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Positive Feedback ISSUE 20


spread spectrum technologies

Son of Ampzilla 2000

as reviewed by Ed Morawski






DIY with Scan Speak 9700 & 8535 Drivers and Series Crossover or Magnepan MMG with modified crossover and stands.

DK Design VS-1 Mark II integrated and Bel Canto EVO2 digital amplifiers (bridged) and an E.A.R. 864 preamplifier.

Musical Fidelity Nu Vista D CD player, Roku M1000 SoundBride Music Server, and Musical Fidelity 21 TriVista DAC.

Empirical Audio interconnects and speaker cables, Stealth XLR interconnects, Analysis Plus Oval 9 Speaker cables, and Cardas Cross XLR interconnects

DIY Flexy rack of plexiglass, dedicated circuits with Brick Wall surge suppression, Balanced power transformer feeding the CDP and Acoustic First foam panels. Vibrapods, Herbie's Magic Feet and good old hockey pucks. Stillpoints ERS paper


The original Ampzilla amplifier was the rave many years ago. The company's current offerings include the Ampzilla 2000, a monoblock design, and the new Son of Ampzilla 2000, a stereo amp. The Son of Ampzilla is rated at 100 watts per side, exactly half that of the monoblock. For those of you who just want the bottom line, the Son of Ampzilla 2000 is smooth, musical, dynamic, unique. For those who want the details, read on.

I'd heard of the Ampzilla, but never had the opportunity to see one, much less hear one. I wish I hadn't waited so long. I picked up the Son of Ampzilla from Bob Levi, fellow PFO reviewer and principal of the LA & OC Audio Society, who told me he had enjoyed his time with it. Since I didn't know anything about Ampzilla, I went to their website and learned a few facts. Then I spoke briefly with John Casler of Summit Audio Video, the local Ampzilla dealer.

Can you say unconventional? It's almost as if the designer, James Bongiorno, went out of his way to make the amp look different. From its odd, 10-inch wide by 8-inch high size to its huge, widely-spaced heatsinks to its lack of RCA inputs, not to mention its blue color, it screams unconventional (apparently, just like its designer). If you use XLR interconnects, you're ready to go, but if you have RCAs, you must use the included adapters. You'll also notice that the binding posts are somewhat oddly placed—they are off to one side instead of along the bottom. The faceplate is also different, with its electric blue paint and huge gold logo. While some may find it hard to take, I didn't mind. The captive power cord will undoubtly upset some audiophiles much more, but at least the cord is heavy-gauge.

The Son of Ampzilla 2000 is a solid state amplifier utilizing twelve output devices. It derives its "2000" designation from its 2000VA transformer (though John Casler informed me the newer versions actually contain 2400VA transformers). This makes for a gutsy low end and plenty of headroom. It's a little hard to nail down the design of the Ampzilla. The website is somewhat confusing, and full of claims of "new" amplifier topology:

The new Ampzilla uses a completely new variation of the Forward Gain topology to achieve unprecedented improvements in linearity. As a matter of fact, the new circuit is so smoot, that it can be actually listened to OPEN LOOP, WITH NO FEEDBACK. Of course, we aren't going to make it that way. The PROPER use of feedback is necessary in order to tie down all of the operating points so there will be no variations in performance from unit to unit. The new Ampzilla uses twelve 250-watt output device; there is also a 2000VA transformer. In addition, the amount of heat sink radiating area is three times greater than the original, meaning that there is NO fan. Also, the B+ and B- supply fuses are EXTERNAL. Also, the circuit is totally balanced from input to output although there is a totally and uniquely new un-balanced to balanced converter for single ended inputs. Each Ampzilla has 100,000ufd of power supply filtering with dual rectification.

Installation went fine. The amp was manageable despite its hefty size, and since I had some Cardas XLR interconnects on hand, connections were quite easy. I fed the Ampzilla with my E.A.R. 864 tube preamp, Musical Fidelity Tri-vista 21 DAC, and Marantz 5400 CD player. I started my listening with Von Schweikert VR-1 speakers. Source-to-preamp interconnects were Empirical Audio and speaker cables were Analysis Plus. I've been playing around with a digital music server—a PC in a different room, connected via Ethernet to a ROKU M1000 Soundbridge in my listening system—but for this review I felt it was fairer to use the more conventional Marantz player. I feel that the DAC makes the biggest impact anyway. Per Bob Levi's advice (read Bob's and Fo's reviews here), I let the amplifier warm up for an hour before doing any serious listening. This wasn't a burden, since my tube preamp and DAC also need a good hour of warmup. I was pleasantly surprised that the Ampzilla did not get hot, or even overly warm. Either the huge heat sinks do a very good job or the amp stays out of Class A mode.

I should have known what to expect, since I had learned that James Bongiorno was an accomplished musician. Anyone who plays a musical instrument understands sound. As it happens, a good many of my relatives are serious musicians (one has even released a CD), so I'm used to hearing live music. As anyone who regularly attends concerts can attest, live music is loud, fast, and dynamic. The Ampzilla certainly knows how to replicate those characteristics. Even though I had the volume very low at first, the Ampzilla sounded very dynamic, like it was straining to let loose.

The first recording I heard through the Ampzilla was my current favorite, From the Ground Up by Antigone Rising (only available from a certain coffee shop). This CD was recorded live, so it was an appropriate place to start. When lead singer Cassidy sings "Hello" to their fans, it was like being there. The Ampzilla brings a burning sense of immediacy to the table—one that I don't recall hearing from any other amplifier. When the CD ended, I realized I was breathless. It had been like I was at a concert. I wasn't paying attention to anything except the music, but I did notice the Ampzilla's extremely deep soundstage and imaging to die for. The soundstage extended from around each side and from top to bottom. It was incredible.

I am struggling to find the words to describe the sound of this amplifier. It sounds so different from other amps that I have been forced to re-examine my stock of words. It is neutral, but not sterile. It is very clean, but eminently musical. My preamp may in fact be shading what I am hearing from the Ampzilla, but if so, I like it!

Smooth jazz in an intimate surrounding, anyone? Keiko Matsui's CD Whisper in the Mirror was so smooth that it turned to liquid and flowed out into every nook and cranny of my listening room. I could hear every note as if I were sitting next to hers. With nary a falter, the Ampzilla got out of the way, but that's a poor description. I've heard neutral amps before, and the Ampzilla seems to be doing much more. It's like it's regenerating the music, only louder.

I fell in love with Diana Krall's The Look of Love all over again. Her fans know that she can sound cold. They know that she doesn't always enunciate perfectly. She should insist that everyone listen to her CDs through an Ampzilla. Never have I heard so much emotion and so much crispness from her voice. The abundance of cymbals and brushes on this CD were so sharp, and so well formed, that it made me think of a fresh winter morning. Krall's piano sounded especially good.

I couldn't resist my all-time favorite female vocalist any longer. I don't like everything Union Station does, but Alison Krauss' voice is so clear and so rich that I like everything she sings. I had high hopes when I placed So Long So Wrong in the CD player. It sounded like it always does—perfect. Then I realized that the Ampzilla really does get out of the way. Krauss produces her own recordings, and does an excellent job. The arrangements and engineering are perfect. I have never heard a wrong note, distortion, or sibilance. I don't think there is a trace of compression or other effects in any of her CDs. The Ampzilla faithfully reproduced what Krauss had laid down.

Madonna's American Life is another of my favorite test CDs. I use it for its driving bass and heavy use of synthesizers. While Madonna generally has very good engineering, her voice is nowhere near as good as Krauss', let alone Krall's. This CD has quite a bit of sibilance, something I was hoping the Ampzilla might suppress a bit. It didn't, but I still enjoyed the CD, and the bass was fast, deep, and firm. As is usual for this recording, the soundstage was extremely wide, extending all the way around my room to almost behind my listening position. Every note was sharp, yet the sound was not fatiguing in any way.

I played one last CD before switching back to my reference system for a final comparison. I played The Corrs' Unplugged, first with the Ampzilla, then with my reference amp, the DK Design VS-1 Mark II. Unplugged is a live acoustic recording, and it can sound rather bright on some systems. I actually use this CD to tune my room. When Andrea Corrs sounds right, I know that my system and listening environment is at peace with the world. The Son of Ampzilla did not disappoint. It had an incredible sense of pace and rhythm, with soaring dynamics, tight bass control, and super-fine detail. In fact, the level of detail was much higher than I had previously noticed. While I was listening to Unplugged, the word that best describes my impression of the Son of Ampzilla finally came to me—it is pleasant! Listening with the Son of Ampzilla was just so enjoyable that I didn't want to stop.

When I switched to the DK Design amp and played the CD again, the sound was certainly different, but there was not as big a difference as I expected. The VS-1 had slightly more bass, but slightly less control. While the Ampzilla was more finely tuned and firm, the VS-1 had slightly more bloom. The Ampzilla also won in the treble and detail departments. Its detail retrieval was not so evident that I wanted to switch amplifiers, but it was more obvious on certain recordings. This may be due to the fact that the VS-1 is an integrated amp. After all, I was comparing it to a pair of components that cost almost twice as much. Both amps were equally refined, and I see that as a tribute to the VS-1.

If you can get past the unique looks of the Son of Ampzilla, and mate it with a really good tube preamp, you will have one of the most enjoyable musical experiences you can have in the privacy of your home. You may never feel the need to go to a concert again! Ed Morawski

Son of Ampzilla 2000
Retail: $3250

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