ALO Audio CDM Disassembly and Tube Rolling
CAUTION: Before you try to open the CDM, make sure you know what you are doing and make sure your working area is free from static including yourself. For the CDM’s protection it is recommended that you use an anti-static wrist strap.
Opening the ALO Continental Dual Mono is no difficult task. You can easily dismantle it by simply removing four hex screws located at the four corners of the CDM. I’m not sure what number of hex screw, I think it was a number 1, the smallest. After removing all four screws make sure to unscrew the volume knob as well with the same hex screw. Be sure to handle the CDM carefully as the aluminum plates are no longer held together at this point.
First remove the small rear cover, then the center U-shaped piece, flip it over (assuming you are facing the bottom portion) and remove the top cover. The battery is attached to the bottom plate, make sure to disconnect it before doing anything. From there you can now do some tube rolling.
Opening the ALO Continental Dual Mono reveals a C-shaped PCB. On the top portion of the PCB is where the tubes, LEDs, connectors and switches are located.
Flip it over and underneath the PCB is where you will see the chips installed. Most noticeable chips are the Wolfson WM8741 24-bit 192kHz high performance DAC, CM6632A USB 2.0 high-speed audio processor, SST 39LF010 CMOS Multi-Purpose Flash and the Burr-Brown BB INA2134UA SS amplifier.
If you need a step by step guide or video on how to open and dismantle the Continental Dual Mono, here’s ALO Audio’s very own Ken Ball showing us how to do it properly.
Tube Rolling or the ability to replace the tubes inside the ALO Continental Dual Mono is one of its key features. It’s fun, it’s exciting and can be dangerous if you are not careful. There are quite a number of different tubes you can try with the CDM and the company is selling some of the tubes you can use with the CDM. ALO is also selling the PCB module only, in case the tubes you are looking for are no longer available from their store, but is available elsewhere. You will have to solder the tubes on to the PCB if that’s the case.
The stock tubes of the Continental Dual Mono are a pair of 6111, and this unit comes with a stock Philips 6111WA tubes. ALO Audio also sent four additional pair of tubes to play with; two pairs of single triodes namely Sonotone 5719 and Sylvania 5718, and two pairs of dual triodes namely Raytheon 6111 and Motorola 6BF7.
Removing and installing the vacuum tubes are a little bit tricky. Be sure to watch Ken Ball’s guide on how to remove/install the tubes.
In my experience with the different tubes sent, comparing it with the stock ones the difference is not oceans apart. The difference on sound quality is rather subtle, sometimes almost unnoticeable, and it’s also dependent on your headphone or IEM. When I tried headphones like the MH40, I couldn’t tell the difference at all. It was only with the HE-400i planar headphone that I was able to somehow tell a little difference. One tubes may affect the lows, or the mids, or the highs, or even its soundstage. But the general sound signature is still the same with the stock ones. So don’t expect a different sound signature when you install another tube.
With the current set of tubes I have here, I find the Raytheon 6111 and Sonotone 5719 to my liking. I think the more popular choice is the Mullard 6112 based on user feedback. But this was also the first one that got out of stock (really fast). If you don’t want to do some tube rolling, the stock tubes are pretty much enough and all you need. However, if you are adventurous and would like to try out several tubes, the guys over at HeadFonia were able to make a comparison of 10 different pair of tubes, and made a three-page guide here.
Next page, how does the ALO Audio Continental Dual Mono sound?