Passive Pre-amp advice

Discussion in 'Hi-Fi Stereo Systems & Separates' started by alchad, Dec 29, 2006.

  1. alchad

    alchad
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    Hi,

    I've a Quad 41 coupled to a Quad 405. I'm more than happy with the combination, but the kit is old and does not have any remote control functions. The only drawback is that Mrs Alchad has more sensitive ears and I often get requests to "turn it down a bit" during louder music passages.

    Getting old and lazy I wondered whether there were any options for remote volume control and have come across the suggestion that I could use a "passive pre-amp". I tried researching on Google but came away more puzzled than when I started and wondered if anyone had any practical experience and advice on them (other than just getting up and adjusting the volume manually!)

    Thanks

    Alchad
     
  2. Nic Rhodes

    Nic Rhodes
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    What are you interested in passive pre amps or remote control of them?
     
  3. alchad

    alchad
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    Sorry for late reply, haven't checked this forum for a while.

    I'm actually interested in remotely controlling the volume! From what little I know, the idea of a remotely controlled passive preamp seemed to offer the best solution in that no signal degredation is involved.

    Any advice appreciated.
     
  4. johngie

    johngie
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    Arguably the only form of so-called passive remote volume control would be a motorised potentiometer. But I honestly think you can get too hung up with the degradation issue - compared with some of the other sources of degradation (mainly loudspeakers in this day and age) that introduced by a well designed "active" device is going to be be very small. And if you have vinyl, it all pales into insignificance!

    johngie
     
  5. alchad

    alchad
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    Hi,

    Thanks for the reply.

    Just to be clear, I'm not really what you would call an "audiophile". I can't get too excited about trying to decide which amplifier/speaker etc is the best. I just have a very simple setup of a quad 34, quad 405, spender BC1's coupled with a recently acquired CA Azur 640H onto which I've loaded most of my CD's.

    All I want to do is to sit back, chill out, listen to whatever music track I choose, but be able to adjust the volume WITHOUT having to throw the Jack Russell of my lap, get up and walk 4 metres to the preamp. So I'd like to install something inbetween, or before, or instead of the quad 34 which will indulge this whim!!!!

    Thanks,

    Alchad
     
  6. Ianfromnotts

    Ianfromnotts
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    If you really want to keep the quad pre then getting some one to change the volume control to a remote type is probably the way to go alternatively and probably a better solution is to buy a new preamp with one already in. Personally I would replace the pre and rebuild the power amp; of course you could run the system with 2 volume controls but it wont help quality but you could use the tape out on the quad to access its phono stage because as any one who has heard a good turntable will tell you it still beats digital and you may just miss the music with the server. Any way one solution to get you going is as follows I cant comment on its quality but in the overall scheme of good hifi its fairly cheap and its a reputed brand

    http://www.hifigear.co.uk/site/scripts/product_browse.php?category_id=195&product_id=18

    PS - I think the 405 uses din sockets so you may need to find adaptors
     
  7. johngie

    johngie
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    Someone after my own heart :smashin: My kit is a motley collection of LS3/5a speakers with AB1 subs, Audiolab 8000C, Quad 303 and other stuff that's "not fashionable" these days. And not an expensive cable in (or out of) sight. But I suppose my background with a degree in electronics :lesson: from the valve days, and much time spent in power electronics and high power RF systems has clouded my judgement!

    But back to your query - go here http://www.velleman.be/ot/en/product/view/?id=345984

    Maplin used to sell these (but no longer) but there is a link to two other UK suppliers. The only problem might be that the input impedance is only 5K.

    Cheers

    johngie
     
  8. alchad

    alchad
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    Johngie,

    Thanks for the link. Someone else has also recommended this to me, the one slight drawback (to me anyway) is that I think it's a kit format and while I can turn my hand to most things I would have preferred something readybuilt (although the same price!). Also I did a quick webcheck on the two UK suppliers and they didn't feature this preamp in their list of Velleman kits, although that's not to say they wouldn't be able to get hold of one for me.

    MORE importantly - excuse the ignorance but my background is high speed gas - what is the significance of the "input impedance being only 5K"?

    Thanks

    Alchad
     
  9. johngie

    johngie
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    Because it's simply a two-gang potentiometer, the resistance of the potentiometer track (5kilohms in this instance) loads up the pre-amplifier or whatever the device is connected to. (I'm assuming here that your arrangement will be pre-amp -> motorised potentiometer -> power amp). It will do no damage, but it may be that the low-frequency response is curtailed if the output of the pre-amp feeds through an internal capacitor. The spec for the pre-amp should tell you what mimimum load impedance it can feed.

    Hope this helps. Post back if you need more help.

    johngie
     
  10. johngie

    johngie
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    I've just had a look at the Quad 34 circuit diagram. The 5K impedance will cause absolutely no problem whatever.

    johngie
     
  11. jon_mendel

    jon_mendel
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  12. alchad

    alchad
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    Jon,

    Thank you for the link. If you check it out now you'll see that I'd found it independantly and was just about to buy when fate intervened in the shape of a OBH 22 (although the price was a lot more).

    Regards

    Alchad
     
  13. jon_mendel

    jon_mendel
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    Glad you've got something sorted, anyway :D
     

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