Aestheix Calypso owners,tube advise needed


Just bought a 1 year old Calypso and need some suggestions.
I am biamping with Pass Lab Aleph 3s into Audio Physic Virgo IIs. I listen to Jazz, Rock and Blues. I have some nos Sylvania 6DJ8 with large yellow lettering with no other info and in the 12AX7 slots????.
gandme
Have you looked into the signature upgrade? I have had both and the signature is a whole different level. I was very surprised at how good the signature is even compared with some of the best preamps. You forget all about low noise tubes with the signature, any noise is all gone.
Not to jump the gun.. I am still in the nos tube mode. Who does the signature upgrade, Aestheix or an after market co.?
The Signature upgrade is an Aesthetix upgrade. They may have authorised people who can do this like great Northern Sound, but I would find out through Jim White at Aesthetix first.
It's only done only at Aesthitex.... Aesthetix has a new website at aesthetix.net. IT's about time!
I have an Aethetix Rhea with the Great Northern Reference Mod and it is wonderful. Steve Huntley is an authorized dealer and a great guy to work with.
I have no affiliation to set the record straight, I'm a satisfied customer passing the word.
Richard