Mullard ecc83 knowledge needed

Discussion in 'Amps and Cabs' started by kingsxman, Oct 5, 2006.

  1. kingsxman

    kingsxman Silver Supporting Member

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    Just curious as to what the difference is between all the different Mullard ecc83/12ax7 tubes out there. Mullard ecc83 is supposed to be the gold standard for preamp tubes. But there appear to be lots of different Mullard ecc83's (12ax7's) that are rebranded (Heaths, EIC), , some called yellows, etc. Some are Braeburn, some are other. I think I even saw something about England vs Russian Mullards...

    How do you know what your getting? Any rebranded ones to stay away from?

    I'd just like to get one or two "real" Mullard tubes to use as a reference for other tubes that I get.
     
  2. mmorse

    mmorse Member

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    If you want to pay through the nose, get a couple from a dealer. Or grab a couple off ebay. Look for one that has the Blackburn factory etched factory and date code on it. Something like "I61 BD01" or similar. The important part of the code is the "B" for Blackburn. Don't worry about what the label is. Make sure the tube is clear with good flashing at the top. They can still be had for $25-$50. I just bought 8 off someone for $135. None have a Mullard label. 5 say Hammond, 2 say V/M (Voice of Music) and one says RCA. Although tube tester results aren't of much value, they do give some indication as to overall condition. Test results won't determine if the tube will be too microphonic or noisy in your amp.

    As for new production "Mullards", Groove Tube makes the GT 12AX7M that is touted as a Mullard reissue. I have a couple and they do sound Mullard like but fall far short of being as good as the real thing IMO. Plus there has been a big quality issue with them.

    Russian Mullards? You must be refering to the New Sensor Mullard EL34s. They are Mullards in name only and in no way compare to real Mullard 34s. Groove Tube just came out with an EL34M that is a Mullard reissue EL34 like the their 12AX7M. I have a pair in one of my Marshalls and they are very nice Mullard like sounding tubes. But, still not as good as the real thing.

    I was curious about the Mullard magic as you are and had the same trepidations about where to go to get some. I've bought all kinds of Mullards off ebay and have only gotten one bad tube. All the others have been good. Just as good as Mullards I got from dealers. In fact, the only Mullard I had actually blow up in one of my amps I got from a respected dealer and paid a small fortune for. It lasted all of one month. The thing shattered in my hand when I tried to take it out so I couldn't even send it back to get a replacement. That's when i decided to try my luck on fleabay.

    If you want to try one or two, I say just go for it. :AOK
     
  3. kingsxman

    kingsxman Silver Supporting Member

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    THanks John. So the key as to whether or not its a Mullard is that "I61 BD01" code? Do ALL Mullards have that code?

    Also, is "flashing" the silver area at the top?
     
  4. Roodboy

    Roodboy Supporting Member

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    The "B" stands for Blackburne, the factory, the "I61" is a date code. I61 and I63 are similar construction, both shortplate. Longplate I think say "I5_"
    Good Luck.
     
  5. rockon1

    rockon1 Member

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    The short plate Mullards dont do much for me at all. Ended up with about 15-20 of them I'll eventually get around to selling I guess.(Im lazy about trying to sell gear) I prefer a lot of other OS tubes over them.The long plates are MUCH nicer. Unfortunately they are much more expensive and being very old and long plate design are more prone to microphonics.Heres a site with date code info for Philips tubes(Amperex,Mullard...)

    http://www.tube-classics.de/TC/Tubes/Valvo/Phlipscode.htm
     
  6. kingsxman

    kingsxman Silver Supporting Member

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    Are there any good pics of longplate vs short plate? I dont know what all these things are in a tube...? Getters? Flashing? etc.
     
  7. rockon1

    rockon1 Member

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  8. Roe

    Roe Member

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    does anybody got info about the mullard m8137/12ax7wa?
    Got a good offer on one here in norway.
     
  9. mmorse

    mmorse Member

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    Same thing as a CV4004 I believe. A mil spec ax7. I have no experience with them but I do have a couple Mullard CV4024s. Mil spec AT7s. Nothing special IMO.
     
  10. kingsxman

    kingsxman Silver Supporting Member

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    As for buying from dealers, yes your going to pay a premium but you also get the ability to send it back if its bad. Thats worth something. I'll give a big shout out to Mike at KCANOS tubes as he's done nothing but good things for me so far.
     
  11. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    The long-plate (17mm = long, 14mm = short) versions are oldest, with square-getter ones being the older. Always look for the second line of etch code to begin with "B"

    [​IMG]

    Type Code mC1 = long-plate/square-getter 12AX7 ('50s)
    Type Code f91 or f92 = long-plate/halo-getter 12AX7 ('58-'59)
    Type Code I61 = short-plate 12AX7A ('59-early '60s)
    Type Code I63 = short-plate 12AX7A (early '60s - '70s)
    (don't know code) = box-plate CV4004/M8137

    I was fortunate enough to try the long-plate Mullard "f91" type first, and instantly recognized it as a vast improvement over every other 12AX7 I'd tried to date (I discovered Raytheon black-plate 12AX7A later). Then I tried several short-plate "I63" types, and found them to be astoundingly mediocre. They're okay, but I'd recommend Tungsram ECC83 as a more cost-effective alternative to short-plate Mullard 12AX7As (similar character, but somewhat improved frequency-extension).

    Just my opinion, but due to the clarity and frequency-extension in the long-plate versions, I'd say - save your money up for those instead of the short-plate versions. Nothing barks quite like an old long-plate Mullard 12AX7 being pushed!

    I'm not familiar with the box-plate CV4004 style.

    - T
     
  12. mmorse

    mmorse Member

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    Interesting Timber Wolf. I have a bunch of I61 and I63 Mullards and a few early 80s Tungsrams and I like the Mullards alot more. I even like the old EIs (pre '84) more than Tungsrams. Ah, it's all so subjective. Always wanted to try an old longplate but the damn audiophiles have pushed the prices on those through the roof. Along with the tunsgrams, may I suggest the old EIs as a cheaper alternative also. Stay away from the post '85 EIs though. They're dreck IMO.

    I read somewhere that Hammond Organs used to have Mullard hand pick the best ax7s out of a production run for their stuff. I've gotten a hold of some of the Hammond labeled Mullards and they do seem to be a little sweeter with that classic mid "bark" that Mullards are famous for. They really do seem to have just a little more tone than the other Mullards I have. Specially when used in V1.

    Do you have any experience with the 10M series Mullards? I'd like to try those also but I don't like the price of admission on them either.
     
  13. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Yeah, opinions may differ. I find the Tungsram to be similar enough to the I63 Mullards that I thought they were worth mentioning. Older Ei are cool, too (by the way, rumor is that all Ei will now be "old," as they're no longer in production - plant closed in August). All three of those choices pale in comparison with the long-plate Mullards, which are in a whole other class (in my opinion).

    The 10M Mullards were just select versions (stricter qc) of whatever Mullard current production was at the time. So there are long-plate and short-plate 10M Mullards, all with the same corresponding etch codes by which you can identify them. If you have a strong, low-noise version of any Mullard 12AX7, it would be the equivalent of a 10M, so save some moolah!

    - Thom
     
  14. rockon1

    rockon1 Member

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    Ive got a pile's of I61's and I63's and 5's sitting around- Mullard and Amperex. I too like timbre Wolf find them unappealling. I'll get around to selling them one of these days. At the moment almost NONE of my imported stock works for me in my amps. That list includes,Telefunken(sterile),Amperex,Mullard,Tungsram, etc. It excludes Mullard long plates (I have a scarce few),long plate amperex and a few Siemens I own. Of coarse this is with my motley collection of high gain amps.
    Some of my favorites are American. Long plate GE's seem to work in all my amps for me. One of my faves! For reasons somewhat unclear to me I am drawn to raytheon black plates. I think all my needs can be met with my american stash.(GE long ,short and black plates,RCA long,short and black plates,sylvania short grey plates,etc)
     
  15. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    I agree with this for my tweed-ish Bandmaster clone (almost all Ken-Rad: 12AX7, 6L6G, 5V4G, 5751 [well, '50s GE is close]), and for the most part, all of my other amps. There are two exceptions: Mullard long-plate 12AX7 in my Triaxis preamp (one position only), and Mullard CV4024 in a couple of amps (including another positon in the Triaxis). No other tubes can sub for these, in my experience/opinion.

    - T
     
  16. BobboVisMe

    BobboVisMe Member

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    I really love Telefunken smooth plate ecc83's .. Even more than Mullards but tone is a subjective thing .....
     

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