stepped volume

Discussion in 'DIY Discussion' started by harrygrey382, Jan 29, 2007.

  1. harrygrey382

    harrygrey382

    Joined:
    Jun 16, 2006
    Messages:
    164
    Likes Received:
    0
    Location:
    Bristol/West Sussex
    Just found a stepped attenuator I pulled out of a wall mounted volume control at home. I've started making a passive line stage. I did a quick test on the pot, and found I can make no sense of it:
    each side (assuming this means channel) has 4 connection plugs/screws. I leave the earths connected, then I put the +ve input into one hole, and the out into another. On one of the holes, the it works, but in reverse! as in anti-clockwise is making it louder... In another hole, it is all silent apart from one notch, where the osund is full blast. On the last hole it's all dead.

    Can someone explain what to connect please, should the earth be wired into the pot? Does it sound like it's buggered?(i can remember it working fine)

    Lastly, it had a thin washer, with a long lug that poked into a hole (with 11 options) around the base of the input shaft, this seems to restrict the number of notches. Could this be wrong (as it lifts easily)? I've done some trial and error and can't work out where it's meant to go.

    Can one of you experienced DIYers shed some light please?
    Thanks
     
    harrygrey382, Jan 29, 2007
    #1
  2. harrygrey382

    zanash

    Joined:
    Jun 20, 2003
    Messages:
    3,826
    Likes Received:
    2
    Location:
    Notts.
    Well lets see

    the washer with the pin selects the number of clicks [switch positions] the rotator can access. As to the connections

    get your self a multi meter and working with one probe to ground measure all the resistances at each click in all positions....this will check that they are all working for both channels ..it will give you the overal resistance and which way round the connections are.

    once you have this info it should be straight forward working out whats what.

    Alternatively get one like.....ebay 130073185128
     
    zanash, Jan 30, 2007
    #2
  3. harrygrey382

    harrygrey382

    Joined:
    Jun 16, 2006
    Messages:
    164
    Likes Received:
    0
    Location:
    Bristol/West Sussex
    right, well it seems like it's carcked it then. Values are all over the place with multimeter. That ebay one looks nice. But I was also thining about an alps blue velvet. Where are these on the pot food chain, below that stepped attenuator?
     
    harrygrey382, Jan 30, 2007
    #3
  4. harrygrey382

    zanash

    Joined:
    Jun 20, 2003
    Messages:
    3,826
    Likes Received:
    2
    Location:
    Notts.
    There another flavour .....

    dark silky smooth ...

    I've got one of these as well ebay 170068781667

    ......fab value .....

    you need a ac psu to run it and a case ...I built the whole lot for about £40.....

    pm Uncle Ants.....he has the unit at the moment
     
    zanash, Jan 30, 2007
    #4
  5. harrygrey382

    harrygrey382

    Joined:
    Jun 16, 2006
    Messages:
    164
    Likes Received:
    0
    Location:
    Bristol/West Sussex
    hmm, looks tempting. So the relay selects the channel... and needs the ac to work? I suppose otherwise it sounds like a Alps Blue, isn't 100K a little high though?
     
    harrygrey382, Jan 30, 2007
    #5
  6. harrygrey382

    zanash

    Joined:
    Jun 20, 2003
    Messages:
    3,826
    Likes Received:
    2
    Location:
    Notts.
    mine seems fine with 100k into cyber800..... yep a maplins 9v ac powers the switching relays
     
    zanash, Jan 30, 2007
    #6
  7. harrygrey382

    Uncle Ants In Recordeo Speramus

    Joined:
    Dec 5, 2003
    Messages:
    1,928
    Likes Received:
    0
    Location:
    East Midlands
    So far the passive with the alps blue and the relays is a much nicer listen than the pre with the stepped attenuator. Is it the pot or is it the relays? The former would be my guess as the sound is much closer to the passive pre in my Densen which also uses an alps blue, though of a different value judging by where on the control the action is, but doesn't use relays. Could be the stepped attenuator needed running in, but with 23 steps ... bugger that :) Its an interesting exercise so far. I'd never imagined that the volume control could have such a noticeable impact on the sound. I want to try some other pots.

    All in all though for less than fifty quid this ones very hard to fault.
     
    Uncle Ants, Jan 30, 2007
    #7
  8. harrygrey382

    harrygrey382

    Joined:
    Jun 16, 2006
    Messages:
    164
    Likes Received:
    0
    Location:
    Bristol/West Sussex
    right sounding like the alps blue is the one to go for. But each time I get interested, the recommended value increases. Shall I go for a 10K, 50K or 100K for general widespread use?
    Would you two say the relays are better (sonically) than a rotary selector switch?
     
    harrygrey382, Jan 30, 2007
    #8
  9. harrygrey382

    zanash

    Joined:
    Jun 20, 2003
    Messages:
    3,826
    Likes Received:
    2
    Location:
    Notts.
    yes .......but its a more costly option

    I'd go 50k on the pot .....you can pick them up cheaply so even if its not quite right you've not lost a shed load of dosh.

    I'n my system the stepped attenuator sounds clean fast and detailed ...against silky smooth and dark for the alps ......I'm goingto have to put the relays and the stepped pot together to see if thats an option ......
     
    zanash, Jan 31, 2007
    #9
  10. harrygrey382

    ben556473

    Joined:
    Dec 20, 2006
    Messages:
    184
    Likes Received:
    1
    Location:
    Dorset
    ben556473, Feb 11, 2007
    #10
  11. harrygrey382

    zanash

    Joined:
    Jun 20, 2003
    Messages:
    3,826
    Likes Received:
    2
    Location:
    Notts.
    interesting ...anyone heard it ?
     
    zanash, Feb 11, 2007
    #11
  12. harrygrey382

    Uncle Ants In Recordeo Speramus

    Joined:
    Dec 5, 2003
    Messages:
    1,928
    Likes Received:
    0
    Location:
    East Midlands
    That's certainly a handy looking lump wouldn't you say?
     
    Uncle Ants, Feb 14, 2007
    #12
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.