The problem is the combination of EL39 + 6BL7 + 6080. Those tubes have very different electrical specs. Ask any major tube amp builders if they would consider using this combination in their top of the line tube amps and they will look at you funny !
Precisely UT...the problem's not the
straightforward use of 'alternative' tubes I have experimented (exhaustively!) with and found - along with many others - to be safe as well as at least equal in performance to some of the best conventional tubes...and often superior lol!
And as I explain to LW below, it's only the extreme/excessive use of
multiple tube setups that will definitely void any warranty...as it would with
any other maker if not in the design. And for sure you're also certainly right in that
no-one would even consider making an amp with such diverse combinations!!
Clarifying question for us relative newcomers: Does the use of any adapter (EG - for an EL type tube) void the warranty?
Hi LW.
There's a world of difference between using
single adapters and
multi ones in an amp not specifically designed for such use. All the 'alternative' tubes I have adapted for years now have been extensively tested, not only by myself but many other users also.... and none more so than the EL family of tubes. And although F-A can't
officially endorse their use, Lukasz has confirmed to me that he isn't now at all
unhappy with them, even though they did find the bench readings 'unusual' lol! And he agreed that they are obviously
safe to use, given how long I especially have used them without anything untoward whatsoever, in either Elise or Euforia....further reinforced by my testing of every single internal component's operating temperature, showing that they ran at
10 deg C (
50 F)
cooler than with stock tubes, and a section immediately below the trafo at
20 deg C (68 F) cooler!!
Therefore, the use of such tubes will not, of itself, cause any warranty-voiding damage. Naturally - as with
any tube - there's always the
slight possibility of it 'blowing'/arcing, but hopefully our amps' protective circuitry should be able to prevent major damage, and cannot be blamed upon it being an 'alternative' tube. With regard to the adapter itself, although the occasional Chinese one has failed (which Mrsx has always happily replaced), I've yet to hear of it causing any damage to the amp. And I would recommend that if ever anyone has the slightest doubt about an adapter's functioning, it is reported to the maker and replaced...assuming all the usual tests have been made to eliminate any other cause first...ie. swapping adapters/tubes; checking the tube's pins are shiny clean; tubes and adapters are seated properly; all cable connections in the system are secure/clean, including the power supply connector!...etc.
And so, in short, so long as one hasn't gone more extreme than this; taken the usual care in using the amp, and with tubes that I myself have proved to be safe, there's no reason why the warranty should be voided, if the worst should happen...they can (usually) soon determine the actual cause of any problem!
So fear not, mes amis!
...CJ
And as far as I'm concerned, if one is lucky enough to bag a pair of EL39s especially, Euforia will deliver a sound to satisfy the most demanding of tastes lol! 
). Whatever, I do think it looks real classy...
Those ClarityCaps capacitors and Constant Current Source alone sound very interesting indeed...not to mention an even better transformer - the latter 2 especially, given the importance of power supply in all amps lol! 
I'd even be prepared to pay extra and ask for a custom amp with my favourite Neotech UP-OCC silver wire in addition to the copper (won't use anything else these days!), if the amp can win over my wallet lol!! 
