More amp headroom with HPF (Fdeck or Thumpinator)

Discussion in 'Amps [BG]' started by GK Breivik, Feb 20, 2014.


  1. GK Breivik

    GK Breivik

    Joined:
    Apr 23, 2013
    Disclosures:
    Endorsing Artist: Spector Basses
    I was wondering if anybody who has used either the Fdeck HPF or the sfx Thumpinator could share their experiences with regards to amp headroom.

    My amp runs out of steam before my cabinets, and I’m wondering if I could expect an appreciable volume increase if I hi-passed at 30 or 35. This is a Thunderfunk TFB-750 into an eight ohm load, if it helps.
  2. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Location:
    New Zealand
    Running out of amp with 750w at 4ohm doesn't sound likely. What cab?

    HPF-3 is the weapon of choice for curbing unwanted fundamentals or tightening up room response.
  3. mrmills

    mrmills

    Joined:
    Jun 22, 2009
    Location:
    Kent, UK
    Removing very low frequency content will help as it is wasted energy if the speaker is not responsive at that frequency. How much it will help really does depend.

    Question is, how much being sent to the speakers below 35Hz? You can only really tell with a signal generator and frequency analysis of the amplifiers output.

    Remember that a a doubling in volume requires a squaring of power so a few extra Watts will make little difference.
  4. GK Breivik

    GK Breivik

    Joined:
    Apr 23, 2013
    Disclosures:
    Endorsing Artist: Spector Basses
    @Downunderwoofer: This is an 8 ohm cab, so I think the amp puts out 400 W.
    @mrmills: I understand about the volume/ watts relationship. OTOH, low frequencies need more power than higher frequencies too.

    I seem to remember that people claim increased headroom with an external hpf, so I’m looking for real world user experiences.
  5. jnewmark

    jnewmark Supporting Member

    Joined:
    Aug 31, 2006
    Location:
    Stax 1966
    Disclosures:
    Play guitar.
    Some bass amps already have a built in high pass filter. Does your manual state anything about it ?
  6. mjmeche

    mjmeche Supporting Member

    Joined:
    Jul 14, 2007
    the fdeck does tighten up low end. I will find out this weekend when i use it with my headlite and schroder cab which tends to fart out on low end.
  7. GK Breivik

    GK Breivik

    Joined:
    Apr 23, 2013
    Disclosures:
    Endorsing Artist: Spector Basses
    The amp probably has a filter way down low, to filter out the infrasonics at least. he manual doesn’t say. My streamliner 900 feels a little louder thru the same cabs, and that one has a hpf @ 35 IIRC.
  8. dincz

    dincz

    Joined:
    Sep 25, 2010
    Location:
    Czech Republic
    " Remember that a a doubling in volume requires a squaring of power so a few extra Watts will make little difference."

    There's no need to exaggerate!

Share This Page