Tubes Asylum

RE: Mullard CV4004 or Mullard ECC83?

57.66.65.3

Al Noakes

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In Reply to: RE: Mullard CV4004 or Mullard ECC83? posted by unclestu on October 15, 2014 at 11:33:10

'Mullard CV4004 were originally built for Britih military'

I doubt it , this type has the commercial designator of M8137 so was also used commercially . It is a ruggedised 12AX7 and what you suggest is a common misconception around here . Just because it has a CV number , doesn't necessarily mean it was intended for the military . The UKAEA and GPO , for example , were government organisations that used valves designated this way . CV=common valve

Al

Follow Ups:

RE: Mullard CV4004 or Mullard ECC83? - Tre' 08:51:03 10/16/14 (7)
CV=common valve, as in common to all three branches of the British military. Army, Navy and Air Force.

" CV numbers were applied to valves used by the British Services, gradually replacing the Army, Navy and Air Force nomenclature in use at that time."

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
- http://www.tubecollector.org/cv-valves.htm (Open in New Window)
- RE: Mullard CV4004 or Mullard ECC83? - Al Noakes 07:45:47 10/17/14 (6)
  CV numbers are not limited to the forces , it covered a vast array of government ministries... I mentioned the UKAEA as I once cleared out a decommisioned research station of a lot of it's old valves . Instrumentation was updated but their stores still had retained a lot of old stock valves , all with CV designators . Ditto for the post office (GPO) which is now known as BT (British Telecom) who used a phenomenal quantity of CV140 (EB91) . Initially the navy , air force and army all had their own designators which were amalgamated during WW2 , hence the CV 'common valve' designation . 'A' datecodes started in 1945 . This eventually covered all government sourcing valves post war . Some people believe that valves with CV designators are better or 'mil-spec' which is a very common misconception .
  Al
  
  Edits: 10/17/14
  - RE: Mullard CV4004 or Mullard ECC83? - ralpheburns 21:14:11 10/21/14 (5)
    Hopefully not to steal the OP thread, but I could use some advice as well. I'm running Quicksilver Silver 88s with KT 150 output tubes into SF Elipsa SE. I'd like to find tubes that have articulate bass extension, partly because I often listen at low levels where the woofers are inefficient and partly I like that musical emotion anyway. I am now enjoying some input tubes I got from Brent Jessee; RCA NOS grey plate 12BH7 and Amperex Bugle Boy NOS 12AX7. The sound is damn good, and much more pleasing than the some re-issue tubes I tried. The only criticism is that I'd appreciate more coherent sound staging, but not to sacrifice bottom end tonality. Now I'm thinking to stock up a replacement set for a rainy day, and wondering if to try something else. Brent only seems to have the RCA 12BH7s although I ought to try the black plates next time; and there are some unmatched Brimar 12BH7s on eBay that I'm curious about (item 310871915920).
    
    For the 12AX7, Brent is offering some Mullard longplate halo getter ($325) and square getter ($475)...hmmm or the same eBay seller as the OP's purchse has them both for less (I figure with Brent I'm paying the premium for selection service). And last, there's some unmatched Genelex B759 on eBay that will probably net a fortune.
    
    Thanks for the input!
    - eBay Mullard square getter (Open in New Window)
    - RE: Mullard CV4004 or Mullard ECC83? - ralpheburns 06:34:47 10/22/14 (4)
      Here's the link to the eBay Brimar 12BH7s, and the seller says he will match into pairs, so I wonder about those vs. RCA black plates. For any of these like the square getter Mullard 12AX7s on eBay, I'm clueless on how to read those test stats to determine tube condition, and could use some pointers.
      
      - thanks in advance!
      eBay Brimar 12BH7 (Open in New Window)
      - what preamp - unclestu 23:34:47 10/23/14 (3)
        
        In Reply to: RE: Mullard CV4004 or Mullard ECC83? posted by ralpheburns on October 22, 2014 at 06:34:47
        
        Are you running?
        
        RE: what preamp - ralpheburns 07:57:23 10/24/14 (2)
        
        In Reply to: RE: what preamp posted by unclestu on October 23, 2014 at 23:34:47
        
        Preamp is solid state, a Hegel P30. It's clean and neutral, kinda like I found in the Quicksilver Silver 88s. I had a tube pre-out DAC (AMR DP-777), and the sounds were close, but I had reliability problems with the AMR. The Heel is not without a problem though, and that's the remote jumps in big db steps... I wouldn't have bought it had I demo'd the remote. Source are FLACS and DSD from a SoTM Zuma CAPS music computer into a Hegel HD25 DAC (strong, warm sound).
        
        RE: what preamp - unclestu 00:57:14 10/25/14 (1)
        
        In Reply to: RE: what preamp posted by ralpheburns on October 24, 2014 at 07:57:23
        
        Shucks , with a tube amp like a Quicksilver thought you had a tube preamp and sometimes rolling tubes there is more helpful.
        
        Sorry not familiar at all with the Hegel
        
        RE: what preamp - ralpheburns 07:34:56 10/25/14 (0)
        
        In Reply to: RE: what preamp posted by unclestu on October 25, 2014 at 00:57:14
        
        Thanks ok, the Hegel is very neutral... so much so it derailed my notions of getting a tube preamp. Anyways, I'm not necessarily looking for a big change in the sound, just want to stock up on a set of tubes that will project a good soundstage and have articulate bass extension.
        
        Wondering about Brimar 12BH7 vs. RCA Blackplate
        Wondering about Mullard 12AX7 square vs. halo getter
        
        Thanks!

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