Passive attack

Discussion in 'Hi-Fi and General Audio' started by Toride, Sep 12, 2006.

  1. Toride

    Toride

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    Hi

    Here are couple of passive preamps people might be interested in:

    1. The Promitheus TVC from Malaysia (review upcoming on 6moons.com)

    http://www.promitheusaudio.com/tvc.htm

    2. The Lightspeed LDR passive preamp from Australia

    http://www.diyaudio.com/forums/showt...t=lightsp eed

    Both work well into my amp (AKSA).

    The Promitheus is currently burning in (sounds good out of the box but a little closed in at high freqs - hopefully will open up after 100 hours or so).

    The Lightspeed sounds absolutely stunning - extremely dynamic and detailed.

    IMO both are worth exploring if you are interested in trying out a passive preamp.
     
    Toride, Sep 12, 2006
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  2. Toride

    bottleneck talks a load of rubbish

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    hi

    your second link doesnt work?

    cheers
    Chris
     
    bottleneck, Sep 12, 2006
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  3. Toride

    Dik Dolan

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    Dik Dolan, Sep 13, 2006
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  4. Toride

    Riverdog

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    Promitheus

    The Promitheus has been burning in here as well. About 20hrs on the clock so far. Even at this stage no temptation to go back to my Luminous Audio Axiom passive (Noble pot with shunt mod). Fuller account to follow. Must add, great service from Nicholas at Promitheus.
     
    Riverdog, Sep 13, 2006
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  5. Toride

    Toride

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    sorry should have checked. try:
    http://www.diyaudio.com/forums/show...&perpage=10&highlight=Lightspeed&pagenumber=1

    Agree - service is excellent from Nicholas. Would be interested in you account after burn in. Does volume setting matter for burn in? (transformer windings used?)

    LDR passive was a shot in the dark (bought one from George who came up with the idea) but I have to say I'm shocked as to how good it is.
     
    Toride, Sep 13, 2006
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  6. Toride

    Riverdog

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    Toride, I would guess each volume setting needs to burn in. Straight out of the box there was one position (at about 9 o' Clock) at which the music has noticebly more air and dynamics. May be that was the position Nicholas burned in for 10 hours.

    Just out of interest how do i go about getting hold of a LDR passive?
     
    Riverdog, Sep 14, 2006
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  7. Toride

    Tenson Moderator

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    The transformer attenuators should just use loop-outs every now and again from what is effectively a single winding, so as long as you burn-in at minimum attenuation (full volume) it should burn in the full secondary winding. ...I think! Just put a resistive load across the outputs so you don’t need to listen to it burning in.
     
    Tenson, Sep 14, 2006
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  8. Toride

    Toride

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    Tenson - thanks for burn-in info. It's definately working - noticeable improvement in dynamics and detail. There's still a bit of sibilance in some 'S' sounds though - hope it clears up.

    Riverdog - You can contact George at georgehifi_at_optusnet.com.au (replace "_at_" with "@") - I paid AU$ 575 (about £230) including postage and 'wallwart' power supply (Aussie plug) - it's not exactly audio jewellery but it sounds great. Also there's only one input so it won't suit everyone but I listen mostly to LPs. You could make one - but I've been 'building' a Dave Slage AVC for 9 months - so I bought one to hear now rather than later/never.

    For the record, I have no connection with George, Lightspeed etc - just an enthusiastic user.

    If you get one I'd be interested to hear your opinion (maybe I'm just hearing just some freakish synergy with my equipment) - I'll put the Lightspeed back in this eve to see if it still sounds as good as I think.
     
    Toride, Sep 15, 2006
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  9. Toride

    Baudrillard

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    You don't even need to have your power amp on when burning in the pre- just a source- I think.

    But don't accidentally turn it on if at minimum attenuation :eek:
     
    Baudrillard, Sep 15, 2006
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  10. Toride

    Tenson Moderator

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    Exactly, just put a resistor across the outputs of the pre-amp[. I used 100R but you could probably get away with less and burn-in quicker. S&B put a rather silly amount of power through their TX's (at least the MF ones I think) to burn them in very quickly.
     
    Tenson, Sep 15, 2006
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  11. Toride

    Baudrillard

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    Tenson

    Do you even need a resistor? Just plug the pre into the power amp with the power turned off and that's fine.
     
    Baudrillard, Sep 15, 2006
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  12. Toride

    Riverdog

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    Sorry of sounding like a complete dunce... Baudrillard, do you mean I should turn the attenuation to minimum and leave the pre connected to my monoblocks with their power off and leave the source (in my case CDP) on repeat?
     
    Riverdog, Sep 15, 2006
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  13. Toride

    Tenson Moderator

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    You could do, but I think you can get more current flowing with a lower value choice of resistor which will make burn-in happen faster.
     
    Tenson, Sep 15, 2006
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  14. Toride

    Baudrillard

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    Yes, that's the way I do it. :)
     
    Baudrillard, Sep 15, 2006
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  15. Toride

    Promitheusaudio

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    Hi guys
    sorry for coming on late on this.

    Let me know how does the preamp works out for you.

    You see since we started we have slowly upgraded our preamps without increasing our preamp price. We have upgrade our trannies 2 times aready. Each upgrade brings about a whole better sounding unit.
    Recently after completing our balanced version, this transformers because of its true balanced winding 2 separate windings per trans (same core) address better high frequency with more openess and better focusing. This when compared the unit in single ended mode (RCA in RCA out)

    So from now on we are changing all of our transformers into this version whether balanced or single ended version

    If you feel the highs to be lacking after 300 hours what we can do is upgrade your units to this new trans. So what you need to do is send it back to us then we upgrade it for you. However just help us by bearing the shipping cost to ship to us and back to you. We will be offering this service perhaps in november/december (by then 300 hours should have passed)

    Cheers
    Nicholas
     
    Promitheusaudio, Sep 29, 2006
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  16. Toride

    larkrise Sheepdogs prefer red wine

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    Myself and a friend have just ordered a couple of these - one RCA and the other balanced XLR - on their way and will let you know what I think. Interested to dem it against my Music First which was a lot lot more money.
     
    larkrise, Sep 29, 2006
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  17. Toride

    johnfromnorwich Tannerd.

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    Bump!

    I stumbled accross this thread whilst wading through endless reams of information about passive vs. TVC vs. active preamps. I'm looking for something to join my Gyrodek/Creek phono stage to a WAD power amp. I can't claim to be any the wiser so far but those Promethius TVC jobbies do look awful tempting for the price if they're all they're cranked up to be.

    So. A couple of weeks down the line, what do the new TVC owners think? Actually great or just a great bargain?

    = John
     
    johnfromnorwich, Oct 17, 2006
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  18. Toride

    georgehifi

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    georgehifi, Apr 3, 2007
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  19. Toride

    el spanner tut

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    very interested in this thread.

    any winner in the promitheus v lightspeed?
     
    el spanner, Apr 21, 2007
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  20. Toride

    anubisgrau

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    pardon my ignorance, but what is LDR?
     
    anubisgrau, Apr 21, 2007
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