Nagra VPA 845 retubing


Hi. I have a pair of Nagra VPA monoblocks with 845 tubes. I bought these used. When I contacted a local dealer I was told that I should only buy tubes from Nagra, because Nagra supposedly ensures that they are perfectly matched and are fully compatible with the amps (they costs 900 a pair!). Is this true, or is this a racket? Has anyone tried other matched 845 tubes than those sold by Nagra? If so, any preferences? Thanks
obrennan1963
Hi I don't have Nagra VPA's, but I do have a Nagra PLL and VPS. They do heavily test their tubes and warranty them. Not all 845's also are perfectly to the same specs and could possibly cause a issue. Those are GREAT amps, I've heard them lot's at my dealers...I spend the $$'s....it's not a racket.

I agree it's a little pricey...but you also don't have to worry a about a bad tube and matching is important in balanced amps...like you VPA's

Out of curiosity, what preamp are you using with them?
$900/pr for current production 845 tubes is a lot of money. What make are the Nagra supplied tubes?
Online prices range from approx USD 95 for a single tube to 950 or so for a pair depending on the brand etc. Nagra prices don't appear to be unreasonable .
All the best
Pradeep
Nagra at one time used KR Audio 845 which retail in the 900/pr range but I thought Nagra dropped them due to reliability issues and started using Chinese sourced 845.

Which version of the VPA do you own? Does it have the built in tube protection circuit?