Topping NX1s Portable Headphone Amp Review

[ZolaIII]

Got an NX1a today for a bargaining price of 10€ (11.50$) new. It's a small brother of this one and simple as much as it can be. I couldn't resist it for that price and I need it to amp weak device's (phone, BT reciver & cetera) to RCA input line to amplifier. So far it works good & sounds as it should. Just enough power with low gain at full volume. Tomorrow I will try to get EarStudio ES100 Mk2 for also a bargaining price.

 

[HerbertThePervert]

Is there any problem converting the amp to a non battery driven device? Like 5V supply+3,7V converter?
Is power supply noise an issue in this case?

Seems like a good low budget solution.