Sano Ultrasonic High Fidelity Amplifier 1950's - 1960's - Black

Sano Ultrasonic High Fidelity Amplifier from the mid/late 50's to early/mid 60's from the original location (the rear of Major Music) on Springfield Ave. in Irvington, NJ. I purchased this from a major national music retail chain a couple of years ago. They didn't know much about it, but I don't think it's the original 12" speaker because of the speaker wire splices. It's an Alnico speaker and sounds great in this amp. A previous owner installed a black plywood bottom with rubber feet , I assume for protection and strength, also to prevent sliding. Very cool art deco chrome handle and chrome front "Sano" and "Hi-Fi" logos. Sounds really good, but does have a slight residual hum that I didn't notice when I purchased it years ago, so I think it's recent. I'm going swap out the two 12AX7's one at a time to see if that solves it. If not, swap the 12AT7, see what happens. And if not, I'll swap the two EL-84's both at the same time to see if that does it. I'll eventually have time to get to it. LOL.. Appears to be point to point wiring and definitely handmade. I adore all Sano amps and have owned a few over the years. Even the solid state ones are cool. Local pickup in Union County, NJ. Any questions or additional pics, just let me know. Thanks for looking!