Silver bells, cockle shell and little Maids standing in a row....or what's in a line?

Discussion in 'DIY Discussion' started by zanash, Jul 16, 2003.

  1. zanash

    zanash

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    I saw a post in the other place, that talked about inline attenuators. I posted that it would be a simple matter to be able to construct your own.
    So this is my recipe for an inline attenuator [approx 10db].

    Those nice people at Rothwell are charging £38 a pair, to put this project into perspective.

    Take one pair each of RCA plugs and sockets. The sockets shaft must be able to fit the cable clamp of the RCA plug. you will require two high tolerance 10k5 resistors. Trim the res. so only 1mm of lead is left, scrape with a stanley blade to provide a clean metal surface.

    Solder the res. to the centre pin of plug and socket, then clamp the socket to the plug. this should provide a sturdy connection. Oh yes throw the rca plug cover.

    Repeat for other channel

    In my system this provides about 20 clicks of the volume control at 0.5 Db a click.....approx 10db attenuation [hopefully !] Unless you know better as they say.

    How do they sound....
    Well in my system no difference, just quiter.

    But I've an old Incatech Claymore with a poor vol. pot with mis matched channels at low level. This now sound much better now it's passed the worn tracks and both channels are in balance.
     
    Last edited by a moderator: Jul 17, 2003
    zanash, Jul 16, 2003
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  2. zanash

    timpy Snake Oil free!!!

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    You could always re-place the volume pot, it won't be difficult in a Claymore. Better (I feel) than adding another noise source in the line in feed. Resistors make their own noise you know, all on their very own, by virtue o just being there...

    ...actually I'm certain you do know. Probably not that significant but.......

    Cheers
     
    timpy, Jul 17, 2003
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  3. zanash

    zanash

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    Thanks I was just useing it to illistrate the point !

    I've been looking at the Bournes conductive film pots....but just not got round to it.
     
    zanash, Jul 17, 2003
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  4. zanash

    robs

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    Hi Zanash, I tried this a couple of weeks ago (between CD & Linn LK1/2 amps). The reason being that the volume cannot be turned down to zero on these amps, and is still too loud when on minimum (for SWMBO). I'd already done a (Linn recommended) internal mod, which was ~10dB, but this is still not enough.
    I ended up trying a 10K in the XLR plug at the amp, which was not enough, and settled on a 30K. After listening for only a few minutes, and comparing at similar volume levels between the DIY 'Rothwelled' & another unfettled lead, I decided something did not sound right. After a couple of hours, I decided it sounded S***e. Seemed to lose a lot of detail, and become a bit 'blurry' for want of a better description...wooly bass & definate loss of detail. I took them out again, and SWMBO will just have to suffer(?!). Not sure if this is beacuse of the amp type or what, but didn't work for me...

    p.s any idea where the digilink thingy bob widget is on it round the world travels?!
     
    robs, Jul 17, 2003
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  5. zanash

    zanash

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    Yes I've heard very poor attenuation too.

    But if you use the very best resistors and good connectors there should be much less degredation of the signal. I was listing to 10k attenuation and was thinking that I had overestimated the effect so I'm going to try 20k, or even another 10 k on the ground side but this creats problems with keeping the plug and socket isolated.

    This is specifically to help people with volume pots that have a dodgey low volume tracking, I'm not suggesting it should be used at an other time.

    I do remember seeing RA having IC's with attenuation, that reportedly improved the sound.IMO this is a difficult case to justify, as any addition to the audio signal normally takes information away.
     
    zanash, Jul 18, 2003
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  6. zanash

    Chea Johndle Bizarre Serpent Foomaster

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    The vast majority of volume controls have really crap tracking....at Roksan we used a Penny & Giles control @ £135 trade price and still the tracking was at best 2db.....

    D.A.C.T. it's the way to go...tracking on these is 0.05db....Yeah, Yeah I know they are not cheap, but its one of the best upgrades for the money....think of where it is...and what it's doing....you know it makes sense......

    Regards
     
    Chea Johndle, Jul 18, 2003
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  7. zanash

    timpy Snake Oil free!!!

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    Hi John

    What does that stand for?...and where do you get them?? .....

    Cheers
     
    timpy, Jul 18, 2003
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  8. zanash

    Chea Johndle Bizarre Serpent Foomaster

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    Hi,

    Danish Audio ConnecT..... Audiocon supplies them in this country, but you may be able to order them elsewhere over the Web...I will have a look to see wot I can find.... a few other people do stepped att as well....

    Regards
     
    Chea Johndle, Jul 18, 2003
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  9. zanash

    Chea Johndle Bizarre Serpent Foomaster

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    Chea Johndle, Jul 18, 2003
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  10. zanash

    SCIDB Moderator

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    Hi

    I can vouch for the DACT attenuator. It's not cheap but is a quality device. I have one in a passive pre that I have modded.

    It is a series resistor type attenuator with quite smooth action. It uses surface mounted Device resistors with low capacitance & inductance.

    You can get better but the cost goes up.

    A ladder type is rated to be better as this type as only two resistors in the signal path. Again you can use high quality resistors.

    Here are two site which explain more


    Goldpoint

    Dact


    SCIDB
     
    SCIDB, Jul 18, 2003
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  11. zanash

    timpy Snake Oil free!!!

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    Thanks John

    Cheers
     
    timpy, Jul 18, 2003
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  12. zanash

    zanash

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    Hi chaps

    err this is about in line attenuattion not stepped attenuator's !

    but, yes the dact is by all account very very good.
     
    zanash, Jul 18, 2003
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