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Thread: 9th Generation Chinese 12AX7

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    Default 9th Generation Chinese 12AX7

    Hi guys,

    Regarding the difference between the China 12AX7s we use in production and the so-called C9 or 9th generation 12AX7, our position is that there is none other than the normal progression towards continuing improvements in quality which is always ongoing. Hence the tubes we use are the same as those designated by others as C9. None of the suppliers we use can confirm or verify that this is anything more that creative marketing on the part of some 3rd tier tube resellers.

    Most likely any difference you may hear would be attributed to either normal performance variations from one production run to the next, or just the difference between a fresh tube and one with a bit of mileage on it.

    I'm still prodding our suppliers to do their own research, and will post an update as soon as I get more information. Until then, our position that this claim lacks substantive documentation stands.

    Based on the most recent production batches of preamp tubes we evaluated, we will continue to ship our amplifiers with the same tube complement that we have been using all along:
    V1 stage: 12AX7WB or V1 grade Selected Shuguang 12AX7A
    All other 12AX7 positions: Low Noise Selected Shuguang 12AX7A
    All 12AU7 or 12AT7 applications: Shuguang 12AU7 or 12AT7
    Valvulator 1: 12AX7WB or JJ12AX7/ECC83
    GP3 V1 and V2: 12AX7WB.
    GP3 All other 12AX7 positions: Low Noise Selected Shuguang 12AX7A
    Power amps: Low Noise Selected Shuguang 12AX7A and 12AU7.

    Recently evaluated tubes:
    12AX7A/7025 Shuguang
    Well balanced tonal spectrum, low noise with moderate microphonic tendencies, easily selected out in production. Excellent for clean and overdrive sounds.
    12AX7WB Sovtek
    Lower gain, somewhat less bass response, and not as bright as Shuguang, but not dull sounding. Very low microphonic tendencies.
    12AX7A Tung-Sol
    Very good gain and low microphonics. Nice low end. Somewhat forward in the upper mids. Basically a fatter higher gain EH 12AX7. Appears to be an EH with a different getter.
    12AX7 EH
    Very good gain and low microphonics. Less low end than Tung-Sol and not as smooth on top. More pronounced in the upper mids.
    12AX7LPS Sovtek
    Similar to the EH but generally a little less of everything. Nice balance and a good alternative to the Shuguang if you like less top and a little more mid.
    12AX7/ECC83 JJ
    Works well in Valvulator 1, which was surprising, since it did not fare as well in prior testing. Apparently the hum and microphonic issues have been addressed. A little darker sounding than the WB.
    When used in the amplifier V1 stage, this tube performs similarly to the WB, but the mids are more pronounced, the top end is dullish and overall somewhat harsh sounding for high gain settings.

    Hope you find this useful...

    smf

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    Thanks for the info, Steve. I have several 12AX7s, including some RCAs and GEs, but I've been so happy with my Deliverance that I haven't felt the need to swap any out yet. Why anyone would waste their money on a new Marshall or Mesa is beyond me.

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    Nice!
    The C9's may just be normal progression, but they do sound better than the older ones, pretty similar just bigger sounding, a little brighter, and a little more bass response.
    A source for documentation could be www.dougstubes.com , he's a very personable guy and I'm sure he'd give the scoop on his C9's that he sells, it's where I get 'em from.
    Edit: Just fer fuck's sake I'm gonna stick a new Ruby China I got from you in V1 and see if I can tell a difference.
    Last edited by Grendel; 03-10-2006 at 01:02 AM.
    VHT CLX w/graphic
    Mesa Trad. 412
    Earcandy 212 w/P50E's

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    Thanks alot Steve!! Very useful info there, especially since Im about to buy some new preamp tubes soon. Nice to see you around.

    Ralphie, this would be a good sticky thread!
    dave

    CLX / Fatbottom 412, Deliverance 412

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    Man, thanks so much Steve! That is extremely helpful, particularly your experiences when you rolled other current production 12AX7s. Dave's right, this is the type of information that's perfect for a sticky!

    What a great company and a great guy! THANKS STEVE!
    Last edited by kleinm; 03-10-2006 at 08:22 AM.

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    [QUOTE=Grendel]
    The C9's may just be normal progression, but they do sound better than the older onesQUOTE]

    WHICH "older ones". Used older ones? A perfectly fresh older one? How old?
    Specifically, date of manufacture, production batch, etc?

    [QUOTE=Grendel]
    A source for documentation could be www.dougstubes.com , he's a very personable guy and I'm sure he'd give the scoop on his C9's that he sells, it's where I get 'em from.QUOTE]

    I've been buying chinese 12AX7 for almost 30 years - and still have stock of 20 and 30 year old pieces for reference. I doubt that there is anything dougstubes knows about this that I don't other than who originated the C9 mystery juice concept.


    Quote Originally Posted by Grendel
    Edit: Just fer fuck's sake I'm gonna stick a new Ruby China I got from you in V1 and see if I can tell a difference.
    When did you get it and what does it look like? After you do the test, send them both to me.

    The original post was mean to inform and make people aware of a situation that we believe is not in the best interest of consumers who may find themselves taking out a perfectly good tube and replacing it with an identical part just because of a nifty designation..

    smf

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    Quote Originally Posted by sfryette
    Hi guys,
    None of the suppliers we use can confirm or verify that this is anything more that creative marketing on the part of some 3rd tier tube resellers.
    No big surprise there...

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    The only info on 9th gen tubes I could find was actually at Doug's site...

    http://dougstubes.com/12ax7.htm

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    Quote Originally Posted by Kelly
    The only info on 9th gen tubes I could find was actually at Doug's site...

    http://dougstubes.com/12ax7.htm
    It looks like he's saying that the 9th gen are consistent in quality, which is what Steve inferred, and that the 8th gen sound identical to 9th.

    " 8th Generation Chinese, exactly the same plate and filament structure as 9th. Gen, only difference is the second spacer is square instead of octogonal. Curve trace and sound exactly the same as the C9"

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    Quote Originally Posted by Bob Savage
    It looks like he's saying that the 9th gen are consistent in quality, which is what Steve inferred, and that the 8th gen sound identical to 9th.

    " 8th Generation Chinese, exactly the same plate and filament structure as 9th. Gen, only difference is the second spacer is square instead of octogonal. Curve trace and sound exactly the same as the C9"
    See attached pic.
    On the right is a Shugaung 12AX7 from 1995. Note the square spacer on top and round one just below it, sandwiched round and square spacer on bottom. A little more difficult to see is the single square getter.

    On the left is a Shugaung 12AX7 just received from the most recent production run. Note the square spacer on top and octagonal one of the same thickness as the round one in the old tube, same sandwiched round and square spacer on bottom. The single round getter is the only really significant difference, but not different enough to make a noticable audible impact.

    The slight differences in the spacers ony affect the microphonic behavior of the tube, assuming that they both provide similar alignment of the components. If they didn't you'd hear it a mile away.

    In comparing the sound, the difference between these two is practically imperceptible, which is remarkable considering the difference in age, and no more than one would expect to hear from one new tube to the next.
    All of this only reinforces what we already believed about the inherent consistency of these tubes.

    smf
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