Is It Worh Modding An Amp

I suggest a look at the Mullard CV 4004 and then play with the Ultra-linear vs Triode.

When the U-L or Tetrode is discovered, then the 12 AU7 can be looked at for an exchange tube.   

I have had excellent results modding multiple amps, both solid state and tube.  Never once failed to get an improvement in sound.  What's the downside?  One downside is resale value.  However, I buy my equipment for my own sonic enjoyment so...

Jay mark agree ++++. My plinius was modded by changing the wiring and speaker binding post. I have it for almost 20yrs now.

I would just roll tubes. Easy to do, easily reversible, many combinations available between all the preamp and power tube combos, won’t hurt resale, plus the unused tubes can be kept for future amps or just resold.

The Dialogue 1 uses pretty inexpensive coupling caps and shunt filtering caps on the input tubes. There are much better caps out there but they are not cheap. The problem is most of these caps are considerably large in size than the stock caps so are not going to fit on the bias PCB. They will have to hang somewhere. Where are you going to place them? They will help the sound a bit but what is the point if you are not using the amp. Would be better off selling it and moving on to something else. Have owned most of the PL line from the very early models to the later models.