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Diamond BCP-1

Discussion in 'Effects [BG]' started by boomertech, Nov 30, 2017.


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  1. boomertech

    boomertech Frank Appleton Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    Over the years, I have been asked questions about the Diamond compressors to compare against other compressors. I really couldn’t give an answer other than ‘the Diamond is a highly regarded optical compressor’. So, I bought a Diamond BCP-1 to get more familiar with it. The following is data that I collected from S/N 0706.

    The comp control sets the signal gain for the internal amplifier. The max gain is approximately 20dB with the comp knob.

    The current draw is approximately 14mA with 18V adapter.

    The minimum threshold (comp knob set to max) is approximately -33dBu.

    The maximum threshold (comp knob set to min) is approximately -15dBu.

    The ratio graphs were taken with thresholds of -25dBu and -30dBu.
    Diamond BCP1 -25.
    Diamond BCP1 -30.


    The ratio graphs have the ratio slopes calculated between the 5dB input data increments above the plot.

    From the first plot where the threshold was set to a -25dBu input: The average slopes from -20dBu to 0dBu (where the plot is the straightest) is 2.64:1

    From the second plot where the threshold was set to a -30dBu input: The average slopes from -25dBu to 0dBu (where the plot is the straightest) is 2.63:1

    EDIT 1/24/2018:

    Here are the frequency plots with the EQ switch in 250Hz and 900Hz positions:
    BCP-1 Tilt 250Hz.
    BCP-1 Tilt 900Hz.
    The frequency response is excellent. It is basically flat from 20Hz to 20KHz with a -1dB roll-off at 20Hz and -1.5dB roll-off at 20KHz.

    With the EQ switch at 250Hz the tilt pivot is very near the 250Hz mark. When the 900Hz position is selected the tilt pivot is just above 1KHz.

    Very nice!:thumbsup:

    -Frank
     
    Last edited: Jan 24, 2018
  2. I own one of these. I don’t understand any of this.
     
  3. boomertech

    boomertech Frank Appleton Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    Most people won't care about what this data means. :)

    -Frank
     
  4. So basically this compressor kind of tops out at a 3-1 ratio?
     
    loopee and boomertech like this.
  5. Very cool to see, thanks Frank!

    This reinforces for me that as much as I loved the Diamond for its tone, grabbing an Opti-Fet was the right thing for me. I really needed way more squish than 2.6:1. :laugh:
     
    petrus61, boomertech and willsellout like this.
  6. boomertech

    boomertech Frank Appleton Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    Slightly less... about a max 2.6:1 ratio.

    I was mentally seeing a different ratio curve from what I've been told and with what people were posting in forums.

    -Frank
     
    bdplaid, kat888 and blindrabbit like this.
  7. boomertech

    boomertech Frank Appleton Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    The data makes it much easier to understand what people are saying about their BCP-1.

    With a -15dBu max threshold, I can see why some say they have too much compression even with a minimum comp knob setting.

    -Frank
     
    rugrat, Fuzzbass, kat888 and 2 others like this.
  8. Gotcha. Yeah it’s definitely a very polite compressor. I can hear it working a bit but really it just has a great tone enhancement to it. I can really hear the Empress working whereas I can hear the effect of the Diamond. It works out for me though because that slight compression works really well with my playing.
     
    Al Kraft, wmmj and boomertech like this.
  9. kat888

    kat888 Guest

    Oct 13, 2015
    @boomertech

    For comparison purposes ... and to save me having to look for one (which isn't your avatar), would you be so kind as to (re)post an FEA plot?
     
    Last edited: Dec 1, 2017
    boomertech likes this.
  10. superdick2112

    superdick2112 Mile High Bassist Supporting Member

    Nov 20, 2010
    The Centennial State
    I only have one question;

    How long until the next batch of DE-CLs are ready? :bassist: ;)
     
    boomertech, Fuzzbass and willsellout like this.
  11. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    Thanks, Frank! It's good to know that my ears weren't playing tricks (it happens sometimes).
     
    boomertech likes this.
  12. boomertech

    boomertech Frank Appleton Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    The plot in my avatar is from a design that I have been playing around with for a few years. It is an extreme soft-knee similar to the principle of the dbx 163x.

    Here are the plots for the DB-CL that go to a +10dBu input... the LIMIT plot is from the low-band side (the high-band does not have a limit switch):

    Threshold -25dBu
    DBCL Min Max Ratio. DBCL LIMIT Ratio.

    -Frank
     
  13. boomertech

    boomertech Frank Appleton Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    We are still in a DB-CL build cycle... DE-CL's are next.:)

    -Frank
     
  14. Many thanks for posting your findings, Frank.
     
    Al Kraft and boomertech like this.
  15. I'm almost positive Im on the De-CL list. I am really looking forward to having another one, although the DB-CL might dethrone it as my favorite, who knows.
     
    superdick2112 and boomertech like this.
  16. jmlee

    jmlee Catgut? Not funny. Supporting Member

    Jun 16, 2005
    Halifax, Nova Scotia
    The 2.63:1 is even less than the 3:1 estimated in the review here:

    Diamond BCP-1

    I used to have one of these. If you’re not looking to squish your signal too much, the effect is quite nice.
     
    Al Kraft, blindrabbit and boomertech like this.
  17. boomertech

    boomertech Frank Appleton Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    If you round 2.6:1 to the nearest whole number you get an approximately 3:1 ratio.:) So that ratio approximation in the review is accurate.

    -Frank
     
    blindrabbit and bdplaid like this.
  18. Jim C

    Jim C Is that what you meant to play or is this jazz? Supporting Member

    Nov 29, 2008
    Bethesda, MD
    Maybe a little lean at 2.6:1

    4:1 has been my favorite for many applications; at least as a starting point
     
    Al Kraft and willsellout like this.
  19. ranat

    ranat

    Dec 22, 2010
    LA California
    Mine has arrived, I own the Empress comp too, both are nice in a different way. BCP is simpler and to the point
     
  20. J.Wolf

    J.Wolf Gear Reviewer - Bass Musician Magazine Supporting Member

    Apr 29, 2003
    Asheville, NC
    All I need to know: this thing is the absolute shizz with passive fender style instruments :)
     

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