Carver Crimson 275 Measurements

[paulbottlehead]

Folks at AK are trying to figure out what "adamantine steel" is, if it even exists. ;-)

This relates to a fallacy I bring up frequently with my local customers. If an audio company is able to violate some fundamental law of physics, chemistry, magnetics, etc., these are the kinds of discoveries that win you Nobel prizes and millions of dollars. A transformer lamination alloy that would allow for significantly higher flux density than what we have now would be worth a lot of money. This kind of tech tends to trickle down into audio rather than the other way around.

 

[JJB70]

I don't think the dealer would have any right to complain about a customer returning a product that has been wrongly advertised. I personally don't agree with the way some people use return policies as a form of equipment lending, ordering gear to try out then returning it (though if policies allow that they're not doing anything wrong in terms of sale agreements and law). I order stuff in good faith to keep and use return policies if it is not as advertised or doesn't work. In that context I can understand the idea of re-stocking fees if people just change their mind or want to use retailers as lending libraries for gear. As long as re-stocking fees are transparent and made clear it is for the purchaser to decide if they're happy to complete a transaction. In this case if an amplifier cannot meet advertised performance and specification then why should a customer pay a re-stocking fee? In such a case a product has been wrongly sold and the customer has every right to a refund. I get that it isn't the retailers fault if they've sold it in good faith based on manufacturer supplied information but it is for the retailers to chase the manufacturer to recover any costs as ultimately it is the manufacturer which is at fault (it becomes less clear cut if such a performance gap is a known issue).

 

[LTig]

as an on-topic aside I just read an interesting post in a parallel thread on this topic at Another Forum by Bob Fitzgerald ("Bob@FM"):

Bob Carver 275 Stereo Vacuum Tube Amplifier

I'm sure Bob is just fine. But judging by your signature, you're the lucky owner of no less than seven pieces of classic tube gear that delivered every bit of performance they were expected to. Would you trade your Marantz 8 or Citation V for a Carver 275? What I own has absolutely no bearing...

audiokarma.org

I mention this mostly because it contains a link to a newer version of the Carver 275 manual than the version which I had seen previouly.

The posting cites from the manual that in Bob Carvers world power is peak power which is 10 times the average power. Is this a new standard? Power = 75Wbcw?

 

[pma]

I wonder why so much turmoil about this mediocre tube circuit. A cult?

 

[anmpr1]

I wonder why so much turmoil about this mediocre tube circuit. A cult?

To understand, you have to understand Bob and his history. Bob has always done things 'a little differently', and with commensurate bombast. But, historically, he's always offered value for the dollar, and he's always delivered on his promises. Bob has always been about delivering legitimate amplifier power. Usually, a lot of it.

So, when he advertises a 75 watt amp, you naturally expect 75 clean, honest watts. Now, if this was just some guy no one has heard of, building one-offs in his basement or garage, as a hobby, and then selling them over the 'Net willy nilly, few would care one way or the other.

Likewise, if Bob was advertising a hand made 15 watt tube amp, no one would care. They might think it odd, given his history of high-powered designs. But no one would criticize him, as long as he gave you his promised 15 watts.

In a way, and from a strictly design standpoint, it's similar to Nelson Pass, and his little amp-camp toy. Not that (to his credit) Nelson sold it as anything other than what it offered; in fact, he didn't sell it at all (but I think someone is selling his design as a kit). Instead, he advertised it as a DIY way to have a good time, with like-minded fellows at a meet 'n greet, lunch and learn get-together. No problems there. However, when people investigated it, especially after the ASR review, it seemed odd that Nelson would stick his name to something so low-grade in the design department, given his history. From a practical standpoint it would have made more sense to assemble a Dynakit.

Think of it this way, there's a guy out there selling a 2 watt (stereo) SET amp for three large. It is a very nice looking two watt times two amp, with meters, retro knobs, and a polished wood case. But there's more people than not who would categorize a two watt SET selling for three thousand dollars as idiotic. However, that is not the point. At least from a commercial standpoint. As long as the maker is selling you his promised two watts, then there's no problem. At that point, it becomes simply a matter of personal value.

 

[mhardy6647]

I wonder why so much turmoil about this mediocre tube circuit. A cult?

Fair to say that Dr. Carver's status is cultish. He and his companies and products over the decades (some pretty decent, some dangerous to hearth and home, and some just whacky) are so widespread that it's kind of a macro-cult, and it spans lots of "disciplines". High-power solid state, loudspeakers/subwoofers, vacuum tube hifi, "Digital Time Lenses", "Sonic Holography".

I am not a member of this particular cult.

 

[anmpr1]

Fair to say that Dr. Carver's status is cultish. He and his companies and products over the decades (some pretty decent, some dangerous to hearth and home, and some just whacky) are so widespread that it's kind of a macro-cult, and it spans lots of "disciplines". High-power solid state, loudspeakers/subwoofers, vacuum tube hifi, "Digital Time Lenses", "Sonic Holography".

I always saw Bob as--to use an analogy--an audio counterpart to Carroll Shelby. What I mean by that, is Carroll had an out of the box type of automotive thinking. He didn't really care about ultimate refinement (in his street cars, not the racing stuff). His idea was to take a rough and ready, but marginal quality, British sports car, and stuff it with a small block V8, adding as much carburation as Ed Weber could sell him. As long as it had a seat belt and a roll bar, that was enough. It took people by surprise. But they were happy to see it. And he gave them what he promised.

When that wasn't enough for him, he ordered some big block crates, and got the Holley brothers on the phone. And that was that. At the time, and in context of the market, his stuff was 'affordable'. Certainly not overpriced. [Now, of course, you have to have more money than a 19th century robber baron to own an original, but that's not Carroll's fault.]

The analogy goes deeper, because (maybe) like current Bob, once Carroll started modding Dodge Omnis and Shadows, people started scratching their heads and moved on. The magic was gone, and they started wondering, 'why'?

In contrast, you had engineering teams, headed by people like Ferdinand Piech, who didn't relate to Shelby's 'off the shelf' (and off the wall) brand of automotive engineering. These men were into finesse. They didn't primarily care about the initial cost, as long as the body panels didn't have a gap. Straight line 'balls to the walls' performance was not their thing, but overall balance, and how it performed on the Nordschleife. They were not 'hot-rodders'.

Is Bob the leader of a 'cult'? I see him more as a 'blue collar' type of audio designer. Maybe a hot-rodder. I guess it depends on your definition. Is the SET crowd a cult? Or Nelson Pass's fans. What about John Curl? Peter Walker? Yoshiaki Sugano... All of those men have their die-hard fans. Some of them meet up, for 'amp camps'. But as far as I know, none of these guys have ever told their fans that the next camp will be in Guyana, and don't worry about bringing your own Kool-Aid, as drinks will be provided.

To me it doesn't matter who or what you like, but as a consumer, you deserve to get what is advertised, when they open the box.

 

[anmpr1]

The posting cites from the manual that in Bob Carvers world power is peak power which is 10 times the average power. Is this a new standard? Power = 75Wbcw?

Peak power is bogus for a guy like Bob. If that's what he's claiming, then that's pretty cheesy. Below is how Bob used to advertise, and how his gear used to test:

 

[mhardy6647]

Peak power is bogus for a guy like Bob. If that's what he's claiming, then that's pretty cheesy.

We just don't know, do we?
The power spec is, from my biased* perspective, cagily written, since it lacks any qualifier (e.g., [FTC-style] continuous, or peak, or IHF music power, for that matter). On the other hand, Bob Fitz's comment @ AK about the 10x power figure, extrapolating from the fusing, strikes me as a requiring a fairly large stretch to apply to the power "spec". But... we just don't know.
THAT said, we will know soon what the capability of a QC-passed, regular production amp tested by "normal" (industry standard, if you will) methods is. That's worth more than a spec -- and worth more than my/our spec-ulation.

spec page reproduced from the 275 manual at https://9d0691c9-2bb0-4a51-acf2-a4e...d/7c4708_fe81ce14b4b54e618bcfd77c7628d241.pdf
_________________
* That's probably fixed bias, to stick with the metaphors and the literal topic of the thread.

 

[LTig]

View attachment 176403
spec page reproduced from the 275 manual at https://9d0691c9-2bb0-4a51-acf2-a4e...d/7c4708_fe81ce14b4b54e618bcfd77c7628d241.pdf

There are no output transformer taps for 4, 8 and 16 Ohm. How's it possible that this amp delivers the same max power both to 4 and 8 Ohm loads?

 

[Martin]

Folks at AK are trying to figure out what "adamantine steel" is, if it even exists. ;-)

It is in make believe land...

Adamantine (Metal)

Amadeus Cho Like what's on your claw. Only godlier. Known as the Metal of the Gods,[1] Adamantine was an extremely durable metallic ore commonly used by the Olympian god Hephaestus. Adamantine had a golden appearance and several magical properties including: Enhanced Durability: Adamantine is...

marvel.fandom.com

I thought Malcolm McLaren may have had something to do with its invention.

Martin

 

[MaxBuck]

Carver seems to me to be a lot like Sears, Roebuck. Both companies were great when they stuck to their basic competencies (high-power SS amps and hardware, respectively), but lost the thread when they started to futz around with other stuff.

 

[mhardy6647]

There are no output transformer taps for 4, 8 and 16 Ohm. How's it possible that this amp delivers the same max power both to 4 and 8 Ohm loads?

I've been wondering about that too. Some more Carverian "sonic digital time lens magnetic field amazing holographics" (EDIT) magic, doubtless. Oops, I am displaying a hint of non-objectivity.
The original ("amp camp", so to speak) amps apparently have the OPTs with 8 ohm secondaries, per @paulbottlehead's photo in the first post of this thread.

 

[MakeMineVinyl]

There are no output transformer taps for 4, 8 and 16 Ohm. How's it possible that this amp delivers the same max power both to 4 and 8 Ohm loads?

As far as I know, with an output transformer, different load impedances will have different power delivered. Its always worked that way with every tube amp I've ever had/built.

 

[JayGilb]

Does anyone know if Mr Carver himself had any input into this design ? I'm guessing that he has got to be near or past 80 years old and would be surprised to see him still designing products.

 

[sarumbear]

Does anyone know if Mr Carver himself had any input into this design ? I'm guessing that he has got to be near or past 80 years old and would be surprised to see him still designing products.

https://viterbi.usc.edu/news/news/2014/usc-professor-ramo.htm

 

[JayGilb]

https://viterbi.usc.edu/news/news/2014/usc-professor-ramo.htm

Thanks for answering my question. After reading your linked article, I can say with 100% certainty that Bob designed every part of the circuit and hand painted the stripes on every resistor.

 

[mhardy6647]

Carver seems to me to be a lot like Sears, Roebuck. Both companies were great when they stuck to their basic competencies (high-power SS amps and hardware, respectively), but lost the thread when they started to futz around with other stuff.

I suspect that Dr. Bob himself would opine that he has/had some cred in the vacuum tube arena.

The irony is why, after all of his song and dance about transfer functions and the Stereophile (or TAS or wherever) challenge, that he even bothered to make vacuum tube products! His tube amps came well after the 'challenge' stuff, AFAIK.

Seems like a blatantly cynical move -- not unlike Schiit's SOL turntable debacle, (or, perhaps more to the point, seeming debacle), which I still think was just a raised middle digit from the Schiit Boys to the vinylista.

 

[LTig]

As far as I know, with an output transformer, different load impedances will have different power delivered. Its always worked that way with every tube amp I've ever had/built.

So is my theoretical knowledge about transformers with one tap. With separate taps on the secondary side the power stage on the primary side sees a 4 Ohm load at the 4 Ohm tap as being identical to an 8 Ohm load at the 8 Ohm tap (or 2 Ohm/16 Ohms loads at their respective taps, if they are supplied).

 

[mhardy6647]

So is my theoretical knowledge about transformers with one tap. With separate taps on the secondary side the power stage on the primary side sees a 4 Ohm load at the 4 Ohm tap as being identical to an 8 Ohm load at the 8 Ohm tap (or 2 Ohm/16 Ohms loads at their respective taps, if they are supplied).

That's the idea, AFAIK. matching the source to the load (impedance-wise).
Transformers aren't as evil as some folks think they are. Indeed, they're pretty enabling components, and their operation (heck, their existence) is just on this side of magic -- at least from my perspective.