Peeking inside a Carver Crimson 275 Tube Amplifier

Oh you mean 4.5x more power… but in two channels with bass frequencies? Yeah, I’m sure the next one will do all that.

I have to agree with funky54 now.  I would be surprised if the amp tested substantially better than ASRs previous measurements on wattage.  I'll less surprised if distortion measures a touch better.  

I've built and tweak stuff--sometimes to excellent ends, and sometimes not so much.  I have a firsthand experience with price point construction decisions--granted I'm not an expert and my experience is limited in scope.  Most all of my thoughts way above (before this testing/fraud issue rose) remain true. One thought was, Why shoehorn this product into the $2700 price point?  I'm not saying overbuild it or price folks out of it, but wouldn't an extra $1,000-$1,500 charge allow the manufacture to (a) use legitimate capacitors where they matter instead of $1 junk; (b) beef up the transformers.  

I question whether it was as much about "cheaping out" as it was about creating a *lightweight* yet powerful tube amp.  Small couping caps notwithstanding (they've gotten a lot smaller these days due to better manufacturing techniques), I'd propose that the amp is an experiment in just that.  The design isn't sloppy, as Gordon pointed out at AK, there's a lot of tailoring to accomodate the small output transformer.  Another point of speculation over at AK is that the lower octaves are reinforced by harmonic doubling, much in the way that old console stereos used small, low-wattage amplifiers coupled with large, highly efficient woofers in a resonant cabinet to create the feeling of low bass, albeit at higher distortion levels.

I'm firmly on the side of honesty in marketing.  I've also been building my own tube amps for 20+ years now and finally learned to use an oscilloscope to see what's going on and improve my projects.  If I set out to build a 75wpc amp I certainly wouldn't be happy with those measurements, and would seek to improve them.  *That said* I'm curious to know if jbhiller has actually tried the amp in his big room, and if so, how it sounded.  Maybe the damn thing works, I don't know.

first i would say this thread is nice in that folks raising issues, and @jbhiller and i as current owners of these amps chiming in with thoughts and info, are keeping it positive and cordial - i think that is important, we can see other threads being much less so, and that can be become awfully unpleasant

second, i think to j-b’s comment about pricing of the 275, my own take is that the carver principal(s) were careful to choose their price point, knowing a higher one would considerably reduce their market interest, and i think that is also why they chose to skate on thin ice to write 75 wpc - that was the desired proposition: light amp, kt120’s, $2750 new, 75 wpc, drive most real speakers in real rooms to real volumes - thusly can undercut alot of the competition with a superior value propositon - whether they did this (the power rating specifically) ethically is a fair question -- for me, as an illustration, i bought the amp a touch under $2000 used - had it been a $4000 retail amp, selling for $3000 used, i may well have not gone for it

third, i would just reiterate that in my experience and use, i am not using super efficient speakers - spendor sp100 r2 @ 89 dbwm 8 ohms nominal, harbeth monitor 40.3 xd and shl5+ both @ 86 dbwm 6 ohms - in my 19x17 dedicated room, speakers well away from room boundaries - the amp drives all the speakers very well (i listen at low to mid 70’s db average with 80+ db peaks), has terrific bass response... not bass like a pass or a hegel, but roughly as good as much more expensive tube amps such as my audio research ref series -- how it does it, with xyz feedback circuitry, maybe it is managing the distortion, maybe it is playing some nice sounding distortion, but to my ears it works very well for a tube amp, sounds very good - good detail, excellent warmth and imaging, nice drive/prat - just what one would seek from a tube amp

last point i would add, and a bit of re-emphasis on what j-b said earlier, bob carver has always been an ’against the conventional grain’ type of character/designer in the audio world, he does things differently, thinks very much out of the box, so to speak... if one understands his long history (as i do, i have been at this as an avid hobbyist since the early ’80’s), he is never been shy to push the envelope -- more often than not, he can back it up... so we shouldn’t be surprised this amp with his name on it follows that tradition - importantly, at least in my case, the amp performs, making very good music to real volumes capably

all this said, the stated specs should be honest, and that may well be on bob carver himself, at his current ripe old age, or the folks running the business at present

+1 JJSS49 on how we are keeping it cordial and respectful.  It makes the thread so much more informative and entertaining.  I love the differing opinions, especially those that differ from my own.  

@grovergardner , I didn't know that about console systems of yore.  Very interesting!

The original coupling caps in this unit were really unimpressive.  Take a look on my system page (even though the page is out of date), I have a pic of the original caps. They are the size of a fingernail!  There's a good bit of juice going through them per my tests and the schematic.  I really didn't like seeing that quality on such an important spot on the board. 

Take a look at this--same brand in the 275:   

It's a video of a Suntan cap blowing up.  Not acceptable in my book to use these.  You can always find an inexpensive but quality Wima, right?  Nelson Pass stuff is loaded with nice WIMAs and so are many other great brands. Why skimp here? Suntan? I wouldn't put it in an old guitar amp. :)