Your point of contact will be Greg Christensen. He's an affable young fellow.
Greg said that since the scamdemic everybody is pulling their old gear out of storage and wanting it fixed. Apparently it deteriorates in storage. ie corrosion in the pots, cap bleed, etc.
You will send an email for a place in the que, get an acknowledgement back, then you will get an email about 7 months later telling you you're getting close (30-ish days) to the ship-in time bit "don't ship it now". About 45-60 days later you will be told to ship- when, where and how.
That was my experience since August 2022 for an SP-15 refresh. Meanwhile you can enjoy your Ref 6 and fall in love with old recordings you rediscover anew.
The 750s and an Anniversary preamp are my dream system. I just need to finish the kitchen remodel first before my anticipated upgrade. The anticipation is as much or more fun than the event. :)
