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Recapping HiCaps and 250

Discussion in 'd.i.y.' started by ariegur, Jan 21, 2020.

  1. ariegur

    ariegur pfm Member

    Hi all,
    I have old 3 HiCaps, two are running a NAC 82, one runs Prefix. The Nap is an old 250 - all the units are olive.
    Lately I have the feeling that the sound lacks the base.
    I think that the easiest fix is recapping the 250 and the HiCaps. The first question is - where can I get the right capacitors?
    The second question is - do you have experience with Avondale’s “drop in” circuits for HiCap? I am sure that they do the job, but I am afraid, as it happened to me when I tried Teddy cap, that it changes the character of the sound of Naim which I love and I don’t want to give it up.
    Do you have more ideas?

  2. grahamdocman

    grahamdocman pfm Member

    Quick answer: get an Avondale TPR4

    Les' TPR4 regulator is a no brainer, simply superb. I too like the Naim sound and the TPR4 (IMHO) does not change the "Naim sound", but simply improves and brings out whats is there, even better. In my case SWMBO actually noticed the difference, commented and asked what I'd done to improve the sound.
    BUT: if you don't like it, Les offers a full refund (except P&P) if you are not happy with it. Search on TPR4 on this forum for more info.

    As a drop in, it really is easy with a few simple tags to solder. You will get a CD with instructions. Don;t forget heat paste.

    If you ask Les, he may sell you the relevant power caps for the Hi Cap and 250's. I would caution against buying the caps from anyone other than a reputable retailer (i.e. caution with certain auction and bargain websites)

    Hope this helps,
    ariegur likes this.
  3. PhilDick

    PhilDick pfm Member

    I have a very similar setup to you:
    Bolt down nap250
    2 CB Hicaps

    I have a TPR4 in each HICAP and have found the improvement stunning. Not sure if it changes the Naim sound (not sure what it is!) but sure does improve it.

    I installed them myself. If you can solder and use a screwdriver it's easy. 15mins per box.
    ariegur likes this.
  4. ariegur

    ariegur pfm Member


    I will email Les.

  5. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Any decent caps will do. Farnell, RS, Mouser, Digikey etc can supply.
    ariegur likes this.
  6. nuit73

    nuit73 nuit73

    I agree with the precedent post.The Avondale Audio TPR4 power supply is a great improvement in all area et you preserve the "PRAT".

    For the Naim Nap 250, i can recommand the HCR 200 (replace the Naim Regulator in the amp), you have a great improvement too, more natural et more "musical" bass.
    Very easy to install in the Naim amp
    ariegur likes this.
  7. ariegur

    ariegur pfm Member

    What about the Nac 82? Maybe I will go for the all devices in one big step - only if it is easy for an hobbyist with no technical knowledge and experience?

  8. david ellwood

    david ellwood Kirabosi Kognoscente

    If you can afford it the naim discrete regulators are amazeballs
  9. ariegur

    ariegur pfm Member

    Where can I get them?

  10. Loz828

    Loz828 Member

    I dont think Naim offer a "DR upgrade" on any olive gear, this is just one reason why Avondales TPR4 for the hicaps is a great idea.

    And for a recap, you can get most stuff from RS / Farnell / Mouser etc. -
    Tantalum bead caps - Kemet T356 series work just fine in NAP250 and Hicap.
    Electrolytics on NAP250 regulator boards - Nichicon VX series
    PSU smoothing caps - I've tried Kemet ALS30 22000uF/63V, Kendeil 22000uF/63V and Sic Safco CO39 Felsic 15000uF/63V and TBH I just cannot tell the difference in either my 250 or Hicap - Kemet ALS30s are available everywhere and relatively cheap so.......
    The other thing you shoud do in the 250 is change the discharge resistors on the regulator boards if they show signs of heat, I used 3K3 2W 5% BC comp PR02 series and raised them slightly from the circuit board - duh.
    ariegur likes this.
  11. ariegur

    ariegur pfm Member

    Thank you very much for the detailed post, loz.
    I am not a technician and I will not go to the level of replacing components on the circuit because I am afraid that I will damage the amp.
    The idea of dropping in the TPR4 to the HiCap seems to be easy and I have decided to go for it.
    Les suggests Kemet capacitors. Are these recommended for the HiCap?

  12. nuit73

    nuit73 nuit73

    Yes, Kemet capacitors are good and are always a good choice...and Les is a (very) good choice

    To my taste, il prefer the Kendeil K01 22000 uf, but not in 63 volts in 75 volts.The 75 volts version sound better with more dynamic.
    I put the 75 volts in Hi-cap, All amp with CO39 and Supercap or 52 PS
    It's more evident (for the improve sound) on the Nap 250 or other amp like Nap 135
    ariegur likes this.
  13. ariegur

    ariegur pfm Member

    Thank you all for the advices.
    I will start with the tpr4 for the two HiCaps that are running the 82 including the capacitors and I hope that it will be ok. If it will, I’ll go for the HiCap that runs the prefix and then if I feel that I have to, I”ll ask again about the 250.

  14. nuit73

    nuit73 nuit73

    Yes, the TPR4 is the best regulator for HiCaps you can find at this day and Les (Avondale Audio) board are "jewel electronic"
    The audio result is excellent in all criteria.
    The music is life with TPR4 !
    ariegur likes this.
  15. ariegur

    ariegur pfm Member

    I bought 2, waiting to see how good they are..,

  16. nuit73

    nuit73 nuit73

    Very good choice and buy....
    You will not be disappointed with the audio result, it's really excellent!
    The best you can do right now
    Thanks to Les for his fine board
    ariegur likes this.
  17. nobeone

    nobeone pfm Member

    I like the bold assertion:

    Have you tried what WitchHat are up to?
    The RSL regulators?
    The Teddy Pardo?
    I'm sure there are other options!

    I tried TPR4 Hicap versus Hicap versus RSL ZapCap and I know which I think is best, the RSL. Would be interested in your experience of other regs.
    ariegur likes this.
  18. nuit73

    nuit73 nuit73

    The Teddy Pardo is not at the same level and lack body of the music
    Witch Hat Audio don't sell the kit for DIY (only for their work)....i don't think there are many in nature.....

    The RSL, i did not try...,and i'm not interested, because it is a module with CMS and we can no longer solder by yourself
    I prefer easily repairable electronics...the basis of DIY for me
    I do not dispute that it can work well
    ariegur likes this.
  19. nobeone

    nobeone pfm Member

    I don't see the RSL modules as unrepairable, surface mount is not unrepairable, besides at this level you are buying a module not a bag of bits. Send it back if it fails. Same for TPR4.

    No idea about the WitchHat regs, perhaps @MJS can comment? I know replacement regs were being developed.
  20. nuit73

    nuit73 nuit73

    I don't say the RSL modules is unrepairable, but it's impossible to do it by yourself with specific equipment

    We are in the DIY section no?

    The advantage with a discrete component module is that it can be repaired endlessly by yourself like classic Naim Audio electronic cards....and especially at lower cost...and this heaven if the product is no longer produced

    MJS mainly used avondale module in its repairs
    The amplifier they manufactured and then stopped had Avondale Audio NCC 200 amp module

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