Carver Crimson 275 Measurements

[paulbottlehead]

I'm on day 11 of waiting for my 275 to arrive. Hopefully FedEx hasn't lost it!

 

[mhardy6647]

Yeah.
"lost" it...

 

[paulbottlehead]

What's really disturbing is there is also a Blue Apron box of food in the FedEx system that has been sitting somewhere for even longer. I definitely will be refusing to accept that one!

 

[mhardy6647]

What's really disturbing is there is also a Blue Apron box of food in the FedEx system that has been sitting somewhere for even longer. I definitely will be refusing to accept that one!

oh the humanity!

 

[Larry B. Larabee]

Since the Carver will be delivered soon can you tell us about your test equipment and your test methods. For instance, did you make any of the previously posted measurements in room with say, a laptop and mic and maybe free software?
Just curious.
I have a sinking feeling that the results of this ordeal won't turn out positively for anyone involved in it.
That includes Carver, you and ASR.

 

[Zackthedog]

I have never tried to pull transformer covers. Absent first hand knowledge, is it typical to have to do so much disassembly to get them off? Is it that way on say...a McIntosh 275? If not usually the case, does this feel like a deliberate design to impede casual examination of the transformers? Or am I talkin' out the side of my neck?

According to the promotional literature, the small output transformer was a bragging point. If they had wanted to conceal it, they would have potted it.

 

[Larry B. Larabee]

What an odd thing to say.

I wouldn't say it's odd since we don't really know anything for sure, yet. Let's wait for independent, valid tests and see.

 

[mhardy6647]

There was some indication of a small power transformer, too, IIRC, in the promotional blurbs that accompanied the introduction of this amplifier. More revolutionary stuff, like the Carver Cube's power supply, I guess. But the Cube was ss, not tubed.

My hunch is that the small power transformer correlates with the notion that the amp was not designed to allow 75 watts of continuous power output, both channels, broad band. The printed specs, indeed, make no such claim. Caveat emptor, you know?

 

[teched58]

There was some indication of a small power transformer, too, IIRC, in the promotional blurbs that accompanied the introduction of this amplifier. More revolutionary stuff, like the Carver Cube's power supply, I guess. But the Cube was ss, not tubed.

My hunch is that the small power transformer correlates with the notion that the amp was not designed to allow 75 watts of continuous power output, both channels, broad band. The printed specs, indeed, make no such claim. Caveat emptor, you know?

Can you point me to the printed specs you reference? The ones I see (which are here) certainly indicate continuous power, both channels driven, full frequency response:

////////////////////////
Rated Power:
More than 75 Watts Per Channel, minimum, typically 90 watts, both channels driven at eight ohms, from 20Hz to 20kHz with no more than 1% total harmonic distortion. Distortion decreases at lower levels.

4Ω 75 Watts Per Channel
8Ω 75 Watts Per Channel
16Ω 60 Watts Per Channel

/////////////////////

 

[Zackthedog]

Since the Carver will be delivered soon can you tell us about your test equipment and your test methods. For instance, did you make any of the previously posted measurements in room with say, a laptop and mic and maybe free software?
Just curious.
I have a sinking feeling that the results of this ordeal won't turn out positively for anyone involved in it.
That includes Carver, you and ASR.

Larry, he connected the amps to a high-quality 'scope and signal generator and measured the results directly, which is a perfectly valid method of testing. It doesn't tell you *everything* but it tells you an awful lot. After some initial skepticism, I don't think any technically-minded contributor here questions that, though I'm happy to be corrected. I don't think Paul or ASR have anything to worry about here. Since the Audiogon thread confirms that the production amps use the exact same output transformer, I don't expect the results will be much different.

I would be interested to see the square waves. I also wonder how the amp performs with a reactive load, like an actual loudspeaker. But that's a difficult test to perform.

 

[mhardy6647]

Can you point me to the printed specs you reference? The ones I see (which are here) certainly indicate continuous power, both channels driven, full frequency response:

////////////////////////
Rated Power:
More than 75 Watts Per Channel, minimum, typically 90 watts, both channels driven at eight ohms, from 20Hz to 20kHz with no more than 1% total harmonic distortion. Distortion decreases at lower levels.

4Ω 75 Watts Per Channel
8Ω 75 Watts Per Channel
16Ω 60 Watts Per Channel

/////////////////////

Same specs you quoted. I believe I posted a screenshot earlier.
I don't see the word continuous in there -- do you?
I don't think it was an innocent omission. I'll rephrase that. It is a curious omission.

 

[Larry B. Larabee]

Larry, he connected the amps to a high-quality 'scope and signal generator and measured the results directly, which is a perfectly valid method of testing. It doesn't tell you *everything* but it tells you an awful lot. After some initial skepticism, I don't think any technically-minded contributor here questions that, though I'm happy to be corrected. I don't think Paul or ASR have anything to worry about here. Since the Audiogon thread confirms that the production amps use the exact same output transformer, I don't expect the results will be much different.

I would be interested to see the square waves. I also wonder how the amp performs with a reactive load, like an actual loudspeaker. But that's a difficult test to perform.

Hi,
I asked at the beginning of thread for a measurement at any low frequency at any power level necessary to reproduce something that looked like a sine wave instead of the severely crippled output shown that represented nothing about the (lack of) performance of the amp. The OP insisted on setting the output close to clipping at 1khz and moving down from there. I want graphs everyone is familiar with instead of rudimentary pictures where the test conditions can't be readily determined. The point is, I want someone else to test the amp before commiting to anything.

 

[tmtomh]

Hi,
I asked at the beginning of thread for a measurement at any low frequency at any power level necessary to reproduce something that looked like a sine wave instead of the severely crippled output shown that represented nothing about the (lack of) performance of the amp. The OP insisted on setting the output close to clipping at 1khz and moving down from there. I want graphs everyone is familiar with instead of rudimentary pictures where the test conditions can't be readily determined. The point is, I want someone else to test the amp before commiting to anything.

You’re certainly free to want what you want.

 

[Grumpish]

then someone drops something on it

I did exactly that with one of my last builds while I had it on the bench doing the checkouts and initial bias setup - it was way beyond my limited skills to repair the fine connections from the windings. And those Lundahl transformers ain't cheap.

 

[mhardy6647]

So, after perusing a bunch of modern two-channel consumer (domestic) audio equipment specs, I'll back down on my continuous power harangue.

Even though, AFAIK, some remnant of the US FTC power claims regulations are yet in place for such equipment, most specs even from reputable manufacturers for their products (e.g., McIntosh MC275) make no claim of continuous power capability, although I do note the words "rated power" appear in many contemporary specifications (including the Mac's).

 

[Thermionics]

oh the humanity!

Perhaps it contains some fresh Soylent Green(tm). It is 2022, after all.

 

[Zackthedog]

Hi,
I asked at the beginning of thread for a measurement at any low frequency at any power level necessary to reproduce something that looked like a sine wave instead of the severely crippled output shown that represented nothing about the (lack of) performance of the amp. The OP insisted on setting the output close to clipping at 1khz and moving down from there. I want graphs everyone is familiar with instead of rudimentary pictures where the test conditions can't be readily determined. The point is, I want someone else to test the amp before commiting to anything.

That's why he's having Amir test it when it arrives.

 

[MakeMineVinyl]

So, after perusing a bunch of modern two-channel consumer (domestic) audio equipment specs, I'll back down on my continuous power harangue.

Even though, AFAIK, some remnant of the US FTC power claims regulations are yet in place for such equipment, most specs even from reputable manufacturers for their products (e.g., McIntosh MC275) make no claim of continuous power capability, although I do note the words "rated power" appear in many contemporary specifications (including the Mac's).

My MC240 does say 'continuous' in the owner's manual:

 

[Omar Cumming]

If your advertised power rating is anything other than continuous (which is what everyone expects these days) you should specify it. Otherwise you are deliberately misleading people.

Cheers

 

[paulbottlehead]

Hi,
I asked at the beginning of thread for a measurement at any low frequency at any power level necessary to reproduce something that looked like a sine wave instead of the severely crippled output shown that represented nothing about the (lack of) performance of the amp. The OP insisted on setting the output close to clipping at 1khz and moving down from there. I want graphs everyone is familiar with instead of rudimentary pictures where the test conditions can't be readily determined. The point is, I want someone else to test the amp before commiting to anything.

Here's a sine wave. 50Hz at about 8W into an 8 ohm resistor.