Creating an Aux Input in a Car Radio without Built-in Option: CD Player Connection

I have a problem, I have a car radio that does not have an aux input and it is impossible to connect to it, for example, a CD player !! Someone knows how you can make an auxiliary input for this radio, the radio is not original or some kind of company! I know that you can buy a cassette adapter but it is out!

Many thanks !!
Regards
OGI !!

Withe!
If it's a player with a volume control on a potentiometer, that's fine
simpler than giving the signal directly to it.
You should only add a switch that would disconnect the audio signal when you want to listen to the CD.
The correct pin to which you should connect is easy to recognize by a simple "brum" test by touching the potentiometer tips
e.g. with a screwdriver, which will make you hear a hum in the speakers and you can
regulate its gain.
This should be done on two channels.
These terminals should be desoldered from the receiver's tracks and here the signals should be given after the switch contacts:
L and P CD and the mass of the receiver in one position of the switch
In the second switch position, connect the state to before the change
Hi.

I do not quite agree.
This way you will lose the "bandwidth" of playback, quality and dynamics. It will be narrowed down due to the resistive mismatch and the difference in signal levels. You have to compare these two devices with each other, maybe you will need an "emitter follower" circuit, it is difficult for me to say without knowing the type of radio.

GREETINGS

I agree with the resistor that you need to carefully analyze the circuit. You provide too little data to give a precise answer. I can only say that I sometimes use simple diode circuits (sometimes found in original versions as well). Two diodes, e.g. 1N4148 type, connect together with cathodes, which are connected to ground by a resistor. From the connected cathodes you feed the signal to the amplifier circuits (before the adjustments). You feed the anodes with signals through capacitors from two different sources. The source of the signal is determined by the voltage applied to the anode, set at certain levels by dividers.

As for the radio, it is a pioneer fake, of course, but it doesn't say anything like this version or anything like that !! The volume control is not done with the potentiometer but it is electronic, i.e. with the buttons !! I tried to disconnect it with the cable with the end of the minijack connected to the head of the tape recorder and I made a tape without a tape which, if I put it in, it would turn into a tape recorder !! it sounded like it was meant to be played !!
Regards'

OGI

My opinion is this. To let go of such fun, it's a waste of time. But if you insist, a simple solution is a ready-made dummy cassette for this purpose, to be bought on Allegro for not so much money.
And when it comes to connecting to the tape recorder head, you would have to build a signal splitter. On the head you have a signal of about 1mV and let's assume about 1V from the CD output. The difference is considerable, not to mention the correction of the characteristics. It can't play well.
Maybe it would be easier to suggest something if you described the integrated circuits used in this radio dummy.
And the best advice would be to look for an original player for your car on the exchanges, in the advertisements, which has such an entrance.
Write what car you have, maybe I can advise you on an inexpensive and good model that is worth looking for. May it not be just a toddler, because there were no factory players except Safari2 and Tramp.
Many Blaupunkts had such an input at the rear, and for example the Renault version called G4 had a Jack socket on the front panel.


SławeK

It is true that it is a pity to invest in such radios, but I sometimes interrupted the signal from the radio head with a 2-track relay, which switched the radio-CD. Outside, I led a miniature switch. Relay and circuit breaker with recovery, so cheap solution.

An RF signal usually comes out of the VHF head. 10.7MHz I wonder how you connected there with the CD signal, without looking at the difference in signal levels, you still have a not such bandwidth.
If you write like that, so as not to confuse the inexperienced ones, write that you plugged into the stereo decoder output behind the MPX filters.

Of course, you can switch such a signal even with an energy plane, but does such a solution make sense and is it elegant?
For signal switching, it is best to use a simple and cheap CD40xx series dice, e.g. CD4066 or CD4053, they are cheap (about PLN 2) and easy to use, as well as very functional with a very large bandwidth.


SławeK

Or maybe to do as in Lubeck CC20 switching radio / cassette? The signal from the tuner is blocked by a constant component through diodes. I used to wonder how it works and it turned out to be a very simple and effective solution. It is true that the CD4066 relay is better, but in the tompsonic the quality is still not high. Oh, I put the adapter cassette on the Audio because someone was looking for it again.

I was talking about the tape head, not the ukf !! But the rest of the jush is a thing of the past because I coped with this problem and I did !!
Works ok !!

GREETINGS!!

OGI