Aleph 5 question

In my Aleph 4 rendering I tried 1watt zeners and then replaced them with 1/2watt one (just in the current source for the differential pair) and for what ever reason the sound of the amp improved.
I've also varied the amount of current throught the zeners and each time the change was noticeable. Instead of the original 3.9ma throught the zeners I'm running 5.6ma. Makes a heck of alot more difference then the blue LED in my transport! :bigeyes:
For interests sake I'm using Digi-Key PN# 1N5239BDICT-ND. Perhaps the differences I'm hearing are the sort comings of this specific part?
I wish to thank you guys for your willingness to share your experience and knowledge I've another question about the zener diode, Actually I purchased them 1N4739A X 10 units / BZX85C9V1 X 40 units couple years back for Pass labs A75 DIY project.

Does this make sense? I recently try to match the zener diodes that's probably because nothing to do while waiting for the FETs.

Both zener diodes are 9.1V 1.0 W 5% but the actual measurement that I got is
1N4739A ------9.6xxx Vdc whereas BZX85C9V1------- 8.7xxx Vdc

Now I am unsure of which to go for? should I go for the higher or lower voltages one.

Thanks in advance for answering my silly question?

Best regads
It is still very close to 5%, just the opposite ways. Do you only have to Zeners left? If it's gonna make you feel better, choose two with similar readings, otherwise you shouldn't worry.

The important thing is, you should be getting 4-5V volatage drop on drain resistor (392 ohm) in differencial pair. If it's off that value, then you should be concerned with zeners.;)