Idiot ohm question?

Discussion in 'Amps, Mics & Pickups [DB]' started by Basschair, Dec 12, 2007.

  1. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    Hey guys,

    How many ohms in a Mohm? I ask because my new Schertler STAT-B has a 100 ohm impedance, and I'm trying to decide which input to run it to in my AI Contra (Low, Hi-low at 1 Mohm or Hi-Hi at 10 Mohm).

    My head hurts.
     
  2. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    Actually, I should probably just ask this:

    According to Wiki-p, one Mohm is 10 to the 6th power ohms. So this probably means that my Stat-b with it's 100 ohm impedance would be considered "low" impedance.

    I'll keep it plugged in to the "low" input. Do I have this right?
     
  3. At 100 ohms, it's quite low impedance, and it won't make any difference whichever input you use on the Contra.
    100 ohms could be the output impedance of a preamp.
    Maybe the STAT-B already has its own preamp?
    In that case, make sure you don't overload the Contra's input.
    Overloading causes distorsion and fuzziness.
     
  4. Mohm is short for megohm or 1 million ohms.

    In the case of the Schertler STAT-B, the integral preamp's output impedance is 100 ohms. Connecting your Schertler preamp to an input impedance of 1000 ohms (1K) or higher should be fine, and it probably won't make any difference which input you use with your Contra.

    Edit: Oops sorry, didn't see Francois' reply before I posted mine. The Schertler Stat-B does indeed have it's own preamp. I'm pretty sure the AI Contra can handle the signal level just fine though.
     
  5. Without preamp: In general, you want the input impedance to be higher than the pickup impedance. This is particularly important with piezos, otherwise you lose all the bottom end. Piezos need input impedance of 1 M-Ohm or greater; 10 M Ohm is typical.

    With preamp: Input impedance becomes irrelevant because the preamp will buffer the pickup. Preamps typically have very high input impedance to avoid loading down the pickup, and very low output impedance so they can drive long cables.
     
  6. 1,048,576

    :)
     
  7. bassist14

    bassist14

    Oct 17, 2005
    Germany
    why don´t you just plug it in and see (listen) what happens? :bag:
     
  8. What does listening have to do with it?

    :)

    :bag:
     
  9. Uncletoad

    Uncletoad

    May 6, 2003
    Columbus Ohio
    Proprietor Fifth Avenue Fret Shop. Technical Editor Bass Gear Magazine
    Try both, see how they sound and report back.

    You can't break anything there.
     
  10. DrChill

    DrChill

    Jan 30, 2007
    New Braunfels, TX
    I could be wrong, but generally Ohms aren't figured using binary math like is used for number of Bytes.

    In this case MegaOhm just means one million.
     
  11. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    :D

    Thanks for all the input guys...hey, "input!" That's funny, right?

    :bag:


    Thanks Phil: that's what I needed to hear. The last thing I need is to tell my pregnant wife that I just blew my DB amp and need to get a new one.
     
  12. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    That tugging you felt was your leg being pulled. ;)
     
  13. Uncletoad

    Uncletoad

    May 6, 2003
    Columbus Ohio
    Proprietor Fifth Avenue Fret Shop. Technical Editor Bass Gear Magazine
    Hardly the last thing.

    1. I just lost my job
    2. I'm tired of our relationship and want to see other people
    3. have you though more about an open marriage
    4. I'm having a midlife crisis with a short asian woman and a $70,000 car
    5. I think we should consider moving to a commune and living naked with other parents and their children
    Did I leave anything out?
     
  14. DrChill

    DrChill

    Jan 30, 2007
    New Braunfels, TX
    How about, "Hmm, that's not how your sister does it."
     
  15. Sorry to get back on topic for a moment, but I thought I'd point out that the Stat-B is not a typical piezo pickup but instead works on the electrostatic principle. The Stat-B system uses an integral preamp with a line level output that can easily drive lower impedance inputs, so it really doesn't matter what the amp's input impedance is. Now back to our regularly scheduled program...
     
  16. Uncletoad

    Uncletoad

    May 6, 2003
    Columbus Ohio
    Proprietor Fifth Avenue Fret Shop. Technical Editor Bass Gear Magazine
    That's swinging for the fences.
     
  17. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    You guys are nuts :D
     
  18. Thank you for the correction.

    You are correct ;)