@immatthewj
Hi,
I have a Cary SLP 05 too and have used several different rectifiers after the stock Sovtek failed after three months and took both fuses with it.
I rate the Sovtek as OK sounding and poor on reliability.
I tried a Gold Lion and it was a mixed experience. Good dynamics but poor transparency and detail.
For NOS I tried an off label Amperex and it had quite a bass punch but the treble was not refined.
Next was a Mullard f31 and it was excellent but not quite as good as the Mullard f32 which is cheaper and easier to find.
The NOS Mullard f32 can be found on ebay under a variety of labels that Mullard made them for, e.g. Haltron, RCA and Westinghouse.
There are a number of very knowledgable and trustworthy tube guys on ebay and they have served me well for NOS rectifiers and 6SN7 tubes for my Cary.
The Mullard f32 sounds so much better in my system than any others. Speed, dynamics, transparency and seperation, refinement, bass, midrage, treble, etc. Reliability is by all accounts a last a life time purchase, mine has lasted 9 months and going strong.
Mullard NOS GZ34 / 5AR4 f32 date code. If you keep looking you should be able to find an unused version for -$150 or so.