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Arkless 640P "Dr T Mode"/current input version interest check

Discussion in 'audio' started by Arkless Electronics, Feb 15, 2020.

  1. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I'll put a thread on DIY when I have it up and running and have had a listen to it but briefly.... Capacitor coupled and single voltage rail (like Quad 303, Sansui AU101 and countless others) but with modern techniques and components... such as the mosfet output devices. Output capacitor included in feedback loop to kinda "take it out of the equation",
    class A monoblocks and about 14-15W but can be scaled to much higher powers and built as class A/B or anywhere in between or built as stereo amp etc. Designed to drive awkward loads no problem and to be largely "user proof" and very reliable and to not be able to "go DC" and take out speakers if the worst came to the worst (capacitor coupled).
    Computer simulation suggests very good measured performance... proof of the pudding yet to come from test bench and lug 'oles.
    Basically if the brief was to design an amp kinda like a Quad 303 (it's 100% Jez though) but class A (and lower power than the 303 in this incarnation of it), can drive any sensible load, do the frequency extremes much better, and you can use modern components that PJ Walker didn't have access to combined to some circuit techniques that hadn't been thought of back then.... then this would be one way of doing it. It was intended as just an Xmas present to myself type little side project to be done over xmas and new year but looks like it's going to be more a birthday present for early next week! As you may gather from the design objectives though it was also done with a weather eye to it being a potential product but many fish to fry before that.... it may sound shite any way!:rolleyes:
  2. davidsrsb

    davidsrsb pfm Member

    I would make the output capacitor feedback optional. Sometimes the capacitor impedance benefits the sound.
  3. gary7751

    gary7751 Member

    I currently have the GTi on loan, and it is sounding superb in my system, Technics sl1200gr with Denon DL 103R and Sansui Au 717 amplification, playing through Russel k speakers.
    I have just purchased a 640p for Jez to convert, but it sounds as if i am at the end of a long queue!
    Jez currently repairing my original Arkless phono stage.
    Arkless Electronics likes this.
  4. Rosewind

    Rosewind Lost in Translation

    Oops. Just got my hands on a 640p for £60. I will join the long queue for the GTI super plus.
  5. deebster

    deebster Half Man Half Biscuit

    A GTi (recapped, non-turbo) has been with me for a week now, replacing a P75 mark II on the end of a WTL Amadeus GTAa and AT PTG33/II. And I think it's a stonker. More detail and dynamics, with less noise. Music makes more sense, if that makes sense. It outputs at a higher volume too, so now is pretty close in level to my Rega DAC.

    These are the only phono stages I have any experience of so don't know how a four figure one might stack up against it, but right now I don't care cos I have albums to play. Nice one Jez.

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