DIY Line Out Cable - Works!

Finally dived into the line out cable project. Already had a Fuze internally jumped for line out, did up a cable this time. Attached a 1/8" stereo mini plug to a Sandisk original 30 pin cable.

NOTE: This DIY mod is for those who have good soldering skills. I will not cover the basic mechanics of taking the 30 pin cable connector apart and reassembling. Here are the connections:

  1. jumper pin 7 to pin 22 (this provides the needed 3volt for enabling the line out pins)

  2. stereo cable right channel to pin 27 (usually red wire)

  3. stereo cable left channel to pin 28 (usually white wire)

  4. stereo cable shield to connector housing shield solder point

Operation will be the same as with the Griffin Dock. Charging still works the same, as the original circuit is not altered.

NOTE: There has been much discussion about this not being a true line out signal, which is probably true. A true line out would be unaffected by volume or tone with constant output. It seems to be all we have to work with in the Fuze though. The volume needs to be at about 50% or greater (doesn’t really increase much from that point on, like the griffin dock). The signal is noticeably stronger than using the headphone out and is still distortion free. It drives my Klipsch Promedia 2.1 very well and my Kenwood car stereo equally well.

The advantage of the cable over the dock is that external power is not needed. You can run off of the battery or connect to a USB power source, your choice.

With the cable connected the headphone out is inactive, same as the Griffin Dock. You could run wires out from the pin 7 to pin 22 jumper to a small switch if you want to shut off the line out and restore headphone out.

Hope this clears up some of the conFuzion!!!

Hi 14124all,

Would you please describe a bit more specific about the connections ? I want to make one.

Much thanks in advance.

Awesome work 14124all!  Thanks for posting.

When I first got my Fuze, I ordered a cheap View A/V cable from eBay on the off chance the line-out might work.  Of course it didn’t, and I’ve been thinking about modding it ever since.  I think all that’s needed is the jumper you describe, but I’ve been afraid to try it.  I’ll give it a shot and post my results.

Could you post a pic of your cable?  I’d like to see how you squeezed the extra cable into the 30-pin connector.

Also, what kind of wire did you use for the jumper?

Hey Skinjob!

You can use a simple 24ga wire wrap lead as a jumper.  The pigtail for the 3.5mm jack depends upon the type of cable you choose, but it’s simplest to make a cut alongside the existing cable’s strain relief, and you can wire tye the cables together for support.

If you have a cable with strain relief, then you can make an individual “port” for the cable in the connector housing.

Bob  :smileyvery-happy:

I’d definitely like some more info on this, and would be interested in seeing a widely produced or even commercial application in the near future.  Having to jump the player itself makes a commercial version unlikely, but SanDisk could easily fix this by allowing line-out w/o any power input (like Ipods do) in a future FW upgrade.  That’s one of the features at the top of my wish-list, as it would allow these cables to be actually produced.  I’m interested in this, and may wish to try it myself, though I’m a little wary of frying my Sansa if something shorts out, or I jumper the wrong pins…

@neutron_bob wrote:

You can use a simple 24ga wire wrap lead as a jumper.

 That’s what I figured, thanks.

@neutron_bob wrote:

The pigtail for the 3.5mm jack depends upon the type of cable you choose, but it’s simplest to make a cut alongside the existing cable’s strain relief, and you can wire tye the cables together for support.

For my first attempt, I’m just going to mod a cheap View A/V cable so I won’t actually be adding any additional cable, just the jumper.  But a cable with both audio and USB would be very usefull (especially in the car).  If the View A/V cable mod works, I think I’ll order another cheap data cable and try to add the audio cable.

Another idea might be to convert the View A/V cable’s video lead into USB.  Just replace the connector and resolder to the appropriate pins in the 30-pin connector.  That would make for a very tidy cable.  Do you think the video wires would be adaquate for USB power?

14124all   Thank you so much for this. It will greatly improve the Fuze’s usability in the car.

Skinjob, Neutron_Bob is right on! I used a 28ga solid strand wirewrap wire to jump pins 7 and 22 on the Sansa connector board. The Sansa cable is nice to work with, it has the full set of 30 contacts and easy to solder at the circuit board connections. NOTE: watch your plus pin side and minus pin side (numbers) and count correctly! I also purchased a cheap View cable, but it was not usable as it did not have any contacts other than those used - el cheapo! Insulate your connections with tape, as the shield passes over everything!!! I removed the strain relief completely and have the wires parallel coming out the large hole. This is temporary, as this was a prototype to make sure it worked. I’ll strain relief it better in the future. Again, Neutron_Bob has a great way to strain relief as he has said!

My player has run daily for over a week now with no problems. This is running with USB end connected to an AC adapter and also running disconnected, it can be plugged in with the unit on without hiccup and will start charging. The player that I internally jumped months ago, serves duty in my garage feeding a Panasonic shelf system. It has the pin7 jumped to one of the 3volt filter caps internally, no more headphone out for that baby!

Using the View cable video wires may be a bit risky! They are probably very thin, but should handle a 500ma USB source. You may pickup some signal noise on a single cable that includes power and audio. Seperate cables give a bit more isolation.

Sorry, no pictures at this time and I really do not want to host pics.

To all others, if you cannot follow the simple connection list shown above and cannot determine the correct pin number locations on a cable connector, you probably should not attempt this modification. It is very easy for people who tinker and have soldering skills to do this. Others may cause BIG problems if they connect wrong or bridge solder connections - do NOT risk your player if you are not experienced with electronic projects.

@14124all wrote:

Finally dived into the line out cable project. Already had a Fuze internally jumped for line out, did up a cable this time. Attached a 1/8" stereo mini plug to a Sandisk original 30 pin cable.

NOTE: This DIY mod is for those who have good soldering skills. I will not cover the basic mechanics of taking the 30 pin cable connector apart and reassembling. Here are the connections:

  1. jumper pin 7 to pin 22 (this provides the needed 3volt for enabling the line out pins)
  1. stereo cable right channel to pin 27 (usually red wire)
  1. stereo cable left channel to pin 28 (usually white wire)
  1. stereo cable shield to connector housing shield solder point

Operation will be the same as with the Griffin Dock. Charging still works the same, as the original circuit is not altered.

NOTE: There has been much discussion about this not being a true line out signal, which is probably true. A true line out would be unaffected by volume or tone with constant output. It seems to be all we have to work with in the Fuze though. The volume needs to be at about 50% or greater (doesn’t really increase much from that point on, like the griffin dock). The signal is noticeably stronger than using the headphone out and is still distortion free. It drives my Klipsch Promedia 2.1 very well and my Kenwood car stereo equally well.

The advantage of the cable over the dock is that external power is not needed. You can run off of the battery or connect to a USB power source, your choice.

With the cable connected the headphone out is inactive, same as the Griffin Dock. You could run wires out from the pin 7 to pin 22 jumper to a small switch if you want to shut off the line out and restore headphone out.

Hope this clears up some of the conFuzion!!!

 Hi 14124all

Nice work on the line out cable.  :slight_smile:

I’m curious about what you said about the line out. I’m new here and haven’t found much information about the nature of the line out on the Fuze.  For instance, why does the line out need 3 volts?  What else might you be able to say about how the line out works?

  • My experience with the Griffin dock is that the volume remains constant until the last 25%…  do you think this decrease in volume is attenuation of the line out signal? 

  • I also found that anywhere from about 25% to full volume out of the dock was the same as full volume from the Fuze’s headphone jack, when connected to my M^3 amp and DT880 headphones. 

  • I found both signals to be distortion free but  did not find the dock to be  stronger nor better than the headphone out of the Fuze. 

  • I thought the cleaner signal came out of the headphone jack on the Fuze , which makes sense considering the cheap electronics in the dock and the additional signal path. 

  • It should be noted that the difference in sound quality  between the dock and the headphone jack on the Fuze were quite small and without a very resolving system, would not be heard easily.

Regards

axon

Now the disclaimer:  I did the comparisons quickly and I’m aware that YMMV.  :wink:

axon01 wrote: 

  • I thought the cleaner signal came out of the headphone jack on the Fuze , which makes sense considering the cheap electronics in the dock and the additional signal path.

The cleanest signal in any system should be the line out as, properly implemented, it is the ‘earliest’ analogue signal in the chain and thus not impacted by any additional signal path such as the Fuze’s headphone amplifier stage. In the Fuze, it should be the signal which feeds the input of the headphone amp stage. The cheap electronics in the dock are irrelevant as they come after the line out stage and it’s up to you what standard of electronics you feed it into.

axon01 wrote: 

I’m curious about what you said about the line out. I’m new here and haven’t found much information about the nature of the line out on the Fuze.  For instance, why does the line out need 3 volts?

The 3 volts is not on the line out itself, but is necessary to enable the line out.  Ordinarilly, the dock would supply the 3 volts on a certain pin.  This tells the Fuze it’s connected to a dock and should enable it’s line-out and disable it’s headphone out.

As to the other comments about SQ through the dock, it will be interesting to see how much difference there is between a simple cable with no extra electronics versus the dock where the signal passes through another circuit board.

@axon01 wrote:


@14124all wrote:

NOTE: There has been much discussion about this not being a true line out signal, which is probably true. A true line out would be unaffected by volume or tone with constant output. It seems to be all we have to work with in the Fuze though. The volume needs to be at about 50% or greater (doesn’t really increase much from that point on, like the griffin dock). The signal is noticeably stronger than using the headphone out and is still distortion free.


My understanding is that it’s a true line-out.  The volume adjustment is applied digitally in the DSP before the analog output stage and the analog signal is not altered in any way.  The voltage on the line-out should be constant.

This is quite different from many (all?) ipods where the volume adjustment is applied to the analog signal, causing a variable output and poor sound quality.

Exactly.  The Sansa is doing the modifications in the digital domain, so it’s not an old school issue of “more things in the signal path”.  The gain of the output is variable, but it’s the same device, not an added gain stage or rheostat.

Bob  :wink:

@fifer wrote:


axon01 wrote: 

  • I thought the cleaner signal came out of the headphone jack on the Fuze , which makes sense considering the cheap electronics in the dock and the additional signal path.

The cleanest signal in any system should be the line out as, properly implemented, it is the ‘earliest’ analogue signal in the chain and thus not impacted by any additional signal path such as the Fuze’s headphone amplifier stage. In the Fuze, it should be the signal which feeds the input of the headphone amp stage. The cheap electronics in the dock are irrelevant as they come after the line out stage and it’s up to you what standard of electronics you feed it into.

I would tend to agree with you, but the Fuze appears to be implemented differently.

axon

I have to agree with Skinjob and neutron_bob. The Fuze is implementing the line out in it’s own way. It should not be a concern about if it is a “true” line out or not. This was probably based on home stereo equipment with a 1volt peak signal. Are car stereos true line out with the 5volt pre-out signals?

The main thing is that there is a high quality, high impedance signal available to drive pre-in inputs harder than the headphone out. If I run the Fuze volume all the way to max, the signal is noticeably lower than with the Griffin Dock or the cable mod. The purpose of this project was to get a signal that is more useable with car stereos and line-in home equipment, as the headphone out does not drive them well. It seems to me that it works quite well without signal degradation, so I am happy with it.

If you are looking for audiophile quality, true to spec line out, you probably should not be using a compressed audio player anyway!

Hey,

Great work!

Just had a thought - wouldn’t it be nice to have a line in as well?

Pity you would have to muck with the firmware in order to get it to record.

Just an idea . . .

WR

@skinjob wrote:


axon01 wrote: 

I’m curious about what you said about the line out. I’m new here and haven’t found much information about the nature of the line out on the Fuze.  For instance, why does the line out need 3 volts?


 

The 3 volts is not on the line out itself, but is necessary to enable the line out.  Ordinarily, the dock would supply the 3 volts on a certain pin.  This tells the Fuzz it’s connected to a dock and should enable it’s liniment and disable it’s headphone out.

 

As to the other comments about SQ through the dock, it will be interesting to see how much difference there is between a simple cable with no extra electronics versus the dock where the signal passes through another circuit board.

Hi Skin and Neutron

It will also be interesting to compare the signals from a line out cable, a high quality dock and the headphone jack.

From what I am beginning to understand, the Fuzz is applying it’s amplification (or attenuation), digitally, through the chip, (thank you Neutron).  It makes sense then, that when the dock is deployed, the headphone jack is not, because the signal from the chip is routed to either the jack or the line out. 

The fact that you are able to get a signal from either the line out or headphone jack but not both and the position SanDisk placed the headphone jack, (intentionally precluding use while docking), seems to bear out that there are not two amplifiers, as I have read. 

The digital concept makes further sense because there is no distortion regardless of the volume level.  The interesting thing is that if Neutron’s supposition is correct,  that the gain is being applied digitally by the chip, the exact same signal would be available through the jack or the line out.   This, btw, agrees with what I heard when comparing the Griffin dock to the headphone jack.  The headphone jack, having less to go through, had the cleaner signal. 

More digital evidence might be when someone reported that when they used the remote on the sansa dock to change the volume, it did so by changing the volume on the Fuze.

axon

@14124all wrote:

I have to agree with Skinjob and neutron_bob. The Fuze is implementing the line out in it’s own way. It should not be a concern about if it is a “true” line out or not. This was probably based on home stereo equipment with a 1volt peak signal. Are car stereos true line out with the 5volt pre-out signals?

The main thing is that there is a high quality, high impedance signal available to drive pre-in inputs harder than the headphone out. If I run the Fuze volume all the way to max, the signal is noticeably lower than with the Griffin Dock or the cable mod. The purpose of this project was to get a signal that is more useable with car stereos and line-in home equipment, as the headphone out does not drive them well. It seems to me that it works quite well without signal degradation, so I am happy with it.

If you are looking for audiophile quality, true to spec line out, you probably should not be using a compressed audio player anyway!

Hi 14

This is really strange.  I don’t know why this was not what I found?  Fuze volume set to 100% gave me the same volume from the Griffin dock and the headphone jack.  I used an 18" Zu  Pivot (mini to RCA) to my M^3 and DT880s for the comparison.  

 

axon

 

Edit to add link:  What I used 

Message Edited by axon01 on 12-02-2008 11:29 AM

@axon01 wrote:


@14124all wrote:

I have to agree with Skinjob and neutron_bob. The Fuze is implementing the line out in it’s own way. It should not be a concern about if it is a “true” line out or not. This was probably based on home stereo equipment with a 1volt peak signal. Are car stereos true line out with the 5volt pre-out signals?

The main thing is that there is a high quality, high impedance signal available to drive pre-in inputs harder than the headphone out. If I run the Fuze volume all the way to max, the signal is noticeably lower than with the Griffin Dock or the cable mod. The purpose of this project was to get a signal that is more useable with car stereos and line-in home equipment, as the headphone out does not drive them well. It seems to me that it works quite well without signal degradation, so I am happy with it.

If you are looking for audiophile quality, true to spec line out, you probably should not be using a compressed audio player anyway!


Hi 14

 

This is really strange.  I don’t know why this was not what I found?  Fuze volume set to 100% gave me the same volume from the Griffin dock and the headphone jack.  I used an 18" Zu  Pivot (mini to RCA) to my M^3 and DT880s for the comparison.  

 

axon

 

Edit to add link:  What I used 

Message Edited by axon01 on 12-02-2008 11:29 AM

Hmm, not sure why you’re not hearing a noticable difference.  It’s fully expected that a headphone-out connected to a normal line-in will result in a low level.  The difference is usually very obvious.  Is it possible the line device you are plugging into has some kind of auto-sensing jack and is compensating for the headphone input?  A lot of newer devices that were designed with portable gear in mind handle headphone input better than devices designed for traditional home a/v gear.

axon01, take a look at the block diagram for the AMS AS3525 SOC. It may answer some of your questions. The system chip has 3 independent audio outputs on chip: headphone amp, line out and speaker amp. All of their inputs are driven by a common signal with the DAC and AGC limiter upstream. Easily manipulated digitally before the DAC output. Note that the line out output does not feed the headphone out input. This may clear up some confusion.

Google for AustriaMicrosystems AS3525 to find the function sheet and block diagram. Sorry, I do not have a URL handy.