PCL86 driver tube and sound quality in Allnic T1500

Do you like the way your amp sounds now? That's the only thing that matters!

The PCL86 is half a 12AX7 and a 6BQ5/EL84. There are plenty of NOS available on eBay. The vintage Yugoslav EI's are a good value! 

Actually contemplating a purchase , hence the question. In the past I had a Cary 300sei and it used 6sn7 and I could affect the sound by switching them out, as it used 3 and one was for the "preamp" section, I have no experience with the Allnic amps.

You can buy and try PCL86's from different mfgrs. Otherwise you are stuck with them in your amp. You cannot substitute 6SN7's for the PCL86's 

What output tubes in your Allnic amp? 300B's? Then the 6BQ5 half of the PCL86 is the driver - a good choice!

Why obsessively worry? Use and enjoy your Allnic amp. I am sure it sounds excellent!

ECL86 (PCL86 should be the same but with different heater voltage) is a great sounding tube; I have an electrostatic headphone amp that uses a quad. Vintage 12ax7 (half) and vintage EL84 in one envelope. The only downside is it’s harder to track down pairs/quads of the different makes, than with the more commonly used audio tubes (like 6SN7, 12AX7, etc).

They probably switched to 6SN7 and 6SL7 because of supply concerns - those types have modern production. But I would think an EL84 (the one in PCL86) would be a hell of a lot better at driving a 300B? If you can source the tubes you might actually have the better version.