The best tubes for the various SP-9's are rare NOS that go now for $75 and up, each. They are getting rare!
I have used all of the SP-9 models for years.
These tubes can last 5000 to 10000 Hours.
ARC can still repair, and refurbish, to original state, all the SP-9's.
I liked the original MKI and the MKIII best. I did not like the MKII.
Buy a lifetime supply of NOS tubes, and do not leave the preamp on for days, when not listening.
You will be set for a lifetime of good sound!
I have used all of the SP-9 models for years.
These tubes can last 5000 to 10000 Hours.
ARC can still repair, and refurbish, to original state, all the SP-9's.
I liked the original MKI and the MKIII best. I did not like the MKII.
Buy a lifetime supply of NOS tubes, and do not leave the preamp on for days, when not listening.
You will be set for a lifetime of good sound!