How to replace volume pot in Dynaco Pas

I would, and have, gone with a 100K pot. The problem being, if you use the phono stage, you will have to replace several of the caps and resistors on the board with different values to return the RIAA curve to being flat. This is not a bad idea, as the original design pretty much sucks and even with the upgrades, you will find that it is probably not up to the quality of the line stage.

BTW, here is a link to a simple graphic by Joe Curcio that shows the mod. Again, once modded, this will only be flat into a 100K volume control:

http://db.audioasylum.com/cgi/m.mpl?forum=dynaco&n=14226&highlight=RIAA&r=

Finally, as Ralph pointed out, moving the time constants to the board will make the first three inputs all phono inputs, which is kinda cool. No more "tape head" and "special".

Thanks guys. I will change my order on the attenuator.

This mod doent' look too bad to perform.

Do you guys recommend any particular caps?

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Ralph would be the expert on caps, for sure. I can say that I don't like the sound of orange drops, but there are really nice caps in all price ranges. For $1 to $2 there are the polypropylene and tin foil Daytons from Parts Express, which are surprisingly nice. Some like the Solens as well. For $5-$6 the Russian K40 caps are fantastic but a bit larger than many other caps. The sky is pretty much the limit from there if you have the budget.

Oh, I am sorry, for the caps that define the RIAA time constants you will need small value caps. The caps that I recommended above are large value coupling caps. I wanted polystyrene for these small values and had a heck of a time finding a suitable vendor. Google "Just Radios", they are a husband and wife team in Canada, the prices were fantastic, the polystyrene caps sound great and service was awesome. Be careful though, polystyrene caps are more sensitive to heat than other compositions so a variable temperature iron or a still, quick hand will help here.