Funny you should ask as I have owned both Atma M-60 amp (with Vcaps and Caddock resistors) and currently own the Carver Cherry 180 mono blocks (Vcap output coupling caps and Gold Point stepped attenuator instead of the stock volume pot). It is the precursor to 200 watt precursor to the Crimson and uses KT88 tubes. The Carver tube amp is a remarkable tube amp. It drove all of my speakers without ever clipping including the relatively inefficient Raidho D2.1 and D1. Compared to the Atma M-60, the Carver is much more dynamic, has more precise imaging and deeper soundstage, although slightly less wide soundstage than the M-60, which has more diffuse imaging and soundstage. As far as bass dynamics and extension, the Carver is hands down better and can drive almost any speaker out there. The M-60 requires careful speaker matching because of its OTL design and can sound very loose in the bass if you don't mate it with the right speaker. I would say the M-60 has a smoother, albeit more bland midrange. The M-60 has hands down the most extended crystalline smooth high frequencies I have ever heard from any amp, solid or tube. My experience is based on stock tubes for both amps.
One thing I didn't like about the M-60 was its reliability. Within 6 months of ownership (bought brand new), 3 output tubes failed with a dramatic POP sound from the speakers every time a tube blew itself. I didn't like power transformer hum and tube hiss either. The Carvers are essentially dead silent unless you have your ear a foot away from the power transformer in a ultra quiet room. Then you will hear a very low level hum. It's as quiet if not quieter than the solid state amps I own. I never heard any tube hiss from the Carvers. |
Ozzy, just realize that all manufacturers claim every new version is significantly better than the older version ;)
You shouldn't have any output tube failure in the first year of operation. I have owned the Carver amp for 8 years now with zero output tube failure.
I think crossing over the speaker at 80 Hz and letting the M-60 handle everything above is a very wise decision. I have a 2 way speaker that is relatively efficient (89-90 dB) with lowest impedance 5.8 Ohm at crossover, mostly >8 ohm. I was told by Atmasphere this shouldn't be a problem, but the bass was just too loose for my taste.
The Carvers should have no problem with Maggies. |
Ozzy, That has never been my experience with any of Bob's tube amps (I've heard the 350 and Silver 700 monster as well.).
Context is very important. What was the preamp, source, and speakers used to evaluate the 350 that showed "severe" drop off of the higher frequencies? Were the tubes in the 350 stock? The stock Shuguang KT88 are on the bright side in my opinion compared to the for example the Golden Lion K88 reissues, which are more natural sounding but can sound a little recessed in the highs. Did the person who evaluated amp make sure the tubes were functioning normally?
Good thing about tube amps is that you can roll tubes and suit the sound to your taste to a certain degree. |
Ozzy, it depends on which amp you’re comparing the Carver’s to and what your preferences are. Are you referring to the review by J. Valin? His reference amps are fast SS amps, I believe. In that context, I’m not surprised by Valin’s assessment. There is a way to significantly improve the sound of the 350’s without spending too much money. You can replace the stock built in volume pots with a mono stepped attenuators from DACT, Gold Point (I have them in my amp), etc. The Gold Points should cost you less than $200 (I have extra set of new Gold Points if you are interested). You can also replace the stock coupling caps with Vcap, Jupiter, or Duelund caps. You’ll need 4 of the 0.22 uF caps (you’ll need to verify values). They’re low value caps so shouldn’t cost arm and a leg. If you go with the tin foil Vcaps (I have them in my amp), you’ll pay around $400. You’ll hear more transparency/detail, increased dynamics, and more extension in the high and low frequencies. These upgrades are well worth the money, and you’ll never think they are "dark" sounding. |
Glad to have helped. Good luck. Let us know what you decided on. |
Glad you ordered the 350. If you want to take the 350s to another level, try the mods I suggested. You won't be disappointed. |
How about Bob's new ALS speakers? It's only 5" wide and 5" depth, but about 7 feet tall, so very small foot print. You already have subs, so you won't need to pay for the subs that come with the ALS. It will play close to 110 +dB with the 350's (ALS can handle 120+ dB). It's dynamic as hell and soundstage and imaging are one of, if not, the best I've come across. You can dial in the speakers to your room because the crossover has controls for treble, midrange, and upper bass balance. Bob designed the ALS with 350's in mind. |
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Also Proac speakers are very dynamic speakers. If you can find a dealer, I'd lug your amplifier over and test the speakers with your amp. Or the dealer may actually let to audition them at home. |
Then I suggest you check out the 2-way stand mounts from Proac and Totem. |
Great! First thing you'll need to do after turning on your amp is check the adjustable bias. Start with withwhat Bob recommends. From there, Increasing bias will make thing sound warmer and more upfront, while decreasing bias will sound leaner with better sound stage and imaging.
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Ozzy, which tap you use depends on the impedance of your speakers. Unless you have really low impedance speakers like 1-2 ohm Apogees, the 8 ohm tap usually sounds better than 4 ohm tap. Bob's tube amps do have a 1 ohm tap. But there is no hard rule regarding this, so you can experiment. |
