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  1. #1
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    Mullard 12AX7 tubes

    I have changed the original tubes 12AX7 in my preamp (JJ tubes) for the Mullard 12AX7 and in the first hours they were very good.

    Nice improvement on mids and trebbles and no changes on Bass but regretfully after 80 hours the sound have changed a lot.

    Now there is too much bass present I was forced to change the tone controls in my preamp from Bass 0 to Bass -2 now.

    Is there an estimated time to complete break in this kind/model of tubes.?

    I really do not know what to do... If I need to wait more hours to see if there is a final improvement on bass and general sound or just to install again the original tubes.

    The original ones were very good for me but I have done this change expecting improvements.

    Thanks in advance for your cooperation... I´m new with tubes.
    McIntosh C302 + C2600 - Lumin A1 - Lenco L75 - Marantz SR6007 - Paradigm S6 - Gaia II - Chord Epic Twin Speaker Cable + Jumpers - Bada LB5500

  2. #2
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    Re: Mullard 12AX7 tubes

    Preamp tubes can take 50-75 hours before finally settling in. I know it seems like a long time but definitely give it more time.
    Fleetwood Deville by Oswald Mills Audio, Vienna Acoustics Haydn Jubilee, Wharfedale Linton w/ stands, Klipsch RB-75, Klipsch RP-160M.

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  3. #3
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    Re: Mullard 12AX7 tubes

    Thanks for your comments..!!!

    Now they have 80 hours and the sound is not good.

    In the very beggining they were very good but now regretfully there are too much bass.

    I will keep them another 50 hours to see what happen.

    If they do not get better I will install again the original ones JJ in my preamp.
    McIntosh C302 + C2600 - Lumin A1 - Lenco L75 - Marantz SR6007 - Paradigm S6 - Gaia II - Chord Epic Twin Speaker Cable + Jumpers - Bada LB5500

  4. #4
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    Re: Mullard 12AX7 tubes

    Interesting turn of events. Sorry you aren’t crazy about them.
    Fleetwood Deville by Oswald Mills Audio, Vienna Acoustics Haydn Jubilee, Wharfedale Linton w/ stands, Klipsch RB-75, Klipsch RP-160M.

    Job INTegrated. Luxman L-595aSE

    NAD C 658 streamer.

    First Watt SIT-3, Job 250 Monos, NuForce STA200, AkitikA GT-102 amp, ASL Wave monos, Dennis Had 45 monos. Absolute Audio Labs PCF 25 amp (improved First Watt F7 super clone)

    Topping D90, RME Audio ADI-2 DAC FS, ModWright Ultimate Sony XA-5400ES.

    Burmester 948, McIntosh MCLK12, Kimber Kable, Siltech, Cardas, Avanti Audio cables.

  5. #5
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    Re: Mullard 12AX7 tubes

    tube rolling......... be careful it can put a large dent in your wallet !
    Cheers ! …. Dave

  6. #6

    Re: Mullard 12AX7 tubes

    I didn't notice a change in mine (Platinum Grade, from Upscale) - but they certainly have a notably darker, warmer balance than most other 12AX7 variants both old and new.

  7. #7
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    Re: Mullard 12AX7 tubes

    Quote Originally Posted by mulveling View Post
    I didn't notice a change in mine (Platinum Grade, from Upscale) - but they certainly have a notably darker, warmer balance than most other 12AX7 variants both old and new.
    This was my experience, too. As in too much for my taste, which leans toward liking warm and dark.
    Analog source: AMG Viella 12; Ortofon Anna cartridge, van den Hul Crimson Stradivarius XGW
    Digital source: Totaldac d1-twelve Mk2 DAC, Totaldac d1-player, Totaldac d1-streamer, Totaldac Live Power supply
    Pre amp: VAC Master with phono
    Phonostage: ​Constellation Andromeda
    Amps: VAC 200iQ monoblocks
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    Power products: Synergistic Research Galileo PowerCell SX and Transporter Ultra. Galileo SX and SRX power cords. Keces P3 LPS for cable modem and router.

  8. #8
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    Re: Mullard 12AX7 tubes

    In relation to this topic, I have changed the 12AX7 of the preamp segment of my Vincent SV700, for current 12AX7 Mullard (Manufactured by New Sensor Corporation in Russia). The improvement was very noticeable, greater dynamics, greater instrument separation, greater extension and control in the bass. They will be in about 40 hours of break in, so I keep waiting and listening to see if there are any major changes.
    Everything has turned out positive for the moment.
    The source is a Lumin T2 and the Tannoy 615 MKII and Sonus Faber Venere 2.0 speakers
    Lumin T2 | Tascam CD 240 | Tascam CD 401 MKII | Teac AP-207 | Behringer Ultracurve Pro 2496
    Vincent SV 700 | EICO ST-40 | Yaqin MS34D
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    Panasonic PT AR 100 U | Pioneer Elite SC 72 | Panasonic DMP BD 605
    Tannoy 615 MKII | 603 MKII | Profile 621 | Tannoy TS 2.12

  9. #9
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    Re: Mullard 12AX7 tubes

    Mullards tend toward the warm side, and can be very good in certain amps / preamps, and can be boomy in others. I love them in my VAC Sigma 160i SE. If you research the 12AX7 types out there on audiotubes.com, you might find some more suitable tubes in your preamp. As a general rule, German tubes tend to be more detailed with tight bass; British tubes are more warm, American tubes are sort of in between.
    Studio/Study:
    Mojo Audio Deja Vu Evo Universal Music Server > or McIntosh MVP-901 > Mojo Audio Mystique Evo Dac > Raven Audio Osprey Integrated Tube Amp > Harbeth P3ESR


    Main Listening Rig:
    Shunyata Denali D6000/SV2>Mojo Audio Deja Vu Evo Universal Music Server > or Jay's Audio CDT2-Mk3 > TotalDac D1-Tube > VAC Master Preamp > VAC Master 300 > JM Reynaud Orfeo Jubile


    Home Theater:
    Xfinity Cable Box or Oppo BDP105D > McIntosh C2300 Preamp > McIntosh MC302 Amp > JM Reynaud Offrande Supreme

  10. #10
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    Re: Mullard 12AX7 tubes

    Many Thanks for your advice Scotty.!!!

    Do you have some idea of how much break in time they require..?

    Best Regards;
    McIntosh C302 + C2600 - Lumin A1 - Lenco L75 - Marantz SR6007 - Paradigm S6 - Gaia II - Chord Epic Twin Speaker Cable + Jumpers - Bada LB5500

  11. #11
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    Re: Mullard 12AX7 tubes

    Fer1000 - I have never noticed a need to break in tubes - others say they sound better after about 15 hours, and the power tubes (output tubes) even longer. After they get up to operating temperature, in my opinion what you hear is what you'll get. The equipment also needs to warm up. Of course, my ears are getting old - so
    Studio/Study:
    Mojo Audio Deja Vu Evo Universal Music Server > or McIntosh MVP-901 > Mojo Audio Mystique Evo Dac > Raven Audio Osprey Integrated Tube Amp > Harbeth P3ESR


    Main Listening Rig:
    Shunyata Denali D6000/SV2>Mojo Audio Deja Vu Evo Universal Music Server > or Jay's Audio CDT2-Mk3 > TotalDac D1-Tube > VAC Master Preamp > VAC Master 300 > JM Reynaud Orfeo Jubile


    Home Theater:
    Xfinity Cable Box or Oppo BDP105D > McIntosh C2300 Preamp > McIntosh MC302 Amp > JM Reynaud Offrande Supreme

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Mullard 12AX7 tubes

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