FWIW: looks as tho' you like the ARC sound. My friend here owns an upgraded & modified SP-6A. Gorgeous sound & I can understand why ARC had its haydays during the times it manuf. the SP-6 --> SP-11. The SP-6A is a 1978 vintage pre but I think that, after modification & upgrading, it'll hold its own vs. many of today's $2000-$3000 preamps. Of course, MHO.
So, I recommend that you call up Steve Huntley @ Great Northern Sound & speak to him about modifying & upgrading your SP-8 Mk2 i.e. hang-on to your SP-8 Mk2!
Mods that should make your pre much better are basically to the power supply & to the coupling caps.
Modifying the RCA jacks (believe it or not) also makes a diff.
Punching a hole in the chassis & installing an IEC so that you can use an after-market powercord will also help.
Use of NOS tubes in key locations (the 1st tube in the phono section of my friend's SP-6A is a NOS. I forget which one tho) will also help.
There is much more life left in that SP-8 Mk2 than you'd believe. I say this after experiencing my friend's SP-6A & would never have believed it until I heard it. BTW, he still owns that pre & is not considering giving it up.
YMMV.
So, I recommend that you call up Steve Huntley @ Great Northern Sound & speak to him about modifying & upgrading your SP-8 Mk2 i.e. hang-on to your SP-8 Mk2!
Mods that should make your pre much better are basically to the power supply & to the coupling caps.
Modifying the RCA jacks (believe it or not) also makes a diff.
Punching a hole in the chassis & installing an IEC so that you can use an after-market powercord will also help.
Use of NOS tubes in key locations (the 1st tube in the phono section of my friend's SP-6A is a NOS. I forget which one tho) will also help.
There is much more life left in that SP-8 Mk2 than you'd believe. I say this after experiencing my friend's SP-6A & would never have believed it until I heard it. BTW, he still owns that pre & is not considering giving it up.
YMMV.