I will have to find mine... From what I remember, it's a yellow cover and titled 'High Quality Sound Reprodcution'. It includes (I think it this order) the 5-20 (EF86, ECC83, 2*EL34, GZ32), preamp for the 5-20 (3*EF86), FM tuner (I can't remember the full line-up, I am pretty sure the IF amplifiers are EF41s, the detector an EB91 with an EM80 tuning indicator), the pre-amps for the 5-10 (EF86) and the 5-10 itself (EF86, ECC83, 2*EL84, EZ81), There were of coruse other FM tuners for the home constructor at one time, Some easier to align than others... I also have the GEC book on audio amplifiers. The _low power_ one is the Williamson (15W, 2*KT66 in the output stage). I think the highest power amplifier schematic in that book gives 1.1kW RMS into the speakers... -tony