive peaks of the rectified mains sine wave (a problem largely overcome in a SMPS), which we see to this day with some amps exceeding 1 F of such capacitance to produce powerful bass.

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.

 

[KEFCarver]

That may depend on how much grass has been consumed.

Bob Carver has some thoughts...

Amplifier Distortion (Bob Carver, 1973)

Results of an informal test project on the audibility of amplifier distortion, by Bob Carver (Stereo Review, May 1973) DISTORTION is one of those specifications that every- one talks about but few really seem to understand.For example, newcomers to the world of high fidelity frequently have the i...

thecarversite.com

... so where did the money go here?


JSmith

Neat Article- thanks for the link..

 

[AdamG]

Hey @BDWoody hold on buddy, it’s about the get rowdy in here. Another 5K chunk of junk. Audiophile jewelry distortion generator, masquerading as a High End Amp gets the Headless Panther Award! Butt Hurt Carver Fan new members incoming. Let the Games commence!

 

[SIY]

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.

Unless the circuits are patented, you can copy them freely.