Lapierre --
The reissued GL KT88's are a good choice from what I hear, and cost about $200+ for a matched quad. The PentaLabs/Shuguang KT88SC's which I tried (and liked) are just as good according to many, and about half the price. Try Doug's tubes http://www.dougstubes.com he's very nice, has reasonable prices, and he sells both.
For the AX's and the AT's, NOS Telefunkens are the minimum place to start. THE 12AX7's AFFECT SONICS THE MOST. There are three of them (V-1, V-2, and V-5) If you are using balanced interconnects (which you should be, with the C46) then the first 12AX7 (V-1) is not in the signal path and so it can be any ol' 12AX7, just to complete the filament circuit.
The first tubes I substituted (for the OEM tubes) were a pair of ratty old TFK 12AX7's (in the V-2 and V-5 spots) and the difference was really amazing in all respects -- air/ambience, detail, dynamics, soundstage/imaging, good hi and lo freq. response. Then came the TFK 12AT7's, and finally a quad of the Penta KT88SC's. The total should run about $300 - $500 depending whether you buy the TFK's on eBay or through an online tube seller. It's hard to beat NOS Telefunkens, but you can. Particularly by substituting Sylvania or RCA 5751's (triple mica black plates) for the 12AX7's. But the price/value ratio starts to go down as with all things audio ;-) (A pair of Sylvania 5751 TMBP goes for $150 or more these days -- but boy do they sing!)
You might want to read the 12AX7/5751 sections of Joe's Tube Lore, if you haven't:
http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html
.
The reissued GL KT88's are a good choice from what I hear, and cost about $200+ for a matched quad. The PentaLabs/Shuguang KT88SC's which I tried (and liked) are just as good according to many, and about half the price. Try Doug's tubes http://www.dougstubes.com he's very nice, has reasonable prices, and he sells both.
For the AX's and the AT's, NOS Telefunkens are the minimum place to start. THE 12AX7's AFFECT SONICS THE MOST. There are three of them (V-1, V-2, and V-5) If you are using balanced interconnects (which you should be, with the C46) then the first 12AX7 (V-1) is not in the signal path and so it can be any ol' 12AX7, just to complete the filament circuit.
The first tubes I substituted (for the OEM tubes) were a pair of ratty old TFK 12AX7's (in the V-2 and V-5 spots) and the difference was really amazing in all respects -- air/ambience, detail, dynamics, soundstage/imaging, good hi and lo freq. response. Then came the TFK 12AT7's, and finally a quad of the Penta KT88SC's. The total should run about $300 - $500 depending whether you buy the TFK's on eBay or through an online tube seller. It's hard to beat NOS Telefunkens, but you can. Particularly by substituting Sylvania or RCA 5751's (triple mica black plates) for the 12AX7's. But the price/value ratio starts to go down as with all things audio ;-) (A pair of Sylvania 5751 TMBP goes for $150 or more these days -- but boy do they sing!)
You might want to read the 12AX7/5751 sections of Joe's Tube Lore, if you haven't:
http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html
.