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    PH16XW NoiseFloor/Hum

    Peter W.
    Peter W.

    Posts : 1302
    Join date : 2016-08-07
    Location : Melrose Park, PA

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    Post by Peter W. on Thu Jan 10, 2019 2:12 pm

    deepee99 wrote:
    cci1492 wrote:
    Peter W. wrote:Three, as it happens.

    Yeah? Spill the beans, which ones?
    Until Peter W. comes off with his mysterious three, I can recommend the phono pre-amp built into the old Hafler DH-101 line pre-amp, at least for 47 uF MM cartridges. I was AB'ing it with the tube phono preamp I have and was pleasantly surprised. Also, there are lots of little tweaks you can do to this and other early Hafler gear to make it run like a $2,000 preamp.

    As it happens, my Hafler is one of them.
    Signal to Noise, weighted (3.12): 87 dB
    Unweighted comes to well over 100 dB

    My HK Citation 17 is another, as specified, 80 dB, as tested, 97 dB (on the hand-written test sheet that came with it) which I am figuring is close enough.

    The last being the Dynaco PAT-5 biFet. As specified, 90 dB. Actual is again, about 97 dB, close enough.

    The Revox A720 has relatively poor written specs, but I will state that it shows the least audible noise from the phono section at full volume.

    Then, there is pretty much everything else.
    solderblob
    solderblob

    Posts : 55
    Join date : 2018-05-20
    Age : 73
    Location : Placerville, California

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    Post by solderblob on Fri Jan 11, 2019 1:03 pm

    cci1492 wrote:If they offered one with that walnut case, the wires on the rear panel and no hum, I might buy one!

    Roy did mine that way with the RCAs, ground lug, and IEC/combo switch on the rear.  He also cut slots in the top cover to access the DIP switches.  

    He probably will charge a bit extra for the cutting of the steel, but not much.

    You could wrap it with wood but cut the rear piece so as to clear the wires/switch.  Or just wrap 3 sides.

    Sorry about the fuzzy picture.

    I love this preamp and there's no hum!

    PH16XW NoiseFloor/Hum - Page 2 Dsc04710
    cci1492
    cci1492

    Posts : 271
    Join date : 2016-05-09
    Age : 58
    Location : Bergen County NJ

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    Post by cci1492 on Fri Jan 11, 2019 2:32 pm

    Looks good, I wonder if there's any benefit to using the toroidal ta instead.
    tubes4hifi
    tubes4hifi
    Admin

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    Join date : 2008-11-30

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    Post by tubes4hifi on Fri Jan 11, 2019 2:45 pm

    the standard "flat-pak" transformers are extremely quiet, no advantage to going with the toroidal in this case

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