Ok, I’m having the same issue except with a Windows 7 PC. Running Audacity 2.1.2. PyleAudio PT659DU using the USB connection. I do not get an option for 2 Channel. Has anyone mentioned whether switching to a RCA to 3.5 mm cable, instead of the USB cable, solve this issue?
Thanks!
Split to a new topic on Windows board. Other users on other other operating systems are not going to help you over a year after the event. 
Not as far as I know, but the PYLE AUDIO PT-659DU USER MANUAL says the play output is stereo. Try it, and let us know. Connect to the blue line-in port of the computer if you have one.
If you only have a mic input, that might be mono too. Keep the input level down, in case it is a mono mic input. Windows Sound will indicate if the mic input is mono or stereo.
Gale
Thanks!
Just ordered a RCA to 3.5 mm cable and will let everyone know.
Weird… I’m going to guess it’s a driver problem. You might try updating the drivers, but it should already be using the regular Microsoft supplied drivers so there shouldn’t be anything tricky about it…
Just ordered a RCA to 3.5 mm cable and will let everyone know.
Does your computer have line-in? If you want the best quality, you can’t use mic-in, even if mic-in is stereo.
Normally, if you don’t have line-in, the solution is a USB audio interface with line-in. …But, you’d probably have the same problem as the Pyle’s USB connection.
I think it’s a limitation in that specific Pyle device, so there is no solution using the USB cable.
It pays to read the customer reviews online before you buy.
Gale
It works! I can now record in stereo using a RCA to 3.5 stereo jack cable into the Line In on my sound card!
Too bad the USB connection didn’t provide for stereo. 