12AX7 use in EVO 100 line

Does anyone know the rationale as to why the Prima Luna 100 series uses both 12ax7 and 12au7  (2 each) tubes in the pre section whereas all of the other series (200, 300, 400) use just the 12au7?  I would have thought it would have been simpler to keep it all the same - is it just a cost savings?


The 100 being the entry level is from the original lineup (12ax7/12AU7) which was used in the entire PL line before the 3 12AU7's per channel. The 3 12 AU7's implemented about 7-8 years ago.

Cost savings is probably PL keeping the original form factor of the case in manufacturing.

A few years ago all the PL products used a mixture of 12AX7s and 12AU7s. Kevin Deal, PL importer in the US, talked the designer into using all 12AU7s because there were more available and many vintage12AU7s were cheaper than comparable 12AX7s.

Someone at Upscale Audio, Kevin's store, could probably tell you why your 100 has a 12AX7 and which brands you might want to try to change the sound a little, if you want to do that.


yep -- good quiet 12ax7’s, american or western european nos or otherwise old stock from the good ol days, especially matched pairs -- are getting quite pricey, whereas relatively speaking au7’s are still plentiful and thus reasonably priced