Review: AMC CVT1030s Tube preamp
For years I've been reading the virtues of vacuum tube components over solid-state (both Sterophile, Listener, and other audio magazines provide great articles on the subject), but I've been pretty much turned off by their rather quirkey nature, lower power amp ratings, and exceedingly high pricetags! I didn't want to give up my powerful 200 watt McIntosh MC7200 amplifier, so I concluded that if I wanted that warm tube sound while maintaining the power and deep bass punch of a solid-state amp, I'd have to switch to a vacuum tube preamp. Unfortunantly, even used tube preamps from McIntosh, Audio Research, conrad-johnson, Sunfire, etc. were out of my price range! What's an audiophile with champagne tastes on a beer budget supposed to do? While searching on eBay for used tube preamp auctions, I stumbled across an auction for a British designed "valve" preamp; a demo AMC Model CVT1030s, with the "Buy It Now" price of $365! I've never seen a vacuum tube audio component of any kind at this unheard of low price, so I was a bit skeptical. I decided to do a bit of research by reading the reviews about this preamp on various websites, and I have to say I was rather impressed with the results, so I decided to take a chance and buy it! This preamp is packed with quality features: seven inputs, including phono; two outputs; a "Direct" switch that bypasses the tone controls; an optional balanced output plug-in module; and three convenience AC outlets (two switched, and one unswitched). The seller, Brent Hite of "Retrodaze Audio Products" (www.retrodazeaudio.com) was extremely communicative, answering all my questions, and wasting no time in shipping the preamp! Within days, UPS delivered what looked like a new unit, even though it was a demo CVT1030s (the "s" representing the socketed version). At no extra charge, Brent installed two JAN Philips 12AU7 tubes, and two Sovtek 12AX7WA tubes, replacing the original Chinese tubes. I disconnected my Carver C-4000 preamp, connected the AMC in its place, and turned my audio system on. Imagine the shock I experienced when with all the gains set to minimum, I heard a howling, buzzing sound that also blew a fuse in my power amp! I immediately shut my system down, and notified Brent that I had what I thought was a defective preamp (I found out later it was a bad 12AU7; there was absolutely nothing wrong with the preamp). Without hesitation, Brent went ahead and sent me a brand new CVT1030 (normally a non-socketed version), but with tube sockets installed, and the very same JAN Philips/Sovtek combo in place...all this even before I could ship my "defective" unit back to him! It has to be said that Brent provides excellent service! When I received the new replacement CVT1030 a couple of days later, I immediately opened the unit to find the JAN Philips/Sovtek vacuum tubes all snug in their newly installed tube sockets. I then installed the new preamp in my system, and carefully turned it on...so far, so good! After letting it warm up for a few minutes, I began to realize what all the fuss was about when listening to my audiophile-quality reference CD's and Direct-to-Disc LP's. Almost instantly, I noticed the midrange harshness usually associated with solid-state equipment, virtually elliminated from my recordings! The grain was gone; in its place was a much warmer, open, airy quality that I've never experienced before. And as the preamp's tubes were broken in for over 48 hours, the sweeter the soundstage became. Unfortunantly, I began to experience another problem; from time to time, there would be a faint popping sound coming from my Klipsch Cornwall loudspeakers, similar to an LP "pop". I knew it wasn't my music, and after searching through various vacuum tube websites, several sites all mentioned the very same noise problem associated with the inexpensive Russian made Sovtek 12AX7WA tubes. As with Brent Hite, major props also have to go to Jim McShane of "Jim's Citation Amp and Vacuum Tube Pages" (http://pages.prodigy.net/jimmcshane/), a proud individual sponsor to www.audioasylum.com. Jim also went way beyond the call to duty by answering each and every question I had concerning the noisy tube, tube matching, mixing and matching by manufacturer, tube functions, etc. By his recommendations, I was able to isolate the popping Sovtek, choose another inexpensive pair of 12AX7WA's (JAN Philips) to replace the Sovteks, purchase them at a discount, and was recommended future (more expensive) upgrades later on. I quickly received the expertly packaged JAN Philips NOS tubes in the mail, popped them in, and not only did the noise disappear, but the tube swap smoothed out my mids and highs even further, without sacrifising the bass. Because of the exceptional customer service that both Brent and Jim provide, I will be doing future business with the two of them. And because of their effortless help they provided me, I now have a bargain vacuum tube preamp that I think blows away most solid-state preamps in the $800 to under $2000 price range. Best of all, I know that I can bring the AMC CVT1030 tube preamp a bit closer sonically to McIntosh, Cary Audio, Manley Labs, or Hovland tube preamps costing three times as much, simply by upgrading the vacuum tubes to Ei, Mullard, or even Telefunken! I wholeheartedly recommend the AMC CVT1030 (including the "a", "s", or "as") for those audiophiles on a strict budget...this is a great preamp for those individuals breaking new ground into the world of vacuum tubes. With the option to experiment by upgrading tubes to acheive musical nirvana, and at such a small cost, I don't know why I didn't do this much sooner!
McIntosh MC7200 power amp; Klipsch Cornwall loudspeakers; Kimber Kable 8TC speaker cables; Carver TX-11 tuner; Carver SD/A-450 CD player; Denon DP-62L turntable; Sumiko Blue Point MC cartridge; Nakamichi DR-1 cassette deck; Monster Power HTS5000 line conditioner; Cardas Quadlink 5C; Cardas Crosslink; Transparent Audio MusicLink; MIT Terminator 2 interconnects; Carver M-400t power amp; AudioControl Richter Scale Series III crossover; Dayton DVC Series 15" subwoofer in a home-made 3 cubic foot sealed enclosure; MIT Terminator 2 speaker cables.
None yet. This is my first experience with entry-level vacuum tube components. I'm debating on replacing the McIntosh with valve monoblocks, and upgrading my CD player with a tube player from either JoLida or Njoe Tjoeb.