Carver Crimson 275 Measurements

[BDWoody]

The amp is here....

Might make a good one for YouTube...

 

[MakeMineVinyl]

The amp is here....

If you need a load resistor to do the testing, I can send you one.

 

[mhardy6647]

The amp is here....

I'll just recycle this .GIF I already posted here someplace in this very thread.

\

@MakeMineVinyl -- I just laughed the hardest I've laughed all day thanks to your post above (and it's been a pretty good day already, laughter-wise).

 

[Blumlein 88]

Wish we could get Bob Carver to comment on this here. So far he it looks like someone with their hand caught in the cookie jar.

 

[TriodeLuvr]

If Jim and Bob want to post some scope shots proving otherwise, I'll be the first to eat my words.

Isn't that like asking the fox to confirm the chickens are OK?

 

[Xulonn]

Tomorrow I will drop off the production unit to Amir.

Bring a shovel - Amir might need help with re-doing his foundation configuration and runnoff water drainage...

 

[Chazz6]

From Carver amp dealer Jim Clark, posted on a forum page at his website:

January 10, 2022 at 12:42 pm

QUESTION: Bob, how can a 75 watt tube amp use such small output transformers and be lightweight ?

ANSWER: I’ve always designed amplifiers that had lots of power and lighter weight than others designs. The transformer size can be made smaller by using fine wire and specified materials. There is no magic, because it adds inefficiencies in other ways like power, but the design has more than enough power.

QUESTION: Bob, A guy is claiming a 275 makes 17 watts with strange distortion numbers any thoughts?

ANSWER: Thats ridiculous, a 75 watt amp.. Isn’t it obvious? It is being test wrong or its damaged.. My amps can be difficult to test, difficult to get the grounding correct. I’ve been dealing with people testing my designs wrong and getting grounding errors effecting measurements, most of my life.

QUESTION: Bob is it fair to say that you design amplifiers for reproducing music into dynamic loudspeaker loads, more so than focusing on reproducing sine waves into load resistors?

ANSWER: There is some truth to that. My amps can perform way above there power rating for a time, a time being several seconds.

Carverfest Amps and how to measure them. A note from Bob. – Carver Stereo Forum

Jim Clark implies this is an excerpt from an interview with Bob Carver, with sloppy formatting and punctuation, but no citation or stated claim that it is from an interview.

Mr. Clark has his retail business to motivate his actions. Frank Malitz seems incapable of talking anything other than carnival spiel. But if Bob Carver actually digs in as this post purports, it is just sad.

 

[teched58]

Have you seen the replies to this thread on the Jim Clark forum? They claim there's a special way to test them?

Carverfest Amps and how to measure them. A note from Bob. – Carver Stereo Forum

QUESTION: Bob, A guy is claiming a 275 makes 17 watts with strange distortion numbers any thoughts?



ANSWER: Thats ridiculous, a 75 watt amp.. Isn’t it obvious? It is being test wrong or its damaged.. My amps can be difficult to test, difficult to get the grounding correct. I’ve been dealing with people testing my designs wrong and getting grounding errors effecting measurements, most of my life.

This is REALLY offensive. They must take their customers to be complete idiots. Jim and Bob (let's just call them Jim Bob) act like electronics is some kind of Harry Potter handwaving magic discipline, instead of a well understood science. They must assume -- and perhaps, based on the evidence (sales), they are correct -- that their customers think things like V = IR are GUIDELINES, and you can get around them if you pack enough b.s. underneath the large metal cans which hide your puny 15W transformer.

I find it completely disgusting, all the more so because it was Bob who 35 years ago stuck a burr under Stereophile's bonnet with his correct observation that what an amplifier produces at its output is a result of its transfer function, not its price. Rules for thee but not for me, I guess.

 

[TriodeLuvr]

It seems likely at this point that Carver intends to combat this with red herrings. What's the next step if Amir (whom I don't know) confirms the shortcomings of the product? Unless the Bob Carver company is willing to voluntarily eat these amplifiers, you'll need a report from an independent testing lab with calibrated equipment to force a remedy or to file a complaint with the FTC. Do Amir's facilities qualify in that respect? Just wondering what the end game might be...

 

[Zackthedog]

It seems likely at this point that Carver intends to combat this with red herrings. What's the next step if Amir (whom I don't know) confirms the shortcomings of the product? Unless the Bob Carver company is willing to voluntarily eat these amplifiers, you'll need a report from an independent testing lab with calibrated equipment to force a remedy or to file a complaint with the FTC. Do Amir's facilities qualify in that respect? Just wondering what the end game might be...

I seriously doubt anything like that is going to happen. Present owners will decide whether or not it works to their satisfaction. Future buyers, if they're diligent, may turn to this forum and be put off by the measurements. Jim will probably convince his customers it's just a mistake and the amp offers musical satisfaction.

 

[sergeauckland]

It seems to me that the way to measure this amp is to use a fully floating level and distortion meter. There can then be no issue with grounding. If Carver is right, and the low power is an artefact of the way it's measured, then all well and good. Although unconventional, there's no requirement for the - terminal to be at ground potential, as in normal use, a loudspeaker load isn't grounded.


Let's leave it to Amir to measure it as the manufacturer suggests Watts is Watts, and if it takes a floating load for this amp to work correctly, so be it.

If grounding the output terminal shorts out the feedback, then it's not surprising the amp won't work as designed. I have to say I'm very sceptical of such a small output transformer doing 75 watts at anything below 1kHz, but until we see the numbers, it remains speculation.

 

[Xulonn]

 

[paulbottlehead]

Have the flood waters receded that is the pressing question?

I definitely took the wrong car to Amir's house! It's still pretty wet out there.

 

[TriodeLuvr]

It seems to me that the way to measure this amp is to use a fully floating level and distortion meter. There can then be no issue with grounding. If Carver is right, and the low power is an artefact of the way it's measured, then all well and good. Although unconventional, there's no requirement for the - terminal to be at ground potential, as in normal use, a loudspeaker load isn't grounded.


Let's leave it to Amir to measure it as the manufacturer suggests Watts is Watts, and if it takes a floating load for this amp to work correctly, so be it.

If grounding the output terminal shorts out the feedback, then it's not surprising the amp won't work as designed. I have to say I'm very sceptical of such a small output transformer doing 75 watts at anything below 1kHz, but until we see the numbers, it remains speculation.

The problem isn't that it's a "small" transformer. The problem is it's a 15 watt transformer. Then there's the main power supply transformer, which also lacks the necessary ratings to provide the power levels claimed for this amp.

 

[TriodeLuvr]

I seriously doubt anything like that is going to happen. Present owners will decide whether or not it works to their satisfaction. Future buyers, if they're diligent, may turn to this forum and be put off by the measurements. Jim will probably convince his customers it's just a mistake and the amp offers musical satisfaction.

I think you're going to find that more than one owner will pursue this to whatever extent it can be reasonably accommodated in the context of time and cost. I certainly would.

 

[mhardy6647]

Not to go all Perry Mason on this*, but:

If the amps are difficult to test (because of some magic grounding scheme that's not intuitive to someone who does this stuff for a living) -- would that not mean that it would be difficult to use for an ordinary dope-smokin' schlub off the mean streets of Seattle?

Would that not mean such, Dr. Carver?


___________________________
* The Raymond Burr version, that is.

 

[amirm]

Have the flood waters receded that is the pressing question?

Mitigation appears to be working....

 

[Xulonn]

Mitigation appears to be working....

Too bad that Carver amp is such a low-power weenie - if it were a true, robust 75WPC tube amp like this VTA-120, you could fire it up and the heat from those big KT120's would help dry out your house.

 

[sergeauckland]

Not to go all Perry Mason on this*, but:

If the amps are difficult to test (because of some magic grounding scheme that's not intuitive to someone who does this stuff for a living) -- would that not mean that it would be difficult to use for an ordinary dope-smokin' schlub off the mean streets of Seattle?

Would that not mean such, Dr. Carver?


___________________________
* The Raymond Burr version, that is.

No, assuming it does work as advertised, something I'm seriously sceptical of, the peculiar grounding only affects measurements, as loudspeakers are floating devices so would connect as the amp requires. Anybody buying this and using it for the purpose of driving loudspeakers won't be affected.

S

 

[Zackthedog]

It seems to me that the way to measure this amp is to use a fully floating level and distortion meter. There can then be no issue with grounding. If Carver is right, and the low power is an artefact of the way it's measured, then all well and good. Although unconventional, there's no requirement for the - terminal to be at ground potential, as in normal use, a loudspeaker load isn't grounded.


Let's leave it to Amir to measure it as the manufacturer suggests Watts is Watts, and if it takes a floating load for this amp to work correctly, so be it.

If grounding the output terminal shorts out the feedback, then it's not surprising the amp won't work as designed. I have to say I'm very sceptical of such a small output transformer doing 75 watts at anything below 1kHz, but until we see the numbers, it remains speculation.

It doesn't short out the main feedback circuit. If that were the case (a short from output to input) there would be almost no gain at all and the amp would behave very badly indeed. If it bypassed the feedback, the gain would be excessive and Paul would surely have noticed. It's just another compensation factor that, if I understand correctly, shouldn't affect the amps behavior into a fixed load.