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I returned to DIY electronics in 2009 after a 20 year pause by building a few kits to get in shape. This blog is for me to keep track of my progress.
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Krell KSA-5 clone

Posted 9th April 2016 at 01:27 PM by alexcp
Updated 11th February 2017 at 03:20 PM by alexcp

When I saw the discussions of KSA-5 headphone amplifier on head-case.org and on this forum, I thought it may be a nice use for the bag of 1000uF capacitors I had at the time. This was the main motivation for putting this Krell KSA-5 clone together.

The main challenge was to drill the front panel. The 10mm aluminum panel that came with the enclosure is easy to work with, but I wanted it to be pretty and asked the people at Modushop to CNC it for me.

Although it works ok, I think it is not a very good power amplifier for loudspeakers. As a headphone amplifier, it is no match for my Musical Fidelity X-CANv8.
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Attached Files
File Type: pdf ksa5.pdf (129.1 KB, 866 views)
File Type: pdf ksa5psschem.pdf (54.7 KB, 788 views)
File Type: zip ksa5ampfinal.zip (2.80 MB, 82 views)
File Type: zip ksa5psg.zip (631.6 KB, 53 views)
File Type: zip ksa5psorig.zip (791.3 KB, 61 views)
Total Comments 2


  1. Old Comment
    I wonder how it will perform as a line preamp
    Posted 24th February 2017 at 02:35 PM by idir idir is offline
  2. Old Comment
    alexcp's Avatar
    KSA-5 is a power amplifier that can drive speakers. I think using it as a line stage is an overkill unless your power amp is a gain-less buffer such as Firstwatt F4. Even then I guess you could live without the power transistors (Q23-Q26) and perhaps with fewer pairs of the driver transistors (Q15-Q22). Personally, I would rather use the BA-3 front end as a line stage, not the KSA-5.
    Posted 26th February 2017 at 08:48 AM by alexcp alexcp is offline

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