Phone preamp question

Welp, SMPS are generally capable of producing more objectionable (irritating) noise than the 120Hz-ish ripple from a rectified 60Hz mains supply, but the economics and physical scale are in the favour of SMPS. Having said that, the manufacturing quality and sourcing of most SMPS wall warts and many SMPS modules is sketchy at best. 

@corelli ,

Thank you also for that tidbit about powering it up before the amp.

Ughhh! There is no such thing as a "passive preamp". The two words are mutually exclusive,

Sorry @sleepwalker65 , going to have to disagree with you on that one!

Anybody know if Amperex makes a 12ax7(ecc83) version of their 12au7/7316?

Here ya go!

Thanks, yogi!

Yes, I believe that’s about as close as it gets to the 7316...

That price is mighty steep for a single tube.