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DIY power amp with NCC220 modules

Discussion in 'd.i.y.' started by Gervais Cote, May 23, 2020.

  1. Gervais Cote

    Gervais Cote Predator

    Hi gents,

    I have been thinking about it for a while but now, I think I will move forward and build my first stereo power amplifier.

    My design would be around the Avondale NCC220 amplifier modules as I think this best suits my needs.

    Here are the components I have in hand at the moment :

    -Dada Electronic stereo power supply with diodes and 4 capacitors of 15 000 uf capacitance so 30 000 uf per channel that is supposed to be good enough for a 2 x 100 watt amplifier. The capacitors are Kemet ALC10C 153 EF 063 and the diodes are GBU603. There are also 2 small resistors between the caps, I guess they just discharge the capacitors when powering off ?

    -A board of speaker protection with time delay. This is a Speaker Protection Circuit V4 I have been using several times in Quad 405 with good success.

    -A small 120 to 12 volts transfo for the speaker protection module. I am also open to buy a new one if you have recommendations as the one I have is rather cheap. The actual size is 1 cubic inch.

    -4 WBT female banana plugs for the speakers.

    -2 high quality/low mass WBT RCA female connectors for the inputs.


    So, according to me, the things I will have to buy are the followings :


    -1 aluminum enclosure with cooling fins.

    -1 toroidal transformers 115 VAC to 35-0-35 VAC. I hesitate between a 500 VA or 300VA. I want my amplifier to be 2 x 100 Watts or maybe a bit less but I am a fan of rock music so I want a good transient and deep bass drum impacts. Also, any brand you would recommend ? I want one that won’t hum.....

    -2 amplifier boards of 100 watts. I could go down to a 50 watts if a single 100 watts doesn’t exist as I don’t want to have 2 boards per channel like in a Naim NAP 250 for example. My first choice is really the Avondale NCC220 as it really sounds like a Naim (which I like) but it’s softer to my ears without losing the PRAT and bass bloom.

    Let me know what you recommend in the list above and don’t be shy to add some if I forgot to include something.

    The preamp I will use is a highly modified Parasound 2100.

    Oh, and I am located in Canada so cannot buy everything from all over the world !
     
  2. Mynamemynaim

    Mynamemynaim 35yrs a Naim owner

    If you're set on 100w per channel...I'm not sure the 220 is up to it
    Having said that...the NCC 220 is a great amp and with a 500 or 600 kv transformer will give a solid 65 to 70 watts which should be plenty for rock!

    Think the little resistors are for filtration on the power supply ...as inductors are also used in this application
     
  3. Gervais Cote

    Gervais Cote Predator

    My speakers are 86db efficiency so I should be okay, thanks for the input.
     
  4. Gervais Cote

    Gervais Cote Predator

    Any recommended brand for the transformer ?
     
  5. Mynamemynaim

    Mynamemynaim 35yrs a Naim owner

    Les W supplies excellent ones...but he's in lockdown so not sure if he's sending out

    I'd put a wanted in DIY first
    Or if inpatient...then canterbury windings ect will oblige
    TM861A is one I've used to good effect with these boards (from Canterbury)
     
  6. Neiro

    Neiro pfm Member

    Just read the Avondale website and it says of the NCC 220 'capable of delivering just over 100 watts'
     
  7. Gervais Cote

    Gervais Cote Predator

    This is a long term project for me because it will be my first experience so better go slower than skip important steps. Also, because of the actual lockdown, all shipments are slow as well but I prefer to wait longer but get the right parts. Thanks for the information sir.
     
  8. Mynamemynaim

    Mynamemynaim 35yrs a Naim owner


    I'm sure Les would agree...if he still was on this forum that the figures I quoted are much more realistic of actual real world performance
    Capable of ( under Idea conditions) is not the same as actual under normal circumstances
    Also...it looks like the OP is on 115v supply
    Not the same as UK 245v supply where output is concerned
     
  9. laverda

    laverda pfm Member

    Output has nothing to do with mains supply voltage, ....??

    It has everything to do with the ability of an amplifier to drive a load (say 8ohms) at a given frequency (1k) at a given input voltage (100mV) before clipping..and what 'RMS' voltage output was achieved at that time from the supplied DC voltage (the power supply) to that amplifier.

    Some one might come along and do the math...53v rails, 8ohm, 28.5vRMS. I think it runs out at about 100watts.
     
    337alant likes this.
  10. Mynamemynaim

    Mynamemynaim 35yrs a Naim owner

    I'll stand corrected then :(
     
  11. 337alant

    337alant Negatively Biased

  12. Gervais Cote

    Gervais Cote Predator

    Any other recommendations for the transfo ?
     
  13. nuit73

    nuit73 nuit73

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