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iPod Boombox DIY Help- Audio problems

 
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chrispknight



Joined: 26 Jul 2005
Posts: 2

PostPosted: Tue Jul 26, 2005 2:13 am    Post subject: iPod Boombox DIY Help- Audio problems Reply with quote

I am just starting to get into audio work, and started by taking apart a standard crummy boombox and trying to input an audio signal from my iPod. I'm trying to prevent having to buy one of those 200 dollar ipod stereos (ripoff). What I did was to take the tape deck out, cut the audio wires from it, and then to splice in a signal from a 1/8th inch stereo jack. Everything went fairly well, and I got it all working, except as soon as I heard the sound coming out, it was terribly distorted, fuzzy, and bad. By turning down the volume on the ipod, it helped slightly but there are still tremendous problems with the sound

1. The highs and middle are soft and small
2. The bass is VERY loud and blown out
3. Overall bad quality sound for a direct in

I was wondering if anyone had any suggestions to make this hack work. I really have very little experience with this kind of work, but I was thinking maybe if I put in a resistor to make the signal less, it would not cut off the highs and lows. I put pictures up so you could understand more of what I was doing. the link is below. Any help would be much appreciated.








more info at www.ghettomod.blogspot.com

Thanks for any help availalbe
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Al_Dodge_Bundy



Joined: 05 Apr 2005
Posts: 93
Location: Netherlands

PostPosted: Tue Jul 26, 2005 4:08 am    Post subject: Reply with quote

Cool That's cool, I did exactly the same when starting with electronics, altough there wasn't an Ipod in those day's Laughing
I wanted to connect an external tapedeck to my crapy portable fm radio!!!


You probably connected the I-Pod to the connector of the tape-drive pickup head!

The signals from these tape-heads, are very low.

The signals coming from the earphone-jack on the I pod is, in contrast to the tape-head, very high!

There are two way's to connect the I pod:

- Lower the signal coming from the Ipod to a level, which is the same as
the tapehead's signal. Try to use a variable resistor (e.g. 0 to 10KOhm)!
(Because the tapehead's signal is very low, it is also very sensitive to noise!!!)

A better way would be:

- Find the pre-amplifier circuit, to which the tape-head's signal is going (just follow the wires/print board).
And connect the Ipod's signal to the output of the pre amplifier.

(Just a tip, before you blow up the output circuit on your Ipod, use an old walkman to first test your cicruit!! It's output is basic the same!!)

Good Luck,

Mark
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absorbentgnome



Joined: 30 May 2005
Posts: 51
Location: Cardiff, UK

PostPosted: Tue Jul 26, 2005 10:24 am    Post subject: Reply with quote

Lol, I remember doing this as well. I'd crank the volume up, lick my finger and touch the pcb around the audio chip to find the channel inputs with 50Hz mains hum! Laughing
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chrispknight



Joined: 26 Jul 2005
Posts: 2

PostPosted: Wed Jul 27, 2005 4:20 am    Post subject: Thanks Reply with quote

Thanks so much for the help. As soon as I get a chance I"m gonna run down to radio shack and pick up the stuff I need. I already have a direct line going into the audio input (the tape deck was cut out), so I think I will follow your advice and put in a resistor. I'll tell you all how it goes after I finish the soldering. Perhaps I will have saved myself from having to spend 200 bucks on a crappy altec lansic ipod thing.
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Al_Dodge_Bundy



Joined: 05 Apr 2005
Posts: 93
Location: Netherlands

PostPosted: Wed Jul 27, 2005 9:32 am    Post subject: Reply with quote

absorbentgnome wrote:
Lol, I remember doing this as well. I'd crank the volume up, lick my finger and touch the pcb around the audio chip to find the channel inputs with 50Hz mains hum! Laughing


How about that!!! I tried the same thing with my portable!! Hahahaha
In those day's I never even heard about any amplifier IC Very Happy
Electronic minds think a like!!!
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absorbentgnome



Joined: 30 May 2005
Posts: 51
Location: Cardiff, UK

PostPosted: Wed Jul 27, 2005 11:57 am    Post subject: Re: Thanks Reply with quote

chrispknight wrote:
Perhaps I will have saved myself from having to spend 200 bucks on a crappy altec lansic ipod thing.


You could grab a small pair of PC speakers (9V input?) and fill one of the cabinets full of rechargeable batteries mounted in a battery holder. You could also put in a resistor to charge the batteries from the PSU and limit the charge current.

Al_Dodge_Bundy wrote:
In those day's I never even heard about any amplifier IC


Hehe I also tried to fix TVs without knowing wtf was going on inside them. If it wasn't poor solder joints or something else simple then it usually got more broken. Or I got an electric shock, learning the hard way. Damn that arcing anode cap! Wink
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Al_Dodge_Bundy



Joined: 05 Apr 2005
Posts: 93
Location: Netherlands

PostPosted: Wed Jul 27, 2005 1:22 pm    Post subject: Re: Thanks Reply with quote

absorbentgnome wrote:
Damn that arcing anode cap! Wink


Been there, touched it!!!!! Hahahaha Laughing
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