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NAIM 102 Capacitor Question

Discussion in 'd.i.y.' started by Kisner, Nov 6, 2018.

  1. Kisner

    Kisner Member


    I recently recapped my second NAIM 102 preamplifier, replacing all 47uf 35v radial capacitors with Samwha RD series. These were the closest to the original Samwha SG series originally used that I could find. Naim currently use Samwha RS series, but cannot find them anywhere.

    The preamp sounds pretty good, but I would like to try another capacitor series.

    I have narrowed it down to the Nichicon KZ MUSE series capacitors as they seem to be well respected and often used in Naim preamplifier recaps.

    The closest match for the Nichicon Muse capacitor is listed below, available from Mouser online.

    The Capacitance is the correct spec, but the voltage is 50v, not 35v as is the original spec, but I believe the higher voltage is OK.

    The narrowest available lead spacing is 3.5 vs. 2 mm on the originals. Will this cause any issues fitting, or are they close enough for the Naim circuit board?

    Thank you for any suggestions!

    Nichicon MUSE UKZ: UKZ1H470MPM1TD

    Capacitance: 47 uF

    Voltage Rating DC: 50 VDC

    Diameter: 8 mm

    Length: 11.5 mm

    Lead Spacing: 3.5 mm
  2. DaveMc64

    DaveMc64 Active Member

    I'm using those exact capacitors for the PSU filtering in my modified 102 and are a good choice.
    The 102 motherboard has holes for both 2mm and 3.5mm spaced capacitors so there is no issue with fitting.
  3. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    It's of zero importance and any make of capacitors will work the same.
  4. Kisner

    Kisner Member

    Thank you for the replies.

    I do now remember seeing the third hole, so that's good news if I decide to try different capacitors.

    But, if they are not going to make a difference, then I may wait until I get another 102 for my office to experiment on.
  5. DaveMc64

    DaveMc64 Active Member

    Well I wouldn't let the opinion of one person sway you one way or the other in that regard but maybe bear in mind the following:

    By nature of their design, Naim pre-amplifier circuits are inherently sensitive to PSU noise.
    Nichicon Muse KZ have an ESR approximately half that of the Samwha RD series at these values.
    With the values being used, the lower ESR will decrease the noise on the power rails at higher frequencies.
    Without further data not available on the data sheets, we cannot say whether other effects such as the ESL and microphony might also come into play.
    Naim only use the Samwha capacitors in their lower spec preamplifiers.
    Also, it is very easy to take them back out again if you don't like them or you think they make no difference.
  6. Kisner

    Kisner Member

    Thank you for the interesting information regarding the Naim pre-amp circuit and capacitor differences.

    I've ordered the Nichicon capacitors to try out as they are relatively inexpensive and easy to drop in.

    I'll report back after a few weeks with my observations.
  7. Jo Sharp

    Jo Sharp Pulls on doors marked push

    In my many years of modding the 62 and 102 pre-amps, I found the power rail and feedback caps did make a clear difference to the sound. It wasn't always huge, but it could be heard. Briefly, the electrolytic ones tried were OSCONs (v good) Nichicon (v good) NOS Roederstein (the original type feedback in 62 -good), SILMIC (poor), Black Gates (good). Various film caps and OSCONs were tried in the signal paths and were all better than the naim originals.

    So I suggest trying it out and see if you like the results. Remember to let them run in for a few days. And if you are going to do lots of swapping it might be wise to insert pins into the PCB holes and connect the caps to those, rather than risk damaging the PCB tracks by repeated de-soldering of cap legs...don't ask me how I know that :(
  8. RichardH

    RichardH Bodging pleb

    ...or even SIL sockets (these snap off so you can get single sockets) so you can swap them out with no further soldering - you can then always solder the final choice in place.
  9. BobMaximus

    BobMaximus pfm Member

    The feedback capacitor makes a huge difference to the sound presentation. It more or less defines it. If you like the Naim sound, then the Nichicon UKZ you mention above is probably the best feedback capacitor currently available as new. If you dislike the Naim sound, then a film capacitor could be your choice. Wet tantalums also have fans here, though I’ve never tried them.

    Since these capacitors are not under any stress, with respect to voltage and temperature, then I’m not so sure there’s much point in changing them. The original Samwar will probably be better (more Naim-like) than the ones you have already replaced them with.

    I believe that all Naim amps from that period used the same capacitors, regardless of price.

    Like everything said above about capacitors, this is all a matter of personal opinion. Using pluggable feedback capacitors might be a good way of changing the sound presentation, depending on the mood you are currently are in.
  10. MJS

    MJS Trade: Consultant at WH Audio

    Despite the fact that the Samwha cap was probably 8p in price, it would have been chosen by Naim because it sounded most like the previously available caps they'd been using. Back in the early 90's they went to very great pains to make sure that any replacement for obsolete components sounded identical where they could. I know because I was testing the various permutations of amps at the time. We've been using the Nichicon KZ for all rail filtering since day one.
  11. DaveMc64

    DaveMc64 Active Member

    The OP is talking about a 102. At the same time, the 82 and the 52 were both using SLCE caps for rail filtering and feedback duties not Samwha.

    That's good to know.
  12. BobMaximus

    BobMaximus pfm Member

    I now see the point you were making. My point was that different capacitors were not used because they were in more expensive kit. For example, my NAC72 uses SLCE caps for rail decoupling in the buffer boards.

    What about for feedback?
  13. DaveMc64

    DaveMc64 Active Member

    In the CB era, the feedback capacitors were the same throughout the range but if you look at the Olive and Black models and compare those with Samwha radials with those with the gold axial caps (SLCE then Promisic etc) there is a clear hierachy.
    Radials: NAC92, NAC102, NAC112, NAC152, NAC202 etc
    Gold: NAC82, NAC52, NAC282, NAC252, NAC552

    Radials go into the lower models, Gold axial into the high end models.

    The 72 is a bit of an anachronism as it was still using CB era caps. The TA boards originally came with axial Roedersteins (my old TA boards still have them) as fitted to the NAC42 & 62 (also gold coloured to confuse matters!) and the gain boards were using the Maroon Roedersteins. Maybe the SLCEs were put in when the axial Roederstein caps stopped being manufactured rather than redesign the TA board around a radial cap.

    I do agree with the rest of what you said about the feedback capacitors though.
  14. S_J

    S_J pfm Member

    You want some original brand new Samwha SG caps? I've got some here, exactly the same as used in the 102 and the other amps mentioned above. If anybody is interested, drop me a PM with how many you need. If there is enough interest I might sell whatever is left on the classified section.
  15. Kisner

    Kisner Member

    Hello S_J,

    I have sent you a message.

    Thank you.
  16. neiljadman

    neiljadman Senior Member

    The second set of holes on the 102 (and the 92/Nait3 and probably others) are set for 5mm - and the KZ 47uF/50 caps with 5mm lead spacing fit perfectly and sound great too!
    DaveMc64 likes this.
  17. Kisner

    Kisner Member

    5mm spacing. That’s good to know. I have the KZ caps here with 5mm spacing. Waiting for delivery of a set of NOS original type Samwha SG caps to try out as well.

    I’ll report back!
  18. DaveMc64

    DaveMc64 Active Member

    Sincere apologies, I admit I didn't actually measure them but went by the OPs posted specs as I knew the KZ 47uF fitted. The quoted part number is indeed 5mm spacing. Thanks for the correction.
  19. Kisner

    Kisner Member

    Mouser had them listed as 3.5mm spacing on their website when I ordered them but they delivered 5mm. Turns out the part number is indeed for for 5mm. Mouser has been notified and may now have the spacing correctly listed as 5mm.

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