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

Re: DIY Line Out Cable - Works!

WhiiteRaven, the AMS chip does have 2 dedicated line inputs. There most likely is no hardware connection on the Fuze board to the chip pins and no enable in the firmware. Maybe the next generation Fuze or another model will enable it. This chip is loaded with features that are not used in the Fuze.
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!


Skinjob wrote:

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 noticeable 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.


 

 

Hey Skin and 1412

 

I ran some comparisons today in my office using the Griffin dock connected to the tape loop out on a mini component unit I bought in the 80's.  There was no obvious difference between volumes of the headphone out jack and the dock jack, with the Fuze set to 100%. 

 

For some reason, I am not getting the expected results.  I had more than one person listen as I switched back and forth and no one seemed to feel there was an obvious volume difference. 

 

This bears out what I was hearing from my headphone amp at home. 

 

This is not the case, however, if the Fuze is set to less than 100% volume.  In that scenario, the dock is noticeably louder than the Fuze, by degrees, as the Fuze approaches 100% volume. 

 

I'll try it again tomorrow, but I'm very confident in what I've heard, through both my headphone amplifier and now my office stereo.

 

I also discovered that (while listening to speakers), I was able to notice a slight increase in volume as I dialed up from 50% to 100% with the Fuze plugged into the dock.  This is not an obvious volume change, but it is detectable.  I only mention this because previously I thought there was no volume increase from 50% upward.

 

axon

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

Re: DIY Line Out Cable - Works!

axon, See what version firmware is on your player. If it is the 07 version try upgrading to the 11 version and retry your testing at 100% volume. I need to further test, but I have players with both versions and they do react differently. The volume control acts different when on my lineout cable between these 2 versions. I will verify with the Griffin Dock what happens (it should still be the same as my cable) and get back to this thread. I don't use the current firmware version 15 due to playback problems encountered with it. Version 11 seems to work the best for audio playback, which is all i'm concerned with.
8GB Blue FUZE w/The Original DIY Lineout Cable and AT Button H-Phones Fitted To AT WM5 Headband:All Custom Built
SanDisk Fanatic
Posts: 363
Registered: ‎08-02-2008

Re: DIY Line Out Cable - Works!

axon, WOW!!! Disregard previous post. There is a difference in firmware versions, but not with affected volume. What I found - You are correct!!! At 100% volume there is barely any differnce in volume output from the Griffin dock out or player headphone out. With my lineout cable there is a noticeable increase in volume! This renders the Griffin Dock rather useless as is for a lineout connection. This should be easy to alter the Griffin Dock to get the signal straight through. The Griffin Dock has series 220uf decoupling caps and parallel 10k impedance output resistors feeding the output jack. Time to bypass the resistors and maybe the caps!

NOTE: Another problem with the Griffin Dock is loss of the FM antenna. The player seems to only connect the FM antenna through the headphone jack common audio connection with no connection on the 30 pin connector. The Griffin dock has no connection for the antenna! Activating it will probably require an internal jump in the player to an unused pin on the 30 pin connector and a single wire to act as antenna on my cable. Getting the antenna to work might take some doing for other alternatives.

8GB Blue FUZE w/The Original DIY Lineout Cable and AT Button H-Phones Fitted To AT WM5 Headband:All Custom Built
SanDisk Fanatic
Posts: 363
Registered: ‎08-02-2008

Re: DIY Line Out Cable - Works!

More finds! Sorry had a typo in the previous post. The output resistors are 100k not 10k. I disconnected them and had no difference in volume level, so it doesn't seem to be impedance mismatch related. I'm going to reverse-engineer the Griffin board completely and come up with a full circuit diagram and hopefully see what is going on here. Since my cable does get a noticeable volume increase, it may be the voltage on pin7 may act as a gain control. Only speculation right now, I need to do more tinkering with the dock.
8GB Blue FUZE w/The Original DIY Lineout Cable and AT Button H-Phones Fitted To AT WM5 Headband:All Custom Built
SanDisk Professor
Posts: 682
Registered: ‎04-18-2008

Re: DIY Line Out Cable - Works!


14124all wrote:

axon, WOW!!! Disregard previous post. There is a difference in firmware versions, but not with affected volume. What I found - You are correct!!! At 100% volume there is barely any differnce in volume output from the Griffin dock out or player headphone out. With my lineout cable there is a noticeable increase in volume! This renders the Griffin Dock rather useless as is for a lineout connection. This should be easy to alter the Griffin Dock to get the signal straight through. The Griffin Dock has series 220uf decoupling caps and parallel 10k impedance output resistors feeding the output jack. Time to bypass the resistors and maybe the caps!

NOTE: Another problem with the Griffin Dock is loss of the FM antenna. The player seems to only connect the FM antenna through the headphone jack common audio connection with no connection on the 30 pin connector. The Griffin dock has no connection for the antenna! Activating it will probably require an internal jump in the player to an unused pin on the 30 pin connector and a single wire to act as antenna on my cable. Getting the antenna to work might take some doing for other alternatives.


 

Interesting.  I was going to get one of the Griffin docs while they were still on clearance, but if it doesn't solve the level issue then there's really no point.  Man, it really shouldn't be this hard to get a decent line out.

 

I still haven't had a chance to mod my cable, but I'm hoping to try this week.

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

Re: DIY Line Out Cable - Works!

Next release of Fuze firmware will output fixed line level when connect to the Dock.
SanDisk Guru
Posts: 5,822
Registered: ‎12-26-2007

Re: DIY Line Out Cable - Works!

I like aspects of either configuration, as one could tweak the volume while docked.

 

The advantage of fixed becomes apparent when I use the e200v2 on the dock: the volume setting for the headphone is retained, and restored when I pull the device from the dock.  Quite convenient!

 

Bob  Smiley Very Happy

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

Re: DIY Line Out Cable - Works!

Doing some quick checks it appears that the voltage on pin7 of the Fuze controls the lineout level. The Griffin Dock feeds 5volt through a series 47k resistor and has 1 volt on pin7. My modded cable feeds 3 volts to pin7 and produces a louder output signal. The Griffin Dock can be modded for a higher than 1 volt feed with a reistor change, or a pot and resistor could be used to produce a voltage limited gain control. I would imagine that the feed should not exceed 3 volts, so values must be chosen correctly if modding the dock due to the 5 volt feed. I do not have a Sansa Dock, but it seems to be more involved internally than the Griffin Dock. I'll be trying mods on the Griffin Dock in the next few days.
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!

[ Edited ]

Skinjob wrote:

14124all wrote:

axon, WOW!!! Disregard previous post. There is a difference in firmware versions, but not with affected volume. What I found - You are correct!!! At 100% volume there is barely any difference in volume output from the Griffin dock out or player headphone out. With my lineout cable there is a noticeable increase in volume! This renders the Griffin Dock rather useless as is for a lineout connection. This should be easy to alter the Griffin Dock to get the signal straight through. The Griffin Dock has series 220uf decoupling caps and parallel 10k impedance output resistors feeding the output jack. Time to bypass the resistors and maybe the caps!

NOTE: Another problem with the Griffin Dock is loss of the FM antenna. The player seems to only connect the FM antenna through the headphone jack common audio connection with no connection on the 30 pin connector. The Griffin dock has no connection for the antenna! Activating it will probably require an internal jump in the player to an unused pin on the 30 pin connector and a single wire to act as antenna on my cable. Getting the antenna to work might take some doing for other alternatives.


 

Interesting.  I was going to get one of the Griffin docs while they were still on clearance, but if it doesn't solve the level issue then there's really no point.  Man, it really shouldn't be this hard to get a decent line out.

 

I still haven't had a chance to mod my cable, but I'm hoping to try this week.


That's no reason not to get a Griffin Dock.  I ordered a 2nd one for home use.  The convenience factor is too great not to have one and they're practically free.   The SQ is from the dock is great, and I'm not sure if a firmware lineout can sound better.

 

axon

Message Edited by axon01 on 12-08-2008 08:51 PM