Carver Crimson 275 Measurements

[paulbottlehead]

Here is a 50W rated Edcor I have in my iron stash sitting on top of one of the shield cans. I have some 100W Edcor PP transformers in a different project, and they are made with lams another size larger and the same stack size.

 

[Martin]

Can we say that? I've seen many measured reviews of Carver gear over the years, but never anything like this. What we know is that a new member of the forum, with no history, posts a very troubling review. Yet we have no background about the gear in question. Where did they come from, how were they bought, how old are they, was any attempt made to contact the dealer or the manufacturer? Many questions, few answers.

Again, if what we have been shown is representative of Bob's current product, then it's a very sad day indeed. Sad for Bob, his company, and consumers who trusted him over the years, and bought his gear. But we really don't know that for sure. Until the questions are answered, until we know more, I think caution is in order.

I'll give Bob the benefit of the doubt if he sends @amirm a Crimson 275 stereo or 350 monoblock amp to test...

Martin

 

[TriodeLuvr]

I am still awaiting an official ruling one way or the other on whether my post comes back or not. I actually asked a moderator about whether I could post this information or not and he said yes. In the discussion thread I let people know measurements were coming, and the site owner was present and replying to that thread.

If they do not put my post back, I will call them out here for it certainly.

A number of posts were deleted from that thread, including several of mine. Didn't the site owner involved in the discussion say he's a long-time friend of Bob Carver? I'm sure that's just a coincidence.

 

[Ron Texas]

Can we say that? I've seen many measured reviews of Carver gear over the years, but never anything like this. What we know is that a new member of the forum, with no history, posts a very troubling review. Yet we have no background about the gear in question. Where did they come from, how were they bought, how old are they, was any attempt made to contact the dealer or the manufacturer? Many questions, few answers.

Again, if what we have been shown is representative of Bob's current product, then it's a very sad day indeed. Sad for Bob, his company, and consumers who trusted him over the years, and bought his gear. But we really don't know that for sure. Until the questions are answered, until we know more, I think caution is in order.

So, let's kill the messenger...

 

[Larry B. Larabee]

I hope the OP put the subwoofer switch in the correct position. In any case how about taking a measurement within the amps linear range if it has one. This guy looks sketchy, nonetheless.

 

[paulbottlehead]

Just to be clear: I'm not saying that these examples are not representative of production. If they are, then that is certainly pathetic. But something doesn't appear totally right, and I'm willing to give Carver the benefit of the doubt until its sorted out.

How many would I need to measure to convince you, or would having Amirm measure these separately be helpful?

 

[paulbottlehead]

I hope the OP put the subwoofer switch in the correct position. In any case how about taking a measurement within the amps linear range if it has one. This guy looks sketchy, nonetheless.

The sub switches were both set to full range, as is evident in the frequency response measurement that was rather flat.

I can certainly bring one of these up till I just see clipping at 1khz, then make a plot of how that amplitude changes at various frequencies.

 

[TriodeLuvr]

Back in the day, one percent distortion was about what you expected from a decent tube amplifier.

1% at rated output, not at one-tenth rated output. I just finished a 30W/ch amp with vintage iron that measures better than 0.05% at 5W out. I don't consider this performance to be atypical.

 

[Vict0r]

@paulbottlehead Good to see you here. I owned a Bottlehead Crack almost a decade ago. It was my first "serious" headphone amplifier. I liked it for my HD600. I bumped it off a table and it died. I was sad. My then-girlfriend bought me a Bravo Tube amp and I feigned enthusiasm because I hoped it was a new Crack.

Is there any way to get this Carver to Amir? Would love to see the results.

 

[TriodeLuvr]

I hope the OP put the subwoofer switch in the correct position. In any case how about taking a measurement within the amps linear range if it has one. This guy looks sketchy, nonetheless.

I hope you're not referring to Paul. He's probably built more tube amps from scratch than most people will ever own. He also works for a highly reputable manufacturer of high-end tube equipment. The only thing questionable in all this is Bob Carver's qualifications in the arena of tube amplification. I've been involved in audio on and off since the late '60s, and as far as I know, Bob's talents lie solely in solid state. The evidence of this is right in front of you.

Jack

 

[paulbottlehead]

I hope he's available in the near future. I believe the signed amp is one I can borrow a little longer than the unsinged one, and I'm certainly happy to drive that over to he can bench test it.

 

[paulbottlehead]

He also works for a highly reputable manufacturer of high-end tube equipment.

That might be a stretch Have you seen our 90s product photos???

 

[Larry B. Larabee]

The sub switches were both set to full range, as is evident in the frequency response measurement that was rather flat.

I can certainly bring one of these up till I just see clipping at 1khz, then make a plot of how that amplitude changes at various frequencies.

That's good, it seemed to be more than a coincidence that you had a hi pass looking output level at low frequencies.
What FR measurement? Can we see it. Why do these 'sine wave' scope pictures look like you unintentionally grounded the output somewhere instead of it floating? Can you show something that looks like a sine wave at any level at any frequency to prove the amp actually works. You have .99%thd at 0W at 20hz, how do you get a thd measurement without a signal?

 

[anmpr1]

So, let's kill the messenger...

Come on, Ron. I'm just asking for some background. The OP has still not answered my questions about contacting the dealer and/or Carver himself. We don't know where the amps came from, their history, and so forth. Are those unreasonable questions to ask?

If what he is saying is the whole story, then he has made an auspicious entry to ASR. But wouldn't you want to know the other half of the story? If there is one?

 

[Ron Texas]

Come on, Ron. I'm just asking for some background. The OP has still not answered my questions about contacting the dealer and/or Carver himself. We don't know where the amps came from, their history, and so forth. Are those unreasonable questions to ask?

If what he is saying is the whole story, then he has made an auspicious entry to ASR. But wouldn't you want to know the other half of the story? If there is one?

Statements like "someone is a new member" are personal attacks. Not knowing where the amps came from implies all tests of vintage gear are suspect. Nobody is obligated to answer your questions.

 

[anmpr1]

How many would I need to measure to convince you, or would having Amirm measure these separately be helpful?

That's not the point. But to answer your question--one is enough it is representative of current production. Again, tell us the history of the amps. Are they still under the five year warranty. Did you contact the dealer? Did you contact Bob? What did the dealer and/or Bob tell you?

I think if you are going to come here and make allegations, then we have a right to know these things. Just to keep everything in context. As I said, if you have discovered something fraudulent about what Bob Carver is doing, then highlighting that is a good thing. But can't we know the background?

Also, someone who is making a 'competing' product should be extra careful about being open and forthcoming. That is always a good practice. Otherwise someone could accuse you of sour grapes, or someone with an ulterior motive. You know that.

 

[anmpr1]

Statements like someone is a new member are personal attacks. Not knowing where the amps came from implies all tests of vintage gear are suspect. Nobody is obligated to answer your questions.

I didn't mean to 'personally attack' the OP. That was not my intentions at all. With most folks here, I have a history, and they have a history, and we can therefore judge each other, based on that. One gets an 'idea' of where one is coming from based on their known history. For all I know the OP is totally legitimate, with no hidden agenda. But since he is new, and provides minimal background, I believe I am justified in asking the questions. Even if it was an 'old timer' I would want to know those questions I asked.

Likewise, Bob Carver has a known history. And this thing is really contrary to what he has done, historically. So I admit to some skepticism. But as I wrote, if it is representative of what he is now doing, then that is a bad situation for him, his customers, and hi-fi in general. And in that case, the OP deserves credit for bringing it everyone's attention.

 

[paulbottlehead]

That's not the point. But to answer your question--one is enough it is representative of current production. Again, tell us the history of the amps. Are they still under the five year warranty. Did you contact the dealer? Did you contact Bob? What did the dealer and/or Bob tell you?

I think if you are going to come here and make allegations, then we have a right to know these things. Just to keep everything in context. As I said, if you have discovered something fraudulent about what Bob Carver is doing, then highlighting that is a good thing. But can't we know the background?

Also, someone who is making a 'competing' product should be extra careful about being open and forthcoming. That is always a good practice. Otherwise someone could accuse you of sour grapes, or someone with an ulterior motive. You know that.

I do not know the history of these amps, and I'm not sure how that matters. I test a lot of vintage amps that are way, way outside of any warranties and they do just fine.

I'm not sure how flea watt single ended amps are really competing with 75+ watt push-pull amps, so while I am in the tube audio industry, we don't make anything that would even be in the same discussion as Carver's products. Still, I thought it was a good idea to be open and honest about who I am.

 

[anmpr1]

I do not know the history of these amps, and I'm not sure how that matters. I test a lot of vintage amps that are way, way outside of any warranties and they do just fine.

I'm not sure how flea watt single ended amps are really competing with 75+ watt push-pull amps, so while I am in the tube audio industry, we don't make anything that would even be in the same discussion as Carver's products. Still, I thought it was a good idea to be open and honest about who I am.

Thanks for that reply. I have no reason to disbelieve what you originally posted. I am, however, surprised. I admit that.

If I was the owner of these, and found out, I'd be on the horn to Carver. If what I had was not broken, I'd be demanding my money back. If that wasn't forthcoming, I'd be on the phone to my state consumer protection agency.

I still can't believe that Carver is selling a 15 watt amp as a 75 watt amp. It's certainly not what anyone would expect. Totally unethical. Probably against the law.

 

[paulbottlehead]

That's good, it seemed to be more than a coincidence that you had a hi pass looking output level at low frequencies.
What FR measurement? Can we see it. Why do these 'sine wave' scope pictures look like you unintentionally grounded the output somewhere instead of it floating? Can you show something that looks like a sine wave at any level at any frequency to prove the amp actually works. You have .99%thd at 0W at 20hz, how do you get a thd measurement without a signal?

Here's a nice big wave with the amp at 1kHz 5% THD making lots and lots of power. Note that this is consistent with my findings of 75W being available at 1kHz but at higher distortion. Now if I take the amp set at this level and just change the frequency to 35Hz, here's what comes out:

For the frequency response, I used an AWG and my scope to find where the amp was -1dB, since admittedly my FFT is limited up top. Here is what ARTA measures for FR. (Some components in the feedback network and around the input stage cathode may explain the dip around 2-5K)

The AWG and a scope make it out to be a bit better on top.

I'm certainly happy to post more measurements. As far as linear output goes, if I set the amp to 1kHz/1% THD at the 15.5W operating level and back the frequency down, THD doesn't go above 1% till 36Hz. THD goes over 2% at 33Hz. The actual amplitude doesn't change until 35Hz, and at this operating level I see -1dB occurring at about 23.5Hz (but at 26% THD).