How to fix my preamp dilemma


My NAD integrated succumbed to old age and I found a Parasound Zamp3/Zpre2 combo on Ebay and pulled the trigger. Even this expenditure was somewhat controversial in my marital landscape, some people just don't understand audio fidelity doesn't grow on trees! For <$400, I couldn't have been happier, everything was great......but 8 months in the preamp started switching between channels and has a loud humming noise that seems like it's coming from the transformer, it powers on but is unresponsive.

From here I could use some advice from the knowledgeable, I'm not sure fixing the Zpre2 is money well spent, my first inclination was to find a used Zpre3, but there aren't any around. What seems more attainable at a reasonable price is a used Schiit Saga+, or an oldler Adcom, is it a bad idea to jump ship to another manufacturer given that the Zamp/Zpre are likely designed to function together?
sturdy
There is a Schiit Audio Modi optical input DAC for sale on Ebay. Current bid is $40 and 10$ shipping. Would make for a true improvement over the TV optical output if that is what it has. 
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@mesch I’m away from home at the moment, but I remember the analog connection from the tv end looking more like a headphone jack than a digital output. Are passive preamps considerably cheaper than active ones? Sounds like possibly I’ve been neglecting my source material by not having it run through a dac
Yes, often the analog output is a 3.5mm headphone output 

you would improve the sonic qualities for both music and video with a outboard DAC. Most DAC outputs would allow for use of a passive preamp. Look up the Schiit Modi DACs. I believe it would be a great place to start. Would serve well with the parasound pre/ amp.

in the interim, a passive pre will work. 
Too bad you dont live in NYC, i have a Adcom GTP-500ii with remote I would sell for under $200 but i hate shipping stuff.