My OPTO•DX customers will often ask for a power-supply recommendation. OPTO•DX requires nominal DC 12V (11V - 15V acceptable) at ~ 200mA so most audiophiles already have a compatible linear supply they can use. For customers who wish to purchase new, they usually ask my opinion of iFi Power ...and these work but, beware, they use switching technology. In general I say use well conditioned AC mains and a separate supply for TX and RX.
When a customer, like David in this post, wants the absolute best sound from OPTO•DX, my ultimate recommendation is to use a battery. Reasons? 1) a battery maintains the galvanic isolation between DAC and upstream, 2) a simple battery (without features like voltage conversion, USB-C PD power delivery or WIFI) offers the lowest RF noise, 3) a battery is inexpensive and OPTO•DX low current draw means many hours of battery time.
David has a Torus RM 15 Isolation Power Conditioner, Teddy Pardo supplies and Moon Audio Bronze Dragon cables so he had to suspend his disbelief and trust my suggestion to purchase this battery from Amazon.
Thanks to David K, New Jersey, USA for this testimonial.
Last Wednesday I received the OPTO-DX and—although I was really tempted to jump out of my chair and compose an email to you as soon as I had heard the first few notes—I resisted my initial impulse in order to live with the OPTO for a few days until I could attempt to write my response to what I was hearing in a comprehensible way. "Mother of God and all the angels" sums up my response! I now know what lies beyond silence—perfection.
I had hoped for an improvement to the sound of my chain: USB into SRC-DX, DBNC into M-Scaler, DBNC into DAVE, XLR into Chord Alto. I anticipated at best a slight-to-moderate improvement in noise reduction, clarity, and precision. I had not, however, anticipated a revelation. The OPTO-DX (TX and RX each powered by the Amazon batteries you recommended) immediately made its full robust presence felt—and heard. I had never realized that despite my Torus power isolation transformer and the insulated power cables connecting all of my components that I was still hearing extraneous noise. With OPTO-DX on batteries, not a buzz, not a hum, not even something of which I was consciously aware. I didn't know this noise existed until it made its presence known only by its absence.
With the OPTO-DX what I hear now through my headphones is nothing but the music—the entire volume of the listening space is filled with the music and nothing else. The extraneous that existed on the fringes of the music was gone, replaced with a greater, fuller expanse of the music itself. Listening to music now provides a remarkable sensation that I had never before experienced. The OPTO-DX turns music into magic. Thank you for this wonderful component and all your help. I was thrilled when I purchased SRC-DX years ago, but not even that device had prepared me for what was still possible. Thanks for inventing the OPTO-DX. I am—and will remain—grateful.
-- David