AMPZILLA HISTORY

 

Ampzilla was created by world famous designer, James Bongiorno in 1974. At the time, James was the director of engineering at SAE. Prior to that he had been the director of engineering at Dynaco where he created the renowned Dynaco 400. While at SAE, James conceived the concept of the full dual differential full complementary amplifier topology which has since, for the last 27 years, become the defacto world standard road map for virtually all high end power amplifiers made today. Ampzilla was originally designed as a construction project for Popular Electronics Magazine. However, the response was so overwhelming, after the rave reviews, that James left SAE to found "The Great American Sound Co. Inc." (GAS CO.). The rest was history.

The Ampzilla circuitry was a refinement of the original circuit created at SAE and the subsequent Ampzilla II, for the first time in history, introduced the world to servo-controlled amplification. It is interesting to note that servo-control has also become a defacto standard on virtually all modern power amplifiers. Subsequently, James, always searching for new and better concepts, sold his interest in GAS and founded Sumo Electric Co. Ltd. for the purpose of introducing yet another completely new concept in amplification. What emerged was the four-quadrant full complementary differential balanced power amplifier, "The Power". At the time, this was the largest power amplifier ever made at 450 Watts per channel into 8 ohms. In addition, James received a patent on a very unique pure class A power amplifier wherein the bias was controlled by a very clever mechanism which allowed the circuit to REMAIN in pure class A all the way down to a short circuit.

Unfortunately, disaster struck and James was afflicted with life threatening liver problems. James has fought this battle for almost 20 years and finally is back to health. During this long absence, James has had plenty of time to assess the current state of amplification. Surprise, surprise!! Since his departure in 1982, there has been no conceptual topological discoveries whatsoever. NONE!! Hard to believe, but true. This is not to say that there aren’t any fine amplifiers being made, as there are quite a few. However, virtually every one of them uses the same tried (or tired) and true circuits created by James way back when, with a lot of variations on a theme.

One thing is for sure. The cost of today’s gear has gone astronomical to say the least. It is just simply not possible to make the kind of super quality 200 watt amplifier today for the same price that existed 20 years ago that is, with the commensurate attention to detail that audio consumers expect today. However, some companies have definitely gone to the moon with megabuck pricing that is positively insane and an insult to consumers in general. James has always been known for producing the finest gear at the most reasonable prices so that the maximum number of people could afford to own them. James still has that same commitment however, today, in order to make a super quality 200 watt amplifier with NO limitations, the retail price must be in the neighborhood of $3000.00 per channel when producing a MONOBLOC.

Twenty-Seven years ago James wrote a brochure describing the "Ultimate Amplifier" while at SAE. Of course, every engineer believes that their current work is the ultimate machine. However, it should be understood that this "Ultimate" design could only be as of the moment. The truth is that there never has been nor will there ever be an absolute "ultimate" perfect amplifier. Hard as we try, we get closer and closer but in reality, we’ll never approach perfection. Therein lies the enigma. Who defines what is perfect? What are the rules, the conditions, the standards, etc. The original Ampzilla set a standard, which has been copied, in topological form, for almost the last 30 years. Obviously something must have been right about it in the first place. Subsequently, the Sumo balanced topology has also been copied for the last 10 or 15 years. As we are now entering the new millennium, it is time for another breakthrough in the original tradition defined by the first Ampzilla.

The new Ampzilla 2000 is a radical departure in amplifier topology. Not many designers can make a claim like this. The only other designer capable of true innovation is Bob Carver although his application of technology and marketing go in different directions. Needless to say, James has created something truly new and innovative. All that can be said is, "It’s about time." To expound on this theme a little, the following words will describe amplifier topological "styles" of which the descriptions are ours alone and are not to be found in any reference.

There are basically five classes of topologies that can be used to make an amplifier. These are:

  1. Forward Gain
  2. Reverse Gain
  3. Quasi-infinite Gain
  4. Common-mode Gain
  5. Remodulation Gain

Forward gain topology has without a doubt been the standard bearer of solid state circuits for the last 35 years. It is virtually impossible to make a tube power amplifier with this topology. However, the latest "foolhardy" rage of single ended tube amplifiers does use this topology WHEN THERE IS ONLY A SINGLE OUTPUT TUBE (OR PARALLEL TUBES) in the entire amplifier. So much for that nonsense.

Reverse gain is the absolute defacto standard for tube amplifier topologies although, some of the earliest solid state amplifiers used this style before all of us engineers learned how to use complementary devices properly.

Quasi-infinite gain topology is something totally new that is being currently worked on however, it will be a while before all of the philosophy of this style is cemented.

Likewise for common-mode gain topology which in the future may become the defacto standard circuitry for the next millennium.

Finally we come to what we call Remodulation gain topology. This topological family includes any and all types of switching, PWM, FM, etc., circuitry. It is our belief that enough damage has already been done to the signal. Why screw it up even more by converting to another format and then have to convert back again?

The new Ampzilla 2000 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 smooth, 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 2000 uses 12 250-watt output devices per monobloc. This is 3 times more devices than the original Ampzilla. In addition, since it is a monobloc, there is a separate 2000VA transformer for each. In addition, the amount of heat sink radiating area is 3 times greater than the original meaning that there is NO fan. Also, the B+ and B- supply fuses are EXTERNAL. Also, The entire 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 monobloc has 100,000 ufd of power supply filtering with dual rectification as pioneered in the original Sumo's.

The nominal specifications are as follows and are very conservative:

    Power output –300 watts into 8 ohms at less than .05% of any kind of distortion known to man.

    Frequency response-- +/- .1db at any power level from 20Hz to 20kHz.

    Rise time – less than 2usec at any power level up to rated output

    Hum & noise – Better than –110db below full output

    Gain – Balanced inputs – 42x (32.5db) with +/- 1 volt RMS input

    Unbalanced 42x(32.5db) with 1 volt RMS input

    Load capability – will drive any load conceived by man

Some other details are as follows. All of the metalwork (except heat sinks) is of 14 Ga. steel. All transformers are our own design and are made in house. The amplifier weighs approximately 40 lbs. All input and output jacks are gold plated and of the highest quality. The line cord is 12 Ga. with "welded connectors" instead of crimped. All internal connectors are gold plated.

Without question, this new Ampzilla 2000 2nd Edition will be a new dimension in amplifier technology for the next millennium and with-out a doubt, as in the past, will be copied by others.


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