Review: ALO Audio CDM – Heartwarming

Depending on the input and output used you can “tune” CDM’s sound from more digital, to analog. From straight up to perfectly balanced. CDM will always have a smooth, detailed and musical character while keeping its clarity at all times. I really like the whole package but to me the CDM’s strongest part is the gorgeous mids section showing lovely detail and layering in a smooth presentation. Bass is right in between too much and not enough for me. That means real bassheads will think it’s lacking and fans of completely neutral will find it too much. Luckily the majority of people prefer something in between. I guarantee you the CDM’s bass is really good. Lots of layering (depending on the tube used), good detail and good body. The choice of tubes also decides on how hard it will hit. Treble, also depending on the tubes used, is good to really good yet always has a smooth edge to it. There only was one tube that gave me the impression of sometimes harsher treble. These are tubes though, and treble will always be more on the soft side.


So many people have been asking me to compare the CDM to the Chord Hugo. A lot of readers see these two devices as contenders. If you look at it from a basic point of view, they both are portable DAC/AMP combos that deliver great sound. So yes, they’re in the same “league”. If you look at it from a different angle though, you could just as easily say they are completely different or at least complimentary. ALO has stated from the beginning they don’t see the CDM as a Hugo competitor, and I do agree. Let’s do a quick comparison:

CDM has (only) one balanced and one Single Ended (SE) output. Hugo has multiple SE outputs, none balanced. Both use colors to show the DAC’s bitrate. One gets hot, one doesn’t. Hugo has a crosstalk feature, CDM doesn’t. CDM’s sound can be changed, Hugo’s can’t. Hugo has an optical and coaxial input, CDM has a balanced input and output. Both aren’t the smallest. Both absolutely rock with a wide range of ear- and headphones and both pack a lot of power. I think that most people will either go for the Hugo or for the CDM but there always are exceptions. I can relate to having both, I clearly prefer some headphones on the Hugo and others on the CDM. So if you have the money and are as addicted as I am, why not go for both. I in example prefer the Beyerdynamic T90 on the Hugo and the Hifiman HE1000 on the CDM. I love my Audeze’s on both. (But the Bakoon HPA-01M still is the unique amp for Audeze Orthodynamics)

When looking at both units as complete “solutions”, the CDM and the Hugo both perform great. If you look at the DAC and AMP separately I do feel there are differences. Personally I feel the DAC of the HUGO (in house developed) is more resolving, more neutral and more detailed. CDM’s DAC -the Wolfson 8741- is great on paper but doesn’t sound as resolving, clear and detailed as Hugo’s. Looking at the amp section my personal preference goes to CDM’s amp, which is smoother and has more character/timbre. The tube flavor really does it for the CDM where Hugo goes for a more musical version of neutral. Again, both units used as a combo are nearly perfect but I have found myself using Hugo’s DAC with the CDM’s amp on several occasions. Overkill? Maybe. Or Chord and ALO could work together on a new “Ultimate” unit 😉

Both units don’t come cheap. CDM costs $1495 or €1495. Hugo is a tad more expensive and is going for €1799 but in USD it is $2495. So it’s actually a smaller difference for us Europeans then it is for US based customers. I have to applaud Chord for that really, there’s no reason EU citizens always have to pay more than US citizens. $1000 does not equal €1000, yet we often have to pay that amount, with taxes and administrative fees on top of that. But I’m getting side tracked.

Tube Rolling Effect

My full sized desktop tube amplifiers are a lot easier to roll tubes in. They also have socket savers and changing tubes doesn’t require 5 minutes. I have no idea how many “rolls” the connector or the PCB inside the CDM can take, I guess only time will tell.

Another thing is that the effect of tube rolling my OTL’s and other tube amps is that their sound changes more than when rolling the hybrid CDM. Sure there’s a difference in sound between all the miniature tubes, but it isn’t as pronounced as with the full sized amps.

The good thing is, tube rolling miniature tubes isn’t too expensive. A lot of these tubes can still be found NOS (New Old Stock) all over the world and prices range from $5 to $15 for a single tube. (You will pay a premium if you don’t know where to look or when you buy them from resellers, but that’s only normal).

Rolling tubes is a lot of fun. Not only do you get to tinker with vintage stuff but you can actually change the way the amplifier sounds to your preference. I love it! More about the CDM tube rolling can be found in the Dedicated Tube Rolling Article here on HFN or in the Head-fi thread.


I haven’t seen or read about anyone that didn’t like the CDM after listening to it. I was hooked the first moment I turned it on, even with the stock tubes installed. Not only does it sound detailed, smooth and musical, it also looks stunning. Desktop quality in a portable package.

I do feel the DAC part could have been even better but it won’t leave you short of anything. The amp part simply is really good. If you haven’t heard the Studio Six before you now have an idea how extremely good ALO’s reference amp sounds. Quality comes at a price but all in all I do feel the ALO CDM is worth its price. Ken, Caleb and Vinnie did one hell of a job. I look forward to the next ALO products.

4.7/5 - (10 votes)

Lieven is living in Europe and he's the leader of the gang. He's running Headfonia as a side project next to his full time day job in Digital Marketing & Consultancy. He's a big fan of tube amps and custom inear monitors and has published hundreds of product reviews over the years.


  • Reply September 10, 2015


    Hi! Good article, thank you. So how does it perform against the older Alo PanAm? 🙂

  • Reply September 11, 2015


    Great stuff! Look forward to the tube rolling article.

    a) i know there are adaptors and stuff, but 2.5mm trrs balanced is still only with iriver A&K right?

    b) Just on the Hugo, the dac and amp output is the same signal. For technical accuracy we are really referring to adding colouration to the Hugo output when using an external amps, which may have pleasing results case-by-case.

    See comments section here:

  • Reply September 13, 2015

    Ted Tillholm

    Hi Liven, welcome back after your big summer.

    I was wondering if you can give a basic comparison between the CDM and HPA-01M?

    I’ve been looking at the Bakoon ever since your review came out, and now this new ALO product looks so good.

    • Reply September 13, 2015


      Hi Ted. Those are completely different units looking at design/technicalities and sound.
      The HPA-01M has the unique Satri current tech and it plays exceptional with Audeze planars. The CDM is a tube DAC/AMP and plays great with a whole lot more headphones.

      It depends on what you need. Do you need a DAC? Do you need it to work with non planars? CDM also is IEM friendly

      • Reply September 14, 2015

        Ted Tillholm

        Liven, I have planars but not Audeze, PM-2/AD. I already have a DAC, Solo-dB. I prefer the sound of my Continental v3 over my Pure II. Any comments on sound differences between the CDM vs. HPA-01M would be great.

        • Reply September 14, 2015


          It’s a tough one. CDM is smoother, wider sound stage and more layering. Bakoon is more power, great bass. the HPA-01M has a really unique sound with the Satri circuit, you really have to hear it for yourself.

          I do think the CDM would be the best one for you, it’s easier to use with other headphones while the Bakoon is really great for Audeze and Hifiman

          • Reply September 15, 2015

            Ted Tillholm

            This decision is not easy, thanks for your help.
            I wonder if Bakoon has a return policy, I really want to hear their amp.

  • Reply October 18, 2015


    Hey, how does the dac section of the CDM compare to the dac section of the theorem 720?

  • Reply January 9, 2017

    Griffin Cui

    This review is not accurate, the stock tubes do not drive CDM near its potential. The DAC of CDM with Mullard tubes almost sound as good as my McIntosh D150. The bass performance out of CDM with SE846 and Messdrop TH-X00 is awesome, anymore bass will give you a headache!

    • Reply January 24, 2017

      Benjamin Fong

      Griffin what Mullard tubes you referring ? I m very new to tube n cdm. Just bought it. Still trying to learn.

  • Reply January 14, 2017

    Benjamin Fong

    Can cdm handle beyerdynaic t1 well ?

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