Kees Heuvelman, Kees Brakenhoff and Wim de Haan's Direct Coupled EL84 Design
The Besta_PAS_ta  mods for Dyna Marantz Scott, etc.
This project started out as a repair (don't they all).  I found a PAS preamplifier in beautiful condition, but the program selector switch was frozen in position.  The performance of the RIAA amplifier was many dB away from the standardized curve and there were power supply problems. 

I chose to first modify the phono stage, picking up where David Koren (1) left off.  I was able to work the equations which relate the impedances of the amplifier stages and the RIAA network such that the performance bettered Koren's design and those of the Audio Research SP-3, SP-6 and SP-8. Like Koren, I consider radio frequency interference and electromagnetic interference to be challenges worth incorporating some protective measures against. L1, L2 and C2, C6, C10 and C14 will help reduce interference.  You have the option of jumpering L1 and omitting the capacitors if your system isn't prone to interference.  Clicking on this LINK will take you to Koren's webzine article.

On the printed circuit board I have provided additional mounting holes so that the blocking caps, C1, C3, C9 and C11 can be modified if you don't want to go to the trouble and expensive of mounting the rather large WIMA polypropylene units.  Also notice that the the RIAA feedback network provides a lot of connectivity if you want to parallel resistors or capacitors to get the best curve-fitting components. 

 You might wish to consider using the regulated 280 volt power supply card found here LINK.  Both the power supply card, and phono card will fit into the allotted space in a Dynaco PAS chassis.

(1) Koren, David "SPICE and the art of preamplifier design", Glass Audio, volume 9 numbers 2 and 4.