Rectifier For Cary SLP 05

Personally; there are only two 5AR4 iterations, that I would consider against the Mullard(Blackburn) GZ34.      Both, from Philips: https://www.ebay.com/c/168100339    and: https://tubeworld.com/gz34metal.htm    No connection to either reference.

@testpilot here's hoping it does last forever.
@rodman99999 how do the Phillips GZ34's sound vis-a-vis the Mullard?
@tvad I am checking with Cary on both the Brimar and the Mullard GZ37 nut as it is the weekend I thought I may get a quicker response here from folk who may have tried one.

Slightly less warm/better definition(realism), but- still with an extended life expectancy(20K to 30K hours).      There are also a few differing iterations, within their metal base, GZ34s, that will vary slightly in presentation.      I prefer the tall bottle, 5R4GYS.      You may find a change from the Blackburn Mullard, a sideways move.      I’d never dissuade one, from experimenting, though.      It’s all about ones own aural palate and system, in their listening room.

Be sure to use the original British-made GZ34. The commonly available (and cheap) Mullard's are made-in-Russia knock-offs! No good! Real Mullard GZ34's have been out of production for decades. Ditto for USA and Japanese production. These are both 5AR4's. And are far better than today's Russian or Slovakian (JJ) types. Real British Mullard GZ34's will cost about $100 - $200. USA and Japanese 5AR4's $50 - $100.