Opportunity to Purchase Sony DAS-703-ES DAC

I currently have a respectable analog system.  Primaluna Dialouge amp, VPI Classic Signature Turntable with a fatboy tone arm, Soundsmith Paua MK, cartridge and Focal Aria 396 floor-standing. speakers. I love the enjoyment my analog provides me!

As far as my digital is concerned, it's probably lacking.  I stream HQ Deezer from my phone to a $200 Audioengine bluetooth enabled DAC.  With that said, my current digital system is very low end for it can't hold a candle to my analog system. I'm ok with that for I don't listen to digital all that much, at least for now.

I have the opportunity to purchase a vintage circa 1985 Sony - 703 ES DAC for $175.  Is this much of an upgrade from the DAC I'm currently using.  At $175, the cost is a moot, I just don't want to waste my time if it isn't a substantial upgrade.

Does anyone out there know anything about this Sony DAC.  I've read some reviews of this DAC and it seemed to be a nice piece of equipment back in the day!  Thank you.
If you like vintage equipment it's  probably  a good deal but a $99 Schiit Modi 3 help your streaming sound better. 
Wow talk about an old warhorse! It would be an interesting comparison and may sound better than what you have now. If the money doesn't matter go for it.
I have no interest in vintage equipment, it's just that this fell in my lap an for $175. I have a friend who is a "picker".  He bought a bunch of stuff out of a house that included a Carver Pre-Amp, amp and this DAC.   In circa 1986, the DAC retailed for in and around $1,500.  I don't know anything about DACs, but what I read, Sony went above and beyond building this unit.  Maybe that's what you mean by "warhorse".

I think I'm gonna give it a go and roll the dice on it!  Could be fun!