Relisting with a new batch of boards.

One new printed circuit board. These fit on the early, wider board Dynaco Mark II amps. This layout matches the original production run from 1955. If you are not familiar please look at the finished amps photo and you will see they are wider than the later version of the Dynaco MK II or the MK III. There were several changes to the MK II over the next several years and one was to implement the narrower board most are familiar with. The early boards were not made to today's standards and they are prone to breaking, traces lifting and/or traces coming off. Both of my boards were in rough shape which prompted making a batch of these new boards. I felt others with the early wide boards may be interested in a restoration so I am selling some of them.

These FR4 boards were developed to match the original circuit both in component values and in their placement on the board. There is plenty of room to put most of today's larger coupling caps. 2 watt carbon film resistors fit in several locations. The top view will show that components are labeled which was not done on the original. The bottom view shows that the holes are thru plated for more secure attachment once soldered. The finished amp photo will show how clean and nice your amps can look after restoration. My amps are not for sale – just the board. One item to think about is the original board did not have a capacitor connected from the power supply to the pentode voltage amplifier plate. The published schematic shows a 25 pF capacitor value and the later MK III used a 12 pF cap in that location. The early boards had no cap. These boards do not have a cap there either. If you want to try adding one it can easily be installed underneath. The marked up bottom view attached will show you where it would be installed. My amps sound fine and are stable without that cap.

These do not come with the tube socket or other components. When installing this board it is a great time to upgrade all of those items rather than just move them from your old amp to this board. The tube socket mount is the nine pin PCB type not the thru hole type from the original. One board with shipping will be $15. If you buy more than one board there will be a 20% discount.

Added layout info photo for caps and resistors to now mate up with labeling. More info and recommendations available after purchase of the board.