Because they don't make them like they used to,

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Doppler Audio

Providing a Range of
Vintage Instrument & Amplifier Repairs

If you own a Tonewheel Hammond organ, Fender Rhodes or Wurlitzer Electronic Piano, or a vintage Guitar Amp, you have come to the right place…

We love everything about them!

But as you know, there can be a few issues… and if you have one that needs some serious TLC or just a tweak here and there, the best solution is to use someone truly passionate about their craft.

Geoff Williamson of Doppler Audio 
IS that person.


Hammond & Leslie

Tone Generator Repairs
Pre-amplifier Service
Leslie Connection & Switching
Leslie Speaker Repairs
Full Restorations


Tuning & Voicing
Reed Replacement
Amplifier Repairs & Biasing
Keyboard & Action Overhaul
Full Restorations

Fender Rhodes

Tuning & Voicing
Pickup & Tine Replacement
Keyboard & Action Overhauls
Suitcase Pre-amp & Amp Repairs
Full Restorations


Guitar Amps

Servicing & Re-Capping
Troubleshoot Badness & Weirdness!
Valve/Tube Biasing & Replacement
Modification & Tweaks
Full Restorations

About Us & Why We are
The Best For the Job

Doppler Audio specialises in servicing, overhauling and fully restoring tonewheel Hammond organs.

We also service and restore Leslie tone cabinets, Wurlitzer and Fender Rhodes electric pianos, as well as vintage tube amplifiers.

Geoff started out fiddling with music electronics in teenage years, building effects and preamps for electric guitars back in the 70s. By the 90s he was fettling amps and electromechanical instruments of days gone by. For the last 15 years Geoff has specialised in Hammond and similar instruments out of sheer love for these classic designs, turning what was once a hobby into a full time service & restoration business. 


Our Work

Our Recent Projects

Leslie Combo Preamp Pedal

  • Converted from 115v to  230v operation
  • For operating 145/147 Leslies
  • Bought on eBay USA by a local customer 
  • Now usable in Australia
  • Play guitar, vocals, anything through a vintage Leslie!


Echoplex EP-2 Tape Echo Sound-on-Sound


  • Converted from 115v/60Hz to  240v/50Hz operation
  • Fresh Pinch Rollers, Tape
  • Last of the tube models
  • Warm & quiet preamp
  • Super rare Sound-on-Sound


I love Geoff’s work. He converted my B-2 Hammond and tallboy 31H Leslie to work on 240volts. He added Trek II Percussion and Reverb units to the old B-2 and I’ve never had a Hammond that played and sounded so good. Geoff loves these instruments and really knows how to look after them.

Peter Geoghegan

Having known Geoff for over 20 years. Geoff has accumulated his knowledge of  the inner workings of vintage keyboards, amplifiers and accessories through sheer persistence, as evidenced by his growing clientele. I have engaged Geoff in a range of jobs and found his work ethic and accountability to be totally trustworthy, keeping you informed as he works and providing a positive outcome always.

Tim Neal


15 + 10 =


216 Old Thorpdale Road
Mirboo North, VIC, 3871


0408 682 172