GEC COSSOR GZ37 CV378 53KU - ONE - NOS BRITISH 1952 BIG BOTTLE BRAND NEW OLD STOCK NEW IN BOX VINTAGE VALVE TUBE .
THERE ARE TWO OF THESE TUBES AVAILABLE ( SEE PHOTOS )
BRITISH VINTAGE COSSOR BIG BOTTLE GZ37 RECTIFIER VALVE WITH A WONDERFUL CLEAR WARM SOUND...SEE REVIEW BELOW
MADE IN THE COSSOR HIGH WYCOME FACTORY IN BUCKINGHAMSHIRE GREAT BRITAIN IN 1952
BIG BLACK BASE WITH CLEAN SHINY UNUSED METAL PINS
RIBBED ANODE PLATES
SWAN NECK UPPER SOUND GETTER
COSSOR GZ37 REPLICA BOX WITH VINTAGE BROWN TISSUE AND CARDBOARD WRAPPING
THIS TUBE TESTS AT 100% STRONG NOS READINGS ON MY B&K 747 + HICKOK TV-7 TUBE TESTERS
TESTED FOR GAS AND SHORTS
INTERNATIONAL AIRMAIL SHIPPING - EXCEPT TO RUSSIA
WE OFFER A LOW CUSTOMS FRIENDLY DECLARATION UPON REQUEST
PLEASE SEE MY EXCELLENT E BAY CUSTOMER FEEDBACK AFTER OVER 15 YEARS OF SELLING VINTAGE VALVES ON EBAY.
PLEASE SEE MY EBAY 15 YEAR SELLING AWARD IN THE PHOTOS
FROM DUBSTEP GIRL WEBSITE
Another British tube, this one made in High Wycombe, England around the early 1950s. I've seen it branded as Cossor, Mullard, and GEC/Osram/Marconi/etc. It comes in brown or black base as well. This is a very nice tube overall. Its slightly warmer than the GEC U52, offering a little more bass body and punch and more warmth while maintaining good speed and PRaT. Transparency is very similar, offering liquid silky smooth transients and a grain-free presentation. However, this tube is warmer, not as airy, and the slight extra fullness and more tubey midrange make it a little slower overall. For brighter setups and headphones, this tube offers top-level performance while maintaining clarity and detail. It doesn't veil the midrange or treble like cheaper tubes would (this is very noticeable on headphones like the T1 or the HD 800). This tube is also great for jazz and vocals, very natural timbre and tube warmth. Great bass performance and warmth make this tube a winner for me. Unfortunately, this tube can be hard to find, often selling for $300-450$. It is cheaper than the U52 or WE422A though and might be good for those wanting to use it in a WA5 or WA6-SE. Compared to the newer and much more commonly available Mullard GZ37/CV378 skinny bottle, this tube is much better since it's not as slow and the bass is better textured and cleaner sounding as well as being faster and more resolving overall.
TUBE ROLLING WITH QUALITY VINTAGE VALVES IS A LOT OF FUN AND WILL PRODUCE WONDERFUL MUSICAL IMPROVEMENTS TO THE TONE OF VALVE DRIVEN AUDIO COMPONENTS