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Placing of attenuator plugs

Discussion in 'audio' started by paulfromcamden, Apr 9, 2021.

  1. paulfromcamden

    paulfromcamden Baffled

    I recall reading somewhere that attenuator plugs behave differently inserted on the source output vs on the amp input.

    Is this audiophile lore or based on genuine electrickery?
  2. Vinny

    Vinny pfm Member

    LLLOL - mentioned only a day or so ago, yes they are "polar", but so far as I am aware, both sorts are available - generally phono each end so male-female and female-male. They only work the right way round.

    Can't find the thread at the minutes - something like wanted, low V output DAC.
  3. Sue Pertwee-Tyr

    Sue Pertwee-Tyr Well, I can dream, can’t I?

    I think the design is genuinely directional, so they’re designed to go either on the output, or the input side of the device, but aren’t interchangeable.
  4. Vinny

    Vinny pfm Member

  5. Darth Vader

    Darth Vader From the Dark Side

    It depends on what you mean. If say you connect DAC----amp then you can use the same attenuator on either the DAC output or the amp input using the correct cable or even in the middle DAC--attenuator--amp. The higher resistance part goes to the DAC and the lower to the amp. Similar with preamp--attenuator--amp. Just use the correct phono cables.

    Use an Ohm meter and make sure the higher resistance side goes to the higher output voltage device. What goes out the smaller resistance side is the lower (attenuated) Voltage. Its just a simple Voltage divider.


  6. paulfromcamden

    paulfromcamden Baffled

    What would constitute a correct or incorrect phono cable?
  7. Vinny

    Vinny pfm Member

    Gender of plugs, although the vast majority of ICs are, as you know, male-male.
    Way simpler to pick the correct end to connect using a male-male.

    Even if yor attenuators aren't Rothwell, I have a distant memory that their website has an explanation.When all is said and done - one end of an IC any particular attenuator will work (drop the V), the other end it won't.
  8. Colin L

    Colin L LOU Attitude Adjuster

    As I understand they are best used on the input of the power amp, not the output of the source.
  9. Vinny

    Vinny pfm Member

    That all depends on what direction that any particular one works.................................... If you are talking mirror images of the same thing - male-female, v female-male, it matters not at all.
  10. Bairnstorm

    Bairnstorm pfm Member

    I am using attenuators between pre and power with them connected at the power end.

    I did a bit of research at the time and it was recommended at that end although can't remember why. I don't think they are directional but it makes more sense as you are attenuating as late as possible and keeping the full signal.
  11. Vinny

    Vinny pfm Member

    Please be assured everyone - THEY ARE polar/directional.
  12. Leemalar

    Leemalar New Member

    YEs I've just fitted a pair (One on the input of each monoblock Amp) and they are making a difference...Almost too much! There's noises (More detail) that I've not heard before
    that almost make some tracks I know so well sound odd!...My previous Volume control knob was at 9 o clock mostly loud enough for a 1500sq ft workshop! I got adjustable one -6 to -20db
    (off the bay) There's more midrange & bass smoother (not abrupt) but clean and vocals have come forward with more texture..

  13. paulfromcamden

    paulfromcamden Baffled

    Time for an exciting experiment!

    I plugged a pair of unbranded 10dB attenuators into the CD player output and measured before/after with my phone. No audible or measurable difference. Plugged them into the input of my Croft integrated and output is reduced ~10dB.

    So it looks like I have a pair of 'innies' not 'outies'.
    Sue Pertwee-Tyr and Vinny like this.
  14. Vinny

    Vinny pfm Member


    Nice round figure for attentuation too LLLLLOL
  15. Mike Reed

    Mike Reed pfm Member

    I've a pair of -6dB Goldenjacks on my I/Cs to attenuate the overly healthy output of my CDP into my pre. (both valved). My attenuators can be used either way as I end up with male RCAs anyway. However, it makes sense to me to put them at the pre. end simply because the signal is truncated with the smallest path to preamplification.

    I've never tried it t'other way around (maybe I should), but when VINNY says they are directional, I assume that I cannot use them at the CDP end, unless he's referring to s.q. rather than actual signal.

    I can, it seems, either keep the I/Cs as is and simply insert the attenuators at the CDP end or just reverse the whole shebang, thus reversing the I/C polarity (not keen on that one).

    I still can't get over the amazement when I first fitted them that there was no discernible effect on s.q., whereas -10 and -15dB attenuators I'd tried previously had a marked negative effect.
  16. mansr

    mansr Objectionist

    All else equal, attenuating at the far end of the cable is preferable since keeping the signal level high as far as possible reduces the impact of any interference the cables might pick up. That's completely separate from the fact that attenuators are directional, and the plugs they are fitted with determine which end they can be used (without additional adapters). Both variants exist, presumably because there are situations where placing them at the source is more practical. If you're buying new ones, get the kind that goes at the amp input unless you have a good reason to put them at the source.
  17. Woodface

    Woodface pfm Member

    I’ve thought about getting some as my ATC pre seems to kick out a lot of level, I rarely get the volume beyond 9am. This would be at the balanced output which feeds active speakers.
  18. Darren L

    Darren L pfm Member

    Rothwell make balanced attenuation plugs, 10 db or 20 db.
  19. Woodface

    Woodface pfm Member

    Yes, I did look into those, heard differing views on them. Think they are about £70 so not a trifling amount if they don’t do the job.
  20. Vinny

    Vinny pfm Member

    They will do the job - drop the output of the pre' by 10dB or 20dB, absolutely no doubt about that. Find out, if you do not know, the output V of your pre and do some simple maths aided by an online dB calculator.

    Or buy some second-hand at realistic cost and give them a try.

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