Review: Tube Rolling The ALO CDM

Motorola 6BF7


  • Very comparable to the stock tubes
  • Upper mids and treble are more layered, this is especially noticeable in the voices
  • Slightly more focus on voices and treble as in “they’re more upfront”
  • I couldn’t really notice a difference in the lower mids region. Bass is a tad looser as stock, but with the same punch and depth
  • Fairly fast and tight sounding tube
  • Same sound stage as Sylvania 6111WA
  • Runs at the same temperature as the stock tubes as well: 42°C


Sylvania 5718 (single triode)

Sylvania 5718

  • Slightly thinner sounding than the stock tubes, especially noticeable in the (upper)mids and treble
  • Treble can sometimes sound a tad harsher
  • Bass goes less deep, has less layering and is looser
  • Less spacious sounding, impression of a smaller sound stage
  • What’s missing most in this tube is depth
  • Very basic sound, not as detailed as the other tubes
  • 35°C and the “coldest” tube of the bunch


Raytheon 6111

Raytheon 6111

  • Portrays more depth than the stock tubes
  • Have a softer and smoother timbre, especially vocals and mids
  • Same type of bass with same depth and punch as the stock set
  • No difference in sound stage
  • Slower sounding than the Sylvania 6111WA
  • 40°C


Raytheon 6BF7

Raytheon 6BF7

  • Less timbre and depth as the stock tubes
  • Bass goes less deep and isn’t as layered
  • Stock tube has more detail and is more musical
  • Mids and treble have less detail and aren’t as spacious
  • Dryer presentation
  • Better with fast music than stock tube
  • 42°C


GE 6021


  • Less depth and timbre overall
  • Less detailed, mostly noticeable in the mids section making treble a bit more forward with a dryer presentation
  • Missing the airier presentation most of the other tubes have
  • Not the most extended treble
  • Bass impact is about the same but the stock tubes are more layered
  • Running at the same temperature as the stock tube: 42°C
  • Of all the tubes in my tube collection there isn’t a single GE I like

It continues on Page 3, after the click HERE or below

4.6/5 - (15 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 October 3, 2015


    Wow no comments yet? Well I liked this article – the CDM sounds like a winner of a niche device. I’m curious how it would work with my Ortho-type headphones.

    • Reply October 3, 2015


      Thank you, it took a lot of work. ALO was supposed to link to here from their site but they still haven’t.

      I really enjoy the HE1000 with the CDM, I haven’t really tried my LCD2 and LCDXC with it. And both my EL-8s are boxedup (not that exciting)

      • Reply October 3, 2015


        Have you listed to the MD Alpha Prime at all? – Do you think that would be a good match?

  • Reply October 17, 2015


    How does it pair with with the HD650?

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