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Carver Crimson 275 - Has anyone heard one?


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13 hours ago, Curious_George said:

A 19lb tube amp IS NOT going to put out 75 Watts per channel at any acceptable distortion measurements.

 I'm old enough to remember the same things being said about the Carver amps from the 80's. 

 

Fact is I love my little 275 amp it is one of the best sounding amplifiers I've owned or heard and it has plenty of power to drive my speakers with ease. Look around on the web at the reviews out there this amp is known for driving hard to drive speakers. 

 

As far as the spec's go I'm open to see how this pan's out. Yes I'd be disappointed if it didn't hit published ratings but I seriously doubt that they'd be that far off. The amps that were tested in that link are clearly Carverfest versions and not production models so I take those test results with a grain of salt.

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11 hours ago, jjptkd said:

 I'm old enough to remember the same things being said about the Carver amps from the 80's. 

 

Fact is I love my little 275 amp it is one of the best sounding amplifiers I've owned or heard and it has plenty of power to drive my speakers with ease. Look around on the web at the reviews out there this amp is known for driving hard to drive speakers. 

 

As far as the spec's go I'm open to see how this pan's out. Yes I'd be disappointed if it didn't hit published ratings but I seriously doubt that they'd be that far off. The amps that were tested in that link are clearly Carverfest versions and not production models so I take those test results with a grain of salt.

 

I'm a Bob Carver fan too, but not all of his products were great. I'm not concerned with the power output or other specs, but what is advertised versus reality. 

 

I would like to see (photos and testing) a verified production unit and then judge from there. 

 

Bob always had clever ways to demonstrate certain test measurements that were part of his marketing. 

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4 hours ago, Curious_George said:

 

I'm a Bob Carver fan too, but not all of his products were great. I'm not concerned with the power output or other specs, but what is advertised versus reality. 

 

I would like to see (photos and testing) a verified production unit and then judge from there. 

 

Bob always had clever ways to demonstrate certain test measurements that were part of his marketing. 

 I reached out to Jim Clark asking him to clarify some things with the manufacturer it only makes sense that each of these amps are tested / bias set prior to shipping for quality control purposes they should know what these amp can and cannot do and that information should be readily available. 

 

Also looking at that forum thread it appears the person who performed and published the test results from the kit amps has ordered a brand new one and will do the same tests on it and post the results so I guess we'll see if there's any difference or not. 

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Wow that meme is too much :laugh:

 

On 12/26/2021 at 11:42 PM, jjptkd said:

The amps that were tested in that link are clearly Carverfest versions and not production models so I take those test results with a grain of salt.

 

How are you so certain they both are Carverfest clones and not production models? I can see the one that's a little rough but the signed one looks every bit the part of the production ones in every detail. I looked at part selections on boards, wiring, hardware, everything and it appears a real one.

 

The facts of the matter though are others have maybe not measured them but have taken the covers off to find the same 15 watt transformers. And not forgetting we do have the known fact it only weighs 19 pounds. I get it when people doubted his coffee tin amp putting out double the power of the McIntosh and half the distortion but a pure transformer coupled power amp wanting to put out 75 watts per channel down to 20Hz just cannot happen at the published weight, as stated it's physics. For example just looking at a few different manufacturers of high quality Audio output transformers you would need on average a 12 pound output transformer to get to rated power at rated bandwidth. That's 24 pounds in just output transformers alone. The only possibility is a hybrid output stage with transistors and tubes to meet rated specs but I am sure that would be as disappointing or more so than just having lower output power than advertised. I know this isn't the case because you cannot see an of that circuitry from any pictures and I am certain the tech would have picked up on that immediately. Besides that it would have probably measured a lot better with a hybrid topology.

 

As we all know power and distortion do not equate to great sound. From the reviews it seems to be a very nice sounding amplifier and that's all that really matters. This is just one of those things that is interesting and everybody likes a good mystery. Many people are interested in how this turns out and really in the end it's just one of those things where the company fudged the specs, not the first time it's happened and won't be the last.

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Judge bangs the gavel - "court is adjourned"

 

The reason the amps still sound good is because most with Klipsch amps 15 watts is plenty but also the amp can produce the mid range to over 70 watts and the gross amounts of low frequency distortion are non-linear giving lower order even harmonics which sound harmonious being only an octave above the fundamental. It's like the old console amps or old tube budget amps with tiny output transformers, they still sounded good but show very high distortion at low frequencies.

 

It's still a great sounding amp I am certain, it's just they marketed it maliciously as a true 75 watt hifi tube amp that puts out full power at 20Hz with low distortion <1%

 

I still blame Frank, he markets these and is raking in the money from them. And they lied about the output transformer metallurgy when asked about the tiny output transformers. Unbelievable.

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I found it I think: here is the guys response

 

"The Crimson 275 I bought (from Music Direct) uses 15w Edcor OPTs.  UGH!!!!  

Frank Malitz, can you please explain this?  While I love the sound of this amp, this hurts my ability to pair it with less efficient speakers, hurts resale substantially, and isn't cool---UNLESS, Frank, you can get Bob Carver to issue a statement explaining how this amp can make specified output.  

Finally, if you're reading this please note:  

Before folks throw Bob under the bus, remember the following.  Bob designed this amp with another esteemed audio sage. He reportedly sold the amp and the rights to sell it to Frank Malitz and/or Carver Corporation--and Bob is not an owner of the company.  Frank told me he's a designer only.  

When Frank says Bob was angry/sad/emotional about the issues being debated on the forums concerning this amp, that may be true.  And Bob may have never intended to post faulty specs, etc.  

Frank Malitz/Carver Corporation, can you have your partners at Wyred4Sound test the output and reconcile it with your specifications for the product?  

I'm more sad than angry about this.  It's still a hopping little amp, but now I know it won't work in my big room (16 x 23 x 10 tall) with inefficient speakers.  Currently I use 102dB efficient in this space, so as I said before I had not way of knowing if this thing could power such speakers.  

This is a very sad day for me. Great amp. More than likely false advertising.  

Should I ask Music Direct for a refund?"

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Another crazy thing to think about is this only has an 8 ohm tap, yet it's rated for 4 ohm speakers. Now 2k6 plate to plate when halved when using a true 4 ohm speaker it's going to be a tough load on the power tubes so I would imagine distortion would increase fairly substantially.

 

With only one secondary tap going either up or down from 8 ohms will result in changes of distortion and output power yet the spec sheet says nothing of this. I have never seen a transformer coupled tube amplifier claim the use of different speaker impedances without providing separate taps for them.

 

I wonder how Frank is going to handle this. How are the vendors that sell these amps going to handle this. Refunds? Clearly there is some serious false advertising that shouldn't be too hard to prove but I worry the they were vague enough in the specifications to get away with it.

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4 hours ago, captainbeefheart said:

Judge bangs the gavel - "court is adjourned"

 

The reason the amps still sound good is because most with Klipsch amps 15 watts is plenty but also the amp can produce the mid range to over 70 watts

 

It's still a great sounding amp I am certain, it's just they marketed it maliciously as a true 75 watt hifi tube amp that puts out full power at 20Hz with low distortion <1%

 

I still blame Frank

Yeah my speakers are rated 102db at one watt yesterday I pulled out my old ratshack spl meter average at my listening position was 70db for normal listening-- when i really cranked things up to the point I feared the neighbors would complain it was low 90's at my seat I measured at the speaker it was high 90's and that was louder than I could stand for any length of time.

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On 1/5/2022 at 1:49 PM, captainbeefheart said:

I have never seen a transformer coupled tube amplifier claim the use of different speaker impedances without providing separate taps for them.

 

 

When you suggested changing to the correct size transformer for the claimed output, will the Crimson power supply as designed handle that improvement? Would they be able to have the proper taps?

 

BTW, did you review the schematic for the specs of the transformers specified in Bob's design?

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4 hours ago, Curious_George said:

I'm surprised the amp is not configured to operate in "Ultralinear Mode". In my opinion, it is the best of triode & pentode operation. 

 

I guess they wanted the Crimson to have that vintage pentode sound. 

 

Speaking of Bob Carver, when he talked to Stu Hegeman about tube amp designs Stu said he wished he never got caught up in the UL fad and making Ultra-linear amps, he made one and said it was the biggest blunder of his career and he would never make another ultralinear amp ever again, and he didn't. The tube plate pulls the transformer end winding down so low the screen tap gets pushed down so far it renders the tube unable to drive difficult loads. That and UL amps usually eat power tubes because of the idle screen dissipation is often very high.

 

UL amps test great on a static resistive load but when asked to drive real loads especially some reactance they kinda fall flat on their face. I'm with Stu and obviously Bob Carver found the same thing as he never makes UL amps either, they are all pure pentode mode.

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14 hours ago, michaelwardjones said:

 

When you suggested changing to the correct size transformer for the claimed output, will the Crimson power supply as designed handle that improvement? Would they be able to have the proper taps?

 

BTW, did you review the schematic for the specs of the transformers specified in Bob's design?

 

The power supply needs no modifications to switch output transformers, the only issue is when the output stage tubes are swinging past a certain voltage swing (15 watts) the output transformer doesn't have enough flux density to keep up at low frequencies. The signal just falls apart and you get a grossly distorted waveform. When installing a properly rated output transformer if you decide to get one with multiple taps it really has nothing to do with the amps power supply, the extra taps are on the secondary and provide the proper reflected impedance to the primary.

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This is an interesting post from a Carver owners on Audiogon:

 

"i just had my amp in for a check (some tube noise and transformer hum) at wyred 4 sound - w4s is the exclusive contract manufacturer for these crimson amps

had a friendly chat with their senior tech who worked on my amp - i know the w4s guys reasonably well, like them, have several pieces of their gear (digital, power supply, class d amps), w4s is a good company, well designed well built, good sounding high value gear, good reputation, and straight shooters in my book

i was told that based on their bench experience, the crimson amp can make 75w driving one channel... (didn’t ask for frequency range spec, sorry), can’t in both channels though (’more like 60 thru both channels’), but this isn’t due to the output transformers as limiting factor, but rather, the power transformer, which can’t quite deliver the juice for 75 wpc

asked how such a small light tube amp makes that kind of power, was told that the reason is the kt120’s are pretty strong, plus ’the neat feedback circuit employed from the output, holds the distortion in check, other guys don’t do this, we were kinda surprised it can do that through those small output transformers...’ "

 

https://forum.audiogon.com/discussions/peeking-inside-a-carver-crimson-275-tube-amplifier?lastpage=true&page=3#2314379

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1 hour ago, captainbeefheart said:

 

Speaking of Bob Carver, when he talked to Stu Hegeman about tube amp designs Stu said he wished he never got caught up in the UL fad and making Ultra-linear amps, he made one and said it was the biggest blunder of his career and he would never make another ultralinear amp ever again, and he didn't. The tube plate pulls the transformer end winding down so low the screen tap gets pushed down so far it renders the tube unable to drive difficult loads. That and UL amps usually eat power tubes because of the idle screen dissipation is often very high.

 

UL amps test great on a static resistive load but when asked to drive real loads especially some reactance they kinda fall flat on their face. I'm with Stu and obviously Bob Carver found the same thing as he never makes UL amps either, they are all pure pentode mode.

 

I have never driven difficult loads with my amps, perhaps that is why I have never had an issue with them. 

 

However, what about the hundreds of thousands of amps made by Dynaco, Eico, Heath, etc that were Ultralinear? Ultralinear was well documented with plenty of test data. 

 

Although I am a fan of Bob, he always had some real unusual amp designs that only he understood. There was nothing "text book" about his "later" designs that is for sure. His magnetic field amps were a smart design and efficient as far as the power supply was concerned. Actually, some of his first designs (early 70's - 700B/400B) were very similar (read: probably copied) from early RCA transistor manuals. Not that it is a big deal, but just saying. 

 

An Ultralinear Amp_Page 2.pdf An Ultralinear Amp_Page 3.pdf An Ultralinear Amp_Page 1.pdf

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