Mike Bettinger began GAS Audio in 1981 when Great American Sound went out of business. The equipment was too good to let it turn into doorstops. Our repair business evolved into restorations as the equipment aged. We've restored over 2300 pieces throughout the world, to the musical delight of many GAS owners. Now it's time to continue GAS Audio, and to use our knowledge and experience to build our own equipment!

When sound quality and musical presentation are important to you, products rebuilt by GAS Audio are a serious alternative to buying new equipment.

Ampzilla II

Ampzilla II

 MUSICAL VALUE AT ITS BEST!

GAS and Sumo amps and preamps were lauded for their innovation, simplicity, efficiency and longevity. Their quality and sonic signature are still clearly evident but, after 30+ years, age has slowly and subtly affected their performance, audible as a loss in purity and bloom on vocals and strings and a filled-in or textured quality as the music becomes full range or more complex. There's a loss in extension and speed of the lower frequencies. Over time, the musical presentation becomes generally less expansive, less involving and more two- dimensional than these exceptional designs are capable of.   

Our approach to rebuilding your amp and preamp retains the signature GAS sound. 

 
Thaedra preamp

Thaedra preamp

Our rebuilds follow 3 basic steps:

  • Resolving current problems with the unit's functionality to ensure longevity
  • Addressing known failure issues and age-related weak points; assuring proper electrical operation
  • Applying current technology to restore the amp and preamp's original sound, removing the major sonic bottlenecks of aged parts trimpots and connectors throughout the circuitry, including the power supply.
 
Son of Ampzilla

Son of Ampzilla

Thoebe preamp                        

Thoebe preamp                        

Thalia preamp

Thalia preamp

Sonic improvements include a very clear articulation on vocals, staying uncluttered sounding as the music becomes more complex. Subtle, fragile supporting instruments maintain their individuality in the presence of more dominating parts of the music. The bottom end is crisp and fast, with a good sense of impact. There is a strong improvement in the overall purity of the sound, with a solid reduction in the low level grain that you previously heard on vocals and strings. The midrange is fully fleshed out, the highs sparkle, and the bass is deep and taut. There is a distinct sense of audible bloom, body and solid imaging with a broad soundstage and accurate decay, making the overall presentation closer to live music. It is enveloping and involving, solidly dynamic, fast and fluid.

We offer a redesign of the input stage using complementary low-noise J-fets (Junction field effect transistors) in place of the original bipolar transistors. Sonically, the J-fets enhance low level detail retrieval and provide a startling improvement in low noise performance; they add a sense of purity on vocals and strings thought to be impossible in transistor amplification. There is also a sense of linearity that allows the amps to maintain consistency of clarity and tonal balance from low to high levels; no more confusion and congestion as the volume is pushed. The staging and depth retrieval is downright spooky and the overall presentation takes on just the right balance of airiness and bloom. Technically the changes involve only the input differential stage; the circuit has been painstakingly balanced and fine tuned for optimum performance and to operate electrically identically to the downstream stages of the amp so that all of the original GAS operating points for the voltage amps, driver and output stages run exactly as before, maintaining their sonic signature and biasing. The J-fets are hand-matched Toshiba devices; the cascode transistors are low-noise graded devices as well. The additional cost is $250.

 
Rebuilt Ampzilla

Rebuilt Ampzilla

Restored Son boards     

Restored Son boards     

Thaedra 200 Vintage Chassis

Thaedra 200 Vintage Chassis

Charlie the Tuner

Charlie the Tuner

Dueling GAS 500's

Dueling GAS 500's

Rebuilds include:

  • IEC connector
  • Instrumentation-grade power cord. Amp p0wer cord is 14 gauge, 6.6 feet in length. The preamp power cord is 16 gauge.
  • Dual binding posts
  • Preamp input connectors
  • Calibration control upgrade
  • Meter circuit rebuild and bulb replacement. We replace the deflector shields in the Son, polish the meter bezels to minimize scratching and scuffing, and modify the circuitry to dim the meter lamps..
  • Chassis cleaning and polishing. We remove as much age effects as possible.
  • Hardware, feet and fuse-cap replacement
  • Son of Ampzilla option: a back-panel mounted power switch.
  • Ampzilla replacement fan if needed, with an NMB industrial grade, quiet ball bearing unit. 

Read Dick OLSher's enjoythemusic.com review of our rebuilt ampzilla ii: http://www.enjoythemusic.com/magazine/equipment/0212/gas_audio_ampzilla_ii.htm

View AV Show Reports: Peter Breuninger interviews Mike Bettinger about GAS Audio Restorations! https://www.youtube.com/watch?v=LMX87HItdPY