This page shows some photographs of early versions of the Sugden A21. In each case you can see a larger and more detailed version if you click on the image.
The above shows a very early JES A21. This has a front panel which is very similar to the initial Richard Allen version.
The above shows an internal view of the early A21 without its wooden sleeve (case), looking at the underside.
The above shows the internals looking at the top.
The above view is of the rear panel of the early A21. This shows the serial number (21025)and the use of DB121 output devices. The serial number implies this was the 25th amplifier made in this series.
This photo is a front view of a later version of the A21. As one of the photos below shows, this unit uses BDY38 output devices and is probably a ‘series two’ version. But the legend on the front panel does not say this. It may therefore be an early example of the A21 series two.
This shows an internal view of the amplifier, looking at the under side.
This photo shows the rear panel. The serial number is 21838, but the sequence of numbers may have had a deliberate break between versions, so it is not clear if this was actually the 838th A21 made. The photo shows the BDY38 output devices.
My thanks to Terry Bateman for kindly providing these photos.