[Amps] Drake L4B

[Gary Smith]

Are both tubes working? Sounds like one of the jugs is soft or has gone south.  With 65-75 watts of drive the figures should be in the 7500 watt area
73,
Gary... wa6fgi
  ----- Original Message ----- 
  From: R at contesting.com;Measures 
  To: Keith Dutson 
  Cc: amps at contesting.com 
  Sent: Friday, July 15, 2005 1:07 PM
  Subject: Re: [Amps] Drake L4B



  On Jul 15, 2005, at 12:43 PM, Keith Dutson wrote:

  > Hi, am new to this list.
  >
  > I recently acquired a Drake L4B.  The previous owner said the amp had 
  > been
  > "refreshed" several years ago but not used for more than 2 years.  A 
  > friend
  > who has all Drake equipment looked it over and gave thumbs up to 
  > condition
  > of the unit.  The bandpass and power switches are tight and smooth.  
  > The fan
  > is quiet and in perfect shape.  The power supply has been rebuilt using
  > modern caps and solid state diodes.  Voltage output has not been 
  > measured.
  > Output in CW/Tune is about 540 watts as measured by an Alpha 4510 
  > wattmeter.
  > This seems low.  What should I look for?

  Input SWR of > 1.4:1 typically reduces the power delivered by a 
  solid-state exciter.  If the AØ anode / plate current is under 700mA, 
  not enough drive is arriving at the cathodes of the 3-500Zs.
  >
  > Thanks in advance for your advice.
  >
  > 73, Keith NM5G
  >
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  Rich Measures, 805.386.3734, AG6K, www.somis.org

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