Rectifier For Cary SLP 05

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.

They don't last forever! The British, US and Japanese versions are good for about 5,000 hours use. More if you are lucky! One of mine in a 1963 Heathkit AA100 integrated amp died after many years of use. I was the second owner.

The GZ37 cannot be subbed for a GZ34. Stick with the GZ34/5AR4!