Acurus A250 and starground

Discussion in 'DIY' started by KNielsen, Mar 24, 2018.

  1. KNielsen

    KNielsen New Member

    Messages:
    36
    The new multiturn foil potentiometers arrived :)
    The black on is the new one, size is very impressive, almost half the original blue 1k pot....
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    Last edited: Jan 7, 2019

     

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  2. KNielsen

    KNielsen New Member

    Messages:
    36
    Selected 220V instead of 240V at the AC input, voltage raising to 92.1Vdc at the rails ;)
     
  3. KNielsen

    KNielsen New Member

    Messages:
    36
    Pics for today...

    Added the new potentiometers, preadjusted to 0.5k ohm like the old pots.
    Also soldered new 10awg wires to the circuit and bridges. The circuit had to be drilled for the bigger cable to fit, here a 3.5mm drill was used and everything vent out perfectly.
    I've added 100nf across the bridge rectifier.

    Next shipment arrives in two days: screws, washers, nuts, techflex, signal cable, ect..... :)

    Regards
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    Last edited: Jan 8, 2019
  4. KNielsen

    KNielsen New Member

    Messages:
    36
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    Last edited: Jan 9, 2019
  5. mondialfan

    mondialfan Active Member

    Messages:
    294
    Location:
    Dallas, Tx
    Looking very nice. The new paint job looks great. :thumbsup:
    You'll have an amazing amp when you're finished.
     
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  6. KNielsen

    KNielsen New Member

    Messages:
    36
    Thanks

    My first project from scratch, so everything is a bit "nervous", but I think it start to come together very nicely and far better then I imagined when project started over two years ago :)
     

     

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  7. KNielsen

    KNielsen New Member

    Messages:
    36
    IMG_20190110_215516-1190x1587.jpg
    Actually the part I struggle the most is getting the new AC wiring as tight looking as possible...... o_O:rolleyes:

    The easy solution would be to disable the voltage selector at the AC plug, and just connect the two wires I'm using at the transformer, but I feel this part should be kept original.

    Maby I buy some solidcore wire for this job, as it seems easier to handle with the angle between the cap and transformer to power switch??:cool:

    Regards
     
    Last edited: Jan 10, 2019
  8. KNielsen

    KNielsen New Member

    Messages:
    36
    No need for solidcore.. I'll post a picture as many times earlier in this thread as the layout progress:)

    Mailman came by to day, only half the parts were in the package :yikes:!!! Enough to finish the wiring, but no screws, nuts ect for mounting the caps and so on....

    Have a nice weekend;)
     
  9. KNielsen

    KNielsen New Member

    Messages:
    36
    Not that good picture, but I did manage to do some work to night :)

    It looks almost to tight right now on the picture, but with the psu-caps in place I can loosen the wires a bit so the transformer gets a bit more space.

    Every wire to AC is in place, only need to be cut in correct length to the AC-input and connected... :beerchug:

    Regards
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    Last edited: Jan 14, 2019 at 7:01 PM
  10. KNielsen

    KNielsen New Member

    Messages:
    36
    I'm struggling a bit how to manage the DC wires from bridge to caps....
    Is it okay if the wires are close together, or should I separate +/- as much as possible and cross them if they meet???? Are there any rules that usually work at this point..?

    Regards
     
    Last edited: Jan 15, 2019 at 2:28 PM
  11. mondialfan

    mondialfan Active Member

    Messages:
    294
    Location:
    Dallas, Tx
    The DC wiring can be tied together no problem. You just want to keep the input signal wiring separate from the power wiring.
     
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  12. KNielsen

    KNielsen New Member

    Messages:
    36
    Psu comming together :)
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    Last edited: Jan 16, 2019 at 9:41 AM
  13. KNielsen

    KNielsen New Member

    Messages:
    36
    I'm very close to finishing this amplifier, my first project, started on paper 3 years ago :)

    Only thing missing is the center ground point across the psu.

    I'll guess the first thing to be aware of when powering up first time is the bias voltage across the emitter resistors??

    Regards
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    Last edited: Jan 17, 2019 at 3:18 PM

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