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Thread: who made this CV4004

  1. #1

    Default who made this CV4004

    Where does this Teonex CV 4004 valve come from I know it is over 10 years old & probably 20 years old it is unused (NOS) also it was bought in bulk for a UK gov./Nuclear industry application. Suggested by the supplier to be Chinese valve, however they sound very good, I did a test buy, result, I just bought a larger order as my pre & maiin amp both use them.

    I knowTeonex was a UK based suplier not manufacturer who marked up valves mostly from Europe & Japan
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    heres what the national vave museum says: The CV4004 is the UK government code for the Commercial M8137 special
    quality version of the definitive audio double triode ECC83.

  3. #3

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    Quote Originally Posted by mike19 View Post
    heres what the national vave museum says: The CV4004 is the UK government code for the Commercial M8137 special
    quality version of the definitive audio double triode ECC83.
    Thanks mike19 I was aware it is a mil spec variation on the ECC83 or M8137. It was the first place I had looked, however your mentioning the NVM prompted me to send an email to them...

    Thank you
    Last edited by Big John; 12th June 2013 at 16:30. Reason: gratitude

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    everything you want to know is here:http://www.r-type.org/exhib/aaa1181.htm

  5. #5

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    I emailed the National Valve Museum I got a nice reply basically they did not know what it was either. My best guess 10-20 year old Chinese valve that sounds good. I have swapped a pair of Mullard CV4004's & a Sovetek 12AX7WXT in my Croft phono stage with them. This querry is done to death now.
    Last edited by Big John; 21st June 2013 at 20:17. Reason: spelling

  6. #6

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    It is indeed Chinese....

  7. #7

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    Thank you Arkless E. I found an answer after my last post, however I had not bothered to include the entry below as there was little interest shown on this forum as you have noted elsewhere. I no longer use them I have replaced all my 12AX7/ECC83's with 1960's NOS Russian valves using adapters these are far better in all areas than the Western European/American valves; again not reported as I did not think there would be any interest. I sold a pair to a member of PFM (for what I paid) he said more expansive than Mullard box plates not quite Telefunkens though.

    The Tubeking's Guide to NOS/Vintage Audio Tubes Part II




    Another tube I really like is the Chinese Military (6N4) Beijing 12AX7. This tube was manufactured in the 1980‘s-1990‘s in the Beijing Factory in China and features a Solid Foil Square Getter, Triple-Micas, and sometimes White Military Markings (6N4 is the Chinese Designation for a Military 12AX7). The sonic hallmarks of this 12AX7 are extreme clarity and a very low-noise floor. A ruggedly-built tube, the Beijing is perfect for high-gain applications, since it is quiet and very resistant to microphonics. In fact, the Beijing contributed a great deal to the 1980‘s “Marshall/Mesa Sound.” A lot of hard-rock guys go crazy for these particular tubes. They have great gain and a viscous rich distortion sound. These tubes have a surprisingly nice clean tone as well, which is good for blues, funk and rhythm guitar. The clean sound can be described as “clear and round with balanced bass, mids and highs." They have a very nice treble that is never harsh. I have used them in many amps, including Peavey Classic 30‘s and 50‘s with great results. In fact, I was shocked at how dead silent my modified Classic 30 became when I popped one of these Beijing 12AX7S into it’s V1 pre-amp slot. You will be surprised at how quiet your amp becomes with it’s ‘jet black’ background in both clean and high-gain use. If you want (V1) a slightly warmer tone with huge overdrive, try a Mullard I61 or I62 in the first slot of your amp and a Beijing in the distortion slot. These 12AX7s also work quite well in the phase-inverter slot in a tube amp, and sound great in home audiophile applications because of their clarity.
    It is important to note that these older production tubes sound nothing like the newer mass-produced Chinese Shuguang 12AX7s, which can have a very harsh and unmusical tone. There is constant debate on the Internet about which new Chinese version is the best, and how to identify a tube from the correct production run. I have found that the older NOS Chinese Beijings are far superior in sonic quality to any new production Chinese tubes. You must make sure to look for the ones that have a Dual-Supported Square Foil Getter. Sometimes these tubes have white Military ‘Star’ markings. Others have ECC83/12AX7 written vertically in thick red paint on the side of the tube. Still others were re-branded by companies such as Groove Tubes. Regardless of the paint, all the Square Getter Beijing 12AX7s are the same tubes and sound great. Remember that the Beijing tubes were produced for the Chinese military and, as such, are very well built and reliable. They are no longer being produced and are still considered a bargain for such a quality tube. Most of these tubes list for around $16.95-$19.95 on the Internet when you can find them. I buy them whenever I can and recommend them to all my customers. The Beijing is a great quality economy pre-amp tube, and you will be surprised at how good these can sound in the right applications.
    Last edited by Big John; 25th August 2014 at 19:32. Reason: Add link

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    Have you tried PsVane? I know there is a lot of hype about them but to my ears they blow away the stock tubes in my 845 compact. Maybe not relevant as they are quite expensive.

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    Quote Originally Posted by Big John View Post
    Another tube I really like is the Chinese Military (6N4) Beijing 12AX7. This tube was manufactured in the 1980‘s-1990‘s in the Beijing Factory in China and features a Solid Foil Square Getter, Triple-Micas, and sometimes White Military Markings (6N4 is the Chinese Designation for a Military 12AX7).
    Do you know if there is an equivalent 6SN7 that they made?

    I'm always on the look out for tubes of that type. Some of the "NOS" ones out there have eye watering prices these days.

    Euan
    20 years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs. Please God, don't take Kevin Bacon

  10. #10

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    I have heard Psvane & like my box plate Mullards are not worth considering compared to the valves I am now using, cost is not such a factor as I have just paid to have my phono stage converted to 6v from 12v ie new transformer, rewire of sockets, new voltage stabilizer to cope with the 600mv heater current on the Russian valves though I can of course still use 12AX7's if the source of Russian triple mica valves @ 8 for 4 dries up.

    If you fancy trying them buy nothing after 1984 when Gorbachev took over and salt mines were no longer an option if you cocked up.

    ESK 6H8C I belive...
    Last edited by Big John; 25th August 2014 at 21:00. Reason: did not see ESK question

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    Thank you.
    20 years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs. Please God, don't take Kevin Bacon

  12. #12

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    ESK Further to the above I do not know if the 6H8C are pin compatible. I am the using NOS Military 6N*P series of valves either EV or ER all are 9 pin with a different pin out, however the adapters to 12A/X-U7/ECC81-83 work with all 6N*P except 6N3P I do not know why. After valve type these letters indicate EV (Cyryllic EB) 5000 hrs life minimum: ER 10000 hrs life minimum. These apparently were used in ICBM nose cones & fighter plane equipment before transistors were hardened to prevent an EMP knocking them out.

  13. #13
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    I have tried various types of Sylvania's (GTAs/GTBs), Philco and EH. All have struggled a bit from noise and or microphonics The ones I have in at the moment are my favourites so far. They are USA Tung Sol and are the quietest so far.

    None are the silly NOS prices. I think the Tung Sols cost me 70 for the quad.

    Looked at some of those Russian ones with the metal bases but the prices being asked on EBAY are just silly and the chances of getting a duffer in my experience is high!
    20 years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs. Please God, don't take Kevin Bacon

  14. #14

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    We had 2 of our Grandchildren with us for 2 weeks took them home to Poole at the weekend saw the Bournemouth Air Show as well over a superb picknick.

    Now I have time to type, I have had no problems with dodgy ie noisy or microphonic Noval (9pin) tubes from Russia, 8 tubes for 24 including 6 with silver grids & 2 with gold pins & grids or adapters from Croatia as for your octal tubes there are adapters to allow 9 pin valves to work in octal sockets.

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