New Kid On The Block FISHER SA-300 WOW

I just got this today.
I put my Threshold S/300 Stasis aside.
This amp has 4 new EL-34 Electro-Harmonix
2 original Fisher 12AU7's I replace with yellow brand Sylvania's
The 12AX7's cant be read and there are 2 GZ34 rectifier tubes one a Philco and the other a Ruby.
I have read Telefunken 12AX7's really make this amp shine.
Anyway,this amp is stock and I dont even have the bias settings yet.Straight up,this 30 wpc toober smoked my Threshold into fine ash.
The Fisher SA-300 sounds very powerful with very clean and smoothe sound that surpasess my Thresholds volume/distortion free headroom.
The imaging is more focused and layered with a deeper and wider soundstage over the Threshold. Im looking for input and where to go from here.DIY mods?
I would suggest you look for early model Tesla ECC803S tubes. They were a copy of the famed Telefunken ECC803S (12ZX7 equivalent). These come in a yellow box. I am not referring to the current JJ production; they are not comparable.

Due to the unit's age you should have the entire amp checked out; if capacitors are original they will almost certainly require replacement. This is a good time to upgrade the coupling capacitors, too.

While it is open you can assess the feasability of installing a detachable AC socket as well as upgrade the RCA inputs/outputs.

Be careful if you open it up; the transformers will hold a charge for quite a bit after you unplug them from the speakers and power the amp down.