Threshold NS10 Preamp Repair


I have a Threshold NS10 which I have had for 30 years.  I only use it as a phono stage, most recently for my VPI turn table.  I have always loved that preamp.  It's such a musical yet invisible phono stage.  I've recently noticed more hum emanating from it when the volume is turned up and nothing is playing. There is also now a pop when I turn my VPI motor pod off and forget to turn down the volume on the preamp, which isn't connected to , or powered by the same circuit.  I am thinking it's time for it to be gone through and possibly repaired if need be.  I was hoping I could get some guidance on who might repair these (I hate to say vintage because that makes me vintage) old Nelson Pass Threshold NS10's.  Thanks in advance for any ideas on the issue and/or recommendations on a repair place.  I live in the SF Bay Area if anyone knows of someone local.  Thanks.
picahenry
vintageamprepair.net

picahenry Threshold NS10 Preamp Repair



Any competent repair technician should be able to fix it, with this circuit diagram. 

 https://ibb.co/FVkWBJQ

Cheers George
I think Pass might repair it. I traded my Threshold and I think my audio guy sent it to Pass and they checked the specs and maybe replaced some of the caps. That is my memory... it’s not great.... but works sometimes.
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”.   



So many great answers here.  Thank you  for the resources guys. This is exactly what I was hoping to get.  Thanks again! 
For sure, get it fixed!

  New caps, whatever she needs!

  Another 30 years,...........
How cool would it be to have Nelson Pass look at it?  I should take it on a trip to Sea Ranch :-)
Lots of good references here. Choose carefully, things like this can effect resale value. Threshold, is new Threshold, but still Threshold. Pass Labs has obvious lineage. Coda are ex-Threshold engineers. Jan Soderberg of Vintage Amp  Repair in California is ex-Threshold as well, and well regarded as a Threshold specialist with Nelson Pass's blessing for such things.

@picahenry, Any news or updates on getting your Threshold NS10 Preamp Repaired?