I have a Focusrite Scarlett Solo and overall it’s a great little USB audio interface. It’s neat, sounds good and works well. Mostly…
After a period of time it started to develop a fault. When listening through the headphone socket on the front of the device, the audio only played through one ear. However, if you pushed on the volume knob, the sound would come back through both channels again.
Looking around online, it appears this is a fairly common issue. Many people report it, with some resorting to stretching an elastic band around the unit to apply constant pressure to the volume knob. I could however not find a definitive answer as to what was the cause. So I decided to break out the screwdriver and soldering iron to take a look.
My instant thought was that it would be a dry or cracked solder joint on the volume pot. Constant use has cracked the joint and pushing on the knob is enough to get the joint to make contact again. Or so I thought. I was however incorrect and the issue is a little different.
Read on to find out what I discovered. If you decide to follow along and take your Scarlett Solo apart, you do so at your own risk.
To get into the Scarlett Solo, you first have to remove the three screws on the back of the unit. These are hex type screws and fairly small. Once the screws have been removed, you should be able to slide the entire board forward out of the metal surround.
Now inside you’ll see a daughter board covering the top that houses the gain pots for the two channels. It’s held on with black cross head screws. This will need to be removed before you can detach the front panel of the Solo as a couple of the screws hold the front plate on. Be careful when unscrewing the daughter board as it is attached to the main board by a couple of fairly stiff ribbon cables. The joints on these cables are susceptible to breaking.
If you haven’t already, pull the knobs off of the volume and gain controls and unscrew the nut that holds the front panel to the volume pot. The nut is recessed fairly deeply within the panel, so you may need some long nose pliers to get to it. Once you have unscrewed the daughter board and removed the nut on the volume control, you should be able to remove the front panel.
Now you should have a clear view of the volume pot. My first instinct was to check the solder joints where the pot is connected to the board, however these all seemed perfectly fine. There was however one fairly obvious issue.
As can be seen in the above photo, the front of the volume pot was bulging. I squeezed the pot back together and used a pair of needle nose pliers to bend the metal hooks at the back of the pot back into place. After this, the pot certainly looked better, so I plugged it in to test. It worked perfectly! Both channels came through fine in my headphones and there was no scratchiness or cutting in and out when I adjusted the volume control.
So, all fixed then!
Not so fast… It may be fixed now, but what’s to stop it from happening again?
Taking a look at the front panel, it appears that when it is in place, there is a small gap between the front of the volume pot and the plastic of the panel. This means that when the nut that holds the volume control is tightened, the pot is pulled towards the plastic panel until it is touching. The pot is attached to the main board very securely, so over time that pressure seems to pull the pot apart.
For a more permanent fix, I needed to fill that gap between the front panel and the front of the volume pot, so reducing the forward pulling force on the volume control.
The easiest solution I could think of was to simply add a couple of washers to the front of the pot. The photo shows three, but that was too thick and I ended up going with two. The picture below shows the front panel after it’s been bolted back on. You can see the washers between the volume pot and the panel.
After screwing everything back together, it works perfectly and almost a year down the line it’s still going strong.