Posted by Doc B. (M) on November 01, 2009 at 11:18:43

I happened across a pair of BCP-16 GC NI grid chokes this week, in an old prototype chassis. Installed them in place of the 45 tubes' 270K ohm grid resistors in my shunt regulated 45 tweeter amps (with MQ output transformers and plate chokes) and was reminded of what a difference they make. I've been wrestling with some imaging issues on my system and along with beefing up the dynamic control like we know these puppies can do, the image got much better focus - quite an obvious transformation. Shawn was saying "D**n! Why didn't we do this before that demo we did a couple weeks ago?"

The only downside of this is that I have 16 more amps in the system that I'm sure will improve with the addition of BCP-16s. Time to start socking away some choke money...

• Coupling cap, or DC? - beeah 11:11:59 11/03/09 (2)
  In Reply to: RE: unabashed plug - grid chokes posted by Doc B. on November 01, 2009 at 11:18:43

  Doc - Is there a coupling cap between the driver and the 45, and if so, did you increase the value after installing the GC?
  
  

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  • RE: Coupling cap, or DC? - Doc B. 21:36:54 11/03/09 (1)
    In Reply to: RE: Coupling cap, or DC? posted by beeah on November 03, 2009 at 11:11:59

    Yes, it is cap coupled, not direct coupled. Direct coupling would preclude the use of a choke tying the grid of the output tube to ground. Actually I lowered the coupling cap value from .1uF to a .056uF, something I had on hand that I thought would sound better than the stock cap. It's a tweeter amp, after all - the tweeter is crossed over at 2200Hz.
    

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    • Of course - thanks for the response. (nt) - beeah 06:00:59 11/04/09 (0)
      In Reply to: RE: Coupling cap, or DC? posted by Doc B. on November 03, 2009 at 21:36:54

      nt
      

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• Grid resistors are an OK blend - Grid Chokes are pure Single Malt! (nt.) - Anthony Dockrill 02:32:32 11/03/09 (0)
  In Reply to: RE: unabashed plug - grid chokes posted by Doc B. on November 01, 2009 at 11:18:43

  
  

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• Doc... thanks, thanks, thanks for the kind words... (read more) - mqracing 13:19:28 11/02/09 (0)
  In Reply to: RE: unabashed plug - grid chokes posted by Doc B. on November 01, 2009 at 11:18:43

  I didn't get the bill yet {smiles}.

  If you need sixteen of these puppies... what I would give a try is the M6 versions... yea... they have less inductance than the nickel critters... but none-the-less even the M6 has a lot of L in them. Just a thought... if you'd like to try out a pair let me know. Or try a pair of nickel pinstripes.

  We also have a second gen nickel version coming out... built on a slightly smaller core... with a pinch less turns... but still beats by a mile our advertised L's. And the beauty is we cut the capacitance (which was near zilch to begin with) to vanishingly ultra low levels of C. Will make them even easier to drive. And make them easier to install space wise... it's basically a win-win. Pricing will remain the same.

  cheers to the Bottlehead crew,

  have all you inmates been over to Dan's new forum yet? Go visit. Sign in.
  and help Dan's new forum home become as great as his stay was on audio asylum.

  Mike

  
  

  
  
  
  Builder of MagneQuest™ & Peerless™ transformers since 1989
  
  

  • Dan's new forum   (Open in New Window)

  
  

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  Edits: 11/02/09   11/02/09

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