December 18, 2012

• conrad-johnson CA200 Control Amplifier, Part 1

  In an attempt to accomplish a number of goals, including simplifying my life, I recently purchased a used conrad-johnson CA200 control (integrated) amplifier.  This installment of my review will serve as an introduction to the unit and has quite a few photographs, as a result. 

  conrad-johnson introduced the CA200 c. 2006 at which time it retailed for $6,500 and was billed as being one-half of their Premier 350 power amplifier housed in the casework of the Premier 18LS preamplifier.  The CA200 weighs-in at 38 pounds (less than half of my 85 pound Premier 140), measures 19" wide x 3.315" high x 15.5" deep, and is rated at 185 watts per channel @ 8 Ohms and 300 watts @ 4 Ohms, all at less than 1% THD and IMD.

  First Opening                                                                                      WBT-0610 Banana Plugs, Remote, and Power Cord 
       

   

  The reader is directed to the following online reviews for some additional impressions:  Tone Audio (Issue 4, 2006), Enjoy The Music (March, 2007), Audiogon Forum (November 26, 2007), Positive Feedback (Issue 32, 2007), The Abso!ute Sound (November 25, 2008).

  The CA200 is described by conrad-johnson as a “control amplifier” due to the fact that it utilizes “a discrete stepped attenuator level control and input selector switches (all operable by remote control) to eliminate the need for a preamplifier. In fact, there is no line-stage integrated into the CA200 - hence the term “control amplifier”.”  So there.

  
  Front View                                                                                          Front Right Display and Indicator LEDs
        

  Front Right Access Buttons
   

  
  Once the power cord is connected to an electrical outlet, the unit goes into standby mode.  You turn the CA200 on and off by depressing the Mute button, either on the front panel or the remote control, for a few seconds.  A slight thump/popping sound is heard on my speakers when powering up and sometimes when powering down.

  The CA200 adds fins to the left side of the Premier 18LS's casework to dissipate heat.  I’ve never been able to get them anything more than warm to the touch.

  
  Top View
   

  
  As is the practice with all conrad-johnson designs, balanced operation is eschewed for the simpler single-ended approach.  Also, no global feedback is used.  c-j are firm believers in the dictum that less is more when it comes to circuitry.  The voltage gain stage utilizes MOSFETs (metal oxide semiconductor field effect transistors) chosen for their tube-like transfer characteristics and bi-polar transistors, with their associated high damping factor, supply the output power.         

  Five source components may be connected to the CA200 plus an external processor loop (this may be used as a sixth input) and there’s also a theater bypass with a unity gain setting if you so desire.  A preamplifier out connection is available for bi-amping, or, should you wish, to totally bypass the CA200’s amplifier section entirely.

  
  Rear View                                                                                           RCA Connectors Close-Up
        

   

  The rear left (as you face the back) of the unit contains the IEC receptacle with a mains fuse underneath in a drawer that can be popped open plus four B-rail fuses.  A future installment will cover the sonic impact of using HiFi-Tuning Gold (B-rails) and Supreme (mains) fuses in place of the stock, glass fuses.

  
  IEC Receptacle, Mains Fuse Drawer and B-Rail Fuses
   

   

  Finally, the rear right of the CA200 houses a single pair of five-way binding posts and the heat sinks.  Both the RCA connectors and the binding posts appear to be of good quality.

  Five-Way Binding Posts
   

   

  • 10:11 am
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