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New! Holo Cyan2 Isolation

The combination of DAC•WRAP (for magnetic fields), USB•FILTER & USB•CABLE (for USB signal) and RF•STOP (for AC power) dramatically improves transparency.

Holo Cyan2 Isolation

Latest Blog Posts

PGGB+TS for Analog Tape Recording

Reel-to-reel 1/4" analog tape remains a niche format cherished by nostalgic audiophiles. Although tape machines have largely been out of production...

PGGB•IT! MAX Now Supports Processing on Azure Virtual Machines

For PGGB•IT! power users who remaster the longest tracks to the highest quality, the issue has always been to accommodate the processing within the...

Holo Cyan2 with PGGB @ DSD512₄₈ is Magical

I have been a long time fan of Chord Electronics and the bulk of my orders are to Chord customers. I do provide a range of isolation solutions for ...

USB DAC Isolation (feat. Holo Cyan2!)

There are a growing number of DACs in the marketplace: affordable and competent and mainly Chinese: Topping, S.M.S.L, Gustard, Denafrips, Holo Audi...

The Incredible RF•STOP SE Signal Filter

My product development iteration involves improving my output chain as I reveal more transparency at the DAC and upstream. So when a change is made...

REFERENCE•M2 System - January 2025 Update (Revised)

I have updated my REFERENCE•M2 Systems. I want to emphasize the following updates: USB and DX (DBNC) Version. The DX (DBNC) version is now compleme...
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Dan's Reference System Testimonials

An incredibly high ceiling and sense of space without any noise or hiss. Everything sounds so smooth and supple ...no harshness or fatigue at all.  The individuality and nuances of instruments and vocals are quite identifiable.

Nicki N., Canada. Singer/Songwriter, Sound Engineer

The music sounded as pure as a live studio experience ...truly present and immersive with incredible detail and dynamic range. If sound was water, it soaks you wet.

Steven J., Canada. Music Teacher (Strings, Vocals)

The sense of space created was unique to my recorded listening experience. I could hear exactly what instruments were in what position and with excellent timbre. The impression was of a live performance ...a wall of music would engulf me and I would listen to the little intricacies as I never have before.

Michael K., Canada. Classically Trained Pianist

This is silky smooth conversion with crystal clear transients and spatial cues. Sounds like the bass amp is in the room! I find myself fully enjoying the music while also able to easily discern the mix effects and recording techniques used. Nice shit! This is as good as I have heard.

Mike B., Canada. Sound Engineer, MuchMusic, CityTV (Toronto)

I have finicky ears but when I heard the distinction and texture of voices, instruments and room atmosphere, my first thought was "Wow! This is not digital music, it is too clear and natural to be digital.”

John S., Canada. Musician, Vocalist, Media & Entertainment Professional

The level of detail is quite nice ...I'm hearing things in the track I did not know were there. Vocals have a natural warmth and I can definitely sense the room and the space around the instruments.

John V.S., Canada. Musician, Recording Engineer, Live Audio Technician

What an incredible experience. From Die Fledermaus to Buck Owens, I've never heard such dynamic range. Instruments and vocals just pop out ...violin, piano, xylophone, percussion ...all sound unbelievably real. Jumping Jesus!

Branko P., Canada. Musician, Master Transcriber, Lifelong Music Lover

OPTO•DX Testimonials

All I have to say is "Wow!" OPTO•DX is absolutely amazing. I was skeptical but the way it cleans the sound is incredible. Highs in particular are less splashy. Bass is tighter but hits harder. I can listen at volume without sheen or harshness. Instruments have more impact and separation is surgical. My Susvara headphones are holographic as never before. I'm really so impressed! Blog Post

Paul R., USA

My system sounded great but with a hardness that gave me headaches. I tried ferrites on the BNC cable without much success. I then bought OPTO•DX together with RF•STOP Isolation Box and the hardness is completely gone! Now I have glorious sound and I can listen whole day without any headaches. Indeed this is one of the best purchases I have ever made.

Anthony C., Hong Kong

OPTO•DX, for a modest investment and small footprint, has rewarded me with an emotive aural experience. My Dave goes deeper into the mix to reveal subtle details and timbre—I'm now more intimate with my favourite recordings! Less hi-fi, more flesh, blood and guts!

Bharat P., UK

When it comes to isolating your digital chain from your analog chain, there is nothing better than an optical air gap.

Ray G., USA

Timbre and transients are off the charts. I'm picking up ambience that I never did before. OPTO•DX is un-muffling the f*ck out of the music. It certainly feels endgame.

Michael D., UK

The best way to eliminate the RFI issue completely is with OPTO•DX. It is one of the most significant upgrades that I have ever made to my Hi-Fi system.

Neil V.M., Ireland

...much larger soundstage, better separation, better dynamics, more vivid sound ...it's the best I've heard my system.

Bernard H., Austria

...the reduction in noise is profound. I’ve never heard a background this black. I honestly can’t believe the sound coming from my speakers.

Ken B., USA

I find it's just so easy to listen...lots going on in 3D too...the sound from OPTO•DX is pretty astounding!

Alfie M., Canada

OPTO•DX is a fantastic product...more depth and holographic representation of the music. I have truly never heard such good sound.

Steve A., Australia

OPTO•DX is lifting up my system very nicely. The degree to which I can hear the benefits on instrument resolution is striking.

Cedric W., UK

It was really hard for me to believe that there was still that much more information being blurred by RF noise. The optical isolation of OPTO•DX just takes things to a whole different level.

Todd N., USA

Wow! OPTO•DX is beyond my expectations! I did not know authentic holographic music until now. It's like entering into a whole new level of music listening that I did not know existed. I'm just so happy to have come upon your site and discovered the power of OPTO•DX! Thank you very much Dan!

Dennis W., USA

Having spent multiple tens of thousands on AC power conditioning in the past to what I considered good effect, it’s now abundantly clear that RF contamination is the limiting factor in any system. Your great products combined with battery isolation have produced a music signal that’s cleaner and more pure than I imagined possible.

Evan S., USA

OPTO•DX made a very big difference in my Dave! It was precisely as Audio Bacon described it in his review. I am very satisfied with the purchase and it was an inexpensive upgrade in terms of the improvement in sound quality. Thank you, Dan.

Richard E., Sweden

More Testimonials...

I'm loving Dan's upgrades to my DAVE and Qutest. OPTO•DX, DAC•WRAP, DC•BLOCK and RF•STOP Filters have brought new levels of clarity, soundstage and incredible imaging to my systems. Chord owners need this equipment!

Brandon B., USA

The effect of DC•BLOCK in my Mscaler+DAVE system is quite extraordinary, I'd even call it transformational. Clarity is improved by a massive amount, and transients sound super fast. 'Hard' sounds, such as percussion, distorted guitars etc. now appear almost frighteningly physical, with plenty of 'body' and great dynamics.

Erik M., Germany

The benefit of adding SRC•DX to my Dave was immediately obvious. Transients and leading edges were more incisive with more heft. USB direct sounded soft in comparison. SRC•DX was quieter and I love how it made female vocals more present. Definitely a keeper!

Zaphod B., USA

With DAC•Wrap and vibration treatment on my Dave I have elevated my system to class level detail retrieval combined with incredible smoothness and realism! I obtained far larger depth and a few spooky moments where it felt like someone was actually in the room. I am delighted!

Cedric W., UK

SRC•DX was the missing link I needed. I use an Antipodes server with HQPlayer embedded. I am now able to pass maximum quality to my TT2 in the way Chord intended... Dual BNC. The signal is stable (no dropouts) and the sound has a black background with accurately reclaimed transients. Well done Audiowise!

Laurie H., Canada

OPTO•DX and SRC•DX have made a huge impact. My TT2 system is better by every measure. From low level details, openness, transparency, lack of high frequency harshness, soundstage is spectacular along with being able to delineate each instrument/voice ...just fantastic.

Robert G., USA

SRC•DX out of the box performance is more than anyone would expect. Very well done!

Atilla G., Germany

With my BluMk2 and Dave, OPTO•DX has been a revelation! Hugely transformative!
...Opened up soundstage ... more micro details ...smoother, more liquid and lush. RF•STOP filtered AC power cables replaced my uber pricey power cables throughout my digital chain so now my digital has a bigger soundstage than my vinyl rig. Blog Post

Albert O., USA

Wow, it’s amazing! SRC•DX with HQPlayer is a big step up for my Hugo 2. So analog sounding and so incredibly detailed.

Andrew H., USA

Very much enjoying SRC•DX with my Dave! It's definitely made a very positive difference versus USB - even with my Taiko Extreme. HQPlayer using the Sinc-L filter is a huge upgrade.

Cedric W., UK

OPTO•DX is fantastic. I can just say my hifi did not sound like some real high end until OPTO•DX was incorporated between HMS and Hugo TT2. I really enjoy listening to music now!

Rudolf L., Slovakia

PGGB•IT! is very good. The software is stable and the speed is fast. I am very happy with 768k 32bit WAV files and PGGB sound from my Gustard X26 Pro!

Peter F., China

SRC•DX and DC•BLOCKs installed on my Qutest definitely adds more drama to my music. Latin jazz and high energy acoustic has much improved attack and brass bites like never before. I can pinpoint instruments easier and everything is clearly and discernibly better. Definitely a worthy addition!


Ricardo P., USA

SRC•DX just arrived and I’m listening to PGGB•IT! upsampled WAV files from JRiver to SRC•DX to Qutest to Anni. My initial impressions are 1) astonishment, 2) pleasure, 3) definitely an enormously worthwhile purchase. SRC•DX is, quite literally, enhanced musical delight to my ears. Thank you for everything, Dan—and bravo!

David K., USA

Bravo, Dan - you’ve done it again! Your DC•BLOCKs sound amazing! A really big step up in transparency for my DAVE. I wasn’t expecting this level of clarity; I’m shocked. Thanks!

Evan S., USA

I am using DC•BLOCK and LP•FILTER filters with great results. I am noticing many areas of improvement. To my ears, the most evident is bass texture, particularly with well recorded songs that make use of acoustic bass.

Mauricio, M., USA

My impressions of PGGB 256 are unforced detail and incredible realism. Natural 3D solidity of phrases and elements. Clear discernment of variations in volume and tempo no matter the complexity. Colour me impressed!

Peter E., U.K.

AUDIOBACON Reviews OPTO•DX!

The RF Noise Killer...

 Check out the review here!    

"A much more nuanced, dimensional, and effortless sound ... Perfect resolution and transparency ... Natural soundstage width and depth ... Ambient and atmospheric cues are made more obvious ... Everything sounds consolidated & fully formed ... Neutral Tonal Variations"

Isolate Your DAC

Musical magic (Qualia) happens when your DAC is free from all RFI/EMI on signal (input and output); on power; and radiated through free air. An unfettered analog D/A section and output clock reveals the DACs maximum transparency.

Isolate Cables

Cables tethered to your DAC don't have a 'sound' — they are not tone controls nor a DSP. What they are is conductors and antennae for RFI/EMI. Consider ways to use optical fiber, filtering, shielding and short lengths to limit their impairment.

Isolate & Filter Power

It’s impossible to completely filter RFI/EMI on AC mains. Digital components will inject more of same back into the wall where it will affect your DAC. For best DAC sound, consider batteries with AC/DC inverters or DC power options.

Avoid Crowding

Don’t stack digital components with your DAC; don’t overlay cables and don’t share digital/analog power. Radiated RFI/EMI is insidious …so use distance between components and the space in your listening room to advantage.

Offload Oversampling

Content at maximum input sample rate will reduce a DACs workload for better sound with less internal RFI/EMI. Consider pre-processing with PGGB or HQPlayer for higher quality reconstruction

Pursue Net Zero

Interference from multiple RFI/EMI sources means that a single change to your system may only shift the frequency of emitted energy impacting your DAC. Be pragmatic and diligent — continue making changes that lower RF noise: Zero is your goal and you will be rewarded.
OPTO•USB Optical Isolation

OPTO•USB Optical Isolation

$530.00 $477.00 Sale

OPTO•USB is a USB optical isolator that provides RF isolated transmission of high-resolution digital audio from a USB source to DAC. OPTO•USB uses all-dielectric multi-mode optical fiber for total galvanic isolation*. An integrated 30 meter optical cable length allows convenient distancing of digital source & networking components away from sensitive DAC and analog amplification.

Operation with Windows, macOS or Linux is plug-and-play. Supports USB 3.2, USB 3.1 Gen 1, USB 3.0 and is backward compatible with USB 2.0. Transmitter connector is USB 'A' male with 5V power directly from source USB port. Receiver connector is USB 'A' female with an associated USB 'A' male 5V power connector on a 75cm lead (supplemental power is required for optical demodulation).

Use short USB cables or adapters for connection from OPTO•USB receiver USB 'A' female to DAC USB input (USB ‘B’, USB ‘micro B’ or USB-C). Be aware that some 3rd party USB-C/A adapters may introduce RF noise from logic circuits and switch mode DC/DC power conversion for USB-C Power Delivery. Dan recommends the optional USB•FILTER + USB-A Adapters to greatly reduce source RF noise injection.

Dan recommends using PURE•DC @ 5V for ultra-low noise and ultra-low ESR (Equivalent Series Resistance) power for OPTO•USB receiver and DAC. Integrate OPTO•USB with SRC•DX for the ultimate transparency of DBNC input to Chord Electronics DX DACs.

OPTO•USB is a core part of Dan's REFERENCE•M2 system**.

*Avoid USB-over-optical solutions that embed a copper wire in the cable. This will conduct RF and act as an antenna for radiated RF noise.

**OPTO•USB includes user applied heat sinks as the units may get warm after long periods of high resolution audio transmission. 

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