https://www.upscaleaudio.com/collections/vacuum-tubes/products/tungsram-pcc88-7d...I prefer buying the Platinum grade = Platinum grade - The best of the best. Lowest noise and microphony with the tightest triode balance we have available. This is typically 10% or tighter, but may be higher depending on available stock.
.....and YES Match, the Mullard's and Ediswan's Platinum, are worth the money. I only use this Tungsram mentioned here as an inverter tube with my Ediswan's as inputs. The real magic is with the Mullard NOS Platinum's/Cryogenic I have for inputs and the Telefunken's as inverter's. Not even subjective....but objective....how good this combo is in the ZMA.
Each to his own, I am just that discerning. I would not own a Power Plant, Zitron Digital pcord to ZDSD, modified Adagio's and the IC's and Speaker Cables I have either..... . But, they make a BIG difference.
Nothing wrong with the "Pig in a Poke" purchase from Parts Connexion...but Driver grade (= not really suitable as a Pre Tube) is probably what you will get....or maybe roll the dice/get lucky and get.....Gold Grade. I also, don't buy the garbage on Ebay either.
READ: You won't get 7500 to 10000 hours out of unlabeled/untested at how strong? .........NOT.
Kevin/Upscale: Lists the tested number's on his tube boxes/LABELED. Yes, I've had them checked too.
You get what you pay for now that NOS (ESPECIALLY, NEW NOS PLATINUM) tubes are running out (getting more rare every day). For example, on shear instinct....I bought another pair of NEW NOS Platinum Ediswans's.....cause Lar's here knew....they were next on the Dodo Bird List.
Good luck. 8-)
Oh, and these Tungsram's that I only use for inverter's now....sound nothing like Ediswan's and certainly nothing like Mullard E188CC/7308's, as Inputs.
BUT, remember I own the NEW NOS Plat's, right?
I'm only 52....and I can still hear and I take care of myself. Now, I could still get hit by a bus tomorrow... I should make the long haul. ;D