Thumbnail for Rebuilt Driver Board - Ready for installation - Here is the completely rebuilt Driver Board. All 1/2 Watt resistors have been replaced with precision-matched NOS Allen-Bradley carbon-composition resistors that were matched within 0.1%. The 82 pF and 390 pF capacitors and the 1 Watt resistors were still closely matched so they were retained.
Thumbnail for The "donor" Power Cord - Restored - About 30 minutes of work netted a pretty nice original beige Dynaco Power Cord. The "Finishing Touch!"
Thumbnail for The "donor" Power Cord - Before Restoration - Yuck! - Pretty nasty lookin' Power Cord, isn't it. About 30 minutes of cleaning took care of that!
Thumbnail for Completed Stereo 70 - "Don't Call Me 'Dimples'!" - Head-on Shot - Classic Iron meets a complete rebuild. Meet "Don't Call Me 'Dimples'!" Now complete!
Thumbnail for "Don't Call Me 'Dimples'!" - Completed Driver Board Installation - Here is the completely rebuilt Driver Board installed in "Don't Call Me 'Dimples'!"
Thumbnail for "Don't Call Me 'Dimples'!" - Complete - Here is our second Stereo 70 project "Don't Call Me 'Dimples'!" Notice the "Dynakit" logo, rather than a "Dynaco" sticker. This amplifier began life in 1962 or 1963 (according to the transformer date codes). This was originally a kit version of the amplifier. Notice the difference in the tube cage/cover. It has a slightly "coarser" hole structure than later models.
Thumbnail for "Don't Call Me 'Dimples'!" - Back of Amplifier Picture - Here is the rear of the amplifier. Notice the *slight* depression around the fuse holder. It was originally a SERIOUS bend in the chassis that pushed the fuse holder area over 3/4 of an inch inward. This photo actually makes the depression look deeper than it actually is. Needless to say, it is a HUGE improvement!
Thumbnail for Completed Stereo 70 - "Don't Call Me 'Dimples'!" - Under-chassis Shot - Here is the under-chassis picture of "Don't Call Me 'Dimples'!" Looks a LOT like our first Stereo 70 project "Nothin' Fancy." But notice the ceramic tube sockets and look VERY carefully at the bias supply. The 1 Watt resistor at the far left side of the terminal strip is now an 8.2K resistor in order to accommodate tubes that require more negative bias to set the "idle" operating point of the EL 34's.
Thumbnail for Completed Stereo 70 - "Don't Call Me 'Dimples'!" - Ceramic octal sockets - Here is a "View From the Top" of "Don't Call Me 'Dimples'!" I removed the octal tubes so you could get a good look at the ceramic tube sockets. These sockets grip the tube pins REALLY well and there is NO chance that the sockets will melt or distort - EVER!
Thumbnail for Completed Stereo 70 - "Don't Call Me 'Dimples'!" - The "Classic" Stereo 70 Pose. - Here is "Don't Call Me 'Dimples'!" with the tube cage/cover removed. Loaded with tubes and ready to deliver some really beautiful music!
Thumbnail for Mechanical Assembly - under chassis picture - Here is an under-chassis picture of my second Stereo 70 rebuild during the initial re-assembly. Note the ceramic tube sockets. Also note that the damage at the fuse holder area has been repaired to a "reasonably acceptable" level. It isn't *perfect*, but it is certainly a LOT better than it started out.
Thumbnail for Initial Assembly - Frontal Shot - Here is the Front Panel and top of chassis picture of my second Stereo 70 rebuild "Don't Call Me 'Dimples'!" The plating on this chassis is significantly better than the plating on "Nothin' Fancy"; my First Stereo 70 rebuild.
Thumbnail for Half Shiny - Half NOT so shiny! - Here is a picture that was taken about half way through the polishing of the Stereo 70 chassis. Note the VERY dull appearance of the right side of the picture. This is how the whole chassis looked when I began the project. That polishing really helped a LOT!
Thumbnail for This is the repaired area of "Don't Call Me 'Dimples'!" Not bad at all! - Considering that this are was initially "punched in" almost 3/4 of an inch, this is a LOT nicer. In its original damaged state, it would have been impossible to use. Now, although not *perfect*, it is still MUCH improved and will certainly be acceptable for a rebuild.
Thumbnail for Completed chassis wiring - waiting for the Driver Board - Here is the completed chassis wiring. All that remains is installation of a restored Driver Board, and this one will be finished.
Thumbnail for Completed chassis - Just waiting for the Driver Board - It's beginning to look like an amplifier again! All we need now is the Driver board, and this one will be ready for testing and "burn-in."
Thumbnail for Driver Board - As removed from the original amplifier. REALLY filthy! - While this doesn't look THAT bad, the TRUTH is that this board is LOADED with caked on "grunge" from 46 years of use and storage. It LOOKS like dust, but it is a LOT more difficult to remove than you might think. Time to strip the parts and clean what's left.
Thumbnail for Driver Board - Stripped of parts and REALLY filthy! - Here you can get an idea of the amount of "crud" this driver board had accumulated since it was manufactured in 1962. While it looks like it's only dusty, this stuff is REALLY "glued" onto the board. It's GOTTA go!
Thumbnail for Driver Board - ready to repopulate with parts - Here is the "stripped" Driver Board after a thorough cleaning. Quite an improvement over the mess we started with.
Thumbnail for Allen-Bradley NOS Carbon Composition Resistors - matched within 0.1%! - Here is the lineup of NOS 1/2 Watt Allen-Bradley Carbon Composition resistors for "Don't Call Me 'Dimples'!" These have been precision-matched to within 0.1% between channels. (Sorry that the colors are a bit off.)