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Replacing a naim nap 110 snaps with a superteddyreg

Discussion in 'd.i.y.' started by KiwiMike, Jan 2, 2021.

  1. KiwiMike

    KiwiMike Member

    Hello there,
    Im planning to replace my naim nap 110 snaps which supplies my nac 42 with a superteddyreg , ive noticed there is a 33ohm resistor before the small power supply cap in the 110 , is this resistor reducing the 40v power rail which the smaller capacitor is on?
    The STR is factory set st 24v.

    Regards
    Mike
     
  2. neiljadman

    neiljadman Senior Member

    Pics would help because I don't recall that 33R is a standard item. The NAP110 takes its 24v preamp supply off the main bridge rectifier AC feeds and then routes that to feed the AC voltage to a smaller rectifier mounted directly on top of the 3300uF/40v cap. The positive and negative unregulated DC voltage feeds then go to the LM317 . You should just be able to remove the LM317 board and replace it with the STR board.
     
  3. timH

    timH pfm Member

    Somebody may have added that 33r in an attempt at a bit of rc filtering
     
  4. KiwiMike

    KiwiMike Member

    Ah, interesting about that resistor, ive been studying alot of images which dont show a resistor, my nap is a nz assembled unit,
    Its really a Nap 125 but a 110 is the closest i can find. With the 125 the preamp power was taken off the +ve side of the 10kuf caps then through that resistor to a 3300uf cap then to the LM317 .
    I have now replaced that LM317 with the STR but i have left that resistor there, maybe i should remove that resistor now?? The system is sounding really good now.
    Mike
     
  5. david ellwood

    david ellwood Kirabosi Kognoscente

    What does the 110 supply have to do with anything if you’re running a snaps?
     
  6. MJS

    MJS Technical Tinkerer

    I have seen early examples of NAP120 where a 27 or 33R was used to filter the pre-amp supply capacitor from the existing positive rail. Later they just used a separate rectifier from the transformer secondary.
     
  7. cctaylor

    cctaylor pfm Member

    My NAP120 (serial number 284 according to the sticker inside) has 3 100R in parallel feeding the supply capacitor in the pre-amp supply. Interestingly the two amp boards seem to come from different batches. One has a round trim pot, the other square, the support pads for the small transistors are black on one and white on the other. Some tanatalums are red on one and blue on the other etc.
     

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