You might also call Coda. These people came from Threshold and might be able to help.
http://www.coda-continuum.com/home/index.php
please also call Threshold Audio.
http://www.threshold-audio.com/about.html
http://www.threshold-audio.com/contact.html
Also please contact this company:
http://vintageamprepair.net/threshold-archives/
Vintage Amp Repair. Vintage Amp Repair performs maintenance, restoration, and custom modifications on all makes and models of audio tube amplifiers.
Another option is True Sound in the SF Bay Area. A phone call is suggested to find out if he can repair your Threshold preamp.
https://www.tsound.com
“Not only do we bring the dead back to life, we specialize in refining the musicality of your equipment by selectively modifying individual elements. We also provide meticulous restorations of vintage equipment, especially valve (vacuum tube) components”.
http://www.coda-continuum.com/home/index.php
please also call Threshold Audio.
http://www.threshold-audio.com/about.html
http://www.threshold-audio.com/contact.html
Also please contact this company:
http://vintageamprepair.net/threshold-archives/
Vintage Amp Repair. Vintage Amp Repair performs maintenance, restoration, and custom modifications on all makes and models of audio tube amplifiers.
Another option is True Sound in the SF Bay Area. A phone call is suggested to find out if he can repair your Threshold preamp.
https://www.tsound.com
“Not only do we bring the dead back to life, we specialize in refining the musicality of your equipment by selectively modifying individual elements. We also provide meticulous restorations of vintage equipment, especially valve (vacuum tube) components”.