How much does tube brand REALLY affect sound in terms of rectifier tubes?

In my Woo Audio all tube class A headphone amp a WWII vintage NOS Tung Sol rectifier tube was noticeably better than whatever rectifier tube came with the unit. That was after I changed out the stock output tubes for 1952 Sylvania 6SN7GT Badboys.

As rodman99999 replied, the  Philips 5R4GYS is a wonderful sounding tube and I do have a pair that I switch out on occasion[in my pre] with the Brimar military CV717/5R4GY. The Brimars sound more open and organic than the Phillips but not as detailed in the highs, with a huge sound-space and crazy good dynamics. They can be hard to find and a bit pricey... but worth the price in my opinion.

The tube rectifier's job is to convert AC into DC.  If the load is greater than the DC supply, this will cause a voltage sag which results in a compressed sound.  My question is, if the pre or amplifier's rectifier is properly designed to avoid voltage sags, will changing the tube rectifier to a different brand, not type, affect the sound? 

Voltage sag and compression aren’t the only cause of changes in the sound of a component's presentation.  Mainly, that affects it’s dynamics. That’s why I said, "sometimes", that will improve with a rectifier change. The short answer to your question is, "yes". BUT- there’s much more involved than just a, "different brand" involved. Most of us that have enjoyed various aural improvements through rectifier upgrades, have been using higher quality, NOS pieces, manufactured decades ago. Given that relatively few newer components have been designed with valve rectifiers(and/or regulators), there’s not been much demand and little motivation to produce great ones, these past 30 years or so.

Thanks rodman9999.  Yes, very few new tube amplifiers are employing tube rectifiers in their circuit because of voltage demands.  I still see quite a few preamps that use tube rectifiers as the voltage demand is within the tube's capabilities.  I am just having a hard time understanding that if a rectifier is providing more than adequate DC current demand, how can a different brand of tube sound different if the DC electrical parameters are identical?  In any event, I going to try again, some different tube brands in my preamp.