To connect your iPhone, iPad or iPod to your home stereo you just need a 3.5mm to RCA cable like this cable above. The RCA cable plugs into the rear of your stereo and the 3.5mm plugs into your iPhone. If you want the best possible audio quality, then an Apple iPod dock will make it sound even better.
Buying a cable
The first thing that you will need is a cable. One end of the cable has a 3.5 mm headphone jack. This looks exactly like the socket on the end of your Apple headphones. The other end of the table has 2 RCA connectors. These will plug straight into your stereo. The cable looks like this:
These cables start as cheaply as 1c (e.g. here) but I’d steer away from one like that which uses cheap cable. Pretty much anyone can tell the difference in the sound on one of these cheap cables even if you don’t know much about music at all. But the difference between a mid-range cable and a high end cable is less noticeable unless you have a good ear and a good stereo. I use one like this which costs about $25, but you can buy one somewhere in the middle range for around $10 like this or this and it should be fine. I find Belkin to be pretty reliable. Steer away from anything on ebay that looks like this:
How to plug the cable in
You can plug the 3.5mm straight into your iPod headphone jack, and the other end will plug into your stereo. This is not the best solution (read on further down in this article) but it works.
For best results set your iPhone volume to about half. If it’s too quiet you may get some noise and hiss. If it’s too loud you may get some distortion.
When plugging into the back of the Stereo Amplifier, the normal input to use would be the AUX-IN, but you can use almost whatever input you want: CD-INPUT, TAPE-IN, TV-IN, DVD-IN or the AUX-IN.
Do not use the PHONO-IN as it is designed specifically for a record player and won’t sound as good.
Buying an iPod Dock
When you plug your iPhone directly into your stereo like this there will be a slight loss of quality. This is because the headphone jack is designed to power headphones, not be plugged into a stereo. (You can read about why here.) For most people this will probably not be noticeable, so unless you have a really good stereo with a nice set of speakers the straight cable will work fine.
If however you are after the best possible audio quality into your stereo, equivalent to or better than a CD player, then can buy a “dock” for your iPhone.
Apple sell iPod and iPhone docks for the new lightning connecto here, but for older iPods that don’t have a lightning connector, Apple don’t sell this product any more. Even their own support article here (dated Feb ’15) now tells you to plug the iPod straight into your home stereo from the headphone jack. (This will work, but it is definitely an inferior sound quality to the dock.)
So, for the best sound quality, you need to track down a 2nd hand iPod or iPhone dock that will suit your iPhone or iPod.
In ebay you will need to search for something like this:
“Apple Universal Dock genuine”
“Apple Dock MA045”
“Apple Dock MC746LL”
“Apple Dock A1371”
Plugging in the iPod dock
This is an Apple iPod dock. It has a ‘line out’ output on the back. (The jack on the left in the above picture). The headphone output on the iPod is not a true ‘line out’, it is a headphone level. This is different. The dock gives you a proper ‘line out’ which will be the exact voltage and impedance to match the ‘line in’ on your stereo. This is important for the best sound quality.
Use exactly the same cable that I talked about above. The headphone jack and plugs into the ‘line out’ from the dock, and the RCA connectors plug into the back of your stereo.
There are several advantages to the dock. The first one is obviously the better audio quality. You can also leave the audio lead and charger cable plugged into the dock permanently, so that whenever your phone or iPod is plugged into the dock it will be charging. The Apple iPod dock also has an infrared receiver on the front which will allow you to control your iPod via any Apple remote control.
Wireless Airplay – no connector!
If you are buying a new stereo, Pioneer and others are now including AIRPLAY into some of their amplifiers. The amplifiers have a Wi-Fi receiver built in which means you can play from your iOS device over your Wi-Fi (Airport) network directly to your Stereo with no loss of quality. You don’t need to connect any cables.