@strats Knowing which speakers you are using, will be helpful.
@strats From PAP's site for the Trio 15s (Vox PiFe): "Technical Data
Given the easy load your PAPs represent...
AND Conceding that the 30.8 is probably best driven using it's XLR inputs,....
I'd save the money on the 'Balanced' version of the Golden Gate and put the savings into a higher calibre / performing single ended cable and an upgraded power cord and outlet to the 30.8. Any additional savings can be invested in tubes, as you pointed out, or elsewhere.
All the best.
@strats You are welcome! Regarding cabling, as you know, making recommendations is tough and fraught with differing opinions and acceptance.
What I can advise is what has worked for me, and what I've preferred. Others are likely to find solutions in opposition to that or have enjoyed other combinations.
For me, cabling has delivered significant benefits.
Pass Labs, in the past has 'stood by' their stock cords, direct into an outlet...and this is pretty good, per their recommendation. More recently, they have reluctantly acknowledged benefits from using after-market power cords.
I have chosen to use Triode Wire Labs 'Obsession' power cords across my components and this PC did result in performance benefits for my Pass XA30.8 from both Furutech and SR outlets. I, however, much prefer the SR outlets (while using Furutech NCF R connectors for my power cables).
For your IC choice, I suggest reaching out to Lampizator and What's Best Forum for recommendations.
I've been very happy with the following ICs: Cardas Clear Reflection, Audience SX, SR Galileo UEF and SR Atmosphere X Euphoria cables. I've done in depth comparisons between all and all of these cables are very good and I can understand an audiophile choosing one over the other for synergy, matching and personal preference reasons.
I have recently also worked with Verastarr's Grand Illusion Signature Silver IC and Scott Sheaffer's Found-Music 2112 silver IC. Both are exceptional as well.
I'm personally using Scott Sheaffer's Found-Music 2112 IC as my preferred cable in my primary system.