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Sansa Fuze's diyLOD (v1 + v2) Guide [56k!!!]

post #1 of 22
Thread Starter 
Hi there, I'm reposting this guide with the permission of the original writer, as he was made to feel that leaving the original guide posted was inappropriate (that's all I'm going to say about that). Anyway, I managed to recover the original post from Google Cache in its entirety; there may be some formatting errors and some links may not work initially, but I'll get it fixed up in a bit. If you find some that don't work, or it looks like a picture is missing, please let me know. Once again, this guide is not my work; everything below this point is a copy and paste job.

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Credit to 14124all @ Sandisk's forum who first described and built fuze's diyLOD (read here) and waino from the same forum who took his time to do the measurement. This guide is merely a more graphical approach to re-describe the same process of building the diyLOD.

Prelude:
There are some discussions on whether the line-out signal from the dock connector is true line-out or not. Sansafix @ Sandisk's forum, who is Sandisk's tech support, has confirmed that it is indeed line-out signal, not headphone-out at 100%. The main benefit of using the line-out signal, from my point of view, is its better SNR compared to Fuze's headphone-out (which makes its LO better for amping). When comparing Fuze's headphone-out and line-out, I do find them to sound differently in some subtle ways. In comparison (flat EQ), line-out (via diyLOD v1) sounds more neutral and spacious. Fine detail and image (soundstage) tend to jump out more easily. LO does seem to have a darker, quieter background as well. Headphone-out on the other hand sounds more mid-focus and energetic. It almost makes me think that HO is somehow EQ'ed, or may be coloration is the correct word for it. Since Fuze's headphone-out already sounds fantastic by its own, it is hard to say that line-out + amp are a major improvement over headphone-out + amp. IMO, it really boils down to personal taste and how one perceives what is the most natural sound. [EDIT] If you want to read more about the tech side of the story, it is at the end of post #2.

One thing you should note is, due to how Fuze's EQ is applied to music (which is in DSP / CPU, before the music reaches DAC), it will still affect the sound in line-out mode. If you insist on getting a 'pure' line-out signal, you should turn EQ off when you are using the diyLOD.

To ensure you are getting the best out of the diyLOD, you'll need to update your Fuze firmware to the latest version!!! The latest firmware are 01.01.22 (for hardware rev.1) and 02.01.17 (for hardware rev.2). You can find more detail on how to update your Fuze here. [UPDATE] The latest firmware is now 0X.02.26, found here.
What you will need:
1 x original sync and charge cable for diyLOD v1.
1 x Fuze's 30 pins connector (*see note 1 below for detail) for diyLOD v2. You can use this connector for v1 as well but please pay attention to pins' orientation.
1 x mini plug
1 x soldering iron, small tip (and some solder of course)
1 x Multimeter
1 x Super glue (diyLOD v2)
2 x Capacitors (diyLOD v2, please read v2 guide for choosing the right caps))
Optional: cables (depends on how fancy you want it to be), Ridax strain relief (diyLOD v2) Note 1: There are two types of Fuze connectors: the snap-on (+ half shielded) and the glue-on (+ full shielded) type. Ridax sells both types, and Qables only sells glue-on type. To make diyLOD v2, you should choose snap-on type. For diyLOD v1, both types can be used (glue-on type is slightly smaller). Note that the Sansa (Fuze) connector is also known as Creative Zen connector.

What you don't need:
Cheap replacement cable from eBay - most of them only have the first 6 pins needed for sync and charge. You will not be able to modify it since pin #7, 22, 27, and 28 are not there. You can, however, use it as you sync and charge cable after you modified the original cable (if you are not using Ridax's connector).

As always, this is a Do-It-At-Your-Own-Risk modification.

*Not sure which version of diyLOD you should use? In short, use diyLOD v1 if your amp has input DC filters (i.e. capacitive coupling / AC coupling). Use diyLOD v2 if your amp doesn't have them (or when you can't be sure). See the 2nd to last section on post #2 for more detail.

[diyLOD v1]
- original sync and charge cable mod

1. Taking apart the connector.
The connector is held together mainly by two hooks at the cable end of the connector (where the two holes on each side are). Those hooks shaped differently which make them a lot more difficult to take apart.


I use the small flathead screwdriver for repairing watches to pry open the bottom side of the connector - first I force the screwdriver underneath where the strain relief goes into the connector, than I pry on each side (black arrow) till it is loose - be careful on this part as you don't want to destroy the housing before you even began the mod.


Red circles mark the hooks and green arrow is where the screwdriver goes in / force applied


You can lift this part of the metal shielding once the whole connector is out of the plastic housing. Don't bend the metal too much or it will break.


The complete disassembly of the connector. Note: you are looking at the bottom side of the connector (pin #2, 4, 6, ... , 30)


The bottom, where the USB connections are wired.


The top, same side as the Sandisk logo is.


2. Rewiring.
I de-solder all the USB wires first as I like it that way (except the USB shielding that connect to the connector shielding). There is no reason to pick one color wire over the other for a particular channel - you can pick what ever way you want to solder them, just be sure to remember to solder them in the correct way when you terminate them at the other end with mini jack. It is also a good time to cut the USB cable to your desired length. I left about 4 inches of USB cable attached from the end of connector strain relief - which is about 3 inches left after I put on the mini jack. You might want to leave a bit more depends on your own preference and future usage.


Here is a sum up of what was / is during the rewiring process:


First, you want to jump pin #7 and pin #22. They are located on two different side. I jumped them with the leftover cable on the original USB cable. The reason for jumping the two pins is because it requires a small voltage (1V ~3V) on pin #7 to activate the LO mode, and it just so happens Fuze's pin #22 has 3V supply that can be utilized in this situation. Note that whether other Sandisk player has the same 3V on pin #22 is yet to know. Until we do know about it, you shouldn't use the diyLOD on any other Sandisk player besides Fuze.

Pin #7:


Pin #22: (I marked #10 and #20 red for better recognition)


Once you jump the pins, should check both the connection b/w the pins with multimeter, as well as the neighboring pins (i.e. pin #5 and #9, #20 and #24) to make sure nothing short! Measure every time you finish soldering a pin!!!

A quick test: To see whether you can activate LO at time point, start playing a songs on Fuze and listen to it, than insert the jumped connector in and you will notice the music is silenced (on headphone) but continue to play on the player. You will also notice the scroll wheel no longer able to control the volume. Remove the connector and everything should go back to normal. Note: Your Fuze must be in the latest firmware to perform this test.

I pick red cable as my right channel, black as my left channel, as green as my audio ground. Note that you should also be able to use Pin #3 and 6 (USB ground) as your audio ground as well. Note: be careful on the cable length b/w the strain relief and the pins - you don't want it to come short when you try to put them back together. If you are not sure, extend the cable by wiring an extra length of wire and insulate it properly (you don't want them to short either!)




Since I didn't use the USB shielding for anything, I insulated it as well.


3. Reassembly
Remember to put some tape over the PCB to avoid short circuit,
Terminate the other end with a mini jack and voila, you have yourself a diyLOD!



Fuze - diyLOD - FiiO E5 - Head-Direct RE0


Fuze - diyLOD - iBasso T4 - Head-Direct RE0


Continue to next post...

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Again, everything above that line is not my work! See the notes at the beginning of this post for an explanation. I did a quick scan of these posts to make sure nothing was missing and I'm pretty sure I tried all the links, but if it looks like an image is missing (or is in the wrong place) or a link is bad, please let me know. Cheers!

The original thread is still available here and contains some additional user-posted images and discussion about the LOD, but please post comments in this thread, linking back to the old one if necessary.
post #2 of 22
Thread Starter 
Hi there, I'm reposting this guide with the permission of the original writer, as he was made to feel that leaving the original guide posted was inappropriate (that's all I'm going to say about that). Anyway, I managed to recover the original post from Google Cache in its entirety; there may be some formatting errors and some links may not work initially, but I'll get it fixed up in a bit. If you find some that don't work, or it looks like a picture is missing, please let me know. Once again, this guide is not my work; everything below this point is a copy and paste job.

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[diyLOD v2]
- Ridax connector with caps

1. Taking apart the connector.
Ridax connector are pretty easy to take apart. Beside the connector and its half metal shield, there are also two small pieces of plastic that are going to be the push buttons of the release mechanism.

An unopened Ridax connector next to Sandisk connector, plus another being disassembled.


Here is a closer look at the pins and its half metal shielding.


Optional: Ridax strain relief
As you can see, Ridax strain relief is actually thicker than the connector housing, you will have to trim it down yourself.


Here is how I trim mine. Make sure you don't over trim yours. BTW. The strain relief only allow cable diameter about 5mm or less to pass. If you are using thick custom cable, you don't need to get this.


2. Wiring.
You can use any cable you find fit. I just use the leftover USB cable of diyLOD v1 mod. Most of the process is identical to diyLOD v1, so read the previous post first.

Here is a sum up of what was / is during the rewiring process:

[IMPORTANT] Notice that the pins on Ridax connector is upside down in compare to the Sandisk connector, so don't mix up!

First, jump pin #7 and #22.


A quick test: To see whether you can activate LO at time point, start playing a songs on Fuze and listen to it, than insert the jumped connector in and you will notice the music is silenced (on headphone) but continue to play on the player. You will also notice the scroll wheel no longer able to control the volume. Remove the connector and everything should go back to normal. Note: Your Fuze must be in the latest firmware to perform this test.

I use a 5 inches pieces of the leftover USB cable as my main cable. I clean up one end and set it up for soldering (like diyLOD v1, red for right channel, black for left, green for ground, and USB shield to connector shield), than I insert the previously prepared strain relief up to that end. To make sure the strain relief will stay in place and does its job, I put a bit of super glue to glue the cable and the strain relief together (see picture). Be sure that the glue is set firmly before you use the cable. On the connector plug, I extend pin #27 (LO right) and #28 (LO left) with two pieces of cable, about one inch should be enough.

Now we can prepare the caps. I use Panasonic audio caps, 220μF, 6.3V. The choice of caps is made because on the similar spec of caps is used in Griffin dock. I strongly advise the use of non-polarized / bi-polar caps (they are more suitable for the purpose). Also, I will advice you to read Tangents' Input Capacitors for Headphone Amps and dsavitsk's Some Notes on Coupling Capacitors articles regarding caps' function and option. The circuit in Griffin dock is a bit more complex (a typical capacitor coupling design). Here is what in Griffin dock (confirmed by 14124all, thanks)


Here is my adaptation:

Note, bi-polar caps are strongly recommended.

First, I punch four small hole on the upper housing with hot needle so the caps can go through. There is not enough space inside the housing for those caps so they have to be place outside. You can place the caps (in series) in any place b/w the amp and the dock, I just choose to do it this way cause I think it is more elegant this way


Note how I bend the legs inside the housing to make sure the caps stay in one place. Apply a tiny bit of super glue on both side to secure the caps' position.


Now the actually wiring following the decouple diagram above. Not an easy job, I can tell you this much (especially in such tight space). Both pin #27 and #28 are coupled to the positive end of one of the caps.


Now you can terminate the other end of the cable with mini jack and test it out before you put everything together.

3. Finish Up
Again, remember to put some tape inside to avoid short circuit. make sure the insulation is perfect!

diyLOD v1, v2, and an empty Ridax connector.




Fuze - diyLOD v2 - 3MOVE



diyLOD v1 vs. v2 - The Difference
So what is the big deal about coupling / decoupling caps that I'll want to make a second LOD just to put two in? The main reason behind diyLOD v2 is to make sure the LO functions as intended. For both the circuit of Griffin dock and AS3525's datasheet, I find out that caps are indeed part of the original design (as DC filter). So what is the main difference b/w v1 (w/o caps) and v2 (w/ caps) beside how caps affect SQ? The differences lie in noise feedback and DC offset problem. First, with out the caps, sometime you can hear distortion caused by turning the potentiometer (volume pot) on the amp. With the caps, it is all silence. Second, There is a ~1.4V DC offset on the line-out signal. When you set the volume too high on some amp (way beyond safe listening volume), you will notice the volume starts to drop out as the volume is going up. I suspect that is DC/AC issue there since not all amp have input filter to deal with DC offset. The 'evil' about DC offset is, amp with no DC filter will amp the DC voltage (along with the music, which is an AC component) and cause it to become too high. The high voltage can kill your headphone transducer, depends on how high the voltage is and how sensitive the transducer to the voltage. Note, some amp do have DC filter as part of the design (i.e. cmoy, Practical Devices' XM3, etc) and there is no need to add more caps in the LOD.

As for SQ difference, here is my take: The caps I used still require a bit burn in before the sound settle, but I can tell there is sonic difference b/w diyLOD v1 and v2. Those caps seem to smooth out the more aggressive v1 sound and tilt it toward the HO signature, yet it is not quite so to both side. Like how diyLOD v1 vs. HO, I can't say which is actually 'better'. It is more like different flavoring instead of improvement at thge moment. Note, the choice of caps affect SQ. If you are not so sure about which caps to use, search around the DIY forum (especially threads about diyMod) and you will get some idea of which caps are known to be better for the purpose. The general consensus is, no caps is better than with caps, but sometime caps are necessary to protect your headphone against DC offset. Thus if you want to add caps just to be safe, I'll suggest you look for bi-polar / non-polar caps. Film caps usually are consider better for the purpose, but they are typically more expensive and odd in size. If you can find one that fit than it will be great, or else you can search the forum to find out what people like to use (especially on thread about diyMod caps choice)

In technical standpoint, I think diyLOD v2 is probably more 'correct' (or 'safer', if you like), but whether you'll find its sound more pleasing if really just a matter of personal taste.

Inside Story

• The word 'same' used by sansafix (Sandisk tech support) at Sansa forum to describe the gain level of both LO and HO, not signal. He means the max volume on LO and HO are the same.
• LO and HO have different signal path after the DAC.
• LO has a constant line-out voltage (700 mV RMS), HO doesn't (see points below).
• LO and HO each have their own amp sections, integrated inside AS3525 for gain (volume) control as part of the original SoC design.
• All amp sections (on-chip) have 32 analog steps, Sandisk implements a digital attenuation into the lower section of the analog steps to extend the total attenuation to 40 steps.
• The latest firmware 'disable' attenuation on LO so the signal is fixed (= not variable anymore) to better resemble conventional LO and offer better result.
• LO offers slightly better SNR, THD and separation than HO, but they are hard to notice by the ears.
• Line-out on pin #7 is activated by 3V.
• EQ is software controlled and integrated into the SoC (in or before the DAC, if I am not mistaken), so it can affect both LO and HO. You should turn off EQ if you want your LO to be 'purer'.

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That's all folks. One last time, everything above that line is not my work! See the notes at the beginning of this post for an explanation. I did a quick scan of these posts to make sure nothing was missing and I'm pretty sure I tried all the links, but if it looks like an image is missing (or is in the wrong place) or a link is bad, please let me know. Cheers!

The original thread is still available here and contains some additional user-posted images and discussion about the LOD, but please post comments in this thread, linking back to the old one if necessary.
post #3 of 22
Thanks for this. I was just about to ask what happened to the original thread. And many many thanks to the original author for all his hard work!
post #4 of 22
If anyone has a built unit and would like to sell it I would love to buy - just pm me and I'll pay a good price
post #5 of 22
Viva ClieOs!!
post #6 of 22
I was watching the original thread to see the outcome of this mod on the older e2xx models.

Was there any more info? Was it a success?
post #7 of 22
Quote:
Originally Posted by S J View Post
• LO offers slightly better SNR, THD and separation than HO, but they are hard to notice by the ears.
Let me add that it also depends on what you are plugging the signal into. I personally notice a difference from the LOD -> E5 vs. HP out with my IE8s as the presentation is more airy and seems more detailed. The difference isn't huge, but enough to cause me to carry around the LOD+ E5 when using my IE8s. I think this is due to the HP out performance at 16 ohms, which per the specs is a step down from the 32 ohm performance, and subsequently the line out. I don't get the same gains when connecting my E5 to the HP out.

With my ADDIEMs, NE-7, and KSC75s there isn't any noticeable improvement vs. HP out. However it is much more convenient for me to not have to adjust the volume of the HP out or volume on the E5, as I have had some loud moments where I forgot to turn the volume back down. The biggest advantage of the HP out to the E5 is the volume can be set more precisely.

Here is a quote from a person that has a LOD:
"When I was using the HP port on the Fuze I didn't feel it could push my headphones properly even at the highest volume (HD595). I have a headphone amp which I had connected to the headphone port, this caused bass distortion as the output of the fuze had to be on max and the amp on near max to be adequete and I don't even listen that loud. With this cable I can have my amp on about 1 and still have the same amplitude as the hp socket on max and the amp on 8-9 and the best bit is there is no distortion"

Audible or not, let us know your experience, I like the increased flexibility of the Fuze. This is a great guide, thanks to ClieOS for the original, and thanks to S_J for reviving it. Hope many people can build their own and benefit.
post #8 of 22
Does the Fuze LO have volume control or is it like a Ipod LO where its a fixed volume?
post #9 of 22
fixed volume if you update to the latest firmware
post #10 of 22
Thread Starter 
The Fuze's volume is fixed with the LOD; as far as I can hear it is fixed at the same volume as the maximum headphone-out volume.
post #11 of 22
anyone build this and test the SQ difference recently?
post #12 of 22
Quote:
Originally Posted by Plex View Post
anyone build this and test the SQ difference recently?
this is interesting. i'm waiting for my fuze to get to me, i'll build one of these and update it hopefully by this weekend, or next week.
post #13 of 22
so i take this to mean that the Fuze volume control will not be functional and that one must only be concerned with the amp volume control?


Quote:
Originally Posted by pdupiano View Post
fixed volume if you update to the latest firmware
post #14 of 22
Quote:
Originally Posted by jh901 View Post
so i take this to mean that the Fuze volume control will not be functional and that one must only be concerned with the amp volume control?
Yes.
post #15 of 22
Just a question. Has anyone tested if the LOD is working correctly with a rockboxed fuze or not?
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