J L Linsley Hood 1969 Amplifier Part 7D

I discuss the “regulator” function and discover that it is a form of “soft start”, as wel as supplying 24 (really 22) VAC to the amplifier.

Part - 7C This is the same amplifier powered with 15VAC.

Part - 7B Here I power-Up the #5 Amplifier with a heat sink and apply some inputs and display the output on an Oscilloscope.

Part - 7A Well, AliE notified me that a different version of the venerable JLH 1969 amplifier was available. This one had an on-board power supply circuit. So, I bit and purchased two of them.

Part – 6 I try to clear up the biasing of the signal input amplifier.

Part – 5 I had great hopes for this one, it uses two FET’s in the final stage. Some damped oscillations caused by the amp were found in the input and these caused some residuals in the output.

Part – 4 This is amplifier No. 3, it was from Ebay and I have updated the Sellers info to show the vendors name. Note that the shipping was not mentioned in the video, it was $9.

Part – 3 This is Amplifier No 2, also from AliExpress, sold, by ZERO ZONE as their Model N1969. The test is what it is, pretty nice.

Part - 2 In this Part I look at the Amplifier designated as “No. 1”, a completed amplifier from AliExpress, I destroy the first amplifier and then test a second one (I had purchased 4 of them),

Part - 1 I have purchased four clones of the well-known JLH 69 Amplifier. I will test them all. One was a completed unit three were kits. I have an HP Distortion Analyzer that I intended to use but it failed when powered up, so I will be using a square wave generator and an oscilloscope for testing.
Link to files;
https://gswagner.com/AudioAmplifiers