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The CSV60 Tube Amp Restoration Project
© 2000   by Peter H. Wendt

CSV60 Amplifier
Introduction


Some time a couple of years ago a friend showed up at my house with "an old amplifier and tuner" in the trunk of his car. He said "It's an old tube amp with a half sized tuner. Probably 15 years old or so."
Little did he know - and little did I know at that point. The amp and tuner were pretty dusty and the metal cases of both units were speckled with rust spots.
Obviously the units had been stored for longer in a very wet cellar.

To my surprise both worked. The tuner attaches directly to the amplifier on a special socket at the rear of the amp having no own power supply. Closer inspection of the amplifier turned up with more damages done by amateur "repair attempts" - or trying to crap the thing. The front of the amp is usually fixed with 4 lens-screws. Someone must have tried to remove the screws - and when this failed - tried to drill them out ... with a much too large drill - and failed on even that. The front panel is only held on the amp with the selector and control knobs, all four fixing screws are damaged.
In addition some of the control knobs fixing screws have been damaged, broken apart or were missing.
At least all knobs were present - an unexplainable miracle in this respect.

Looking inside the units unveiled a lot dirt in both and a set of non-matching tubes in the amplifier. The layout printed on the inside says "4 x PL-500" for the output stage. But there were only 2 x PL-500 installed - and 2 x PL-504 tubes, which are successors of the PL-500 and are drop-in replacements in e.g. a TV, but for a push-pull stereo amplifier you'd better have four near-identical tubes.

The amplifier turned out to be a Braun CSV60, Serial Number 6775 (? req. verification), built at some time from mid-1962 to early 1963 (when the maintainer of these page was just 2 years old). The tuner is the transistorized CET15, successor of the tube-type tuner CET6 and 10 (at least I had been told so ... cannot verify it at that point).

I operated the CSV60 - CET15 combo for something over a year in my computer lab along with a set of two Arcus Sinus TS80 two-way speakers and was pretty surprised on the solid musical output and the (relatively) low hum and noise. I had an older CD Player attached at the "tape" input. I needed to install a voltage divider between the CD-Player and the tape input, because european "DIN" inputs for tape are 100 - 150 mV at 470 KOhms usually, while the more common US / Japan standard (using RCA chinch connectors) defines a higher range for the same "zero dB" output - but at a lower input impedance: 470 mV @ 47 KOhms. Worked fine until I moved out of that house to my girl-friend.

The Braun amp and the tuner were -again- stored in the basement, but this time wrapped in thick plastic sheets and with a lot more care. They had been buried there until recently, when I remembered them while flipping through the internet auction pages of german eBay. Someone offered the Service Diagrams for the Braun CSV13 (small version with 4 x EL-84 tubes) as well as those for the CSV60. Another guy offered the diagrams for the CET15 tuner.
I bid on both - and got them.

As a computer-maniac I took the time to convert the manuals in PDF format ... they can be downloaded from these pages. See the links on the Download Page.


(This text is revision: Draft 0.9.2, January 23rd, 2003)


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