RC-MJ70 Line In DIN question

Hello,

my unit is a European one and does not have the Cinch Line In connector as the american model but a DIN connector for Line In. This is for a 5 pin DIN plug. I do have adapters with DIN Plug and on other end Cinch (which is 4 Cinch connectors = Left +/- and Right +/- .

The problem is, when I connect it via DIN with an external source like an Ipod etc. and then switch source at RC M70 to Line IN, it does not work. Waht I have to do is set the Tape on Record (with or without PAUSE) and then I get the external signal played via the RC M70.

In other posts I have read that there is no such a problem with American models. But I am not sure if this is a problem generally for models with DIN connector or just a problem of my unit.

Maybe someone can tell me.

Klaus,

Please post pictures showing the line in and all for this version of M70. I don't think many of us are familiar with this version of M70.

I own a M70L
You have to press down record if you want to use the line-in, that's how it was designed to work.

Hi,

Here is a picture of the DIN connector at the unit (called REC..) and also the adaptor for Cinch I use. the white and red Cinch are for playing while Yellow and Black would be used for recording on an external unit (Line Out).

The color change in the picture at the DIN connector of the M-70 looks strange, that is why I did change the picture (brightness of that area) so the 5 connectors of the DIN can be seen better.

So I understand that it is regular that you have to press RECORD at European units in order to hear the Line In Signal. I think an electronic specialist should be able to make that work that setting the Source switch to LIne-In would automatically switch the other contact so pressing REC is not necessary anymore.

The 5 Din inputs I've seen always seem to play a lot quieter than the RCA version. A local member had a euro spec M90 with a 5 din input - it was virtually unusable with an MP3 player as the sound level was so low even with the MP3 players volume set to max.

Hi Jimmy,

that is funny - at my unit it is just the other way. I have to set the volume to almost minimum at eg my phone or Ipod. If I have a normal level there and the volume at the M70 is set to very low, it is already loud as hell (but not nicely loud, very distorted, too much input signal. Maybe it also depends on the adaptoers which are used. ? Basically something is strange with the DIN connection of the M70. I thinkt the signals there are not identic with the ones with the Cinch Line In.

EX_m71_Owner said:

Hi Jimmy,

that is funny - at my unit it is just the other way. I have to set the volume to almost minimum at eg my phone or Ipod. If I have a normal level there and the volume at the M70 is set to very low, it is already loud as hell (but not nicely loud, very distorted, too much input signal. Maybe it also depends on the adaptoers which are used. ? Basically something is strange with the DIN connection of the M70. I thinkt the signals there are not identic with the ones with the Cinch Line In.

Click to expand...

If it is too loud and distorted the signal probably goes through the internal phono pre-amplifier.
see
https://de.wikipedia.org/wiki/DIN-Stecker
Read the german version, only there the differences between phono and line-in are explained.
Gruß
Helmar

Hi Klaus,

Try to get this unit which is another option. I can see a phono RCA plug in your pic.

https://www.youtube.com/watch?v=A4WHcrwK7JU

You could modify the RCA jacks so it behaves like a JW model, wouldn't be impossible.

For phono I believe there is a pre amp circuit and one can bypass and use it as a normal line in right?

Yes, but L models seem to expect a line-in signal with different characteristics. Its schematic shows other differences to the JW model that I could not understand well enough to modify it. There are additional parts, perhaps an LC filter in there, and so on, so I left it alone.

caution said:

Yes, but L models seem to expect a line-in signal with different characteristics. Its schematic shows other differences to the JW model that I could not understand well enough to modify it. There are additional parts, perhaps an LC filter in there, and so on, so I left it alone.

Click to expand...

Caution - I was also thinking of Boomboxlover's proposal. I wanted to show that to a tech/electronical specialist who can read (and understand) the circuit schematic plans - to bypass the phono preamp section and by that turning it into a regular Line In. Your last post alerted me and said loudely "CAUTION" (and I do not mean your name ). What you say is, that the circuits and components of my model are different to the US model. I have the Service manual for the US model and that means that its schematics are actually "wrong" and not showing what is really deployed in my system - so I would maybe get the specialist on a wrong track. Where is your knowledge from of the fact, that the schematics of the JW model are different to the US model? Does it mean there is a different service manual specially for JW models, and if so, do you happen to have that maybe?

Yes, like I already said, the JW and L versions are very different on the front end audio circuits.

Save the following two images and view them in full-screen mode, fit to the screen. Then flip back and forth between them. They are the amplifier schematic pages from the L and JW models. Notice all of the differences. There are just too many to bother with.

Thank you for the information Caution. So there are different service manuals around obviousely. Good to know.

To be honest it would be way easier to use an attenuator. Pretty much any L or LB model will sound much better and smoother with one of these.
I use a couple of these for at least 7 euro spec boxes including an M90 and they work very well.

The same problem is solved with phono / line adapter:
https://boomboxery.com/forum/index.php/topic/6081-m70-line-in-problem/

if you understand a bit of electronics you can make a similar mod:
- install 3.5mm jack near the din jack.
- use this scheme with 10 k ohms resistors to adjust input levels.

HisRudeness:
Thank you . When you speak of an attenuator (I had to check in internet what that is , now I know I guess). It is described as a unit that reduces incoming power so the signal coming to the unit "at the end" is weaker than the original power received by the attenuator. So if you look at Goodman's proposal with the 3.5 jack, that is actually an attenuator, right? So I guess a line IN to Phono adpater is also more or less also an attenuator. ?


Goodman:

Thank you for the schematics with 3.5 Jack. By doing this you would not even need any adapter (Cinch/3.5) resp a Line In to phono changer.
that means (as said above to HisRudeness) that the 3.5 jack solution is actually the same (technically) as the Line In to Phono unit, right, you could say a built in Line In to Phono adaptor.
I am not a specialist but I understand a bit of it to say it in your words. Do you confirm that I can also do my next proposal of which I think that it is actually just the same as your solution, or better a variation of it:
I just take a regular cable with a 3.5 plug (for MP3 unit) on one , and 2 Cinch plugs at the other end. Then I cut the cable and apply the 2 10k Ohm resistors in between. That should be the same as yours with the built in jack, right?
By doing it that way I would not change anything inside the unit and keep it original. That is why I came to this idea.

EX_m71_Owner said:

I am not a specialist but I understand a bit of it to say it in your words. Do you confirm that I can also do my next proposal of which I think that it is actually just the same as your solution, or better a variation of it:
I just take a regular cable with a 3.5 plug (for MP3 unit) on one , and 2 Cinch plugs at the other end. Then I cut the cable and apply the 2 10k Ohm resistors in between. That should be the same as yours with the built in jack, right?

Click to expand...

This is impracticable and I think would not work...
This is an attempt to do attenuator,
but he does not only consist of 2 resistors...
Attenuator is specifically designed scheme.
Therefore, it is placed in such a case.

My Idea is to bypassing the phono amp.
In this case, you must open the radio, drill hole for 3.5mm jack,
find 8 pin connector, with a soldering gun making electrical connections.


If you don't want to open the radio and keep it in its original form,
you must buy attenuator, just like this:

I noticed that the aux input on my C-100F uses the same op amp, but it has a switch that allows you to toggle between line-in and phono on the same RCA jacks.

Instead of just using a 10k in series for line-in, they used a voltage divider setup with a 39K in series with a 6.8K to ground, which is probably a little better. When all positions for switch S102 are toward the op amps, it's in phono mode. When they are positioned away, it connects to the resistor divider networks for line-in mode. The part values are all slightly different but accomplish the same task.

If you don't want to add another jack, you could just convert the phono to be line-in instead Or add a switch and have both