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SanDisk Guru
Posts: 1,235
Registered: ‎10-24-2007

Re: DIY Line Out Cable - Works!

Fixed line out will apply to all Docks, including the Griffin.

 

As for the Cable,  you'll have to make you own.

SanDisk Fanatic
Posts: 363
Registered: ‎08-02-2008

Re: DIY Line Out Cable - Works!

sansafix, Thank you very much for the info!

skinjob, The voltage applied to pin7 is DC. It is an enabling input which seems to very the audio output based on it's level. The lineout level is analog AC, so the voltages are not comparable. The Sansa Dock remote probably varies the DC level on pin7 to control output level. The Griffin Dock applies a fixed DC voltage of approx. 1volt to pin7. My original cable jump puts approx. 3volt DC on pin7. It is clear to me now that it is too much and driving the output too hard. The output is louder, but is most likely distorting or clipping. The ideal signal will be with 1volt DC on pin7. I will determine what resistor value to use as a jumper to get the DC voltage down to 1volt from 3volts. This should produce the same level as the Griffin Dock which should be a true 1v p-p AC (.7v p-p rms AC) on the lineout. Sansafix has said that the firmware will set the lineout level as fixed. This is how most lineout devices apply it. If you need a varied output, the headphone out can be used as it is a very clean signal as is even at 100% volume.

8GB Blue FUZE w/The Original DIY Lineout Cable and AT Button H-Phones Fitted To AT WM5 Headband:All Custom Built
SanDisk Guru
Posts: 1,235
Registered: ‎10-24-2007

Re: DIY Line Out Cable - Works!

[ Edited ]

The output signal has nothing to do with the voltage on Pin 7.  That just enables the line out.

 

 

 

Message Edited by sansafix on 12-09-2008 10:44 AM
SanDisk Fanatic
Posts: 363
Registered: ‎08-02-2008

Re: DIY Line Out Cable - Works!

Wow! Than there is more involved. My straight jumped cable increases the output more than the Griffin Dock output. I'll have to keep digging!
8GB Blue FUZE w/The Original DIY Lineout Cable and AT Button H-Phones Fitted To AT WM5 Headband:All Custom Built
SanDisk User
Posts: 49
Registered: ‎12-01-2008

Re: DIY Line Out Cable - Works!


14124all wrote:

axon, Now I'm confused! In 2 of your posts you say the headphone out seems cleaner than the dock out and the volume level is near equal. I thought your dock lineout level was low, maybe I misunderstood. So why bother with the dock? Just use a cable on the headphone out since the level is the same and the quality is better or equal and you retain full volume control. The dock also kills FM reception so why bother with it?


Hey 1412 

 

The dock is only for convenience.  I'm basically using the Fuze as a transportable music player that replaces a CD player in my office system.  All I have to do is plug the Fuze into the dock at my office and I'm good to go.  At the end of the day, I lift the Fuze out of the dock and go home.  The dock is just easier, provides a secure place to hold the Fuze while it's playing and keeps the screen aimed at an effective angle.

 

When I want to go portable, I use the Clip.

 

I ran it the other way before the dock came.  1st I had to plug in the AC power connector, then I had to plug in the headphone jack, then I had to set the volume at 100%, and do the reverse at the end of the day.  Couldn't see the screen, and I had to make sure it was laying on something that wouldn't scratch the back or fall off the shelf it was on. 

 

You don't really need the dock, but it's so inexpensive, there was no reason not to get one or two..... depending on how you want to use it.  Smiley Happy

 

axon

SanDisk User
Posts: 49
Registered: ‎12-01-2008

Re: DIY Line Out Cable - Works!


sansafix wrote:

Line out is clearly specified as a 700 mv RMS P-P signal.

 

When you connect to the dock,  it should drive this level and you adjust the volume on your stereo.  When you remove the device from the dock,  the headphone setting is restored.

 

This is the way it works with the other Sansa Devices,  and docks,  including View.. 

 

There are two different outputs one for Line out and one for Headphone,  but they share the same DAC.  VOlume adjustment is done in the analog domain,  and digital attenuation at lower levels.

 

So generally speaking,  fixed line out will offer the best SNR signal for your stereo.

 

Using the Sansa Base station,  you can adjust the gain of the preamp using the remote,  but the line level should be unchanged.

 

If you want to use a variable output,  you can connect the headphone output directly to your stereo.

Message Edited by sansafix on 12-09-2008 08:55 AM

Hi sansafix

 

I don't understand how the volume is adjusted. 

 

In my Fuze, at 100%, the volume out of the headphone jack = the volume out of the line out dock.

 

Where is the analog amplification applied and where is the digital attenuation applied?

 

 

axon

SanDisk Guru
Posts: 1,235
Registered: ‎10-24-2007

Re: DIY Line Out Cable - Works!

Digital attenuation is before the DAC.

 

Each amplifier,  HP or Line out has adjustable Analog gain.

 

At full scale,  the HP out will be the same level as line out assuming you use the Volume "High" setting.

 

 

SanDisk Professor
Posts: 682
Registered: ‎04-18-2008

Re: DIY Line Out Cable - Works!


sansafix wrote:

The output signal has nothing to do with the voltage on Pin 7.  That just enables the line out.


 


14124all wrote:
Wow! Than there is more involved. My straight jumped cable increases the output more than the Griffin Dock output. I'll have to keep digging!

 

So what what the heck is going on then?  I assume this means 14124all's cable is fine "as is" and doesn't need a resistor.  But, what's up with the dock then?  I guess the dock must be doing something to reduce the output level coming from the Fuze?  Weird...

 

In any case, just to be clear, the jumped cable should be supplying the correct line-out voltage and there shouldn't be any problem with overdriving, right?

SanDisk User
Posts: 87
Registered: ‎11-21-2008

Re: DIY Line Out Cable - Works!

This is great info, and its good to be able to get this much technical information on the inner workings of these devices.  Even better to hear that Sandisk is addressing this further for us.  I do, however, have two simple questions:

 

1) Would it be possible to enable line-out without requiring voltage to pin 7?  If so, what are the chances Sansa would allow this with a future FW upgrade, and what (if anything) would be their reasons for not doing so?

 

2) Why doesn't SanDisk want to make a cable?  Seems like it would be a great way to make some extra money, as well as increasing sales to people who buy Ipods instead due to the much greater accessory market.  I can understand that they want to sell their docks for home use, but it would be great for cars, as well as for the portability factor.  Seems like they'd be missing out NOT to make a cable, so what are the reasons against them doing this? 

SanDisk User
Posts: 49
Registered: ‎12-01-2008

Re: DIY Line Out Cable - Works!


Skinjob wrote:

sansafix wrote:

The output signal has nothing to do with the voltage on Pin 7.  That just enables the line out.


 


14124all wrote:
Wow! Than there is more involved. My straight jumped cable increases the output more than the Griffin Dock output. I'll have to keep digging!

 

So what what the heck is going on then?  I assume this means 14124all's cable is fine "as is" and doesn't need a resistor.  But, what's up with the dock then?  I guess the dock must be doing something to reduce the output level coming from the Fuze?  Weird...

 

In any case, just to be clear, the jumped cable should be supplying the correct line-out voltage and there shouldn't be any problem with overdriving, right?


That is strange. 

 

  • Why do we think the dock reduces the volume? 

 

  • sansafix said the volumes of the lineout and the headphone jack are the same at 100%.

 

  • The dock and the headphone jack sound the same to me volume at 100%, therefore one might assume that the dock does not reduce the volume below the level of the headphone jack.

 

  • Why does 1412's lineout cable increase the volume above the levels produced by the dock and the headphone jack?  How does it do that?

 

  • And why does the Fuze need two amplifiers to send the exact same signal to either the lineout or the headphone jack?  Especially if only one output is operational at a time.

 

I  don't think I understand what's going on yet.

 

axon