This is a nice comb-bond book containing 26 schematics and 19 bill of materials so you can build some of the worlds most famous and best sounding Vacuum Tube Amplifiers ever produced. All of the circuits are from 1950’s the Golden Years of Hi-FI. There is a wide range of output power from 10 to 120 watts, including Class A-B Push-Pull, Class A Triode, output transformer less (OTL) and even a 300B design. Designs using 6V6, 6L6, KT66, 6BG6, 5881, 2A3, EL34, EL84, 6550, KT88, 300B are all found in this book. You can Compare these designs to your own or study and learn from the these circuits or build and test prototypes and have fun. This Comb-Bound book, has a CLEAR PLASTIC COVER for protection, and a Thick, Black Colored, Backing. All articles are reprints from original magazine articles of the 1950’s. There is alot of info here and the price per article is about 66 cents, others on ebay are selling single BUILD A 30 WATT.... articles for about $5 to $6 dollars apiece. So this is a real bargin. THE ARTICLES LISTED BELOW CONTAIN SCHEMATICS AND BILL OF MATERIALS 120 WATTS OF POWER - Design by David Hafler of Dynaco, using 4 - KT88”s A 100 WATT POWER AMPLIFIER - Design by Kenneth Olson, using Tung-Sol 6550’s ADAPTING THE “ULTRA - LINEAR” WILLIAMSON TO 6550 OPERATION - Design by Herbert L Keroes of Arco Products Company A 60 WATT “ULTRA - LINEAR” AMPLIFIER - Design by David Hafler of Arco Products Company, using 4 - KT66’s A 50 WATT POWER AMPLIFIER - Design by David Hafler of Dynaco, using 2 - EL34’s A HEAVY-DUUTY AUDIO AMPLFIER - Design by Serge L. Krauss of C.C. Conn Ltd, using 4 - 6BG6’s NEW 25 WATT POWER AMPLIFIER - Design by Norman Kramer of Allied Radio Corp, using 2 - 5881’s Mullards 520 CIRCUIT (ULTRA - LINEAR) - Design by Mullard Ltd. England, using 2 - EL34’s NEW BRITISH POWER AMPLIFIER - Design by Mullard Ltd. England, using 2 - EL84’s A HIGH-QUALITY AUDIO AMPLIFIER - Design by EDW. S. Miller of The Radio Craftsman Inc. Using 2-KT66’s A 300B AMPLIFIER WITH FEEDBACK DRIVER - Design by Howard T. Sterling of Waveforms Inc. Using 2-300B’s A ULTRA-STABLE OTL HI-FI AMPLIFIER - Design by Julius Futterman, using 8 - 12B4A’s THE STEPHENS OTL AMPLIFIER - Design by Frank H. Gilbert of Stephens MFG Corp. using 4 - 2A3’s HIGH-FIDELITY THE EASY WAY - Design by W. B. Bernard of US Navy, using 2 - 6L6’s A 13 WATT ALL-TRIODE “INFINITE FEEDBACK” AMPLIFIER - Design by Charles P. Boegle of Cincinnati Research Company, using 2 - 5881’s or KT66’s ULTRA-LINEAR OPERATION OF 6V6 TUBES - Design by David Hafler of Arco Products Company, using 2 - 6V6’s HIGH-QUALITY AT LOW COST - Design by Lothar Stern of Allied Radio Corp, using 2 - 6V6’s HI-FI WITH TRIODES - Design by J. N. Still of Sylvania Electric products Inc. Using 2 - 6CK4’s USING THE 6U8 IN A HIGH-QUALITY AUDIO SYSTEM - Design by George E. Jones of University of Pittsburgh, using 2 - 6L6’s THE ARTICLES LISTED BELOW CONTAIN SCHEMATICS ONLY, NO BOM’s NEW TRANSFORMER DESIGN FOR POWER AMPLIFIERS - Fairchild 75 watt using 6550’s model 275 THE HF-60 A NEW POWER AMPLIFIER - ECIO 60 watt using EL34’s model HF-60 THE “PERI-50” POWER AMPLIFIER - Printed Electronics Research Inc. 50 watt using EL34’s model PERI-50 THE “MARK III” - Dynaco 60 watt using KT88’s model MARK III THE “ULTRA - LINEAR II” - Arcrosoud 60 watt using EL34, Model ULTRA - LINEAR II 70 WATTS WITH KT88’s - Sargent-Rayments “Super Seventy” model SR-70 70 WATTS FOR HI-FI - Heathkit W-6M using 2– 6550’s At the end of the book, theres a seperate section devoted to schematics. All of the schematics listed in the above articles are blown up to 8 12 X 11, for easy reading and or copying. See Pictures.