Picture of Connect an MP3 player to a tape player
How to connect an mp3 player, or other stereo source, to a tape player in order to listen to the music.

Step 1: Materials

For this proyect you will need the following tools:

-A soldering iron
-A multimeter
-Headphones or stereo wires and plugs
-A tape player
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I did the same sort of thing to an old AM/FM/Tape Sony boombox I had, but instead of cutting into the tape head and destroying the tape player, I found  that it had a separate tuner board for the radio.  Looking at the cable connecting it, I found the ground, left, and right channels coming out of the tuner.  I spliced the left and right through a double-pole-double-throw toggle switch and also mounted an AUX input jack next to the headphones jack.  Now I can flip the switch to AUX to listen to mp3 player or computer (I also used it to play Xbox on my old TV) or flip it to Radio to use the radio.  Also, the amplifier for the tuner is designed for line-level whereas the amplifier for the tape is designed for a tape head, connecting to the tape head introduces more distortion whereas the tuner input sounds really clear.
@pfmia: Connecting to a LINE level is the correct way to go... Radio tuner usually has close to line level; on the other side, the magnetic head has a much lower signal level, and it is NOT it´s only disadvantage: Magnetic Heads need a large equalization (like the old magnetic phono cartridges). THAT IS THE REASON connecting to the head will get distorted, badly equalized sound!!!
CalProgrammer1 has it ABSOLUTELY RIGHT!
It is WAY better to find Radio or Line level points in the circuit, in that way distortion is avoided (provided the cell phone or MP3 player volume control is NOT pushed too high), and a PROPER, flat equalization is obtained. Head level is too sensitive and not flat responding. Maybe tapping close to the VOLUME control of the boombox is an easier point to locate, in order to connect the pair of shielded cables to the switch and RCA input jacks (or the smaller 3 conductor 1/8" stereo jack, if you prefer. Best Wishes, Amclaussen.
How do you determine which are the right, left and ground channels if you don't have a schematic?
Ground should be easy, but beyond that you'll have to probe it. You can take a headphone speaker, tie one end to ground, and use the other end to find the audio signal. Once you find both signals, determining left from right should be easy (either play a tape recorded with only one channel or introduce a signal into one of the spliced wires and see what speaker the sound comes out of).
pfmia (author)  CalcProgrammer15 years ago
Yeah is the same thing, you are right about the levels of distortion, but i haven't noticed it by keeping the mp3 at low volume. By the way I haven't destroyed the magntic head, so I can still play tapes.
It is nice to see that an Instructable written 3 years ago is still useful to some people

Wafous5 years ago
 really nice, I may try this one
 i have a timex radio clock and i wanna hook the the cord into the amp not just the stero cus some of my songs arent loud so i wanna be able to turn it up on the ipod and the radio
conty9116 years ago
hi ifound ur article and very interesting indeed, But i have 2 questions 1)when we connect the ipod/music player o/p directly to the head leads isn't it going to produce distortion as the input signal from ipod have considerable power where as magnetic head produces power in terms of uW (or signal voltage level of few millivolts) ,the distortiis casued by shifting of opearating point of PREAMP whic is conected immediately after the head unit. 2)like wise some people said using poteniometer will help reducing input signal ,but ifeel it wont be of much use....as they dont give clear demarcation of power limits. What if we solder the input after the preamplifier stage or at the input pins of Amplifier IC of the cassette player??? having tried the given method at my car stereo it aint did good ,plz let me know if something better comes in anybody's mind.thanks
reko7 years ago
pfmia, thank you very much for the instruction. I followed your guide, and it worked ! but my problem is : distorted sound. 1. if i turn-down at lowest volume on the cell, and turn-up my car stereo volume, i got a very noticable hiss sound noise, and the distorted music still there but reduced. 2. if i put 1/3 volume on my cell, then the hiss reduced, but more music distorted. 3. if i put more than 1/2 volume on my cell, then i got a completely distorted music. 4. if i feed the cassette, but not plug the male cable to my cell, turn-up volume on car stereo and then touch the body cable, i hear "dep" from the speaker. what did i do wrong ? i just wonder, is there anyway i can do to normalize all this hiss and distorted sound ? is putting a stereo potentiometer / resistor on the cable will solve ? but i don't know the suitable size of the resistor. anykind of respond will be greatly appreciated, and i'm sorry for my broken english as i'm from asia country and i'm sorry too if this is not the right place to put my question. anykind of respond will be greatly appreciated, thank you in advanced.
pfmia (author)  reko7 years ago
Thank you for your comment, I will try to help you. It seems that your cell, I think that is your mp3 player, saturates the previous amplifier, so you hear the distorted sound. As Jridley says you should put a resistor or a potentiometer in series with your cell, but I can't tell you about the actual values. I think that the best you can do is to put a potentiometer, the smaller you find, and try to find the suitable position to get the less distorted sound. I recommend you to put your cell at 1/2 volume, then put your car audio were you want and then try to adjust with the potentiometer. About the sound you hear when you touch the wire is normal, if what you have touch is the tip of the jack. If not maybe one of the solder joints is broken and you should check it. Some things you must check to avoid noises is to have good solder joints, shiny and clean, and be sure to connect the shield of the wire to the ground of the tip, and the ground of the music equipment. Also the shortest the wire the less noise you have. Luck and don't worry about the English, is quite good, I'm from Spain and I make mistakes too
Austinisi pfmia7 years ago
You put the potentiometer in series with...the mp3 player and head of the cassette player? if i'm using audio cables (left and right), do i buy two potentiometers?
pfmia (author)  Austinisi7 years ago
Well, the potentiometer has 3 leads. Two of them have a fixed impedance between them and the other one shows a variable impedance. You should connect one of the fixed ones to ground, the other to the mp3 player and the last one to the magnetic head. You should buy two potentiometers, one for each channel. The ground is very important, with a good connection you will have a very clean sound, if not you will have lot of noise
Austinisi pfmia7 years ago
I attached the two potentiometers like you said. When I attached the ground to the potentiometer, a lot of the distortion went away, but the a little static/hum remains. Any other ideas?
pfmia (author)  Austinisi7 years ago
Some hum will be normal. Try to minimize the length of the wires and use shielded wires, connect the shield onf the wire to the ground in both ends of the wire
also, how important is it to used the ground between the mp3 player and the circuit board?
reko pfmia7 years ago
thank you - thank you very much indeed. i'm very happy to receive your reply, and your kind information. i will tell you my result as soon as i have tried your suggestion to put the potentio/resistor into the stereo cable. it's not the tip naked cable that i tap, but the cable body which is coated which make sound. so i will also check the solder joints and the grounding connection. i really appreciate your time to enlighten me. thank you once again !
pfmia (author)  reko7 years ago
Try to chek the solder joints before you put the potentiometer, it seems that you may have some of them broken
reko pfmia7 years ago
hi pfmia, it works - it works ! i follow your instruction : "the smaller K-size potentio you can find" so put a 10K potentio between head-unit to the mp3 player connection, and the result : no hiss - no distorted music ! i'm happy now...:-) thank you very much for your kind reply and your great instruction. regards, reko
reko pfmia7 years ago
ok, i will. but i think it will be still more a few days from now, as my mom use the car quite often recently...:-) thank you.
m-arijn reko7 years ago
If you mean your mobile phone with cell, then the noise comes of the radiation of your mobile phone. When you put it next to an amplifier you will hear the same noise..
jabujavi7 years ago
seeemooos los delinqúentess... los vi ace dos dias en paiporta, valencia... por cierto podrias explicar como conectar el mp3
pfmia (author)  jabujavi7 years ago
no te entiendo puedes concretar mas, y si no te importa usa el ingles, asi todos se pueden enterar de lo que preguntas
You can also simply go spend a dollar on a cassette to 3.5 mm adapter. Saves you much grief and you can now still play tapes... Who the hell still has a tape deck in their car lmao.... I took mine out and put in one of those in dash el cheapo DVD multifunction things. Works great but is a real peace of crap... (it was only $150 and it pumps 50 watts X 4.) The best feature is the USB port that it has, I can now listen to my music through my ipod or whatever..
yeah i run my ipod through a tape adapter to. For all thoughs who want to know how its simple. Buy a 3.5mm adapter as computerwiz_222 said (it should look like a tape casset with a wire running from it with a headphone jack at the end of the wire) then simply put the tape into the tape deck, plug the jack at the end of the wire into your mp3 player where the headphones normaly go and then press play on the tape deck and play on the mp3 player. Simple as that, hope it helped people ! Relentless.
dlfynrdr7 years ago
I'm a bit confused On my head (insert crude joke here) there is also a fourth yellow wire. Where does that go? Can somebody help now that I've turned my radio into a jigsaw puzzle?
tecno geek7 years ago
jridley8 years ago
To do this properly you REALLY should either put a resistor in line with it, or trace the circuit and find the actual line-level spot to tap the circuit board. 'Course, that can be tough to find sometimes. What this is doing is feeding a line level (or higher) input into a preamp. You're risking damage to the preamp.
how can I identify this spot(I have the service manual of the fw330)
You need to poke around after the preamp. Take a look at the schematic of the player; there should be an amplifier of some kind that the tape head leads into, and then a line out of that and into the main amplifier. I haven't looked at any really new players; it's possible that newer players just have one big chip that does everything, and if that's the case, unless there's an unused line in pin on the chip (likely, actually) that you can make live (maybe less likely) then you'll have to use the method outlined here.
The Tape idea didn't work. apperently I had to keep the tape deck connected for it to work. I used the AUX instead.
Well, yeah, if you have an aux input then this whole thing is pointless, just use that. The whole point of this instructables was for people who do NOT have an aux input.
My original plan was to keep the AUX free. That's why I wanted to use it on the tape
spacessj8 years ago
Heh I just hacked a phillips mini hi-fi system(fw330) and tossed away the cd(was broken) and tape players. Thanks to this instructable it's still usefull. Only two problems: A the speakers are from an other system and are 4Ohm versus the 6 Ohm out on the amp and the speakers are only 5W and it's a 15w amp
lol if your in the UK I suggest the tesco headphone to tape adapter I picked mine up for £1 but they're £3 really i just swappied a nearby label cos i only had a quid on me and wanted it for the car ride home but you could try skipping the pre-amp and using the cables for the the amp, rip the lot out of the bulky casing and be creative I stealthed my stereo in a locker from ikea but how about an empty beer crate remember style has it's merits also anything with circuits everywhere has a far lower chance of being stolen like my broken prtable DVD player whic i hacksawed into a tiny CD player
babyboi5128 years ago
for easi use...use a 3.5mm jack to cassete u can get it for 5$
Spartan 1178 years ago
You all do relise that all you have to do is hook it(MP3 player) up to the analog or aux adaptor? ill do an instructable when im bothered, oh and you can also use the analog method as a batery powered amp for a guitar or bass etc.not great but usefull
pfmia (author)  Spartan 1178 years ago
And if it doesn't have an analog or aux adaptor?
most stereos do ive no actually seen one without it before but if it doesnt then open it up and find the amplifieng input and hoof it up that way i suppose
I have 3 boxes and NONE have aux input. It's only been common in the last 3 to 5 years, really.
The older or cheaper boom boxes do not have aux input
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