Carver Crimson 275 Review (Tube Amp)

[teched58]

If you have zoned A/C, and especially a zone in your audio room/multi-media equipment closet, running tubes costs about $6 more a month than not running tubes. They have zoned a/c in the EU (mini splits), if you had a dedicated unit in the media room, high SEAR, it would be minuscule. One of the EE's on here could easily figure it out for you.

I do have zoned A/C. It's an air conditioner in the window.

 

[fpitas]

I don't recall ever seeing anyone quote or reference such a rule, except to possibly get EU Certification. I may have missed it, but I don't recall seeing a reference to any requirements, rules, codes regarding how an audio amplifier is grounded in the US.

I *think* that, if the unit has a three-prong plug on the supplied cord, the grounding prong has to go to chassis.

 

[antcollinet]

FFS,go away already...You can't continually live in denial here.If you don't think ASR's honest review(Google ranked NUMBER 1) hasn't damaged his "reputation".Casually hinting at nebulous legal actions and generally being a blowhard.Man you are the worst of the worst of typical audio forum idiocy.

Please try and stick to the argument - this is not the place for ad hominem.

 

[antcollinet]

I *think* that, if the unit has a three-prong plug on the supplied cord, the grounding prong has to go to chassis.

I'm sort of interested in the legal mandates in USA regardiing electrical safety of consumer kit.

Here in in Europe (even still in the UK) we have CE certification - which covers both safety and emc requirements - being a legal mandate - with all the standards that state what is required to meet that.

As far as I can see, the standards in USA have pretty much the same requirements - but I can't find anything clear about the legal mandate for meeting those standards. As far as I can see it is legislated at the state level (which doesn't help clarity), and it seems that most states require compliance with NEC standards of one version or another - but it is far from easy to work out.

Are you (or anyone else) aware of any clear references?

 

[fpitas]

I'm sort of interested in the legal mandates in USA regardiing electrical safety of consumer kit.

Here in in Europe (even still in the UK) we have CE certification - which covers both safety and emc requirements - being a legal mandate - with all the standards that state what is required to meet that.

As far as I can see, the standards in USA have pretty much the same requirements - but I can't find anything clear about the legal mandate for meeting those standards. As far as I can see it is legislated at the state level (which doesn't help clarity), and it seems that most states require compliance with NEC standards of one version or another - but it is far from easy to work out.

Are you (or anyone else) aware of any clear references?

If it seems hazy, that's because it often is. Many manufacturers get UL and/or CE certification as a legal protection.

 

[mhardy6647]

A question would be... on the Black Magic 25 is the ground pin now (properly) connected to the chassis and is that 1M resistor removed ?
There still is no 'double isolated' symbol printed on the back and a 3 prong IEC socket is still used which would be suggesting safety ground works as safetyground should work.
When it is double isolated inside then a 2 pin socket should be used that prevents 3-prong cables to be used.

I too suspect it is the same amp but different paint and naming and 'more accurate' specs.
Someone needs to send one in for testing...

Not exactly the same, at least in the sense that the default output tube seems to have been switched to EL34.

The previous morph (the now infamous "Crimson 275") used a Kinkless Tetrode as the default output tube (KT120).

 

[atmasphere]

I don't recall ever seeing anyone quote or reference such a rule, except to possibly get EU Certification. I may have missed it, but I don't recall seeing a reference to any requirements, rules, codes regarding how an audio amplifier is grounded in the US.

The US is a bit of the wild west. You can get away with murder as long as you don't kill anyone. The US relies on someone bringing a damaging lawsuit. The problem with that is the lawsuit might put an irresponsible/ignorant party out of business, but it won't stop others from doing the exact same thing.

So some amps are properly grounded and others are not. Amps with UL approval or the CE mark, if using a metal chassis, will be grounded through the power cord.

 

[antcollinet]

The US is a bit of the wild west. You can get away with murder as long as you don't kill anyone. The US relies on someone bringing a damaging lawsuit. The problem with that is the lawsuit might put an irresponsible/ignorant party out of business, but it won't stop others from doing the exact same thing.

So some amps are properly grounded and others are not. Amps with UL approval or the CE mark, if using a metal chassis, will be grounded through the power cord.

Or there will be double/reinforced insulation to that chassis.

 

[solderdude]

Not exactly the same, at least in the sense that the default output tube seems to have been switched to EL34.

View attachment 249761

The previous morph (the now infamous "Crimson 275") used a Kinkless Tetrode as the default output tube (KT120).

You can also use the KT120:

KT-120 tubes (customer supplied): Stereo: 75 wpc @ 1 kHz. 8 ohms. Less than .5% THD+N.
Then it is probably the same.. right down to the specified power.

 

[Rottmannash]

"Kinkless Tetrode"- my tetrodes must be kinky or else...

 

[mhardy6647]

You can also use the KT120:

KT-120 tubes (customer supplied): Stereo: 75 wpc @ 1 kHz. 8 ohms. Less than .5% THD+N.
Then it is probably the same.. right down to the specified power.

Well... I assumed the other KT tubes could be used (IIRC the 275 said that EL34 could be used -- of course, with reduced output power). I guess it's OK, since (again, IIRC) the original morph of this amp could deliver 75-ish watts per channel at 1 kHz.
We're talking about transistor-radio grade specifications, though, with 1kHz power output... aren't we?

 

[Travis]

I can't assess anyone's reputation. I get gear, test them using same setup as every other gear, and publish it. I finish every review with asking for feedback and correction. If the company provides such, as has happened in a few times, we discuss it and get to a consensus. In this case as you know, the company hasn't provided any alternative data so my measurements stand. What that does to their reputation is theirs to figure out. I am assuming since they abandoned us, they assume all is OK as you say.

Precisely, you give an honest and fair review, along with measurements done in a consistent and uniform fashion with due care. You provide an opportunity for feedback and the company an opportunity to respond. You do all of that without regard to what it does or doesn't do, to someone's reputation. That's "absence of malice." In the US, almost impossible to have defamation in absence of malice.

 

[Holmz]

Please try and stick to the argument - this is not the place for ad hominem.

Maybe there is an “ad shapeshifter“?

The fanboi crowd has been making “wraith like” appearances in Bob‘s name, so the thread seemed to intimate some frustration.

 

[Travis]

If it seems hazy, that's because it often is. Many manufacturers get UL and/or CE certification as a legal protection.

As I mentioned earlier, few if any hi-fi amplifier manufacturers get UL certification, or other NRTL certifications like CSA or ETL. Why, because you have to submit six samples for testing and you do not get them back. So McIntosh, Benchmark, NAD, Yamaha, Mark Levinson (I know for sure) do not get UL certification. There is no requirement in the US that an amplifier have UL (or similar NRTL certification).

There is zero significance to the fact that Carver, Sunfire, Phase Linear amps do not have a UL/CSA/ETL/EU certification. NONE.

Building, specifically electrical codes are what requires a product to be to have a UL certification/rating. Generally speaking, UL ratings for audio products that are permanently installed into a structure, in public areas where fire safety is critical (movie theaters) or areas that are frequently moist or wet. Pools, outdoors, etc. So, for example, in-wall or in-ceiling speakers are usually UL rated. Speakers AND amplifiers in movie theaters have to be UL rated (some Crown amps are UL and/or CSA and/or ETL rated). Amps and speakers near swimming pools need to be UL rated.

High-dollar amps and preamps for your home/home theater do not have to be UL rated and rarely are.

A UL rating doesn't provide any legal protection if you sell a product that was defective. E.g., didn't solder, terminate, or ground wire. Manufacturers get UL ratings so their products can be installed where building codes require them to be rated.

CE certification is nowhere near what a UL rating is. You pay someone to review your design to determine that it is environmentally and generally safe and they give you a Declaration of Conformance which allows your product to be marketed and sold to the EU. There is one safety standard (from 1998) regarding audio equipment, and about six others that are to confirm the product does not emit excessive radiation (microwave or RF), and is not overly sensitive to picking up radiation. I don't know enough about it to say how deep they go into grounding issues for CE certification. But that alone should not give you a fuzzy feeling to install audio equipment outdoors, near water, etc. A CE certification isn't enough to get the equipment installed where an electrical code requires a UL or other NRTL certification.

 

[dfuller]

"Kinkless Tetrode"- my tetrodes must be kinky or else...

Probably wouldn't want them that way, they tend to do strange things.

(No, but seriously - they self-oscillate and have weird negative resistance behavior - that's why pentodes and later beam tetrodes/kinkless tetrodes became a thing).

 

[mhardy6647]

Probably wouldn't want them that way, they tend to do strange things.

(No, but seriously - they self-oscillate and have weird negative resistance behavior - that's why pentodes and later beam tetrodes/kinkless tetrodes became a thing).

Yeppers. The tetrode kink led to the development of the beam tubes and pentodes -- there were also some some interesting IP/patent issues (as I recall) which is, again IIRC, at least part of the reason we had a proliferation of sort of similar, but sort of different power output tubes (e.g., the 6L6, the EL34 and its kith and kin).

The kink an sich.

See that wiggly-wooglie little disturbance at low plate voltages in the curves? That's the kink.

Notice the 'kink' that appears in the curves for low values of anodic voltage. The cause is the secondary emission caused by the impact of high kinetic energy electrons at the anode, which end up in the screen grid, causing a decrease of the anode current.

https://www.researchgate.net/figure/Typical-family-of-curves-of-a-tetrode-Notice-the-kink-that-appears-in-the-curves-for_fig18_319877861

 

[tomelex]

As I mentioned earlier, few if any hi-fi amplifier manufacturers get UL certification, or other NRTL certifications like CSA or ETL. Why, because you have to submit six samples for testing and you do not get them back. So McIntosh, Benchmark, NAD, Yamaha, Mark Levinson (I know for sure) do not get UL certification. There is no requirement in the US that an amplifier have UL (or similar NRTL certification).

There is zero significance to the fact that Carver, Sunfire, Phase Linear amps do not have a UL/CSA/ETL/EU certification. NONE.

Building, specifically electrical codes are what requires a product to be to have a UL certification/rating. Generally speaking, UL ratings for audio products that are permanently installed into a structure, in public areas where fire safety is critical (movie theaters) or areas that are frequently moist or wet. Pools, outdoors, etc. So, for example, in-wall or in-ceiling speakers are usually UL rated. Speakers AND amplifiers in movie theaters have to be UL rated (some Crown amps are UL and/or CSA and/or ETL rated). Amps and speakers near swimming pools need to be UL rated.

High-dollar amps and preamps for your home/home theater do not have to be UL rated and rarely are.

A UL rating doesn't provide any legal protection if you sell a product that was defective. E.g., didn't solder, terminate, or ground wire. Manufacturers get UL ratings so their products can be installed where building codes require them to be rated.

CE certification is nowhere near what a UL rating is. You pay someone to review your design to determine that it is environmentally and generally safe and they give you a Declaration of Conformance which allows your product to be marketed and sold to the EU. There is one safety standard (from 1998) regarding audio equipment, and about six others that are to confirm the product does not emit excessive radiation (microwave or RF), and is not overly sensitive to picking up radiation. I don't know enough about it to say how deep they go into grounding issues for CE certification. But that alone should not give you a fuzzy feeling to install audio equipment outdoors, near water, etc. A CE certification isn't enough to get the equipment installed where an electrical code requires a UL or other NRTL certification.

It used to be, perhaps still is, that as long as the manager of the company self certified, that was it, no need to pay anyone. Many products that came for example from Denmark just had a letter in the manual from the company president that said the said product conformed to EU norms etc. with a signature, and that was it.

 

[solderdude]

CE is self certification (the manufacturer has to measure or have it done) and also includes safety and ESD aspects and required for the EU market.
For home, industrial, medical, railway and automotive for instance there are different requirements/standards when it comes to electrical gear and countries/companies may have additional requirements.
One can do the measurements themselves or have it done at a certified lab. When the manufacturer states it complies then they can print a CE logo on it.
Every change of component that could influence emission, safety, immunity in the required fields should lead to re-testing, which in practice never happens with smaller businesses.
Only when something happens to someone or it catches fire and causes damages one can go to court and then the manufacturer has to prove the equipment (as designed) complied to the required standards.
A failure of a device is another story though.

For instance, when during testing it does not catch fire it is a pass. (Not Nelson)
But that does not mean a device cannot have a catastrophic failure in the circuit and catch fire and burn the house down. Even when it complies to all requirements in the norms it has to comply to.

In case of this amp when it would have been submitted for EMC testing the company that would have done the testing would have recommended to connect the safety ground lug and maybe some other small things.
While doing such tests Carver would have been allowed to make small modifications (for instance connect the ground pin to the chassis). This would be noted in the report that comes with the certificate.
After that certification all models should have the ground pin connected.
But... the manufacturer then could build the models without the ground pin connected and unless someone or some things get damaged because of the lack of safety ground and goes to court no-one will ever do anything about it.
Even within the testing limits one has classes where for instance with immunity one can pick a class. One can choose classes like 'there is an influence but no damage and self correcting, or allow the device to power off, or want no influence at all. This all needs to be monitored during all the relevant testing and is reported.

If I were EMC testing it I would have remarked about the lack of grounding and either check it for class II instead of class I.
The mains socket suggests it is class I so would recommend to either connect the ground pin or use a class-II IEC60320 C8 or C18 type socket and print a class-II symbol on it.

Fairly certain this device was never EMC tested.

 

[antcollinet]

CE is self certification (the manufacturer has to measure or have it done) and also includes safety and ESD aspects and required for the EU market.
For home, industrial, medical, railway and automotive for instance there are different requirements/standards when it comes to electrical gear and countries/companies may have additional requirements.
One can do the measurements themselves or have it done at a certified lab. When the manufacturer states it complies then they can print a CE logo on it.
Every change of component that could influence emission, safety, immunity in the required fields should lead to re-testing, which in practice never happens with smaller businesses.
Only when something happens to someone or it catches fire and causes damages one can go to court and then the manufacturer has to prove the equipment (as designed) complied to the required standards.
A failure of a device is another story though.

For instance, when during testing it does not catch fire it is a pass. (Not Nelson)
But that does not mean a device cannot have a catastrophic failure in the circuit and catch fire and burn the house down. Even when it complies to all requirements in the norms it has to comply to.

In case of this amp when it would have been submitted for EMC testing the company that would have done the testing would have recommended to connect the safety ground lug and maybe some other small things.
While doing such tests Carver would have been allowed to make small modifications (for instance connect the ground pin to the chassis). This would be noted in the report that comes with the certificate.
After that certification all models should have the ground pin connected.
But... the manufacturer then could build the models without the ground pin connected and unless someone or some things get damaged because of the lack of safety ground and goes to court no-one will ever do anything about it.
Even within the testing limits one has classes where for instance with immunity one can pick a class. One can choose classes like 'there is an influence but no damage and self correcting, or allow the device to power off, or want no influence at all. This all needs to be monitored during all the relevant testing and is reported.

If I were EMC testing it I would have remarked about the lack of grounding and either check it for class II instead of class I.
The mains socket suggests it is class I so would recommend to either connect the ground pin or use a class-II IEC60320 C8 or C18 type socket and print a class-II symbol on it.

Fairly certain this device was never EMC tested.

Only one correction I would make to that - the safety ground is related to the electrical safety requirements of CE, not the EMC (as long as emissions and susceptibility can be passed without it).

Class 1 (grounded) or Class 2 (double insulated) are mandatory for compliance. No wiggle room. You can't test for double insulation - you have to prove it by design. It can be quite challenging to get right.

 

[Travis]

It used to be, perhaps still is, that as long as the manager of the company self certified, that was it, no need to pay anyone. Many products that came for example from Denmark just had a letter in the manual from the company president that said the said product conformed to EU norms etc. with a signature, and that was it.

That may very well be. I know that I see ads for "EU Certification" all the time, it is a design review, not product testing.