Shown above is our Raspberry Pi3B with the plastic case cover removed. Note the heat sink on the top of the Broadcom Processor. That is not enough as extended operation in a hot garage (my shack) will make a Red Thermometer appear on your screen. You can find these small 12 VDC fans at many suppliers. The RPi's don't need a lot of CFM but what you do need to do is remove the heat from the case. My install is to find a circular template about the size of the fan circular shroud and draw that area on the case top. Using an exacto knife I cut out the circular area. Keep the size tight as you want to have enough case top remain to drill the 4 mounting holes. With care you can have a professional looking job and not something done by a shoemaker. [That is an inside Italian joke -- Who gave you that haircut? It looks like it was done by a shoemaker!] Very Important -- use a 5VDC 3 amp supply. One of the problems that plague a RPi3 is that if the supply is undrerated like 1.5 or 2 amps --the voltage sags and you get erratic operation.

In the photo above we have two sound cards. The StarTech 7.1 has three connections. One (not shown) is the USB connection to the Raspberry Pi3B and that is on the back side opposite the two cables that are on the front side. You will need two 1 foot long cables with a 3.5MM stereo plugs at each end. I labled one cable Line Input. That cable plugs into the 2nd jack on the front panel labeled LINE IN. The second cable plugs into the jack labeled SPEAKER (this is Line Out) right next to the LINE IN. The other ends of these two cables connect to two 3.5 MM panel jacks mounted on Ensemble Circuit Board. IMPORTANT: Connect the Line In on the USB to the Line In on the Ensemble. That also applies to Line Out (speaker on the StarTech) to Line Out on the Ensemble. Several years ago I loaned one of my SDR Rigs to a ham -- got the usual phone call --your rig doesn't work. He thought that Line In had to connect to Line Out. In's with the In's and Out's with the Out's.

The smaller device is also a sound card made by Sabrent and is used exclusively for the Headphone (or powered speaker) and the Microphone. Because the 4 USB ports on the RPi3B are close spaced -- this device didn't fit well with the other USB plugs. Simple solution: I have a 2 foot long USB-A to USB-B extension cord and I simply plug in the cable and then plug the Sabrent into the cable. I also have a Logitech Headphone/Mic headset and built into the USB plug end is a similar sound card. BUT if you want to connect your setup to a set of powered speakers then the Sabrent gives you that flexibility.