If you haven't yet done so, download the MRS-8 user manual from here https://www.zoom.co.jp/products/product ... ing-studio
or here https://www.zoom-na.com/products/produc ... zoom-mrs-8
The MRS-8 can not supply phantom power so to use a condenser microphone you will need either a condenser microphone that can operate using battery operation or use an external preamp that can provide phantom power. The internal microphone is an electret condenser microphone that has a self contained charge. The internal microphone is more sensitive than I first thought it would be. When the internal microphone is in use, input 1 on the rear is turned off.
has built-in effect chains and does not have a way to use external effects.
Zoom calls each internal effect chain an algorithm. The MRS-8 algorithms are: clean, distortion, acoustic guitar / bass simulation, bass, microphone, line, dual microphones and mastering. Each algorithm has numerous presets that insert multiple effects into the signal chain along with some empty presets where you can bypass all effects or build your own signal chain. The algorithms presets and a short preset description are listed in the reference section starting on page 134 of the manual.
Assuming you wish to record with the internal microphone and an electric guitar you would use the internal microphone on input 1 and olug the guitar into input 2. You will have to press the buttons for input 1 / internal microphone and input 2 until all three button LEDs are lit. I use three fingers to press all three at the same time so one doesn't cancel the other 2 out. Then adjust both rotary trim knobs as needed.
You will want to assign an algorithm to each input. For the vocal you might want to select the MIC algorithm and try preset 5 to simulate a condenser microphone. Be aware that every time you change algorithms, algorithm presets or the settings for a preset you will need to readjust trim again because the input gain changes just like it will when you have an external signal chain.
It will be well worth your time and money to print the manual to have as a reference while you learn the unit.
Also, you will want to verify the MRS-8 is using the latest firmware and download the Zoom MRS-8 file conversion tool. The file conversion tool converts MRS-8 audio files to WAV or AIFF format so the files can be imported into computer DAWs. Conversely you can convert WAV or AIFF files to MRS-8 audio files and import the converted files into a MRS-8 song project.