[seedubchris]

It depends on the tube . As the amp is a class A tube based input stage and a solid state class A/B output stage the effects of tube rolling are some what subtle but also audible depending on the tube. To my ears the Mullard makes the cdm's rather high harmonic distortion rate a good thing as it becomes a more euphonic even order sounding distortion which translates in a richness to the music which in turn sounds more listenable, less glassy and hard than solid state amps. Listener fatigue will be a thing of the past and the mids and lows will soar but everything will be a trade off as the highs will suffer a bit as a result. There are only 5 or 6 types of semi available 6112 tubes out there but if one were to look harder I bet there are some ridiculously expensive NOS tubes that would bring the CDM to a new level. They just are not the standard fair and are very hard to find especially with matched triodes.

 

[seedubchris]

Maybe when they have a few hundred hours on them they will wake up a bit. Many users have reported a gain in euphony with the Mullards specifically if not so much the other normal suspects. Given the tubes are only effecting the input stage the effects may be hard to discern which speaks to "Bosk" 's concerns...

 

[kukkurovaca]

I recently picked up a CDM and have been hugely impressed. To my ears the sound is far less fatiguing than my Vorzuge Pure II which is now up for sale.

The only drawbacks I've found other than the heat levels produced is the sound is quite smeared until the tubes have had 5 - 10 minutes to warm up (and seem to require an hour or more to sound their best), and despite the amp resolving as much or more detail than the Pure II the presentation is a touch soft or rounded. However I expect that to change after I start rolling tubes, though the 6111s do seem better than most new production Chinese or Russian tubes that ship with many tube amps which can sound hard and brittle.
The CDM is comparatively large and heavy for a portable amp and ergonomics are not ideal with inputs and outputs at different ends. It is fantastically well built though, and the ergonomic quirks fade from notice when the music starts with the one exception of the volume knob that becomes incredibly hot after the amp has been running for a few hours. I will shop around for a substitute hardwood volume knob which should help.

Thank you ALO audio for rekindling my love of tubes!

Sonotone tubes will significantly reduce the operating temp of the CDM. (Or other single triode options like the Mullards that were suggested, but the Sonotone is in stock at ALO already soldered to the boards, so it's a quick and easy solution.) They sound as good or better than the stock tubes.

Also, if you're currently using the DAC section of the CDM, you can lower the operating temp by not doing that and instead feeding it an analog in. (But the DAC tuning of the CDM is very specific, so if you like that sound, you may be disappointed when going to a separate DAC or DAP)

 

[tracyca]

Out of the tubes I have in my collection the Mullard 6021 tubes are the best sounding to my ears. From top end to the bottom the tube just works magic with the CDM. It took me a year to get the courage to change the tubes. The CDM is great stock, but really does change with the right tube. This is my first run at a tube amp and I am having fun tube rolling. Tubes can get up their in cost but if you look you can find some with a reasonable price tag.

 

[thecrow]

In using the cdm with the pha3 and mix and matching analogue and digital inputs/outputs a while ago i remember coning to the conclusion that a lot of the sound nature of the cdm came from the dac as opposed to the (stock) tubes.

The pha 3 is also a very good dac/amp. Nice broad soundtage, highly detailed, perhaps slightly on the bright side of neutral.

Not sure if others feel the same and perhaps the reason that tube rolling has a leaser impact on sound than expected by some

 

[kukkurovaca]

In using the cdm with the pha3 and mix and matching analogue and digital inputs/outputs a while ago i remember coning to the conclusion that a lot of the sound nature of the cdm came from the dac as opposed to the (stock) tubes.

Yeah, the DAC section is much more colored than the amp section. I like the DAC quite a lot, more so than I was expecting to based on reviews. But it's also nice to be able to plug in a more neutral or detail-oriented source sometimes.

 

[tracyca]

I must being doing too much tube rolling, now the top left screw won't tighten. I hope I don't have to send it to ALO for repair.

 

[tracyca]

WOW, the tube for the CDM that I have not heard anyone talk about is Great! The Sylvania 6112 tubes to me sound better than the Mullard 6021. The pair I have are engineer samples of the sylvania 6112. The highs are crisp and the bass is fast and hard hitting, the midrange is sweet and clear. I am real impressed with this pair. CDM+ ie800s + iPad air2 listing to Mozzy from Sacramento ca. Through spotfly.

 

[tracyca]

 

[tracyca]

My collection is getting bigger by the day.

 

[tracyca]

 

[tracyca]

 

[MarcinGD]

Hi,

I just bought from headfi'er used CDM and want to pair it with Oppo PM-3. Does someone use that kind of set ? I goes for CDM because long time ago I owned Panam with The Gateway. All other devices I owned lately was missing something in music reproduction that I had with Panam.

 

[seedubchris]

Sylvania 6112

How does the signature of the Sylvania 6112 differ from the Mullard? Can you describe what you like more about it? Thanks.

 

[cocolinho]

a question to all CDM users. I don't have the original charger anymore so bought a generic one on Amazon (12v, 2A).
Using the CDM while charging I hear some background noise like hearbeat sound which is even louder on high gain mode. I guess this is abnormal, do you confirm?
And how long it takes to full charge the battery?
I think I'm going to return the charger and buy a new one from Alo directly, the issue is I'm in EU...