line level volume control?

Discussion in 'Archived Threads 2001-2004' started by Jeff Hoak, Mar 3, 2003.

  1. Jeff Hoak

    Jeff Hoak Stunt Coordinator

    Joined:
    Jun 26, 2001
    Messages:
    137
    Likes Received:
    0
    Trophy Points:
    0
    Due to space limitations in my entertaiment center I find it necessary to move my PE plate amp (mounted in a box) to the garage. The amp is driving my DIY IB sub. I only use the IB for 2 channel music. It is being driven by the sub output from an Onix P-3000 preamp and is crossed over at 75Hz. I only occasionally diddle with the volume setting on the plate amp and never change the phase or crossover setting.

    What I think I need is a line level control installed between the preamp and the plate amp. That way I could crank the level control on the plate amp all the way up and be able to control the volume of the sub without having to walk back and forth to the garage.

    No it's NOT that far... I'm just that lazy!

    The other option would be a speaker level volume control (Niles?) installed between the plate amp and the IB sub. I see the downside to this method as needing to run a bunch more speaker wire (LR-to-Gar-to-LR-to-IB).

    Has anyone seen anything like a comercially built line level control in a decent looking cabinet? If so can you point me in the right direction?

    I'm reasonably handy with a soldering iron. Can I build one. Seems like all it would take is a decent pot and a couple of RCA jacks. What value should the POT be?

    THANX!
     
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

    Joined:
    Jul 30, 2000
    Messages:
    789
    Likes Received:
    1
    Trophy Points:
    0
    What you need is a voltage divider and you can make one easily. Get a box, drill holes for 2 rca jacks and a pot. The value of the pot is not critical- anywhere in the range of 20-100 K will work fine, linear or log type. Solder the grounds of both RCA jacks to one end of the pot. Solder the "hot" pole of the input RCA jack to the other end, and solder the hot pole of the output RCA jack to the center polr (the wiper). Don't forget to ger a snazzy knob to put on the pot.
     
  3. Jeffrey Stanton

    Jeffrey Stanton Stunt Coordinator

    Joined:
    Feb 25, 2003
    Messages:
    113
    Likes Received:
    0
    Trophy Points:
    0
  4. would be nice, but they are rediculously expensive IMO.


    I mean...it has all the functions of a good plate amp for more $ than the plate amp, but you don't get any amplification.
     
  5. Jeff Hoak

    Jeff Hoak Stunt Coordinator

    Joined:
    Jun 26, 2001
    Messages:
    137
    Likes Received:
    0
    Trophy Points:
    0
    2 bills... That's a bit much for a volume control. I know that it does LOTS more than just control the volume but...

    Brian is on the right track. Sound like that's EXACTLY what I need to do. The project does raise a couple of questions though...

    How much variation is there in the quality of pots? I mean will a $2.99 Radio Shack pot work as well as some of the more expensive units. A quick scan of the Michael Percy Audio catalog shows pots at $29.00 up to $230.00.

    Keep in mind that we're talking about controlling a sub here. If the cheaer pots roll off at upper frequencies that's fine. BUT... If the cheaper ones introduce distortion or noise then it may be worth spending the extra $$$.

    I'm assuming that all of this will need to be mounted in a metal box to act as a bit of shielding to help prevent 60Hz hum.

    THANX!
     
  6. Aaron_Smith

    Aaron_Smith Stunt Coordinator

    Joined:
    Jul 22, 2002
    Messages:
    105
    Likes Received:
    0
    Trophy Points:
    0
    A regular old panasonic pot will work great. I'd probably use a 100K pot with a low level signal, and a log taper will give you better control. Hum shouldn't be any more of an issue than with a long interconnect, so the enclosure should be unimportant.
     

Share This Page