This is a good site:

http://www.decdun.fsnet.co.uk/gaincloneindex.html#top1

I am about to convert an old kit amp with a suitable
power supply to an inverted 1875 gainclone using
pc boards from Scott Nixon.

This is an interesting and vital group these days.
The forum I follow hereis: www.ampchipdiy.com.

This amp is intended for the next Studio 2 PI Tower
I should complete over the weekend.

These amps should be ideal for most high efficiency
speakers. Once I finish my first pass I will have
the S2PIT, and a pair of Lowther Medallions to try
with them. I will report sometime in early Jan.

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