2. amps-preamps
  3. 167868-18279

Peeking inside a Carver Crimson 275 Tube Amplifier

So, I just had to pop the hood on the Carver Crimson 275 tube amplifier. I was so curious as to how this little guy weighs so little and sounds so lovely.

  • The layout is simple and clean looking. Unlike the larger monoblocks (that cost $10k), this model uses a PCB.
  • The DC restorer circuit is nicely off to one side and out of the way. It doesn’t look all that complicated but I’m no electrical engineer. Why don’t more designers use this feature? It allows the power tubes to idle around 9.75w. Amazingly efficient.
  • The amp has very good planned out ventilation and spacing. No parts are on top of each other.
  • Most of the parts quality is good. There’s a host of Dale resistors, what look like Takmans, nice RCA jacks, heavy teflon hookup wire, and so on.
  • Some of the parts quality is questionable. There’s some cheap Suntan (Hong Kong mfr.) film caps coupled to the power tubes and some no name caps linked to the gain signal tubes. I was not happy to see those, but I very much understand building stuff to a price point.
Overall, this is a very tidy build and construction by the Wyred4Sound plant in California is A grade. I’m wondering a few things.

Does the sound quality of this amp bear a relationship to the fact that there’s not too much going on in the unit? There are very few caps--from what this humble hobbyist can tell--in the signal chain. And, none of these caps are even what many would consider decent quality--i.e. they aren’t WIMA level, just generic. This amplifier beat out a PrimaLuna Dialogue HP (in my room/to my ears...much love for what PrimaLuna does). When I explored the innards of the PrimaLuna, it was cramped, busy and had so much going on--a way more complicated design.

Is it possible that Bob Carver, who many regard as a wily electronics expert, is able to truly tweak the sound by adding a resistor here or there, etc.? Surely all designers are doing this, but is he just really adroit at this? I wonder this because while some parts quality is very good to excellent, I was shocked to see the Suntan caps. They might be cheaper than some of the Dale resistors in the unit. I should note that Carver reportedly designed this amp and others similar with Tim de Paravicini--no slouch indeed!

I have described the sound of this amp as delicious. It’s that musical and good. But, as our esteemed member jjss [ @jjss ] pointed out in his review, he wondered if the sound quality could be improved further still. He detected a tiny amount of sheen here and there [I cannot recall his exact words.] even though he loved it like I do.

I may extract the two .22uF caps that look to be dealing with signal related to the 12at7 gain tubes and do a quick listening test.
128x128jbhiller
jbhiller's avatar
jbhiller OP
1,430 posts
 

Well, 

Curiosity and my love of drilling down to get to an answer got the best of me.  I took the PCB off its mounts and got to the output transformer.  I didn't not get to both OPTs, as this would be more work and I think we can assume both OPTs are the same.  I'm sorry that I didn't get to the power transformer (middle can);  this would require me to detach numerous hookup wires and for me it would be an hour's work to properly desolder and reinstall it all.  

Oh my!  I'm an idiot when it comes to posting media via Audiogon's new forum features. So, you'll have to look at the photographs here: 

They are in my virtual system.

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? 

jbhiller's avatar
jbhiller OP
1,430 posts
 

Also, now that I feel it’s appropriate to pile on with questions given the evidence...

 

Even though Frank says these amps are always sold out, they were always available at Music Direct. Just recently, Music Direct’s website started saying the product is "no longer available" --not backordered or special order or drop ships from manufacturer. Did Carver Corporation take this amp off the market in response to criticism?

 

tomic601's avatar
tomic601
12,927 posts
 

Sad. No other words for it. Sorry for your anguish.

Jim

mulveling's avatar
mulveling
1,915 posts
 

@jbhiller

😥

Thanks for that, though. Now we might expect some sort of tug of war over what constitutes acceptable bandwidth at power, THD limits, and measuring setups - and how this should all filter down to single power #. It’s perhaps interesting to look back at Heathkit W5 manual from 1959 and all the wonderful measurement curves provided right in the manual (the bandwidth looks very good for a 25 Watt rated tube amp):

To be fair my VAC amps don’t exactly measure stellar either - and I enjoy them regardless.

jbhiller's avatar
jbhiller OP
1,430 posts
 

Thanks @tomic601 

@mulveling , you make good points. It's still a fine little amp.  One of the biggest reasons I purchased it was its ability to drive all sorts of speakers.  I seriously question it can drive a 4 ohm load at 75 watts even at peak power.  But, I'll leave that for the testing experts and true electrical engineers.  

More to discover