mod to be able to record digitally with the internal microphones of a boombox

H

hansgauffin

New member
Hi I´ve got a boombox with two internal stereo-microphones. These are condenser-type of microphones and I really dig the sound I get from them.
I have been thinking about the possibilities to do some mod´s that will let me use the mics but without recording it to tape, but instead send the signal from the microphones to digital equipment of choise??

I got the block diagram for the specific boombox if somenone could tell by that.
Thanks for any answer.
 
:D


Whatever recorded sound it is that you say you really dig, is most likely the combination of the mics, their internal pres, the tape, and the playback....of the boom-box.
To cut all that of the equation and just go mics ---> some digital interface....may not give you the same results.

If anything...I would use the boom-box as a whole, that way it is now...and just take the output of the boom-box playback and feed that into your digital equipment of choice.
 
Thanks Miroslav for your reply!
Well,, the tape playback isnt working anymore,, so the option that you suggested isnt gonna work..

what I want to do is to just use the whole boom-box as a unique kind of stereo condensator microphone. Do you know of any tech support forum where there are people who might be able to answer this question? or ist this the right place to be?? thanks in advance.
 
We'd need a real schematic to figure out how to hack the thing. Well focused, hi rez photos of both sides of the PCB might help, but probably more work than it's worth.

Here's something I've never tried! Get one of those headphone-to-cassette adapters for $3 and a female 1/8" stereo-to-whatever you need to connect to whatever your connecting to adapter. Jam the cassette thing in the boombox and hit record on both devices. Most likely you'll find that the head on the adapter thingy doesn't line up with the record head on the tape deck. So bust the adapter open, rip out its head, and duct tape it somewhere very close to (but preferably not touching) the record head. Then you'll have to find the little thing that "feels for" the overwrite protection tab and duct tape that thing in so that it will stop trying to save you from recording over your prized Skid Row cassette.

Boom! You're rocking!
 
that´s something I´ve would never thought of, and if it would work, it could be some kind of genious idea.
I don´t know much about these adapters but I found some information on Wikipedia, and this line made me think,,,Because most cassette adapters use a single-sided head, they only work in one direction. There are, however, some cassette adapters that have double-sided heads that work in either direction.

I pressume that a double sided adapter would be needed for this trick, so it sends the audio.
Would this adapter "color" the sound? Is the final result depening on the quality of the tape players recrod head in the boom-box?
 
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Is there a headphone output? Could use that.

Or maybe tap the speakers (would need a pad of some sort to attenuate the ouput).

How about posting clear front and back photos of the boom box to see what, if any, connection points might be available?

And a block diagram was mentioned???
 
PRHunt said:
Is there a headphone output? Could use that.

Or maybe tap the speakers (would need a pad of some sort to attenuate the ouput).

How about posting clear front and back photos of the boom box to see what, if any, connection points might be available?

And a block diagram was mentioned???
Click to expand...

Hi and thanks for the reply. Actually the boombox hasn´t arrived yet (bought it on ebay) but I have experience with the specific model.

It has headphone output, but I guess they don´t send the audio that´s picked up by the internal mic not sure though, if that´s the case the problem is solved.

Yeah, I´´ll post the block diagram
 
PRHunt said:
Is there a headphone output? Could use that.

Or maybe tap the speakers (would need a pad of some sort to attenuate the ouput).

How about posting clear front and back photos of the boom box to see what, if any, connection points might be available?

And a block diagram was mentioned???
Click to expand...

Aw man, I'm going signature crazy these days!

I was pretty much gona say what PR said.
What model is this thing? perhaps there's a simple headphone amp in there an a point where you could tap line level?
It's not likely to be balanced though.
 
I´m sorry, I´ve read the manual with block diagram online, but now I can´t seem to find it! But here is two pictures of the model from the auction. they´re not the best,luma.jpgluma2.jpg
 
Gonna venture guess here, but...

Looks like maybe (2) ext. mic inputs on 1/8" and ext. speaker outs on DIN connector.
:spank::eek:;)
 
The playback not working could be a just a slipping or broken drive belt. If the motor runs but the tape doesn't run, then this could be the problem.
 
PRHunt said:
The playback not working could be a just a slipping or broken drive belt. If the motor runs but the tape doesn't run, then this could be the problem.
Click to expand...

Yeah, that could probably be fixed,, but I´m still interested in trying to make use of the internal mics without the use of tape, it´s a little project. As soon as I get the unit, I will try the ways discussed here, outputs and headphone jack, if it doesnt work I´ll return.thanks
 
Just a suggestion, but you may get better sound out of it if you use batteries instead of the power cable.

-MD
 
hansgauffin said:
Strangest thing I´ve heard!,But interesting,,, In what way could the power supply affect the sound? :eek:
Click to expand...

AC mains power may introduce hum or ripple into the system which would not be present running from batteries.

On some of these machines, just hitting record + play would echo the input sound out of the headphone socket. There used to be a trick where you could poke the cassette-present sensor in so that you could force it into record mode without the cassette present.
This was occasionally popular in the 1980s where computers used cassettes to store data, and often had crappy internal speakers. You could use this trick to output the computer's sound through the cassette deck's speaker, which was usually better.
 
Thanks for useful info on the battery vs AC power topic.

Would there be any benefit from the sensor trick you mentioned vs just keeping the cassette in record/pause mode? Which would also let the microphone pick up sound without having the tape rolling
 
hansgauffin said:
Thanks for useful info on the battery vs AC power topic.

Would there be any benefit from the sensor trick you mentioned vs just keeping the cassette in record/pause mode? Which would also let the microphone pick up sound without having the tape rolling
Click to expand...
You could do that too, yes.
 
I just did a test with my boombox and it turned out that it DOES monitor the internal mics thru the headphone amp. :listeningmusic:
The only problem now is that there is some hum. It could be from the motor, they make some noise even if the tape is´nt running but in pause mode, it could also be from the AC power. I´ll go and buy batteries tomorrow and monitor the sound while running on them instead.

I believe there is some kind of motors that is switched on whenever the rec button is pressed. Does anyone know if it´s possible to monitor the internal mics without having to push the recorder in REC mode?
Thanks for any answer!
 
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