Great and Competitive Pricing

J. · December 4, 2025

I’ve been using with my desktop for over a month now. The amount of power it outputs, especially through the 4.4 mm connection, is awesome. I used to have my Sennheiser HD 650 at little over 50% volume and now with this dac it gets pretty loud at around 25%.It’s easy to use, essentially universal with most computing devices that have USB C connection, and great for the price and with the added bonus of volume controls. Most dacs you see don’t have them included!

Best portable wired dac and amp

C.C. · January 25, 2026

This is something special. I am not an audiophile but thanks to Crin I'm starting to believe. This is a very nice amp and dac (digital to analog converter) i believe that it can power headphones like the sennheiser HD 600. But also you can put on a custom eq it does take a bit of learning and playing with it to get it right. But for someone who sometimes needs to eq headphones to want to use them or to make it better. Throw on an eq on the protocol max and take those headphones with you. It does have an eco mode and boost. And play/pause along with volume controls. (Please note that the volume controls do not control the devices volume. But the volume on the protocol max.) There is a usb c input and a 3.5 mm and 4.4 mm balanced headphone jack outputs i haven't tested if you can play our of both Jack's at the same time. There is no battery so expect if you have it on boost your battery will drain faster.

Awesome upgrade for iOS/Qobuz users

A. · October 31, 2025

UPDATE2: After getting a new unit and using it regularly for about 3 weeks, so far so good. The device is functioning perfectly. Interestingly I think that this unit does not get as warm as the previous one. I can't compare them side by side but it does make me wonder if the previous unit was defective. Updating my rating back to 4 stars.UPDATE: After less than 3 weeks of occasional use the Protocol Max developed a harsh buzzing/static in the right channel. Tried different sources, IEMS, usb cables, and both the 3.5mm and 4.4mm outputs, on both eco and boost modes, and the distortion persisted, making the Protocol Max essentially unusable. Returned. I'm ordering a second unit in the hopes that I just got a bad one but I'm changing this review to one star until I can confirm that this is not a systematic design flaw. Will update with my experiences with the second unit.PREVIOUS REVIEW:Absolutely loving this new DAC, and it's finally allowed me to complete my "travel hi-fi" kit.I use this DAC primarily when traveling, with IEMs (currently Hisenior Mega5-EST), and my source is mostly downloaded Qobuz tracks being played through the Qobuz app on my iPhone. I love Qobuz, but one of the downsides is that the official app doesn't have EQ built in. I have a few pairs of IEMs and while they are all generally good, in every case, the tuning leaves something to be desired without EQ. At my desktop setup I can EQ them to get great results but on the go that (previously) wasn't possible b/c I was just using the Apple DAC dongle.But now, not only am I getting a (noticeable but relatively minor compared to the Apple dongle, for the record) overall sound quality upgrade, I can now set a custom EQ profile on the Protocol Max (just 1 sadly) and *finally* I can now have a hi-fi listening experience on the go that approaches the experience I enjoy so much at home.As thrilled as I am with the listening experience that the Protocol Max has enabled, there is still room for improvement, and some things everyone should know before buying.First, like other USB-powered DACs this is powered by your phone's battery and the battery drain is significant. If you struggle with battery life on your phone lasting through the day this will make that problem worse, and you may be better off with a battery-powered DAC.The DAC also gets pretty warm when it's running. Not dangerously so, but enough that I probably wouldn't run it while it's in an enclosed space like a pocket.The EQ capability is pretty great, and a powerful tool especially given all of the capability that's built into the graph.hangout.audio website (like being able to auto-eq to a particular preference target, and getting to preview an estimate of what your eq changes will do to the eq profile. So power users will be very happy, even if the process of using the website is a bit clunky (see screenshot). Users that are looking for just a simple way to adjust EQ will likely find the website's vast array of capabilities overwhelming. A simplified view/tool would probably be a welcome addition.Lastly, the website (and specifically the desktop version of the website) is the only way to change EQ. So once I set it via my desktop computer, I'm stuck with that profile until I can get back to my PC. No app or other way to adjust the EQ on the go. That's probably the biggest miss of the whole system and the biggest ask I would have of CrinEar - a simple iOS app for setting the EQ would be a godsend.Last point is that the documentation is very minimal. Could be more detailed. What is the difference between ECO and BOOST modes? What do the different colors of the LED mean? A lot of these types of questions you are left to figure out on your own.

Great product price point is a bit steep but works great!

C. · February 2, 2026

So when I first bought this I thought it was trash and the reason why is the volume was so low. Now that I did some research this thing bumps! Goes extremely loud has great audio quality and looks pretty cool. The size is about a flash drive so can be easy to lose but I just use mine for my computer sense I have low impedance iems I will say the $80 price point is a bit steep I think there’s definitely better budget friendly options but if you don’t really care about the money this guy is great!

Great power and sound- Fiddly EQ

C. · March 13, 2026

This is a very powerful and very good DAC, but I find the web software to be a little too fiddly for my tastes. For example, when you want to clear out your PEQ, you have to go through and reset everything to zero and then apply that. I feel like a revision of this down the line is probably going to be the sweet spot for me.​It feels like a bit of a missed opportunity not to have a button that would just do that for me. That being said, it has massive power; so if you're looking to power headphones that require a lot of gain, this thing will do the job.​Like many of the dongle DACs of this style, you also have to deal with the fact that it's going to kind of hang off your phone in an awkward way, but it's not really the end of the world in my experience.For most folks, I think you'd just be powering iems which don't require a lot of gain so this is probably overkill. There might be something a little cheaper that would speak to most users.But then again, this feels like a product aimed toward power users and as such I am perhaps not the target market.

So clean, powerful and accurate for such a reasonable price!

M. · December 27, 2025

Rich and accurate sound. Powerful enough to drive Sundaras with balanced cables. Makes for a high end headphone/IEM experience while on the road or at your desk. I love it. Replaced my THX Onyx which was my previous benchmark.

Excelente producto

R.P. · March 15, 2026

Muy buen producto. Es más complicado de usar ya que al usarlo saliendo de la caja, el sonido es pésimo. Pero al ecualizarlo, brilla ya que se balancea de forma automática y puedes comenzar a modificarlo con presets o de forma manual

YMMV

S. · February 26, 2026

I’m used to the punch or a Dragonfly Red. Although this is nicely built, I found the sound to be not lively enough, and I had to have my phone volume really loud to get to a decent enough level to expose the detail I like to hear - the volume curve is strange for me. The web interface for PEQ is also not great. FWIW, I was running this through the DF Red to Crinear Daybreak IEMs, and I find the Daybreaks to be amazing.

Not good

P.J.M. · March 20, 2026

Not as powerful as described, EQ sucks