Rockbox Technical Forums

Support and General Use => Recording => Topic started by: Johannes on March 20, 2017, 01:12:01 PM

Title: Recording line in SANSA CLIP mod.
Post by: Johannes on March 20, 2017, 01:12:01 PM
Hi guys,

I´m a newbe here. So last time I was looking for a cheap way to to make digital stereo recordings.
I had the idea to modify my SANSA CLIP. Microphone was not an option. So I opened my Sansa and find out, that ther is an external radio chip- SI4702 of Silabs.
I read out the pinning from the manual. Pin 13 and 14 are the L/R outputs of the radio chip. So with a little PCB mod, 2 capacitors, 2 resistors and a 2 contact toggle switch, I can use the input of the cpu in radio mode.

2nd idea is to replace the 4702 by the 4735, its a Multibandreceiver (FM/AM/SW/LW with RDS). But this in another Thread... ;)

regards Johannes
Title: Re: Recording line in SANSA CLIP mod.
Post by: asymsucon on March 22, 2017, 01:25:50 AM
This seems like a teriffic idea, but how would you signal the 4702 NOT to turn on and instead free up the 2 Input channels? It might be necessary to desolder the 4702 for that purpose. Also there isn't that much space on the Clip's body for another input jack.
Title: Re: Recording line in SANSA CLIP mod.
Post by: dreamlayers on March 25, 2017, 10:42:43 AM
> but how would you signal the 4702 NOT to turn on and instead free up the 2 Input channels

That seems easy; it can enter into powerdown mode via its configuration registers.
Title: Re: Recording line in SANSA CLIP mod.
Post by: asymsucon on March 26, 2017, 01:58:32 AM
Thanks for the info.
Now only to determine what's the output voltage of that analog out.

Not sure though, wouldn't powering down the 4702 leave the ground floating?