Manufacturers with great customer service

VPI for sure.

Veritas Cables

DH Labs Cables

Cambridge Audio US ...

Almost of all of them I have dealed with.

Innuos!, great customer support.  I bought a Pulse Mini used and discovered that the little LED that shines down from under the faceplate, when the unit is on, was not working.  I contacted Innuos and they sent me a replacement mini circuit board that housed the LED and the on switch with the instructions to replace it.  I got it free of charge from Portugal in less than a week!  That’s outstanding customer service!

I've had amazing service from Merrill Audio, Innuos, Audeze and EMM Labs. Merrill fixed my monoblocs over the holidays, perfectly, out of warranty and without charge. Mr. Vitorino first remotely fixed my Zenith configuration issues, and then when a spring failed on the power button, fixed the whole thing at no charge, again out of warranty.  Audeze was simply great and fast accepting my Crbn's at full price to trade against against Crbn II's. Meitner was similarly professional and prompt in upgrading my Ma3 to an Ma3i. Top notch service from all four companies that can't be beat.

Pass Labs provided excellent service, parts and labor, when I had an out of warranty issue with my Aleph 3, even though it was years after it went out of production.

VPI was graciously accommodating when I asked them to fit a standard SME mount for my Graham Phantom on a TNT HRX.

Manley was promptly responsive when I had a technical question about my Steelhead.

And Magnum Dynalab came through in the end when I requested a replacement center tuning meter for my FT-101A Etude tuner, decades out of production.

I should also mention Vizio replaced for free a 60" TV which stopped working years after the warranty expired.  They said the production run had a part that was found defective after some years of use, and they chose to replace the whole screen for free, including sending a service guy to remove the old unit and mount the new one.  Gotta luv'em for that!