The problem: how to play and stream NES Tetris at the same time? Well, there are a couple of solutions, of which here are presented 3 fairly common and simple ones.

First of all, you have to have a computer, a TV (preferably an old CRT) and, of course, an NES:

A computer, a CRT TV and an NES
A computer, a CRT TV and an NES

So, how to connect those 3? Basically what you need is:

A) a capture device:
Option A1) an RCA-input capture stick, for example a GV-USB2 capture stick (mid-priced, readily available, works with both NTSC and PAL NES’s)
Option A2) an HDMI-input capture device (for example Elgato) with which you need an RCA-to-HDMI converter (or a SCART-to-HDMI, if you’re using such cables/adapters)

B) connection cables:
Option B1) RCA-cable from NES to the capture device and an RF-cable from NES to TV
Option B2) RCA-splitter to split the RCA-signal from NES to both capture device and TV

C) streaming software:
Option C1) OBS Studio is one of the widely used free streaming softwares
Option C2) Streamlabs, another widely used free software
Option C#) there are plenty of different software, just pick one that your friends use so you can ask them for advice 🙂
NOTE: You’ll also need, for example, a Youtube or a Twitch account (all free) to send your gameplay from you streaming software to the internet!

The relevant connectors on an NES:

The power and RF-connector (white) at the back of an NES
The power and RF-connector (white) at the back of an NES
The RCA-connectors on the side of an NES (red for audio, yellow for video)
The RCA-connectors on the side of an NES (red for audio, yellow for video)

Note that even though the connectors are color coded, it doesn’t really matter what color RCA-cables you use!

Examples

A combination of options A1 and B1:

NES is connected to the CRT with and RF-modulator (all brand new NES’s had one in their package), and to the PC with an RCA-cable and a GV-USB2 capture stick.

NES to PC with RCA+capture stick, NES to TV with an RF-modulator
NES to PC with RCA+capture stick, NES to TV with an RF-modulator

Cables and the capture device:
– RF-modulator (the cable with the gray box) –> basically the cable that connects to the TV’s antenna port, and you probably have to make a channel search on the TV to make the image visible. On modern TV’s this might be a bit tricky as it often requires switching the TV to analog mode etc.
– GV-USB2 capture stick
– regular male-to-male RCA-cable (2xMale-to-2xMale) –> these can be any RCA-cables, and the colors of the connectors don’t matter

Capture stick, RF-modulator and an RCA-cable
Capture stick, RF-modulator and an RCA-cable
RCA-cable is connected to the side of NES, RF-cable to the back (next to power cable, not present in picture)
RCA-cable is connected to the side of NES, RF-cable to the back (next to power cable, not present in picture)

A combination of options A1 and B2:

NES is connected to the CRT and PC with RCA-splitters (in this case Male-to-2xFemale), RCA-cables and a GV-USB2 capture stick.

NES connected to CRT and PC with a capture stick and RCA-splitters
NES connected to CRT and PC with a capture stick and RCA-splitters

Cables and the capture device:
– GV-USB2 capture stick
– Two Male-to-2xFemale RCA-splitters (the blue short cables)
– regular male-to-male RCA-cables (one 2xMale-to-2xMale and one 3xMale-to-3xMale) –> these can be any RCA-cables, and the colors of the connectors don’t matter

Capture stick and RCA-cables + RCA-splitters
Capture stick and RCA-cables + RCA-splitters
RCA-splitters connected to the side of NES
RCA-splitters connected to the side of NES

Another combination of options A1 and B2

NES can be connected to the CRT and PC with Female-to-2xMale RCA-splitters (in the previous example it was Male-to-2xFemale splitter), RCA-cables and a GV-USB2 capture stick.

2xFemale-to-Male RCA-splitter
2xFemale-to-Male RCA-splitter

And the connection with two 2xFemale-toMale RCA-splitters (drawing in the picture below) would be something like:

dav

Cables and the capture device:
– GV-USB2 capture stick
– Two Female-to-2xMale RCA-splitters (the drawing in the picture above)
– regular male-to-male RCA-cables (from NES to the RCA-splitter) –> these can be any RCA-cables, and the colors of the connectors don’t matter