Stereo Power Amplifier Restoration & Repair Service

Audio Upgrade Modifications


 "When You Are Serious About Sound"


Located approximately 15 miles east of the Continental Divide in “Big Sky” country.

We offer exceptional service and personal attention in the restoration, repair, and audio upgrading of stereo Hi-Fi power amplifiers and preamplifiers as our specialty.  Our goal is to provide audiophiles and music lovers with the best performance from their audio systems.  We strive for quality and integrity in everything we do.


Brands we service:  ADCOM, B&K, BGW, Creek, Denon, Dynaco, Hafler, Harman Kardon Citation, Kenwood, Luxman, Marantz, McIntosh, Mitsubishi, Musical Fidelity, Onkyo Integra, Parasound, Rotel, Sansui, Sony, Yamaha.

*** ADCOM is our most popular brand ***


Specialists in classic and vintage stereo power amplifier restoration, repair, and upgrade services for ADCOM GFA-545/555/565/585 classic series, Harman Kardon Citation 16/16A, Parasound HCA-2200II, HCA-2205A, HCA-3500, HCA-1500A series, Parasound Halo A21, A31, A51.  We do NOT service or upgrade ADCOM GFA-5400, GFA-5500, GFA-5503, GFA-5800 or GFA-5802 MOSFET amplifiers. 

*** We now offer superb upgrades for the new ADCOM GFA-555se, GFA-565se, GFA-575se & GFA-585se amplifiers.

We also have audio upgrades for ADCOM GFP series preamplifiers (750, 715, 710, 565, 555II, 555, 345), Parasound P/LD-1100, P/LD-2000 preamplifiers and Harman Kardon Citation 17/17S & 21 preamplifiers.

We also specialize in upgrading Creek OBH-11 headphone amplifiers along with Creek OBH-8 & OBH-18 phono preamplifiers.

>>> Before shipping your equipment to us for restoration and/or upgrading, please review both the AUDIO UPGRADES page along with the FAQ page to become familiar with our policies and terms of service. We do not accept 3rd party shipments and they will be refused if sent.


*** Please click on the AUDIO UPGRADES tab at the top of any page to learn more about our audio upgrades. Information on our most popular products for upgrades are located further down on that page ***     


 Authorized Service Center for ADCOM

Authorized Service Center for Parasound





We are a fully-equipped audio service facility utilizing Audio Precision, Leader, Sencore, Stanford Research Systems, and Tektronix test equipment. 



  Our newest audio analyzer, the Stanford Research Systems SR1+.



BSA Newfoundland Dog "Tia" (2003-2015)



*** We use FedEx ground service shipping exclusively for our long distance customers ***


   Big Sky Audio, LLP services are available to USA residents only - no international shipping is available. We do not ship to APO/FPO addresses.


Acceptance Mark

©2008-2018 - Big Sky Audio, LLP. All rights reserved. 'When You Are Serious About Sound' is a USPTO Federal trademark registered to Big Sky Audio, LLP. All photos and text are property of Big Sky Audio, LLP. Brand names and logos are trademarks of their respective owners.