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Courtiestown - Naim Amplifier (Avondale) Upgrade Project

Discussion in 'd.i.y.' started by Richard Lines, Dec 7, 2021.

  1. Richard Lines

    Richard Lines pfm Member

    Mike,

    The answer is yes to both points and it didn't go bang when I powered it up 5 minute ago.............

    I've added purple and brown wire to my list of things to buy. I intend following the 'Naim' colour coding in other amplifiers.

    Regards

    Richard
     
    Mike Hanson likes this.
  2. Richard Lines

    Richard Lines pfm Member

    Good Afternoon All,

    I really don't want to re-invent the wheel so having gotten some Molex terminals from AA and acquired some other larger capacity double crimp terminals I'm wondering what tool I have to buy in order to crimp them.

    I contacted Wirefly directly attaching a photo of a terminal and they advised they don't have a set of jaws for these. I contacted Molex who replied:-

    [​IMG]

    How do I crimp these terminals if tools don't seem to be readily available?

    Regards

    Richard
     
    Last edited: Jan 14, 2022
  3. Mike Hanson

    Mike Hanson Lovely!

  4. Richard Lines

    Richard Lines pfm Member

    Good Morning All,

    I have now ordered another crimping tool which should have a suitable set of jaws, I still can't believe Molex can't supply.............

    On a more positive note another box of goodies arrived from AA yesterday:-

    [​IMG]

    I started on a second set of NCC200 boards yesterday:-

    [​IMG]

    As you can see these two boards are using the 86uF capacitors recently bought. The legs on these silver mica capacitors are a very tight fit in the PCB so I drilled the holes out slightly. Whilst these are plated though holes there is no topside connection. I am doing the same with the test point pin holes as the pins I have are 'too big'.

    I'm waiting on some MFR5 680R resistors arriving from the eBay seller. Once I've completed the other board I'll know whether to fit a 1.2 or 2.2k resistor for the trimmer.

    Depending on how today goes I might rig the toroid to power a HackerCap/ VBE to drive the other pair of NCC200's to measure between TP3/ 4 before going any further.

    Regards

    Richard
     
    Mike Hanson likes this.
  5. Richard Lines

    Richard Lines pfm Member

    Good Afternoon All,

    Today's arrivals:-

    [​IMG]

    Regards

    Richard
     
    Mike Hanson, chiily and gavreid like this.
  6. Golfinho

    Golfinho Member

    Hey guys...

    After more than a year of listening and making small adjustments to my mono Avondale Qudos + HCR200, I decide to install the Soft Start module and take the opportunity to put the fontar shutdown button.
    Can you help with the reference (similar) of the buttons used by Naim?
    Like that, I think Tic Tac?

    [​IMG]
     
  7. GWM

    GWM Lost in the 70's

    Yea best to measure voltage between test points before you fit the output transistors,adjust to around 1.7V dc and then your good to go, if you can't then there's a problem.
    Geoff
     
  8. 337alant

    337alant Negatively Biased

    Nice wet tantalums:cool:
    I agree the holes for the silver mica cap are tight I sanded the legs down on mine, just carful drilling out the holes as these boards are double sided, if you have to do it then just solder the pads on either side of the board
    Alan
     
    Mike Hanson likes this.
  9. Richard Lines

    Richard Lines pfm Member

    Good Afternoon All,

    This picture is from yesterday evening when I trial fitted the heatsink so I could line the BD237 and solder it in place so I can carry out the first 'test' of the PCB. Once it is soldered in place I'll remove the heatsink and BUV20's.

    I'll need to ask AA for some stainless fixings for the BD device, this is a temporary 3mm x 12mm bolt I had to hand.

    No prizes for spotting I've used the wrong diode in the D5 position.

    [​IMG]

    Now back at work (up at Invergordon now) so it'll be a few days before work resumes.

    Regards

    Richard
     
  10. Mike Hanson

    Mike Hanson Lovely!

    You might want to add a bit of solder to the top pads of the spade lugs. It's good to keep them as sturdy as possible, considering the force applied during connects and disconnects.
     
    Last edited: Jan 17, 2022
    Richard Lines likes this.
  11. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    And add an insulator for that BD237 (unless its a insulated package)

    Pete
     
  12. Richard Lines

    Richard Lines pfm Member

    Good Morning All,

    As mentioned elsewhere I want to try some modifications to the NCC200 PCB's and have been in discussion with Martin over some possibilities based on posts in previous threads going back a few years around alternatives to R21.

    The first picture shows two options:-

    [​IMG]

    Martin suggests a CRD in place of the J505 as being both cheaper and more readily available - https://www.rapidonline.com/Catalogue/Search?query=CRD

    A combination of the two produces:-

    [​IMG]

    Whilst all three will improve the PSRR (apparently), as Martin says, this doesn't mean they will automatically sound 'better'. I am hoping to try these out along with the Teddy Pardo FE modifications posted previously.

    Regards

    Richard
     
  13. martin clark

    martin clark pinko bodger

    Exactly that.
    As little as 100R+ 1-10uF as an RC filter 'wrapped around' the defining elements of the current source (I like ATC Semitec 2mA CRDs, as linked) makes a for an utterly-bulletproof, out to HF way of driving a voltage reference- which is what the two diodes are, in the Naim (and many comparable) LTPs.

    But also, and exactly as Richard notes - I'd call this sort of thing as very very low on the list of things that might have direct bearing on how you perceive the amp performing overall.
     
    Mike Hanson likes this.
  14. Richard Lines

    Richard Lines pfm Member

    Martin,

    That is staying up into the early hours - at least I'm on shift...............

    Regards

    Richard
     
  15. GWM

    GWM Lost in the 70's

    I have messed about quite a bit around the LTP, the negative rail has a small influence on the sound even adding a full rectified supply gives only a small improvement ,ended up with a 10uF film splitting the 22k resister as in Hackernap plus the 220R/100uFdecoupler Fed by VBE as best.The real gains are in the positive rail, the 2 resisters feeding the LTP have a surprising influence on the presentation, Les changed the 22K to 1K on the Qudos version which lots of people like I don't I suggest you experiment with this first.The positive rail really benefits from a low impedance rectifier closely coupled on the board itself, I had some made by Paul Haynes which is fed by the VBE best result I ever had.Not sure about Teddys regs here as he has it back to front,the VBE section should be on the inlet.
     
  16. Richard Lines

    Richard Lines pfm Member

    Geoff,

    As I'm sure others are aware but for the benefit of some from the NCC200v1.5 schematic:-

    [​IMG]

    and from the NCC220 schematic:-

    [​IMG]

    and then from the HackerNap schematic:-

    [​IMG]

    That's everything in the one place to save chasing all over........... I'll PM you about your last comment.

    Regards

    Richard
     
    Last edited: Jan 19, 2022
    Mike Hanson likes this.
  17. GWM

    GWM Lost in the 70's

    Yea those are the areas,the 3.3 changed to 10 no big deal though,the change from 22K to 1K is very much a personal thing, best way I can describe it is less Naim like so it's what you prefer no best way.
    Before you start tinkering though I'd get used to the Avondale way of doing things it's easy to change stuff and get a bit lost, been there.
     
  18. martin clark

    martin clark pinko bodger

    The kernel of an eternal DIY modification truth right there!

    Make one change, at one time and live with it for a bit. Even, reverse it after a week or two of listening to sense-check. Do not be afraid to undo.​

    Wholesale parts-cannon mods&swaps leave you with no clear understanding of what each increment does, let alone the occasional inter-dependancy. It might even effectively break or spoil a thing - and you are left with having little or no understanding where along the way things went south.
     
    GWM and Mike Hanson like this.
  19. Richard Lines

    Richard Lines pfm Member

    Good Evening All,

    Struggling to find much information about the MiniCap6! Obviously fitted with 6off 6800uF capacitors and given they're going to be hit with 71V out of a 0 - 50V transformer these will need to be 100V rated. Inductors are 100uH parts and the (SMD) resistors 4R7? Which Schottky rectifiers are being used?

    Regards

    Richard
     
  20. Mike Hanson

    Mike Hanson Lovely!

    Whenever I've asked Les about inductors between cap pairs, he's always told my 12µH, so 100µH seems a bit high.
     

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