AMPZiLLA
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The original AMPZiLLA audio amplifier was a solid-state power amplifier designed by Mr. James Bongiorno and was featured in Popular Electronics Magazine in September 1974. The response was so successful that James left his current employer (Scientific Audio Electronics) or SAE and help form (Great American Sound Company) or GAS to sell the amplifier commercially. GAS went on to offer a whole family of audio products including more amplifiers. AMPZiLLA was a high-power amplifier rated at 200W/channel @ 8 Ohms and used full complementary symmetry circuitry from input to output. The input stage used a complementary dual differential topology while the output stage used a push pull topology consisting of complementary Darlington emitter followers. The output stage use four power devices, two for the positive rail and two for the negative rail uniquely configured in a series connected circuit. The design offered low level Class A operation. The front panel design was also unique with 2 very large VU meter projecting forward relative to what would normally considered the front panel. It was fan cooled.
[edit] Later versions
All of the following GAS amplifiers also used full complementary symmetry circuitry from input to output that included the dual differential input.
The AMPZiLLA II that followed was the first solid-state power amplifier to use DC servo feedback circuit. It also added constant current sources on the input differentials and added cascodes on the voltage gain output stage. Rated at 200 Watts/Channel @ 8 Ohms.
The AMPZiLLA IIa was a GAS modified AMPZiLLA II design done after James left GAS. Rated at 200 Watts/Channel @ 8 Ohms.
The AMPZiLLA III was a kit by A-Train Ltd. and was featured in Audio Amateur magazine Apr-1984. The input stage was used a full-wave, balanced bridge with ground as a reference only for the input while the output stage is a RAEF Darlington circuit. It also had DC servo feedback circuit. The amplifier overall circuit was like the SUMO Andromeda with the main difference was in the output stage.
The AMPZiLLA500 was last amplifier product made by GAS Co. It remained fan cooled but took air from the front panel and blew it out the back. No VU meters.
The Son of AMPZiLLA operated at a lower power of 80 Watts/Channel @ 8 Ohms and was designed to handle 2 Ohm loads since it also used 4 power devices like it's "father". However the devices were configured in the more conventional parallel topology. It offered the power capability to put out 300 W @ 8 Ohms loads when used in a bridged configuration. The front panel has two VU meters and the large passive heatsink located on the side eliminated any need for a fan. This amplifier was also a James Bongiorno design.
The GRANDSON of AMPZiLLA was the lowest power amplifier offering 40 Watts/Channel @ 8 Ohms operating in Class A to 1 W and a DC servo control circuit. It also can handle 2 Ohm loads. Small in terms of size as well, the amplifier had it's heatsinks located on the back with the back half of the power transformer occupying center section similar in style relative to the Phase Linear 400. No fan and no VU meters. This amplifier was also a James Bongiorno design.
The GODZiLLA was dual monobloc with very high bias and is used a bridge circuit output stage designed by Andrew Hefley. But only 20 units were ever made. It was fan cooled.
The Ampzilla 2000 is a new designed by James Bongiorno for new millennium and is produced by Spread Spectrum Tech. Inc. It's used totally balanced circuit like SUMO, but uses a completely new variation of the Forward Gain topology to achieve unprecedented improvements in linearity.
[edit] Awards
- 1976 "STATE OF THE ART - GRAND PRIX AWARD 1976" -- Stereo Sound (Japan)
- 01/2003 "STATE OF THE ART - GRAND PRIX AWARD 2002" - Stereo Sound (Japan)
- 01/2003 "Jazz component AWARD 2002" - Swing Journal (Japan)
- 01/2003 "Grand Prix award 2003" - Stereo Sound (Japan)
- 01/2003 "Grand Prix award 2003" - Radio Engineer (Japan)
- 2003 "Products Of The Year 2003 Awards: Power Amplifier" - HiFi Review (HongKong)
- The November 2002 edition of "Stereophile" magazine listed AMPZiLLA for the 100 top audio products in the last 40 years.
