# FiiO X3 mod - AD8397 to AD8620



## ClieOS

Someone asked me to post the mod, so I thought I'll make it into an independent thread instead of putting it somewhere inside a X3 discussion.
  
 Basically the mod is as simple as it gets: open the X3 up, disconnect the battery, desolder the AD8397, solder in the AD8620, and put everything back.
  
 The goal is to remove the warmness from the AD8397 and replace it with something that sounds more neutral. AD8620 has been one of my personal favourite on portable amp, so it is my first choice. Another candidate will be OPA2209. Both will never be able to match the current output of AD8397 - however, realistically speaking, both already have more than enough output for_ typical _headphone anyway (* = won't be suitable for low impedance, low sensitivity, hard-to-drive 'phone). From experience, OPA2209 probably won't sound as neutral as AD8620, but it should be a good middle point between AD8620 and AD8397 - as alternative for those who find AD8620 too bright to their taste. Another side benefit of the mod will be a likely extended battery life, since both opamps draw less power than AD8397.
  





 AD8620 on top of X3, just for size reference.
  




 Be careful on the hold switch (just next to the silver battery). You need to see how it comes off so you will know how to put it back.
  




 Pull the battery connector out before any mod.
  




 The stock AD8397, just under the yet-to-solder AD8620. Do check the orientation carefully before desoldering / soldering!
  




 Done. Put everything back together now. If X3 shows some error on headphone connection, that means you have weak solder joint and you should retouch them with the iron.
  
 Note: Desoldering SMT is far harder than soldering. If this is your first SMT project, I seriously think you should practice on other thing first. The way I do is pretty much destructive to the original opamp, as I heated and pry a leg at a time, so they either break off or bend out of shape completely. I am sure there are far more elegant and least destructive way of doing it, just search youtube and you should find quite a few of the tutorials. I am however too lazy to bother, as I have some spare AD8397 around and don't need to save this one.
  
 The result is as I have expected, a much more neutral and detail presentation. I can almost compare it to the X3's line-out + O2. Well worth the effort as this finally brings out the transparency of the player than is somewhat hindered by the AD8397's warmness. Now the new X3 is a proper AK100 killer.


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## Levanter

nice!
  can i send you my X3 to mod too? =D


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## AmberOzL

Nicely done. I am not good on that skills I would probably ruin if I try something like that. Too bad for me.
   
  X3 is already an AK100 killer. Now it even kills it faster


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## RAFA

ClieOs you are awesome.


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## ClieOS

Thanks.
   
  There is actually another opamp inside, the AD8692 on the DAC output stage. Upgrading it will further improve headphone-out as well as line-out. I am thinking whether LM4562 will be suitable. But AD8692 is nice enough that I think I will keep it for now, maybe reserves as a future DIY project.


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## pekingduck

I also findthat the sound is not as detailed as I would like.... wish I had some DIY skills...


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## Emospence

AK100 killer


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## thegrobe

Wow this is awesome! 

Thanks for posting this. I have been avidly following the x3 development, and will certainly buy one as soon as it is available in the US. The one thing that is a bit of a worry to me is the "warm" sound signature. I really would prefer something more neutral. 

I have the soldering skills, this mod is a 100% no-brainer. Now just awaiting x3 availability.

Brilliant! Thanks!


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## RAFA

clieos said:


> Thanks.
> 
> There is actually another opamp inside, the AD8692 on the DAC output stage. Upgrading it will further improve headphone-out as well as line-out. I am thinking whether LM4562 will be suitable. But AD8692 is nice enough that I think I will keep it for now, maybe reserves as a future DIY project.




As soon as I get one X3,I will try at least the swap to ad8620, though I like warm sound.

Wonder how much diffeeence there will be when changing the dac output stage.

Just a few questions.

Is the DAC-output stage = the DAC buffer?

Is it a single ic?

Thanks rafa


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## ClieOS

Quote: 





rafa said:


> Is the DAC-output stage = the DAC buffer?
> 
> Is it a single ic?


 
   
  It is a dual channel opamp. Yes and no on the buffer - yes that it does act like a buffer; but no that it isn't there as buffer. WM8740 only outputs differential signal (positive+negative for both left and right) so you need an opamp to convert it to single ended signal (left/right/ground).


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## RAFA

Quote: 





clieos said:


> It is a dual channel opamp. Yes and no on the buffer - yes that it does act like a buffer; but no that it isn't there as buffer. WM8740 only outputs differential signal (positive+negative for both left and right) so you need an opamp to convert it to single ended signal (left/right/ground).


 
   
  Thanks for the info. I can prepare myself a little.


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## ClieOS

I abandon the idea of LM4562 for AD8692. Need to find a rail-to-rail, low power, low noise opamp for the job, and LM4562 isn't rail-to-rail. The search continues...


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## Armaegis

Heh, so now who's going to be adventurous and try to bend and fit this in with two OPA627's?


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## AmberOzL

Quote: 





clieos said:


> I abandon the idea of LM4562 for AD8692. Need to find a rail-to-rail, low power, low noise opamp for the job, and LM4562 isn't rail-to-rail. The search continues...


 
  ClieOS, at your signature it says almost time to leave with very small letters. Does it mean soon you will close head-fi account? I hope not


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## phantompersona

Can I send a x3 for you to mod?I'll gladly pay you


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## ClieOS

Quote: 





armaegis said:


> Heh, so now who's going to be adventurous and try to bend and fit this in with two OPA627's?


 
   
  I have a similar idea, but instead I was trying to make it into a rollable SOIC socket. However, it didn't materialize at the end because there is simple no space inside the X3. Anything taller than a typical SO8 opamp will hit the battery.
   
  Quote: 





amberozl said:


> ClieOS, at your signature it says almost time to leave with very small letters. Does it mean soon you will close head-fi account? I hope not


 
   
  I'll remain a member, but mostly as a lurker.
   
  Quote: 





phantompersona said:


> Can I send a x3 for you to mod?I'll gladly pay you


 
   
  Sorry, I don't have enough confidence in my DIY skill to take on another person's X3.


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## ButtUglyJeff

Hilarious...
   
  The X3 isn't even fully released, and someone is modding it.  Fantastic...


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## AmberOzL

Quote: 





> Originally Posted by *ClieOS* /img/forum/go_quote.gif
> 
> I'll remain a member, but mostly as a lurker.


 
  That's rather sad. I assume you have your reasons so I don't ask but I am sure you will be missed mate.


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## dw1narso

I hope James is reading this thread... , and offering X3HR  (hot-rod-ed edition 
	

	
	
		
		

		
		
	


	




 )


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## ClieOS

FiiO R&D team suggested ADA4896 as good candidate for modding, as it is also more neutral than stock and still does rail-to-rail. I am going to throw in AD8066 as an alternative as well. It is more aggressive and bright compared to AD8620, but it is rail-to-rail so you will keep the dynamic.


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## RAFA

Quote: 





clieos said:


> FiiO R&D team suggested ADA4896 as good candidate for modding, as it is also more neutral than stock and still does rail-to-rail. I am going to throw in AD8066 as an alternative as well. It is more aggressive and bright compared to AD8620, but it is rail-to-rail so you will keep the dynamic.


 
   
  I think, the higher the slew rate, the faster or more detailed the sound is.
   
  Why rail to rail?


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## ClieOS

Quote: 





rafa said:


> I think, the higher the slew rate, the faster or more detailed the sound is.
> 
> Why rail to rail?


 
   
  Not so much about detail sound - you want it not to be slew rate limited, but excessively fast slew rate doesn't do you much good. That is, you need it to be fast enough for music. Faster doesn't make much sense since we don't need it to be fast enough for ultrasound range and slower is definitely not going to be good.
   
  Rail-to-rail means the output of the opamp can swing very close to the supply voltage rail. Supply voltage in X3 is around +/-5V ~ +/-5.5V. So in theory, the stock AD8397's output can swing around +/- 5V (which is already more than X3's output volume in high gain) in full without clipping or inducing any noticeable noise. AD8620 on the other hand isn't rail-to-rail, so it will swing in much smaller range. If you have low sensitivity load that requires you to push for very high volume, AD8620 will begin to clip and distort. That's the downside of using AD8620 as it doesn't do rail-to-rail and doesn't have that much current output to deal with low sensitivity and low impedance load. But given those are more extreme cases, and usually not the kind of headphones I will use portably, AD8620 will still serve my purpose. Having a rail-to-rail opamp just gives you a bit more versatility when it comes to different headphone load. AD8397 in this case is actually technically a really good all-in-one solution. I would have kept it if not fro the obvious warmness. The way I see it is, if I really want to use a difficult to drive headphone, I'll just carry an amp with me. That's why AD8620 suits me just fine.


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## RAFA

Quote: 





clieos said:


> Not so much about detail sound - you want it not to be slew rate limited, but excessively fast slew rate doesn't do you much good. That is, you need it to be fast enough for music. Faster doesn't make much sense since we don't need it to be fast enough for ultrasound range and slower is definitely not going to be good.
> 
> Rail-to-rail means the output of the opamp can swing very close to the supply voltage rail. Supply voltage in X3 is around +/-5V ~ +/-5.5V. So in theory, the stock AD8397's output can swing around +/- 5V (which is already more than X3's output volume in high gain) in full without clipping or inducing any noticeable noise. AD8620 on the other hand isn't rail-to-rail, so it will swing in much smaller range. If you have low sensitivity load that requires you to push for very high volume, AD8620 will begin to clip and distort. That's the downside of using AD8620 as it doesn't do rail-to-rail and doesn't have that much current output to deal with low sensitivity and low impedance load. But given those are more extreme cases, and usually not the kind of headphones I will use portably, AD8620 will still serve my purpose. Having a rail-to-rail opamp just gives you a bit more versatility when it comes to different headphone load. AD8397 in this case is actually technically a really good all-in-one solution. I would have kept it if not fro the obvious warmness. The way I see it is, if I really want to use a difficult to drive headphone, I'll just carry an amp with me. That's why AD8620 suits me just fine.


 
   
  Thank you for the input. I always read these opamp specific designations and do not really understand them in connection with headphone audio.


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## wiser87

*ClieOS, your modified FiiO X3 with what you are listening to headphones? *


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## ClieOS

Quote: 





wiser87 said:


> *ClieOS, your modified FiiO X3 with what you are listening to headphones? *


 
   
  I am not sure what your question is. Are you asking which headphone I mod'ed my X3 for? If that's the question - I didn't mod the X3 with any particular headphone in mind. I have quite a large collection and don't usually listen to just one set. But most of them are not very difficult to drive so they should work on the mod'ed X3 just fine.


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## wiser87

ClieOS, Excuse me for my English. What headphones do you use? Together with FiiO X3?


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## ClieOS

Quote: 





wiser87 said:


> ClieOS, Excuse me for my English. What headphones do you use? Together with FiiO X3?


 
   
  Check out my profile to see what headphone I have. I really don't stick to just a pair of headphone. Some of the headphone I use frequently with X3 include HiFiman RE0, Etymotic ER4S, Sony MDR-1R, Beyerdynamic DT1350, LEAR LCM-5, JVC FXZ200, Sennheiser MX985, Blox TM7/ANV3, Denon C300 - just to name a few.


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## hoichi

Have you ever heard the AD835? I've seen at least one guy on HF preferring it to at least a dozen other op amps. He was talking about CMOY though.
  Going by the specs it's rail-to-rail too, so I'm thinking of trying it, once I get my X3.


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## ClieOS

Quote: 





hoichi said:


> Have you ever heard the AD835? I've seen at least one guy on HF preferring it to at least a dozen other op amps. He was talking about CMOY though.
> Going by the specs it's rail-to-rail too, so I'm thinking of trying it, once I get my X3.


 
   
  It is single channel so it is not suitable for X3 at all. It is also not rail-to-rail, according to the datasheet (typical +/-2.5V swing from +/-5V supply, so it is 50%). I don't even think it is classified as opamp. It is just not something I will use as opamp replacement without carefully looking into the circuit design it will be sitting in.
   
  Wait, are you sure it is AD835 and not AD827?


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## hoichi

Quote: 





clieos said:


> It is single channel so it is not suitable for X3 at all. It is also not rail-to-rail, according to the datasheet (typical +/-2.5V swing from +/-5V supply, so it is 50%). I don't even think it is classified as opamp. It is just not something I will use as opamp replacement without carefully looking into the circuit design it will be sitting in.
> 
> Wait, are you sure it is AD835 and not AD827?


 
  Man, this guy was talking about AD825. Why was I thinking about 835 all this time? Sorry for the confusion 
	

	
	
		
		

		
		
	


	



  Well, maybe the AD827 is the dual op-amp closest to the AD825. But obviously I don't know what I'm talking about


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## ClieOS

AD825 isn't rail-to-rail but it is close. However, it is still a mono channel and there is the concern over its 8 ohm output impedance. AD827 doesn't have a lot of voltage swing on low impedance load or current output as well. Also the output impedance is 15 ohm, worst than AD825.
   
  These are the kind of opamp that are more suitable if there is a buffer stage followed.


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## hoichi

15 ohm is sad news. I don't plan on using anything more than 50 ohm any time soon.


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## wiser87

*ClieOS*, say, sound good headphones VSonic GR-01 with the player FiiO X3?


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## ClieOS

Quote: 





wiser87 said:


> *ClieOS*, say, sound good headphones VSonic GR-01 with the player FiiO X3?


 
   
  They sound pretty good together.


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## wiser87

Thank you very much!


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## chengsta

"The result is as I have expected, a much more neutral and detail presentation. I can almost compare it to the X3's line-out + O2"
   
  so if I'm using the lineout I don't need this mod?  This is my takeaway from your tutorial.  So does that also mean that the line out is more neutral than the built in amp?


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## ClieOS

Quote: 





chengsta said:


> "The result is as I have expected, a much more neutral and detail presentation. I can almost compare it to the X3's line-out + O2"
> 
> so if I'm using the lineout I don't need this mod?  This is my takeaway from your tutorial.  So does that also mean that the line out is more neutral than the built in amp?


 
   
  Well, I think the more correct way of describing this will be, the amp section adds a touch of warmness to the line-out. Remember that the line-out isn't just an output on its own. The same line signal feeds into the amp section as well.
   
  Yes, what this means is that if you are using an external amp on the line-out, there is absolutely no need to mod the AD8397.


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## CH23

Subscribed.

Thanks for the mod&info, ClieOS!

And also thank you for all your reviews and advise


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## wiser87

ClieOS may I say stupid, because not very good at that. What do you think of mod in the THS4082?


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## ClieOS

Quote: 





wiser87 said:


> ClieOS may I say stupid, because not very good at that. What do you think of mod in the THS4082?


 
   
  The opamp meets the minimum voltage and has a decent swing, so it might work. However, it does seem it need a higher output resistance to be stable so I am not sure if this is a safe choice.


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## wiser87

What is the output resistance at the THS4082 compared to the AD8397 and AD8620?


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## ClieOS

Open loop resistance for THS4082 is 13 ohm. Also, a minimum of 20 ohm output resistor is suggested to avoid any oscillation. The actual output impedance will be over 20 ohm.
   
  In comparison, output impedance on AD8397 and AD8620 are all under 1 ohm.


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## wiser87

What opamp you have any advice for replacement AD8397?


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## ClieOS

Quote: 





wiser87 said:


> What opamp you have any advice for replacement AD8397?


 
   
  ADA4896 has been suggested by the FiiO R&D team to be suitable replacement.


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## cyberalpha11

Quote: 





clieos said:


> ADA4896 has been suggested by the FiiO R&D team to be suitable replacement.


 
  Will James (Fiio) consider to use ADA4896 for the new production batch of X3?


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## wiser87

ClieOS, but in your opinion what is better to use the opamp to modify FiiO X3: AD8620, ADA4896 or AD8066?


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## ClieOS

Quote: 





cyberalpha11 said:


> Will James (Fiio) consider to use ADA4896 for the new production batch of X3?


 
   
  I doubt that. FiiO picks AD8397 not just because it outputs a lot of power (more than any opamp that I know of. In fact, more than some buffer), but also offers a warmish sound. They thought a warmer sound is more suitable for the mainstream users, which is their targeted group of buyer.
   
  Quote: 





wiser87 said:


> ClieOS, but in your opinion what is better to use the opamp to modify FiiO X3: AD8620, ADA4896 or AD8066?


 
   
  By spec, ADA4896 seems to be the best. I have no experience with ADA4896 so I really can't say for sure. AD8066 will be the second choice (by spec). I pick AD8620 over AD8066 because I know I like AD8620 better, and it should be enough for my headphone. It is really hard to say for sure until you solder the opamp in as you can't really keep changing the opamp. Every time you desolder / solder an opamp, you will inflict more and more damage onto the PCB. So there is no easy way to try out all the opamp.


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## cyberalpha11

Quote: 





clieos said:


> I doubt that. FiiO picks AD8397 not just because it outputs a lot of power (more than any opamp that I know of. In fact, more than some buffer), but also offers a warmish sound. They thought a warmer sound is more suitable for the mainstream users, which is their targeted group of buyer.
> 
> 
> By spec, ADA4896 seems to be the best. I have no experience with ADA4896 so I really can't say for sure. AD8066 will be the second choice (by spec). I pick AD8620 over AD8066 because I know I like AD8620 better, and it should be enough for my headphone. It is really hard to say for sure until you solder the opamp in as you can't really keep changing the opamp. Every time you desolder / solder an opamp, you will inflict more and more damage onto the PCB. So there is no easy way to try out all the opamp.


 
  Now I can understand the reason.Thanks ClieOS.


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## ButtUglyJeff

Quote: 





cyberalpha11 said:


> Will James (Fiio) consider to use ADA4896 for the new production batch of X3?


 
   
  I wouldn't hold your breath.  But other companies, like VentureCraft, have had success with small batch/limited edition runs of their product, with minor changes like different opamps...


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## serious7

can the AD8397 be avoided by using the amp bypass lineout of the x3?


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## wiser87

ClieOS, in opamp ADA4896 socket MSOP-8. It is exactly suitable for modification?
   
  Can you talk about the opamp ADA4898-2?


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## ClieOS

Quote: 





serious7 said:


> can the AD8397 be avoided by using the amp bypass lineout of the x3?


 
   
  I think I mentioned it before, AD8397 only affects the headphone-out. If you use line-out, there is no need for mod.
   
   
  Quote: 





wiser87 said:


> ClieOS, in opamp ADA4896 socket MSOP-8. It is exactly suitable for modification?
> 
> Can you talk about the opamp ADA4898-2?


 
   
  MSOP-8 is pin compatible with SOP8 but comes in a smaller package. If you are good with SMD soldering you can bend the legs slightly and solder a MSOP-8 IC to a SOP-8 pad. It will require some skill and probably not for the faint of heart.
   
  ADA4898-2 look nice overall. But I am not sure if the epad soldering (which you can't do with a soldering iron) is required or not as the IC seems to run better with proper heat dispensation. It doesn't seem like an easy drop-in option as there are mentioning of circuit optimization for using this chip.


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## wiser87

*ClieOS*, say, ADA4896 can be installed instead of the AD8397 without intervention into the scheme of the device? It is only necessary to unsolder the AD8397, and solder the ADA4896?


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## ClieOS

Quote: 





wiser87 said:


> *ClieOS*, say, ADA4896 can be installed instead of the AD8397 without intervention into the scheme of the device? It is only necessary to unsolder the AD8397, and solder the ADA4896?


 
   
  Not just ADA4896. If you want to replace the AD8397 with any other opamp, you will of course need to remove / desolder it first. After that it is just a matter of carefully soldering the new opamp in. The tricky bit is of course ADA4896 is smaller so you need to be extra careful that the individual leg doesn't short circuit / touch other non-intended pad. As far as pins go, they are compatible according to the data sheet.
   
  Also, I haven't tried ADA4896 myself to say how it will sound. It is merely the suggestion from FiiO R&D team as a possible alternative of AD8397.


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## purk

Thanks for sharing, although the thought of desoldering such a small op-amp really scare me.


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## Armaegis

It's definitely not a project for someone who has never worked with surface mount stuff before. Even for someone that has, desoldering can be a pain if you don't have the proper tools. If you can be destructive, then it's easier. If you're trying to save the chip, the "simplest" method is probably to buy some "desoldering" solder (I forget the proper name of the stuff, but it basically lowers the melting temperature of the solder quite a bit once it's mixed in). Now you'll have a few seconds rather than a split second to move the chip once you've heated the pins. Heck, I think you might even be able to do it with a heat gun.


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## purk

Quote: 





armaegis said:


> It's definitely not a project for someone who has never worked with surface mount stuff before. Even for someone that has, desoldering can be a pain if you don't have the proper tools. If you can be destructive, then it's easier. If you're trying to save the chip, the "simplest" method is probably to buy some "desoldering" solder (I forget the proper name of the stuff, but it basically lowers the melting temperature of the solder quite a bit once it's mixed in). Now you'll have a few seconds rather than a split second to move the chip once you've heated the pins. Heck, I think you might even be able to do it with a heat gun.


 
  I've done it before but not with smaller op-amp such as this.  Thanks for your input though.


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## sinsiang

Has anyone heard the ADA4896 opamp before? Cos i can't find any reviews of this opamp and thus don't know it's sound.


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## Dixter

Well...  I'm thinking that I have phones that are bright at times and I have phones that aren't so bright at times.. and depending on what I'm listening to I chose the phones to match my listening mood...
   
  So for versatility I'm thinking to keep the X3 stock when I need the warmer output to the phones and when I need to get a neutral output to the phones I'll just plug in the O2 to the X3 output...
   
  I can't wait to plug the X3 into a Woo  
	

	
	
		
		

		
		
	


	



   
  Now if my wallet can stand the outflow for the FLAC files...


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## ClieOS

Was at a mini meet the other days. We let people blind listen to both mod'ed and stock X3, then decide which one they like better. I think almost everyone agree the mod'ed X3 sounds more balanced.


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## burtomr

Quote: 





clieos said:


> Was at a mini meet the other days. We let people blind listen to both mod'ed and stock X3, then decide which one they like better. I think almost everyone agree the mod'ed X3 sounds more balanced.


 
   
  Hmmm..... wonder why Fiio went with the 8397 if the 8620 sounds better or "more balanced"?


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## Armaegis

More current capacity on the AD8397?


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## hoichi

Quote: 





armaegis said:


> More current capacity on the AD8397?


 
  And more fun for an average consumer. Not everyone prefers flat signature, even among the head-fiers.


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## ClieOS

Quote: 





burtomr said:


> Hmmm..... wonder why Fiio went with the 8397 if the 8620 sounds better or "more balanced"?


 

 ^ what they said 
   
  AD8397 is a fine opamp. In fact, I really like how it sounds on the HM901's standard amp module. AD8620 sounds great but it is much less power. It drives my IEM well but will not meet the need of demanding headphones. It is basically a compromise to go with the AD8620 for a more balanced sound.


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## hoichi

Quote: 





clieos said:


> ^ what they said
> 
> AD8397 is a fine opamp. In fact, I really like how it sounds on the HM901's standard amp module. AD8620 sounds great but it is much less power. It drives my IEM well but will not meet the need of demanding headphones. It is basically a compromise to go with the AD8620 for a more balanced sound.


 
  BTW, what are the downsides of using OPA2209 instead of AD8620? I'm kinda scared of brightness so I thought maybe the OPA2209 is the safer choice.


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## ClieOS

Quote: 





hoichi said:


> BTW, what are the downsides of using OPA2209 instead of AD8620? I'm kinda scared of brightness so I thought maybe the OPA2209 is the safer choice.


 
   
  It is rail-to-rail and will work on X3's supply voltage, so those are the good thing. It is however not very high on current output and more importantly, the open-loop output impedance is very high. However, the actual output impedance will depends on the feed back resistor - I don't know the value of the resistor so I can't say for sure.


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## hoichi

Quote: 





clieos said:


> It is rail-to-rail and will work on X3's supply voltage, so those are the good thing. It is however not very high on current output and more importantly, the open-loop output impedance is very high. However, the actual output impedance will depends on the feed back resistor - I don't know the value of the resistor so I can't say for sure.


 
  So, (looking at the impendance/frequency graph) the OPA2209 might need an additional resistor even for, say, 30-50 Ohm cans?


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## ClieOS

Quote: 





hoichi said:


> So, (looking at the impendance/frequency graph) the OPA2209 might need an additional resistor even for, say, 30-50 Ohm cans?


 
   
  Open loop means there is no feedback to the opamp, gain will be way too high to be usable. Most amp section will have resistor feeding back the output to the negative input to set for gain. So the actual output impedance is basically the serial of load and feedback resistance. Anyway, this is a little too complicated for me to explain - Just note that it doesn't mean you need extra resistor on the output.


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## hoichi

Quote: 





clieos said:


> Open loop means there is no feedback to the opamp, gain will be way too high to be usable. Most amp section will have resistor feeding back the output to the negative input to set for gain. So the actual output impedance is basically the serial of load and feedback resistance. Anyway, this is a little too complicated for me to explain - Just note that it doesn't mean you need extra resistor on the output.


 
  Meaning I'll probably wait for someone more knowledgeable (or just daring) to try and use OPA2209 first.
  Anyway, I was curious how does the OPA2209 _sound_, compared to the AD8620? Is it the dual-channel variant of OPA209?
  Sorry for nagging you like this but I think your mod can be useful to a lot of people and maybe some other variants might be useful too.


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## ClieOS

Yes, OPA2209 is the dual version of OPA209. Basically it sounds like an improved version of OPA2227 (that you will find in most cmoy). It has the forwardness of the OPA2227, but in lesser degree, and better overall soundstage. Also, it doesn't have the graininess of the OPA2227 in the vocal range. I am not a big fan on the OPA2209 myself but it is a sound I prefer a lot over OPA2227.


----------



## rockaphile21

Will a fiio x3 go nicely with grado iem ? Which op-amp I have to use ?


----------



## serious7

so.. how many of you guys actually went ahead and modded your x3?


----------



## hoichi

Quote: 





clieos said:


> Yes, OPA2209 is the dual version of OPA209. Basically it sounds like an improved version of OPA2227 (that you will find in most cmoy). It has the forwardness of the OPA2227, but in lesser degree, and better overall soundstage. Also, it doesn't have the graininess of the OPA2227 in the vocal range. I am not a big fan on the OPA2209 myself but it is a sound I prefer a lot over OPA2227.


 
  I see. Thanks a lot for your time!


----------



## tomb

I really don't understand this thread, unless the FiiO implementation of the AD8397 is suspect.


----------



## ClieOS

Quote: 





tomb said:


> I really don't understand this thread, unless the FiiO implementation of the AD8397 is suspect.


 
   
  You don't need to suspect of OPA2134 on a cmoy to swap in a OPA2227, don't you?


----------



## tomb

Quote: 





clieos said:


> You don't need to suspect of OPA2134 on a cmoy to swap in a OPA2227, don't you?


 
  Apples and oranges.  The point is, the AD8397 is a superior opamp in every way.  More - it's quite tricky to design a circuit and PCB layout to get the AD8397 to run stable.
   
  I was simply pointing out that it just seemed the focus of the thread is - no offense - gutting the amp.


----------



## ClieOS

Quote: 





tomb said:


> Apples and oranges.  The point is, the AD8397 is a superior opamp in every way.  More - it's quite tricky to design a circuit and PCB layout to get the AD8397 to run stable.
> 
> I was simply pointing out that it just seemed the focus of the thread is - no offense - gutting the amp.


 
   
  Not offended. As I have pointed out in this thread before, technically AD8397 is a better chip. But I also pointed out why I have done this mod - willingly to go for a (technically) lesser chip for a sound I wanted. I did some RMAA measurement on both, and AD8397 wins (or at least par) on most accounts. However, last week we had a small local meet where we have two X3, one stock and one mod'ed (mine), and we asked people to listen to both without telling them which is which (so it is kind of a semi-blind test). Everyone on the meet who listened to both prefer mine, including a girls who isn't really an audiophiles herself but only went to the meet with her audiophiles boyfriend and being asked by her boyfriend to try out both X3.
   
  The point is, though AD8397 is technically better on spec - however, in the range of headphones I'll use portably (not demanding IEM mostly), AD8620 sounds better. So the mod makes sense for me based on what I need for a DAP. If I really need to use more demanding headphone that AD8620 can't handle, I'll go with an TOTL portable amp instead, which will outperform the stock AD8397 amp section just as well.


----------



## boombobby289

Quote: 





clieos said:


> Not offended. As I have pointed out in this thread before, technically AD8397 is a better chip. But I also pointed out why I have done this mod - willingly to go for a (technically) lesser chip for a sound I wanted. I did some RMAA measurement on both, and AD8397 wins (or at least par) on most accounts. However, last week we had a small local meet where we have two X3, one stock and one mod'ed (mine), and we asked people to listen to both without telling them which is which (so it is kind of a semi-blind test). Everyone on the meet who listened to both prefer mine, including a girls who isn't really an audiophiles herself but only went to the meet with her audiophiles boyfriend and being asked by her boyfriend to try out both X3.
> 
> The point is, though AD8397 is technically better on spec - however, in the range of headphones I'll use portably (not demanding IEM mostly), AD8620 sounds better. So the mod makes sense for me based on what I need for a DAP. If I really need to use more demanding headphone that AD8620 can't handle, I'll go with an TOTL portable amp instead, which will outperform the stock AD8397 amp section just as well.


 
  Between the modified Fiio X3 (with AD8620) vs Colorfly C3, which one has better detail, clarity, sound stage, separation and real bass?


----------



## ClieOS

Quote: 





boombobby289 said:


> Between the modified Fiio X3 (with AD8620) vs Colorfly C3, which one has better detail, clarity, sound stage, separation and real bass?


 
   
  Detail: X3 > C3, main on mid to low frequency with better texture.
  Clarity: on par
  SoundStage: almost on par, but C3 is a hair wider.
  Separation: C3 > X3, mainly because C3 has a slightly bigger soundstage but again, they are close.
  Bass: X3 > C3, more solid in body.
   
  The main difference between the two is that C3 is wide and clean, but lacks some of the lower end detail and texture. The mod'ed X3 has better lower end detail and texture and overall a more balance tonal distribution, but lesser in soundstage (though not bad per se).


----------



## Mr Trev

Maybe a stupid question, but I'll ask it anyways. Does swapping opamps have any benefits other than sound? If you swap for a lower power opamp wouldn't you get an extended battery life and lower heat generation.
  Cheers


----------



## burtomr

Quote: 





mr trev said:


> Maybe a stupid question, but I'll ask it anyways. Does swapping opamps have any benefits other than sound? If you swap for a lower power opamp wouldn't you get an extended battery life and lower heat generation.
> Cheers


 
   
  Quoting from 1st post: "Another side benefit of the mod will be a likely extended battery life, since both opamps draw less power than AD8397"
   
  Curious:  How did you get this far into the thread without reading the 1st post?


----------



## Mr Trev

It was a long time since I read the 1st post.....guess I forgot.


----------



## traililanam

I have seen some facebook pages that's modding x3's OPamp and DAC. As seen here (they also can mod it to be balanced)
   
https://www.facebook.com/media/set/?set=a.520435121356816.1073741858.489487097784952&type=3
   
  Any thoughts what will happen if you also change the WM8740 to WM8741? Better SQ?
   
  And "maybe" someone can compare the modded x3 (ad8620) to those android players with external DAC(HifimeDIY or ODAC) + c5 SQ?


----------



## ClieOS

Quote: 





traililanam said:


> I have seen some facebook pages that's modding x3's OPamp and DAC. As seen here (they also can mod it to be balanced)
> 
> https://www.facebook.com/media/set/?set=a.520435121356816.1073741858.489487097784952&type=3
> 
> ...


 
   
  Good thing those are HKD instead of USD they are quoting, or else the price are way over the top.
   
  Mod to balanced is actually fairly easy once you read WM8740's datasheet. The DAC itself is inherently balanced so you just need to bypass the I/V stage.
   
  I don't know whether WM8741 is actually that good a sound over WM8740, but I know it will further reduce the battery life by quite an significant amount as I remember WM8741 requires 3~4 times more power.


----------



## sunny25

After I replace AD8620. Test with GRADO 325is, GRADO 225, SONY XBA4- there is some distortion!!!!!
 UMMMM.......
 I take AD8397 back. for good result.


----------



## ClieOS

sunny25 said:


> After I replace AD8620. Test with GRADO 325is, GRADO 225, SONY XBA4- there is some distortion!!!!!
> UMMMM.......
> I take AD8397 back. for good result.


 
  
 Most likely sometime is wrong (faulty opamp or a weak solder join, perhaps?). I don't hear any distortion on my SR-325is and XBA-4.
  
 However, I do want to reiterate that AD8620 does clip when the volume is too high, but I have yet to find an IEM or headphone in my collection that actually causes clipping.


----------



## s0lar

Does the X3 have buffers? Some other rail-to-rail opamps that I know of might be usable.
 OPA1612 (doens't even need buffers) or AD8066 (stock opamp for iBasso D4).


----------



## ClieOS

s0lar said:


> Does the X3 have buffers? Some other rail-to-rail opamps that I know of might be usable.
> OPA1612 (doens't even need buffers) or AD8066 (stock opamp for iBasso D4).


 
  
 No. AD8397 already has buffer internally.


----------



## s0lar

clieos said:


> No. AD8397 already has buffer internally.


 
  
 Thanks. Then LMH6643, LT1678, OPA1612 might be suitable.


----------



## chesterqw

will the opa1662 work?


----------



## csumm

clieos said:


> Well, I think the more correct way of describing this will be, the amp section adds a touch of warmness to the line-out. Remember that the line-out isn't just an output on its own. The same line signal feeds into the amp section as well.
> 
> Yes, what this means is that if you are using an external amp on the line-out, there is absolutely no need to mod the AD8397.


 
  
 Hi
  
 I just got my X3 and love it, but have been intrigued by this thread. Thanks ClieOS! Having had and/or modified high end home audio equipment in the past, I am fully aware of the benefits and gains that can be made.
  
 But before I rush into anything (i.e. Ripping open my X3 and performing major surgery) you mentioned that if using the Line out with a suitable amp may give similar results.  Do you or anyone have any suggestions of a suitable portable headphone amp that would make the sound more neutral?  I guess I should be posting this on the help and suggestions forum..


----------



## ClieOS

chesterqw said:


>





> will the opa1662 work?


 
  
 On brief look, I don't see any problem.
  


csumm said:


> ... But before I rush into anything (i.e. Ripping open my X3 and performing major surgery) you mentioned that if using the Line out with a suitable amp may give similar results.  Do you or anyone have any suggestions of a suitable portable headphone amp that would make the sound more neutral?  I guess I should be posting this on the help and suggestions forum..


 
  
 If you are planning on using an amp with X3, then getting a good quality amp will just save you all the trouble of modding and possibly better sounding than a mod'ed amp section.


----------



## csumm

clieos said:


> On brief look, I don't see any problem.
> 
> 
> If you are planning on using an amp with X3, then getting a good quality amp will just save you all the trouble of modding and possibly better sounding than a mod'ed amp section.


 
  
 Thank you, that was what I am after.
  
 Are there any particular amps that you would suggest? While I have spent more years (and money) than I would care to remember in home audio, I am relatively new to high end portable sound. Any suggestions as to where to begin this new quest (ah, my wife will be angry at my new hobby, but at least it is not another woman!) would be appreciated. Any particular brands, models...?
  
 Thanks again


----------



## ClieOS

csumm said:


> Thank you, that was what I am after.
> 
> Are there any particular amps that you would suggest? While I have spent more years (and money) than I would care to remember in home audio, I am relatively new to high end portable sound. Any suggestions as to where to begin this new quest (ah, my wife will be angry at my new hobby, but at least it is not another woman!) would be appreciated. Any particular brands, models...?
> 
> Thanks again


 
  
 Depends on your budget and how much weight you are willing to carry, I'll say O2 (by JDS Labs, or other companies as it is an open source design) is one of the most colorless amp you can get for a very good price (~$150 or so). Meier Audio QuickStep is another amp I can wholeheartedly recommend for its balanced ground topology (similar to the sound of a balanced setup, I own the first gen. StepDance, QuickStep is the 3rd gen). Leckerton Audio UHA-6S MK2 is also a really good choice as well (I own the UHA-4, a stepdown with similar topology). UHA-6S MK2 also has SPDIF input that you can use with X3, though it doesn't support over 24/96. These will be my top three portable amp to recommend.


----------



## csumm

clieos said:


> Depends on your budget and how much weight you are willing to carry, I'll say O2 (by JDS Labs, or other companies as it is an open source design) is one of the most colorless amp you can get for a very good price (~$150 or so). Meier Audio QuickStep is another amp I can wholeheartedly recommend for its balanced ground topology (similar to the sound of a balanced setup, I own the first gen. StepDance, QuickStep is the 3rd gen). Leckerton Audio UHA-6S MK2 is also a really good choice as well (I own the UHA-4, a stepdown with similar topology). UHA-6S MK2 also has SPDIF input that you can use with X3, though it doesn't support over 24/96. These will be my top three portable amp to recommend.


 
  
 Thank you so much, this makes the search much easier to begin. I will see what is available in Taiwan, then look online
  
 Cheers for the advice!


----------



## CH23

Are there any websites where i could buy the ADA4896 or AD8620 opamps, that ships internationally? Google gives me nothing, and i wasn't planning on buying 100pcs.

-CH23


----------



## burtomr

ch23 said:


> Are there any websites where i could buy the ADA4896 or AD8620 opamps, that ships internationally? Google gives me nothing, and i wasn't planning on buying 100pcs.
> 
> -CH23


 
  
 Here it is....ready......*>>>* *eBay* *<<<*
  
http://www.ebay.com/itm/AD8620-Low-Noise-Wide-BandWidth-JFET-Precision-Dual-Op-Amp-AD8620ARZ-/171128413497?pt=LH_DefaultDomain_0&hash=item27d80c5d39


----------



## CH23

burtomr said:


> Here it is....ready......*>>>* *eBay* *<<<*
> 
> http://www.ebay.com/itm/AD8620-Low-Noise-Wide-BandWidth-JFET-Precision-Dual-Op-Amp-AD8620ARZ-/171128413497?pt=LH_DefaultDomain_0&hash=item27d80c5d39




Yes it seems that eBay is my only choice then, thank you


----------



## ClieOS

ch23 said:


> Yes it seems that eBay is my only choice then, thank you


 
  
 Don't buy opamp from eBay unless it is your ONLY / LAST choice, as there are too many fake opamp on there.
  
 Try Element 14 or RS Component for international location. Digikey or Mouser for USA. These are all well respected electronic component suppliers.


----------



## CH23

clieos said:


> Don't buy opamp from eBay unless it is your ONLY / LAST choice, as there are too many fake opamp on there.
> 
> Try Element 14 or RS Component for international location. Digikey or Mouser for USA. These are all well respected electronic component suppliers.




Thank you very much, ClieOS!

Now i have one question regarding the AD8620:

There's an AD8620 A, and an AD8620 B, but apart from their price, i don't know the difference between them. Which one should i buy?


----------



## ClieOS

ch23 said:


> Thank you very much, ClieOS!
> 
> Now i have one question regarding the AD8620:
> 
> There's an AD8620 A, and an AD8620 B, but apart from their price, i don't know the difference between them. Which one should i buy?


 
  
 'B' has a tighter spec than 'A', but for the content of the mod, A is totally fine.
  
 Even on the same wafer, there are some chips on the board that will perform slightly ahead / average / worst than others. It is a common practice for chip manufacturer to test chip and sell the tighter spec batch (of the same chip) for a higher price, where the average batch will be sold at normal price and the worst batch be sold as a lower model number at cheaper price. That's how they maximize profit.


----------



## sgrossklass

tomb said:


> I really don't understand this thread, unless the FiiO implementation of the AD8397 is suspect.


 
 It might actually be. Output impedance for the X3 is very low (spec = <0.3 ohms), and the AD8397 does not like driving significant amounts of capacitance without some extra series resistance. 2.2 ohms is recommended for up to 470 pF in the datasheet, while otherwise 270 pF is the recommended maximum. Now your average 3m Sennheiser cable, for example, weighs in at about 1 nF. That may be enough to upset the chip.
  
 By contrast, the AD8620 datasheet claims "excellent capacitive load driving capability" ... "can safely drive up to 10 nF". _Ta-Dah._
  
 AD8397 is a bit of a stupid chip. While it has significant current drive capability, it is not suitable for driving cans at very low output impedance, so it kinda falls flat in practice when you need to drive one of these super picky IEMs. A bit like the TPA6120A2 that requires a 10 ohm output resistor (well, rumor has it that this one was a failed DSL line driver anyway...).
  
 Using an MSOP part (like the ADA4896) for a headphone output driver is something that I wouldn't feel comfortable recommending. Such a tiny package has like no power dissipation at all. SO-8 is bad enough, they didn't come up with power pads for no reason. If you can accept a temperature of 100K above ambient, the ADA4896 can still dissipate 450 mW, but I wouldn't really want the poor chip to get that hot. At 55K above ambient, we're talking about 250 mW. Idle PD would be about 60 mW in the X3.


----------



## ClieOS

On the topic of TPA6120A2 - actually it can be implemented with output impedance under 1 ohm, just not by the book.. iFi Audio did that in their iCAN and the result is excellent.


----------



## wakibaki

clieos said:


> Don't buy opamp from eBay unless it is your ONLY / LAST choice, as there are too many fake opamp on there.
> 
> Try Element 14 or RS Component for international location. Digikey or Mouser for USA. These are all well respected electronic component suppliers.


 
  
 I bought many components on ebay without problems. Tubes from Russia, opamps, capacitors and pots from Thailand, PCBs and resistors from China. Be careful buying exotic transistors from China or parts known to be in short supply, but TPA6120 or PGA2320 from USA, or 50 NE5532 from Thailand, no problem at all. Some things just aren't worth counterfeiting. It's much less trouble, more convenient, and much less expensive than going to Farnell and having to buy £20 in components or have to pay shipping and handling. The one good thing about Farnell or RS is the next-day delivery.
  
 I'm with tomb. Unless there are multiple reports of the Fiio failing or oscillating with high capacitance cables, and I don't see any evidence of that, then dragging a surface mount chip off its pads to replace it with one which will have less current drive, the AD8397 being unsurpassed in that package, just seems to me like going looking for trouble. I'd be careful myself about designing the part into an enclosure with a shorting output connector like a 3.5mm stereo jack, since the datasheet suggests no output short-circuit tolerance, but there are probably 10's of thousands of these Fiios sold worldwide and all the problem reports I can find relate to a firmware problem with not starting up on first power-on.
  
 w


----------



## ClieOS

Of course not everything is counterfeited, but AD8620 is actually widely known among the Chinese as one of the most counterfeited opamp. If the Chinese counterfeit it a lot, then I'll assume many of them will be in the international market as well. For my POV, there is no need to take that risk unless it is out of necessity.
  
 As for the sound - I wish I can let you demo both a mod'ed vs a stock X3 like we have done on the Singapore meet, then it will be clean to you why the mod makes sense - just as it does to almost everyone who did the blind testing that day.


----------



## wakibaki

Well, I searched google for AD8620 counterfeit, problem, fake, I could only find 4 references, and 2 of them were on Head-fi, you were the author, and you had no direct experience, you were relying only on reports from other people. The other references weren't well supported, one at least being based only on a suspicion that the price was too low.
  
 You have to be careful about starting or propagating 'Internet Legends' especially when substituting opamps doesn't work out as well as hoped, an ill-advised opamp change can easily degrade performance.
  
 Consider that the AD8397 will drive 310mA into a 32 ohm load, where the 8620 is good for 30mA only, and that into an unspecified load. This is a factor of 10+ in only a single parameter, albeit quite a significant one where driving low impedances is concerned. A little arithmetic suggests that (11.8V/0.03A = 393 ohms) the AD8620 will only happily drive just under 400 ohms before the output voltage starts to become restricted, whether it simply falls off or clips is open to speculation. What is certainly true is that with lower impedance loads the distortion will rise, perhaps giving rise to the differences detected in your 'blind testing'.
  
 As for the necessity of taking risks, surely it would be a lot less risky to just leave the original opamp in place and not risk damaging the PCB?
  
 w


----------



## ClieOS

I guess you didn't search in Chinese? Well, never mind that. Maybe I am just being overcautious there but as I have said - if you can get 100% genuine part without concern over how much you pay (or any other factors on that matter), why don't you? What is the bad in that?
  
 Also, all of the downside of swapping the opamp has been mentioned, if you have read my posts in this thread more carefully. While RMAA test isn't exactly an industry standard like an AP machines, I did carry out measurement on multiple loads to at least confirm my mod didn't ruin the day, at least to the kind of load I was planning to use. Unless someone is willing to give / loan me an AP, I am afraid that isn't much I can do more. As for the risk management on mod'ing - I am sure that's mostly relate to individual's soldering skill more than anything? Last I checked,  I did warn people about it.


----------



## EuphonicArin

Don't mean to bring this OT, but, Clieos which version of the AD8066 should I use when I want to do this mod (I'm new to Opamps, so I was wondering which would work the best on this list: http://components.arrow.com/part/search/ad8066?region=na)?


----------



## ClieOS

euphonicarin said:


> Don't mean to bring this OT, but, Clieos which version of the AD8066 should I use when I want to do this mod (I'm new to Opamps, so I was wondering which would work the best on this list: http://components.arrow.com/part/search/ad8066?region=na)?


 
  
 You don't want to order 1000 or 2000 opamp (under 'multiple' tab), so you can cross those out. That leaves you with 5 options. Then you don't want the evaluation board (-EBZ) for sure, so now there are only 4 options. Anything with an M (ARMZ and ARM) means it is MSOP8 instead of SOIC8, so we don't want those as well. The two choices left are the AD8066AR and AD8066ARZ - Z means RoHS compliance, which doesn't matter to us, so either one of them will do. But ARZ is cheaper, so that's the one to get.


----------



## s0lar

I have done my mod. AD8397 replaced with OPA1602. OPA1612 and OPA1602 sounded very similar and OPA1602 is even less power hungry. Output current is the same for both, 30mA but plenty for IEMs.
  
 I used flux, a temperature controlled soldering station, desoldering wick, leaded solder, tweezers, a screwdriver and a light.
  
 I ran into some problems.
  
 First I was not carefull with desoldering/removing the AD8397 and loosend a connection pin on the circuit board. I put it back into place and started soldering the OPA1602 but again screwed up and this time the pin broke. I thought this is the end but I saw the pin was connected to one end of a SMD-part and figured I could connect the opamp pin to that. After soldering the pins on the other side of the opamp, I put on enough solder to connect the two points and made sure they were connected without making other shorts. All was into place, the HOLD-button was another obstacle.
  
 Luckely it works and now it sounds a lot better to my ears. There is almost no difference between my iBasso D4 with OPA1612 and my X3, using T5 is no longer required to get the sound I want.
  
 The mod is not easy! The most difficult part is removing the AD8397, if you do that in a careless way, you can screw up hard. I have quite good soldering skills but at my previous job I had a better soldering iron (tip).


----------



## ClieOS

s0lar said:


> The mod is not easy! The most difficult part is removing the AD8397, if you do that in a careless way, you can screw up hard. I have quite good soldering skills but at my previous job I had a better soldering iron (tip).


 
  
 Great that you find the reborn X3 better. Yep, this is definitely not for novice.


----------



## wakibaki

If you _must_ attempt this mod, then it's better to _cut_ the AD8397 off the board. You do this with the tip of a scalpel or craft knife, cutting the legs one-by-one, as close to the chip's body as you can get the knife. If you do it right the blade will come to rest on a tiny ledge on the chip instead of contacting the PCB. You have to press hard, holding the knife very firmly to avoid breaking the blade. You will hear a tiny 'click' when the chip leg parts. When the chip falls away from the board pick up all the legs on a hot soldering iron, they will stick to it, and tidy up the remaining solder on the pads with solder wick. Work quickly to avoid lifting a pad from the board.
  
 Of course the AD8397 will be useless for any further electronics, but it's probably better not to try to re-use it anyway.
  
 w


----------



## docentore

Ok, I'm almost ready for the mod myself. I'm loving X3 as DAP, but I still feel like I'm missing something there, but this is just my nature 
  
 So I gathered all op-amps I had around and this is what I have left:
  
 AD8599, AD8620, AD8022, LME49720 - all tested in my C-Moy at some stage, liked all of them, loved AD8599 and L49720
 AD8512, OPA1662 - not tested.
  
 I know that none of you have crystal ball to answer if above will sound good to me, but do you think that apart from AD8620 (which was already tested) can be fitted? I really want to try 8599 or/and 49720, but I'm aware that number of tries is limited.
 What do you think about the rest?
  
 Cheers


----------



## burtomr

^.........


----------



## CH23

docentore said:


> Ok, I'm almost ready for the mod myself. I'm loving X3 as DAP, but I still feel like I'm missing something there, but this is just my nature
> 
> So I gathered all op-amps I had around and this is what I have left:
> 
> ...




I would suggest soldering some wires to the points where you would normally put the OPAMPs, and try each opamp, soldering them to the wires

This way you don't screw up the X3's board.


----------



## docentore

ch23 said:


> I would suggest soldering some wires to the points where you would normally put the OPAMPs, and try each opamp, soldering them to the wires
> 
> This way you don't screw up the X3's board.


 
  
 Thanks for the suggestion, but:
 1. I would be concerned about the noise, distance to the components (ie coupling caps), etc.
 2. I actually screwed my last mod by using this method on my amp, I could test the op-amps ok, but the sq was deteriorated because of the reasons above and I messed up the board because I wasn't careful enough. Nothing that cannot be repaired but I would like to avoid this.
  
 Hence I want to make the swap on the first, worst case scenario on the second try


----------



## CH23

docentore said:


> Thanks for the suggestion, but:
> 1. I would be concerned about the noise, distance to the components (ie coupling caps), etc.
> 2. I actually screwed my last mod by using this method on my amp, I could test the op-amps ok, but the sq was deteriorated because of the reasons above and I messed up the board because I wasn't careful enough. Nothing that cannot be repaired but I would like to avoid this.
> 
> Hence I want to make the swap on the first, worst case scenario on the second try




I wish you the best of luck. 

I haven't bought components yet to mod mine, so i'm glad you're also willing to test it ;P


----------



## serious7

docentore said:


> Thanks for the suggestion, but:
> 1. I would be concerned about the noise, distance to the components (ie coupling caps), etc.
> 2. I actually screwed my last mod by using this method on my amp, I could test the op-amps ok, but the sq was deteriorated because of the reasons above and I messed up the board because I wasn't careful enough. Nothing that cannot be repaired but I would like to avoid this.
> 
> Hence I want to make the swap on the first, worst case scenario on the second try


 
 I think the issues you described above were due to poor modding skills. Wires sounds like a proper bet to me. I mean we use wires on bread boards and it all works fine. Why won't it work in your case?


----------



## docentore

serious7 said:


> I think the issues you described above were due to poor modding skills. Wires sounds like a proper bet to me. I mean we use wires on bread boards and it all works fine. Why won't it work in your case?


 
 I'm new to audio DIY and I assumed that wire testing of elements to choose the best op-amp in smd enviroment, were resistance of few ohms and capacitance difference of couple of pico-farrads on wires, which are also acting as antenna makes a difference. But obviously it was my poor modding skills made the sq bad as you noticed.
  
 My modding skills are completely fine actually the only problem is I have trouble with attention to details. Because it isn't cMoy breadboard build anymore I prefer not to make any mistakes and not to choose the ic that cannot be rolled to many times carefully. 
  
 Re:1 I'm not new to modding/building/repairing, I've fixed and modded tones of PC's and consoles (that's including reballing bga chips when I was doing this for living), but I'm completely new to DIY audio. I've build my first kind-o-cmoy 4 months ago with opamp I found on old tv pcb when I was bored. But as I've said sometimes I make stupid mistakes.
 Re:2 I damaged it because I wasn't careful when taking off "the test wire installation" (lack of attention)


----------



## serious7

docentore said:


> I'm new to audio DIY and I assumed that wire testing of elements to choose the best op-amp in smd enviroment, were resistance of few ohms and capacitance difference of couple of pico-farrads on wires, which are also acting as antenna makes a difference. But obviously it was my poor modding skills made the sq bad as you noticed.
> 
> My modding skills are completely fine actually the only problem is I have trouble with attention to details. Because it isn't cMoy breadboard build anymore I prefer not to make any mistakes and not to choose the ic that cannot be rolled to many times carefully.
> 
> ...


 
 You must have access to oscilloscopes then? I'm sure you can design a test amplifier circuit where you can measure the impact a wire can have on the entire design. Have the oscilloscope point between the two outputs and see for yourself if the wire did any damage for your circuit.  My experiences with this is that there is no impact of introducing a wire whatsoever to an amplifier circuit.


----------



## docentore

serious7 said:


> You must have access to oscilloscopes then? I'm sure you can design a test amplifier circuit where you can measure the impact a wire can have on the entire design. Have the oscilloscope point between the two outputs and see for yourself if the wire did any damage for your circuit.  My experiences with this is that there is no impact of introducing a wire whatsoever to an amplifier circuit.


 
  
 I do have access to oscilloscope but prefer to use my ears to judge sq differences. 
  
 I'm sure that in simple wire breadboard design extra 30-40cm of metal wire doesn't make huge difference, but again this is a little more complicated design.


----------



## s0lar

I first tried the opamps in the iBasso D4 and auditioned every opamp. I also tried the AD8397 in the D4 to hear if the opamp sounded similar in the iBasso D4 as it did in the X3. Since it did sound very similar I concluded the other way around would also apply. So I suggest you to try the opamps in a swappable config and find out AD8397 shares the same sound with that setup as it does inside the X3. iBasso D4 has the same DAC-chip as X3.


----------



## serious7

docentore said:


> I do have access to oscilloscope but prefer to use my ears to judge sq differences.
> 
> I'm sure that in simple wire breadboard design extra 30-40cm of metal wire doesn't make huge difference, but again this is a little more complicated design.


 
 if there is no noise found in signal readings, then what makes you think the human ear can detect signal noise better? It's not like we have the mental capacity to calculate SNR with just our eardrums! 
 You have the tools in place as you have said. Take the advice of the other member and use the wire (if it's possible to do so)  just to be safe 
	

	
	
		
		

		
			





. Please do tell us of your findings.


----------



## docentore

serious7 said:


> if there is no noise found in signal readings, then what makes you think the human ear can detect signal noise better? It's not like we have the mental capacity to calculate SNR with just our eardrums!
> You have the tools in place as you have said. Take the advice of the other member and use the wire (if it's possible to do so)  just to be safe
> 
> 
> ...


 
  
 You are almost right, but you know that one's opinion about SQ is very subjective and vulnerable to many factors. Seeing wires hanging could affect my view. But I'll give it a go (I'll have the AD8397 out anyway). 
 I'll use the IC's that I already have in BrownDog dip adaptors and use short wires connected to dip socket on piece of protoboard. Much less soldering , results would be same.


----------



## serious7

docentore said:


> You are almost right, but you know that one's opinion about SQ is very subjective and vulnerable to many factors. Seeing wires hanging could affect my view. But I'll give it a go (I'll have the AD8397 out anyway).
> I'll use the IC's that I already have in BrownDog dip adaptors and use short wires connected to dip socket on piece of protoboard. Much less soldering , results would be same.


 
 take pictures and post them here!


----------



## docentore

Once I'll have a day to spare will do. Wouldn't like to be left without DAP.

EDIT: 16/10/13

Decided to mod the DAP anyway without test phase. The choice was between 3 chips anyway - AD8599, AD8620 and AD8066. I liked all of them in my JDS cMoy but here decided to solder the 8066 op-amp.
I like it, I like it a lot. The sound lost some warmness but also a bit of muddiness. There is a lot more bass but it's punchy bass, I actually had to take 2 points down on bass. Listening some classic Jarre now and new dubstep tracks. With dubstep I feel like someone is massaging my ears, with Jarre I can almost hear him touching the keyboard


----------



## veracocha

How can you describe the sound differences modded and unmodded x3 ?


----------



## docentore

The sound is definitely more clear, but there is also more bass. It's not not muddy bass though, feels faster, sounds better, just had to drop it 2 points down.
 Overall after week of listening I'm glad I did it.


----------



## puskuruk

What do you think 8620+wm8741 with the er4s?


----------



## EuphonicArin

Does anyone know the amount of juice that the batteries in the x3 have?


----------



## RochRx7

euphonicarin said:


> Does anyone know the amount of juice that the batteries in the x3 have?


 
 I'm getting 7-9 hours average depending on volume,gain,cans used... if that's what you're asking heh


----------



## serious7

docentore said:


> Once I'll have a day to spare will do. Wouldn't like to be left without DAP.
> 
> EDIT: 16/10/13
> 
> ...


 
 Thanks for the update! I'm personally too scared to mod the X3 since I have poor soldering skills.  
  
 Glad you are enjoying the DAP!


----------



## docentore

During last 2 days i did some more testing. First I decided to swap the second op-amp (DAC output one) and I found how if hugely affects the sound! First tried LM7332 - it was awful, slow and muddy, but I didn't had many more options. The ic works on +5V (single supply) and it's r2r. Today decided to move the AD8066 from the headphone output in place of AD8692 and solder AD8599 in place where AD8397. 
  
 Loving the combination so far.


----------



## JuicyBruce

Hi Folks - I have a chap lined up to do the soldering work and I was wondering if the ISL5502 would suit?
  
 A link to the datasheet
http://www.ic-on-line.cn/view_online.php?id=1161594&file=0077\isl55020irz-t13_711159.pdf
  
 Cheers! JB


----------



## chesterqw

is the muses8820 okay for this mod? it is bipolar too but didn't state it is rail to rail in datasheet.


----------



## docentore

juicybruce said:


> Hi Folks - I have a chap lined up to do the soldering work and I was wondering if the ISL5502 would suit?
> 
> A link to the datasheet
> http://www.ic-on-line.cn/view_online.php?id=1161594&file=0077\isl55020irz-t13_711159.pdf
> ...


 
  
 100% not, the one that you have listed is in 16qfp packacge. Pin wise one you need is 8-SOIC


----------



## JuicyBruce

docentore said:


> 100% not, the one that you have listed is in 16qfp packacge. Pin wise one you need is 8-SOIC


 
  
 Sorry - probably sent that too quickly. This is it mounted on an adaptor inside my D10 (with class A mod).
 Ill do a bit more hunting for specs...
  

  
 Edit - right so im an idiot. Had a missing zero. Here are the specs:
  
 http://www.intersil.com/en/products/amplifiers-and-buffers/all-amplifiers/amplifiers/ISL55002.html


----------



## vale25

hello guys
 from what I understood, dac buffer opamp is in a single supply design. Am I right?
 Does someone know why? could not they use negative rail of ad8387 also for the buffer opamp?
 I think ad8692 is a very low quality chip, and it's the bottleneck of the player.
 what do you think about it?


----------



## docentore

vale25 said:


> hello guys
> from what I understood, dac buffer opamp is in a single supply design. Am I right?
> Does someone know why? could not they use negative rail of ad8387 also for the buffer opamp?
> I think ad8692 is a very low quality chip, and it's the bottleneck of the player.
> what do you think about it?


 
  
  You are right - it is single supply op-amp. I didn't want to risk and connecting the -/+5.5V rail to it.
  
 Any suggestions regarding which chip could we use? I was thinking of ADA4841-2 or ADA4896-2, but I don't have any experience with them. Which op-amp could be suitable that is considered as good for audio and DAC buffer?


----------



## vale25

docentore said:


> You are right - it is single supply op-amp. I didn't want to risk and connecting the -/+5.5V rail to it.
> 
> Any suggestions regarding which chip could we use? I was thinking of ADA4841-2 or ADA4896-2, but I don't have any experience with them. Which op-amp could be suitable that is considered as good for audio and DAC buffer?


 
 I checked in the data scheet. AD8692 does not accept negative voltage rail. I think that the only way to make a real improvement on  sonic performance is changing this opamp with an audio grade opamp and give it negative supply through a hard wire. Also a cap should be used near the opamp pin. But this is sci-fi for me.


----------



## wakibaki

vale25 said:


> hello ad8692 is a very low quality chip, and it's the bottleneck of the player.
> what do you think about it?




Why do you think that? Because it says 'low cost' in the datasheet?

The 8692 is a high performance, single-supply device, intended for portable audio devices.

If you guys don't understand that cost and performance aren't synonymous, then it won't be any surprise to the rest of us when you end up breaking your DAPs.

Wiring in a dual-rail device and wiring in a negative supply will have unknown consequences in terms of the output DC offset of the DAC section without detailed knowledge of the circuit. This will have an unknown knock-on effect on the amplifier section. A single-rail supply device has been employed for some reason when a dual-rail supply was available. The DAC output is almost certainly a current one, and the opamp is being used for I-V conversion. Current-output DACs frequently have a DC output offset to keep the (dual-rail) opamp working in class A, but this may not have been considered desirable in a battery-powered device because of the drain on the battery, or there may have been some other reason, but whatever it is, _you don't know._

Get a grip, and don't mess with what you don't understand.

w


----------



## docentore

wakibaki said:


> The 8692 is a high performance, single-supply device, intended for portable audio devices.
> 
> If you guys don't understand that cost and performance aren't synonymous, then it won't be any surprise to the rest of us when you end up breaking your DAPs.
> 
> ...


 
  
 Great advice, leave all learning and experimenting because we don't understand. Sorry, I wasn't born with this great knowledge so I need to learn if I want to know. And I'm learning by reading, asking questions and experimenting. And I'm experimenting on stuff that I own, if I'll break it - well life is hard but one needs to break some eggs to make an omelette.
  
 Get a grip and share some of your great knowledge instead of criticise and patronise other members.


----------



## wakibaki

docentore said:


> Great advice, leave all learning and experimenting because we don't understand. Sorry, I wasn't born with this great knowledge so I need to learn if I want to know. And I'm learning by reading, asking questions and experimenting. And I'm experimenting on stuff that I own, if I'll break it - well life is hard but one needs to break some eggs to make an omelette.
> 
> Get a grip and share some of your great knowledge instead of criticise and patronise other members.




If you think that gets it then you obviously haven't read my other contributions to this thread.

w


----------



## docentore

wakibaki said:


> If you think that gets it then you obviously haven't read my other contributions to this thread.
> 
> w


 
  
 Actually I did, and I found the one with using knife to extract ic quite useful, but the rest is just "manufacturer knows better what sound you like, leave this as is".


----------



## s0lar

Changing the AD8397 should have more influence than changing DAC output opamp (AD8692) I would think. 
  
 You could ask James at Fiio, he responds quite fast to questions.


----------



## vale25

wakibaki said:


> Why do you think that? Because it says 'low cost' in the datasheet?
> 
> The 8692 is a high performance, single-supply device, intended for portable audio devices.
> 
> ...


 
 I think it not for datasheet low cost indication. The reason is that when I use the DAP from line output, I notice a harshness and a grain in the treble that can't be attributed to wolfson wm8740. (I know there are a lot of other possible reasons for this, but buffer opamp appear to be the most probable)
  
 WM8740 is a voltage output dac.
 I believe single supply op amp was chosen to keep low the power consumption, but if there is any reason would be nice to know.
I'm always ready to learn; maybe my poor mastery of english language gave you a different impression, but when I wrote "what do you think about", I really wanted to know your thought about it. A little less arrogance from your side would have been great.
Said this, unless James fiio say to me " change that opamp, it was placed there only for long battery life", I'd never open my x3


----------



## docentore

s0lar said:


> Changing the AD8397 should have more influence than changing DAC output opamp (AD8692) I would think.
> 
> You could ask James at Fiio, he responds quite fast to questions.


 
  
 You are right it does affects the sound more than DAC output, but changing the ad8692 does change the signature of the DAP significantly. I was able to say straight away that there is something different, better or worse (tried 3 or 4 differents chips already).
  
 I'm not going to mod anymore until someone more experienced could advise *in polite* way what are good candidates for the DAC output op-amp.


----------



## s0lar

I just checked and my iBasso D4 uses AD8616 as DAC output opamp. It works single supply 2.7V to 5V and is a CMOS rail-to-rail opamp, just like the AD8692.
 AD8066 is a FET opamp.
 iBasso D4 has dual DACs though.
 You should be carefull since clipping can occur at the DAC output when you swap the opamp. I have no idea about the signal that the DAC puts out, safest is to ask Fiio directly.


----------



## wakibaki

So sorry to trample on your delicate sensitivities. My advice, grow a thicker skin and just push ahead with the 'experiment' next time without asking. Wire in a dual-rail opamp, after all the worst that it can cost you is the price of a new X3...   
	

	
	
		
		

		
			





 
  
 w


----------



## Mad Max

wakibaki said:


> So sorry to trample on your delicate sensitivities. My advice, grow a thicker skin and just push ahead with the 'experiment' next time without asking. Wire in a dual-rail opamp, after all the worst that it can cost you is *the price of a new X3*...
> 
> 
> 
> ...


 
  
 Or the price of whatever headphone that you choose to test the sound with.


----------



## docentore

s0lar said:


> I just checked and my iBasso D4 uses AD8616 as DAC output opamp. It works single supply 2.7V to 5V and is a CMOS rail-to-rail opamp, just like the AD8692.
> AD8066 is a FET opamp.
> iBasso D4 has dual DACs though.
> You should be carefull since clipping can occur at the DAC output when you swap the opamp. I have no idea about the signal that the DAC puts out, safest is to ask Fiio directly.


 
  
 I took your advice and ordered some AD8656 and ADA4841-2. Both were mentioned in iBasso D1 thread, the latter was recomended on erji.net (I used google translate).
 So another day another swap 
  
 I've soldered ADA4841-2 as DAC output IC and LMH6643 as headphone amp (as per erji.net and D1 threads). I've listened the DAP for literaly 5 minutes before going back to work, so no opinion as yet, apart from the facts it works. I'm going to leave ADA in place and do some rolling on the headphone output - LMH6643, LME49720, AD8599 and AD8620.
  
 EDIT: after 2 hours of constant listening to my favourites tracks decided to keep the DAP like it is now, with ADA4841-2 and LMH6643. The sound blew my mind, the level of details, clarity and dynamics is just right. No more rolling for now


----------



## Septique

​​Dear friends,
 ​
 Could anyone send me HiRes photo of Fiio X3 board with removed (unsolder) Wm8740 DAC chip 
  which would have been clearly visible line contacts under the chip?

 I casually damaged a few contacts under the chip
​and now it's difficult to restore them​ without a photo 
 I will be very grateful to you for your help!!!!
 Thank you!!
 my email: discostyle@gmail.com


----------



## chesterqw

modded it with the muses 8820 just now, and it works 
  
 unfortunately i don't have another x3 with me so i can't really test whether it was for the better or worst :x
  
 it stills sounds great to me though.
  
 the 2 caps at the side was PITA and not soldering anything for months was making things very hard.


----------



## palermo

sorry, I am not very clear with this mod, just give me answer for this silly question.
 I thought AD8397 is an opamp with gain (amplifier), and after ask to my google, I found wolfson wm8740 follow by lowpass filter, so which one in this X3 design? 
 If I have to mod this X3, I would go to replace the lowpass filter opamp, rather than amplifier opamp.


----------



## GiantTree

The X3 doesnt have Low pass filter.


----------



## palermo

I mean, differential to single ended opamp.


----------



## SergBill

just replaced the AD8397 to AD8620, but the sound change is not found.
 headphone DT 770 Pro 80 ohm
 perhaps only the amount of bass was slightly less


----------



## CH23

sergbill said:


> just replaced the AD8397 to AD8620, but the* sound change is not found*.
> headphone DT 770 Pro 80 ohm
> perhaps only the amount of *bass was slightly less*


 
 i would say that it does exactly what it should then?


----------



## SergBill

I'm not sure. i have no x3 else to compare


----------



## SergBill

_LT1886 is better_ for low-resistance headphones. I recommend, very good result.


----------



## SergBill

lt1886 is very good for low-impedance headphones, I recommend.


----------



## fnb1

I havent read the whole tread, but where can I get the OPA2229? The only thing I can find that comes close to the Number is OPA228 or 2227?
 I would like some more clarity and maybe less bass, but dont like anything to become sharp or harsh!


----------



## ClieOS

It is OPA2209. OPA2229 is just a typo, sorry.


----------



## csumm

I really want to thank you so much.
  
 I ordered an O2 amp from Epiphany acoustics that arrived on New Years's Eve. I bought the connecting cable yesterday and hooked it up and it has already improved my system. The Fiio X3 sounded good already; the new Fiio cables on my Shure SE215s made a big difference, but this amp has truly transformed my system from the first time I plugged it in.
  
 Thanks for your great advice. It saved me a lot of time and made a huge difference for very little money
  
 Thanks again
  
 Cheers


----------



## csumm

ClieOS

 


Sorry, I made a mistake in replying to an earlier answer you gave to me.


 


I wish to credit you with the invaluable information you gave me (Previous post)


 


Thank you so much. You are my new God. Can I marry you and bear your children?


 


Cheers


----------



## ClieOS

I'll take the proposal under consideration.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
 ....well, maybe not. Enjoy the new toys!


----------



## csumm

the offer is till there.. in kind..  I could perhaps offer my wife instead of myself while I listen to my wonderful new sounds..
  
 Not sure she would agree,
  
 She is cute though
  
 Haha, thanks again


----------



## e30pilot

This might sound like a silly question but is there a way to maybe emulate the 8620 sound signature by maybe dialling down the bass setting on a stock X3?


----------



## ClieOS

e30pilot said:


> This might sound like a silly question but is there a way to maybe emulate the 8620 sound signature by maybe dialling down the bass setting on a stock X3?


 
  
 Would be great if that could be done, but no.


----------



## razorblader

csumm said:


> I really want to thank you so much.
> 
> I ordered an O2 amp from Epiphany acoustics that arrived on New Years's Eve. I bought the connecting cable yesterday and hooked it up and it has already improved my system. The Fiio X3 sounded good already; the new Fiio cables on my Shure SE215s made a big difference, but this amp has truly transformed my system from the first time I plugged it in.
> 
> ...


 

 Got mine from Oliver a few days after New Year's, the Epiphany Acoustics O2 is really nice. Congrats on money well spent...to both of us.


----------



## csumm

Quote: 





razorblader said:


> Got mine from Oliver a few days after New Year's, the Epiphany Acoustics O2 is really nice. Congrats on money well spent...to both of us.


 
 I'll drink to that!
  
 Oh, wait.. I am already.. While listening to the X3/O2 combo. ha
  
 Cheers


----------



## razorblader

csumm said:


> I'll drink to that!
> 
> Oh, wait.. I am already.. While listening to the X3/O2 combo. ha
> 
> Cheers


 





 Scientists have proven that drink&X3&O2 can significantly improve your well-being! Burp!
  
 Cheers


----------



## Techtard

Would just like to ask, does this mod make a noticeable difference in SQ?
 Currently using my stock X3(+2db treble) with the beyerdynamic custom one pro's(may upgrade to some jh customs later)
 Wish to have more clarity and soundstage.Listen mostly to alternative rock, pop)
 Btw this is my first post on head-fi


----------



## locksbury

razorblader said:


> Scientists have proven that drink&X3&O2 can significantly improve your well-being! Burp!
> 
> Cheers


 
 Well I hope it does, as I'm seriously considering this combo of gear later in the year. 
	

	
	
		
		

		
		
	


	



  
 Would I be better off just using the X3 in DAC mode to drive the O2 amp on the desk and do the mod in post 1 of this thread for when I'm on the move or is it worth getting the ODAC as well? (Presently use Grado SR60s at home and Senn PMX-60 neckbands when out and about).


----------



## Berkovajazz

So, what is the best opamp for x3?


----------



## lsamod

Guys, If I use external amplification through lineout,will I be able to get rid of the warmish sound signature????? Just wandering!!!


----------



## ClieOS

lsamod said:


> Guys, If I use external amplification through lineout,will I be able to get rid of the warmish sound signature????? Just wandering!!!


 
  
 The warmness comes mostly from the headphone amp section and not the line-out.


----------



## lsamod

clieos said:


> The warmness comes mostly from the headphone amp section and not the line-out.


that means if I pair e12 with x3,I can get more neutral sound. Is it?


----------



## ClieOS

lsamod said:


> that means if I pair e12 with x3,I can get more neutral sound. Is it?


 
  
 Yes, E12 will be more neutral than X3's internal headphone amp.


----------



## lsamod

Thanks!


----------



## peter123

Subscribed


----------



## Mmet

I find the stock x3 midrange is shouty and fatiguing! .... And not so clear and wide as I like ... I am using shure se535 and I don't want to carry an amp to drive those ...so is modding will be worthy in that case ? And what op amp should I get ?
and what is the output power of the ad8620 ? I am confused between the ad8620 and the one which suggested by the fiio team !!


----------



## pe3ucTop

Hey ClieOS,
  
 The new X5 seems to be using the same opamp AD8397. I don't know if it would be worth it, having in mind that X5 already sounds pretty neutral, but do you think, first, that doing the same mod is possible on an X5 and, second, do you think it would be beneficial to X5's performance and sound quality? Thank you in advance for your response 
  
 Cheers


----------



## ClieOS

pe3uctop said:


> Hey ClieOS,
> 
> The new X5 seems to be using the same opamp AD8397. I don't know if it would be worth it, having in mind that X5 already sounds pretty neutral, but do you think, first, that doing the same mod is possible on an X5 and, second, do you think it would be beneficial to X5's performance and sound quality? Thank you in advance for your response
> 
> Cheers


 
  
 Not sure where you get that info, but X5 doesn't use AD8397 at all.
  
 Firstly, It has a more complex opamp+buffer topology with better parts no less, so there is no reason to mod it unless you want to degrade the SQ / performance. Secondly, the idea of modding X3 is to get a more neutral sound. But given X5 is already much more neutral, that reason no long applies. Simply put, there is nothing to gain by modding X5. I can only imagine some DIYer somewhere want to mod an X5 just to try to sell it for double the money (which happened to X3, unfortunately).


----------



## pe3ucTop

Oh, damn... I just read the info page I got that info from more carefully, and it seems like I've simply misread it - you are right, they are using completely different sequence. I apologize for that ... that's totally my fault.


----------



## Mmet

So..... I red that thread about 3times now ...and I have different mind now ....i am planning to use ad8066 because of its better specs and it is rail to rail but I know now that it have more bass presence than ad8620 so I don't know if its bass will mask the details like the stock X3 's op amp or not ? If so I will end by using the ad8620 for more clarity


----------



## Mr Trev

Just curious if anyone can comment on the sound of the new beta firmware. I've read many comments about the improved sound quality. Is it still worth doing a mod? Would you consider using different op-amp?
 Cheers


----------



## Mmet

mr trev said:


> Just curious if anyone can comment on the sound of the new beta firmware. I've read many comments about the improved sound quality. Is it still worth doing a mod? Would you consider using different op-amp?
> Cheers


 
 +1


----------



## ClieOS

The problem is that those of us who already done the mod, there is just no way to easily compare it with stock X3 unless someone happens to own two, one stock, one mod. Not that likely.


----------



## Mr Trev

I thought that might be the situation, was hoping tho that some of you might have had a chance to hear both.
  
 BTW now that it's been a while since mods have been done, how would you rate improvements to heat/battery life, and is there a list some where of compatible op-amps?


----------



## ClieOS

I never ran my X3's battery dry before, but overall I think it goes from the original 8~10 hours to easily over 12 hours now (and might be more). Warmth is never an issue of mine, so I didn't play much attention to it.
  
 Many of the compatible opamp have been mentioned in this thread, though I don't know anyone has compiled a list.


----------



## Mr Trev

I'll have a look through the thread again and see what folks are using.
  
 Say I wanted to get a sound closest to an E12, what would be the best choice (could I just use the same opamp)?
 (sorry I'm new to this whole modding thing)


----------



## ClieOS

E12 runs on OPA1611+LME49600, so logic dictates OPA1612 (dual channel version of OPA1611) might be a good choice to approximate the sound. But unfortunately OPA1611/1612 is not a opamp that is suitable to drive a headphone load directly. If you want E12 sound on X3, the easier way is still using E12 with X3, instead of trying to make X3 sounds like E12.


----------



## recephasan

Why is no one talking about OPA1642?
 I've been using OPA1641 on my Leckerton UHA-6S (MK1), they're fantastic.
  
 I have the 1642 on order, will attack my X3 with a soldering iron as soon as it arrives.


----------



## recephasan

clieos said:


> E12 runs on OPA1611+LME49600, so logic dictates OPA1612 (dual channel version of OPA1611) might be a good choice to approximate the sound. But unfortunately OPA1611/1612 is not a opamp that is suitable to drive a headphone load directly. If you want E12 sound on X3, the easier way is still using E12 with X3, instead of trying to make X3 sounds like E12.


 

 The output current of OPA1611 is greater than +/-45mA (from Fig.27 on the datasheet), plenty for a whole bunch of headphones.


----------



## ClieOS

recephasan said:


> Why is no one talking about OPA1642?
> I've been using OPA1641 on my Leckerton UHA-6S (MK1), they're fantastic.
> 
> I have the 1642 on order, will attack my X3 with a soldering iron as soon as it arrives.


 
  
 Seems nice overall, based on spec. I am however a little worry about its output impedance.


----------



## ClieOS

recephasan said:


> The output current of OPA1611 is greater than +/-45mA (from Fig.27 on the datasheet), plenty for a whole bunch of headphones.


 
  
 The worry is on output impedance and the possibility of oscillation since it is not designed to drive big capacitance load.


----------



## recephasan

clieos said:


> Seems nice overall, based on spec. I am however a little worry about its output impedance.


 
 OPA1642 is doing fine in my X3 with my HD600, RS-1, Ortofon E-Q5. What headphones do you suppose it would have a difficult time driving?


----------



## ClieOS

recephasan said:


> OPA1642 is doing fine in my X3 with my HD600, RS-1, Ortofon E-Q5. What headphones do you suppose it would have a difficult time driving?


 
  
 Multi-driver headphones / IEM, especially those with wonky impedance curve. It is not about how demanding the load is, but whether the uneven output impedance might introduce excessive coloration to the headphone or not.


----------



## Mmet

Just ordered the AD8066 as it is rail to rail op amp .... i've red online that its sound DC coupled is different and have more low bass ..... any way i wish that it will be less warm , more detailed than AD8397


----------



## Mmet

if i want to mod the DAC section with wm8741 (after installing ad8066) ... is it will work fine ? and will the change in sound quality will be significant ? ... i know it will affect the battery life ... but i don't care about that


----------



## ClieOS

mmet said:


> if i want to mod the DAC section with wm8741 (after installing ad8066) ... is it will work fine ? and will the change in sound quality will be significant ? ... i know it will affect the battery life ... but i don't care about that


 
  
 There are probably something extra you need to do to the WM8741 for it to work in X3, as that chip needs to be set to hardware mode, I think. I don't really have any detail on it but I think I read it somewhere before, so search around.


----------



## SergBill

Good result whith LT1886 (phone amp) and ADA4898-2 (preamp, bipolar power, which will remove the capacitors from the signal circuit). and strengthened the power of chips using capacitors Nichicon SW 220uF (5 pieces)
 If anyone is interested, I can put photos with explanations.
 Sorry for my bad English


----------



## Mmet

I am very very interested but I already purchased the ad8066 for the amp section only .... When it arrives we will see


----------



## SergBill

AD8066 Single-Supply, AD8397 - Bipolar, this is probably a small problem


----------



## Mmet

sergbill said:


> AD8066 Single-Supply, AD8397 - Bipolar, this is probably a small problem


 
 BTW .... i don't know what is that means 
	

	
	
		
		

		
		
	


	




 .... but some guy here made that mod and he was pleased with it


----------



## Mmet

oh DAMN !!! those things are sooo small !!


----------



## Mmet

FWIW .... my first smd work is done successfully by replacing AD8397 with AD8066 
	

	
	
		
		

		
		
	


	




 and it was a very dangerous move as i don't have any experience with SMD work before and with my poor eyes it was more difficult
  
 seems clearer now ... much clearer ... with a nice sound signature and nicer bass than stock 
  
 thanks to @ClieOS for that awesome thread and very helpful mod
 and thanks to @wakibaki for his advise about cutting the original opamp's legs as he described
  
  the mod is great ... better clarity and details .. more defined sound stage ... no more warm sound but with beautiful bass ... and with the same power (  same volume level i used before with the stock opamp ) but now i listen to lower volume levels as the clarity of sound and neutrality no  need to increase the volume to enjoy details ......  
  
 about the heating issue ... the player before can go truly hot ( it is normal i know ) but a bit disturbing too ..... now and after day and half it is cold .... no heat at all ... except for one time it was sightly warm ... just slightly and that is all 
  
 about the battery life i don't know yet the exact time it takes from 100 % full until shut down 
 but i will update soon


----------



## fullcircling

^^are you on the new 3.0 firmware? if so, no hickups with it?


----------



## ClieOS

fullcircling said:


> ^^are you on the new 3.0 firmware? if so, no hickups with it?


 
  
 Firmware won't interfere with what opamp you uses.


----------



## Mmet

No ... No interfere with the firmware..i just want to add that ... Heat still there after a while of use ... Less than the stock one .. But it is there ... And with high gain it sound very bright


----------



## SergBill

put a description of mods with photo pictures and explanations in this thread or create a new one?


----------



## Benno

Description and pics would be awesome!
  
 I am on to lookout for a better line out. This looks like a good idea.


----------



## Mmet

benno said:


> Description and pics would be awesome!
> 
> I am on to lookout for a better line out. This looks like a good idea.


i think there is no better mod for the line out


----------



## Benno

By any change, is the schematic of the x3 available?
 I could not find it but that might be because of my bad search skills..
 Thanks!


----------



## ClieOS

benno said:


> By any change, is the schematic of the x3 available?
> I could not find it but that might be because of my bad search skills..
> Thanks!


 
  
 Schematic of the whole DAP? That's never going to happen.


----------



## Mmet

is there any method to measure the THD values , S/N ratio and power in mw of the new opamp installed in the modded X3 compared to the original opamp ... as i want to know how the AD8066 which i installed in my X3 performs compared to the AD8397


----------



## 380000

clieos said:


> Someone asked me to post the mod, so I thought I'll make it into an independent thread instead of putting it somewhere inside a X3 discussion.
> 
> Basically the mod is as simple as it gets: open the X3 up, disconnect the battery, desolder the AD8397, solder in the AD8620, and put everything back.
> 
> ...


 
 Sorry guys, I need some help.
 I've ordered the AD8620 and a friend has done the work for me. But instead of desolder the AD8397, he desorder another component (the identical piece in the middle of the circuit).
 When I notice that, we solder the component in the original place, but when I plug the headphones X3 send me an error (something like "output error! please reinsert headphones"). We retry to sold the component with a 180 degree rotation, but the result is the same.
 What is that component? What can I do to solve the problem? I have to reorder it?
 I want to specify that in line-out the X3 works perfectly.
 Thanks, Mattia


----------



## Mmet

v4ever16 said:


> Sorry guys, I need some help.
> 
> I've ordered the AD8620 and a friend has done the work for me. But instead of desolder the AD8397, he desorder another component (the identical piece in the middle of the circuit).
> 
> ...



This is a common error appears because of a weak joint of soldering .. It requires to retouch your soldering with the hot iron to make sure that all legs are soldered well ( with its original orientation and direction ) .. I may advice you to replace that op amp with a newer one because all that soldering and disordering may affect the opamp negatively


----------



## ClieOS

v4ever16 said:


> Sorry guys, I need some help.
> I've ordered the AD8620 and a friend has done the work for me. But instead of desolder the AD8397, he desorder another component (the identical piece in the middle of the circuit).
> When I notice that, we solder the component in the original place, but when I plug the headphones X3 send me an error (something like "output error! please reinsert headphones"). We retry to sold the *component *with a 180 degree rotation, but the result is the same.
> What is that component? What can I do to solve the problem? I have to reorder it?
> ...


 
  
 Which "component" are we talking here? AD8620 or the wrongly desoldered chip?
  
 The chip your friend wrongly desoldered is LM2663, a voltage charge pump.. Rotate it 180 degree would have burnt the chip out for good. Same goes for AD8620. I'll also suggest you to replace the chips (both of them). If that still doesn't work, then you must have burnt some other things out and your X3 is pretty much gone for good.


----------



## 380000

In that case the wrongly desoldered chip, which is probably, as you said, the LM2663.
 It's not a problem for me to reorder them, but I need to be sure about the component I need to order.

 I've noticed that my "middle component" hasn't got the black dot for the orientation (as I can see from your original photo). Why?
 https://drive.google.com/file/d/0B6ILhPiNX0UXcVU1U3VvcFdBN0E/view?usp=sharing


----------



## Mmet

v4ever16 said:


> In that case the wrongly desoldered chip, which is probably, as you said, the LM2663.
> It's not a problem for me to reorder them, but I need to be sure about the component I need to order.
> 
> I've noticed that my "middle component" hasn't got the black dot for the orientation (as I can see from your original photo). Why?
> https://drive.google.com/file/d/0B6ILhPiNX0UXcVU1U3VvcFdBN0E/view?usp=sharing


 
 wrong turn


----------



## ClieOS

v4ever16 said:


> In that case the wrongly desoldered chip, which is probably, as you said, the LM2663.
> It's not a problem for me to reorder them, but I need to be sure about the component I need to order.
> 
> I've noticed that my "middle component" hasn't got the black dot for the orientation (as I can see from your original photo). Why?
> https://drive.google.com/file/d/0B6ILhPiNX0UXcVU1U3VvcFdBN0E/view?usp=sharing


 
  
 Take a close up picture of your X3 will help a lot, though newer stock of LM2663 comes with a sloped edge for orientation instead of dot.


----------



## 380000

clieos said:


> Take a close up picture of your X3 will help a lot, though newer stock of LM2663 comes with a sloped edge for orientation instead of dot.


 
 Many thanks ClieOS.
 I'll be at home on friday and I'll do all the photos.

 Mattia


----------



## AudioCats

very interesting mod, do you know what the opamp supply rail voltages are?


----------



## ClieOS

+/-5.5V, IIRC.


----------



## Benno

Hi All,
  
 Can anyone help me locate the dac/buffer opamp? Is this the one in the middle. Headphone output is good enough for me. I use the x3 a lot as audio player.
  
 Also, what would be a good choice? 
 ADA4896 
 ADA4898-2
  
 Also somebody wrote about shorten some caps is using ADA4898-2. Which ones would that be?
 Or another one. I'd like to have a more detailed sound.
  
 Thanks!


----------



## AudioCats

clieos said:


> +/-5.5V, IIRC.


 

 Thanks, there is quite a bit of upgrade potential then.
  
 what is the white block between the two phone jacks (marked HFD4/5-S)? is it a relay? Is it for the SPDIF or the headphone-out? or only for the reset function?


----------



## AudioCats

just saw a X3 mod picture in which the relay was moved to the side to free up the space between jacks, looks like there might be enough room for a pair of LME49600 buffers to sit between the jacks (if too tight, grind down the LME49600's plastic case..) . The opamp can stay in the original location (probably change to LME49720/LM4562, though), with its output leads lifted off the pads and wired to the buffers' input leads, then the buffers output wire back down to the pads.
  
 if the opamp is not too fast the whole thing should be stable enough, if it works it should improve the performance quite a bit. The potential problem is power consumption.... adding the buffers will add 15mA to the idle current, don't know how well the on-board power supply can handle that.


----------



## ClieOS

audiocats said:


> Thanks, there is quite a bit of upgrade potential then.
> 
> what is the white block between the two phone jacks (marked HFD4/5-S)?* is it a relay?* Is it for the SPDIF or the headphone-out? or only for the reset function?


 
  
 Yes, relay for headphone-out.


----------



## recephasan

audiocats said:


> just saw a X3 mod picture in which the relay was moved to the side to free up the space between jacks, looks like there might be enough room for a pair of LME49600 buffers to sit between the jacks (if too tight, grind down the LME49600's plastic case..) . The opamp can stay in the original location (probably change to LME49720/LM4562, though), with its output leads lifted off the pads and wired to the buffers' input leads, then the buffers output wire back down to the pads.
> 
> if the opamp is not too fast the whole thing should be stable enough, if it works it should improve the performance quite a bit. The potential problem is power consumption.... adding the buffers will add 15mA to the idle current, don't know how well the on-board power supply can handle that.


 

 The main issue is power delivery into the opamp.
 Yes, AD8397 spec says 310mA peak. And the LME49600 is 250mA.
 However, there is a reason there are big capacitors in amps meant for power-hungry headphones.
 Even if you ran lines of power and ground to the buffers straight from the power rails (as opposed to the power pins of the AD8397 opamp),
 the buffer would still be starved of juice at the transients. Meaning, it would not sound as good as a good dedicated amp.
 My 2 cents.


----------



## AudioCats

portable amps will likely use DC/DC converters to generate higher voltage rails and regulate the rail voltage, not that much better than what is already on the board. I still think adding buffers can be beneficial to SQ, probably not so much for the battery life...


----------



## KorkiPoo

Just did the mod right now, sounds much cleaner than the original AD8397. Thanks OP.


----------



## ryanjsoo

So I`ve built a small JDS labs cmoy and run my iPod Touch 4 through it and especially enjoy the 8066, I was wondering if the 8066 would support low sensitivity headphones and higher current than the 8620 which doesn`t support rail to rail i believe?, also which part do I order, the opamp used in my cmoy is the ad8066ar, but there is also the arz, what`s the difference and which one is preferable?, thanks.


----------



## Mmet

ryanjsoo said:


> So I`ve built a small JDS labs cmoy and run my iPod Touch 4 through it and especially enjoy the 8066, I was wondering if the 8066 would support low sensitivity headphones and higher current than the 8620 which doesn`t support rail to rail i believe?, also which part do I order, the opamp used in my cmoy is the ad8066ar, but there is also the arz, what`s the difference and which one is preferable?, thanks.



Yes it supports that as i modded my x3 with it too and it is very good opamp .. It some times sound a little bright but it has very good bass ..you can order from mouser or digikey


----------



## imackler

I so wish i had the skillset to do this mod. Looks awesome.


----------



## ryanjsoo

Thanks, do you notice any more noise/hiss with the mod?, the 8397 notes on the product page that it has low noise, the 8066 doesn`t say much...., Sounds great in my cmoy but it definitely has hiss, not more than my other opamps but definitely more than ho of the stock X3, and I`m not sure if its the opamp or the amp itself which is running dual rail splitters and low gain.


----------



## Mmet

ryanjsoo said:


> Thanks, do you notice any more noise/hiss with the mod?, the 8397 notes on the product page that it has low noise, the 8066 doesn`t say much...., Sounds great in my cmoy but it definitely has hiss, not more than my other opamps but definitely more than ho of the stock X3, and I`m not sure if its the opamp or the amp itself which is running dual rail splitters and low gain.



No noise .. Just a small amount of hissing more or less like the stock op amp ( with Shure se535 )


----------



## 380000

clieos said:


> Take a close up picture of your X3 will help a lot, though newer stock of LM2663 comes with a sloped edge for orientation instead of dot.


 
 Sorry for the latency.
 Here it is my device. In the middle you can see the resoldered component.


----------



## ClieOS

v4ever16 said:


> Sorry for the latency.
> Here it is my device. In the middle you can see the resoldered component.


 
  
 Your friend has soldered it in the wrong orientation. The sloped edge should have faced upward (toward the SD slot) in the picture, but it is not. My guess is the chip has likely burnt out, better order a new one and hopefully no other hidden damage that will render the X3 unrepairable.


----------



## 380000

clieos said:


> Your friend has soldered it in the wrong orientation. The sloped edge should have faced upward (toward the SD slot) in the picture, but it is not. My guess is the chip has likely burnt out, better order a new one and hopefully no other hidden damage that will render the X3 unrepairable.


 
 I've bought the new component (the exact same model) and we've soldered it in the right direction.
 Unfortunately, when I play a song and I plug the headphones, I can hear "TAC" sound from the player and then, after maybe 2 seconds, another from the headphones, and it gives me the message: "Output error Please reinsert earphones".
 I specify that the music works from the LINE OUT.


----------



## 380000

v4ever16 said:


> I've bought the new component (the exact same model) and we've soldered it in the right direction.
> Unfortunately, when I play a song and I plug the headphones, I can hear "TAC" sound from the player and then, after maybe 2 seconds, another from the headphones, and it gives me the message: "Output error Please reinsert earphones".
> I specify that the music works from the LINE OUT.


 
 I think that the first TAC is the relay.
 But I cannot understand the second. Maybe is there some short-circuit?


----------



## ClieOS

There is only one relay inside X3 so what you are hearing is the opening and closing of the same relay. My guess is, there is either no power / signal on of the the channel due to unknown damage to the voltage supply rail (as the headphone-out opamp is only half powered), or your opamp has a cold solder join (less likely). The worst case is there might be some high DC offset (which the relay has protected you from). The opamp buffer on the line-out actually can work with a single supply rail so it might not get affected by the problem on the supply rail. There is no easy way for me to tell which is which though.


----------



## 380000

clieos said:


> There is only one relay inside X3 so what you are hearing is the opening and closing of the same relay. My guess is, there is either no power / signal on of the the channel due to unknown damage to the voltage supply rail (as the headphone-out opamp is only half powered), or your opamp has a cold solder join (less likely). The worst case is there might be some high DC offset (which the relay has protected you from). The opamp buffer on the line-out actually can work with a single supply rail so it might not get affected by the problem on the supply rail. There is no easy way for me to tell which is which though.



Many thanks ClieOS.
You have been clear, now I can't do anything else. Now I'm trying to send it to Fiio for a reparation.


----------



## Benno

clieos said:


> Thanks.
> 
> There is actually another opamp inside, the AD8692 on the DAC output stage. Upgrading it will further improve headphone-out as well as line-out. I am thinking whether LM4562 will be suitable. But AD8692 is nice enough that I think I will keep it for now, maybe reserves as a future DIY project.


 
  
 Hi ClieOS,
 Could you help me to locate this AD8692 opamp?
 Thanks,
 Benno


----------



## ClieOS

benno said:


> Hi ClieOS,
> Could you help me to locate this AD8692 opamp?
> Thanks,
> Benno


 
  
 It is on the front of the PCB, right next to the buttons.


----------



## Benno

> !


 
 Thanks for Clieos, Is this the spot you ment?
 I only see the ad8397 here, but i'm looking for the line-out buffer opamp, the ad8692.
  
 Sorry for my noobness. I made pictures but i'm not permitted to attach them.


----------



## AudioCats

*^^^*  ad8692 is on the other side of the board, (below the press-switches).
  
  
  
  
 Thanks to this thread, I now own a X3 and of course, the stock chip has now been replaced (never was very impressed with the 8397 anyway.....). It now sports an AD8599 for headphone-out, the sound is a bit darker and more "emotionally involving", with about enough power for driving my EarSonic SM3's.
  
 But neither the 8397 nor the 8599 has enough juice to run my Fostex T50rp.  I think there is enough (barely) room on the board to add a pair of BUF634's next to the AD8599, that should provide some more firepower, hopefully enough to drive the small ortho's.  so....I have a pair of SOIC BUF634 coming


----------



## DingoSmuggler

audiocats said:


> *^^^*  ad8692 is on the other side of the board, (below the press-switches).
> 
> 
> 
> ...


 
 The x3 at stock will be volt limited into the T50rp 50 ohm load, not current limited. If you need more oomph for your orthos, you'll need an external amp with some voltage gain.


----------



## Benno

audiocats said:


> *^^^*  ad8692 is on the other side of the board, (below the press-switches).
> 
> 
> 
> ...


 
 Thanks AudioCats for clarifying this!


----------



## AudioCats

Got the BUF634 buffers installed the other day.
  
  

  
 Both BUF's are installed up-side-down, each has two pins soldered to the AD8599 pins, so they are mounted quite securely machanically (the SOIC-8 package doesn't weight anything, with two direct attachment points they are not going any where ). All jumper wires have teflon insulation, I think power wires (the yellow and grey) are 24awg and the white signal wires are 30awg.
  
 The whole mod took a lot longer than I expected, about 30 minutes on figuring-out/planning the mod and another 1.5hr for the actual operation. If I have to do it again, I suspect it will still take at least 45 minutes since everything has to be done quite carefully, including folding some of the buf634 leads backwards. A magnifier of some kind is an absolute must if one want to do the mod, ideally you should have access to a stereo microscope (which I did use, very helpful during the soldering).
  
 I took a lot of step-by-step photo's thinking I mgiht want to do a tutorial, but at this point I don't think they are needed. I have to admit I don't like the sound, at least for now:
 -- with sensitive phones (such as my EarSonic SM3, which sounded quite groovy driven by just the AD8599), the sound seems to be harder and missing the "feel" of music (missing low level details, I suspect), and it is a bit too bright....and this is with SM3 which is a supposedly dark-sounding IEM....
 --for the more power hungry phones such as T50rp, the buffered circuit has a bit more power than before,  the bass for T50rp is now quite ok, but the sound has a certain brightness/hardness to it. And it might be less detailed (don't remember how detailed the T50rp was with the original AD8397, it was a while back and all I remembered was thinking the T50rp's bass sounded too soft with the stock X3; AD8599 without buffer couldn't run the T50rp well either ).
  
 Maybe the new buf's just need more burn-in. 
	

	
	
		
		

		
		
	


	







  The X3 is now playing in repeat mode with charger plugged-in, I will let it run non-stop for the next 2~3 days and then take another listen.
  
 But I suspect the bright/hardness of the buffered sound is due to the x3 power supply can not keep up with the now much larger power demand. Maybe I will have to add at least some larger power caps. Not sure where to mount them yet.


----------



## AudioCats

ran the x3 for about 20 hours, off and on. The sound mellowed down a little but the irritating brightness was still very much there. Sounded ok with my Fostex T20 (the original V1 ), but that was about it.
  
 So I paralleled 400uf reservoir caps to each stock power cap (stock caps are 100uf), and gave it a listen.
  

  
 With the added reservoir caps in place, the sound got better right away, more or less back to the AD8599's dark and intimate sound signature, but with more power to support the bass. It is full and engaging, though a little rounded (comparing to the X3 line-out driving a desktop amp) , I guess some of the micro-details are still missing . But the rounded-ness in a mobile player doesn't bother me . If I want all the micro-details I would use the X3 line-out to feed a desktop amp.
  
 The next step is to relocate the reservoir caps to area around the 3.5mm jacks and the white relay. The good news is, there is plenty of room available, if I stick to using the relatively large low-ESR 16v tantalum caps (like the ones in this experiment), there is room for adding 1000 uf per rail. If using the same kind of tiny cap like the stock caps on the board, which is about 1/4 the size , I suppose one can add 2000~3000 uf per rail very easily (but I suspect those are "not so low-ESR", not sure how they would affect the sound in large value). The question now is how much is really needed here. The larger the reservoirs, the more bouncy the bass but it can also soften the sound too much if over done, I guess 300~500uf per rail of fast/low-ESR caps might be a good balance.  
  
  
  
 A note about the *battery life* *with the buffer mod*: 
 I did a run-time test during the burn-in, both to see how long the battery will last with the mod in place, and to see if there is any undetected oscillation going on (the oscillation might not be easily audible but it would cause extra current drain if it is there) . The buffered X3 was driving the Fostex T50rp at volume 100 (which is quite loud, my normal listening would be at 80 and background listening at 60 or less). Starting from a full charge, the battery indicator dropped down to the last bar at around 10.5hr mark. There was still one bar left so I suspect it could have played for another hour or so, but I didn't want to drain the battery dry so I ended there test there. Looks like the BUF634 buffers did not cause any major increase in battery power consumption.


----------



## AudioCats

got lazy and ended up only adding 320uf per rail. (220uf + 100uf, 16v low-ESR tantalum caps). Wire used is teflon insulated 22 awg. Clear heatshrink to cover the caps.
  
 The sound is somewhat brighter than in the experiment above, probably because of the longer wire length added unwanted resistances. Or maybe 220uf caps don't sound the same as 100uf, not sure. Still sounding quite good, can drive all my dynamic phones (600 ohms Beyer 990 and AKG K240, Fostex T20v1/T50rp, and Earsonic SM3) to satisfactory. Good enough for me, for now.


----------



## imackler

@ClieOS Any thoughts how the X3ii compare to the X3 w/ the AD8620? (Sorry if I missed them any comparisons in other threads...)


----------



## ClieOS

imackler said:


> @ClieOS Any thoughts how the X3ii compare to the X3 w/ the AD8620? (Sorry if I missed them any comparisons in other threads...)


 
  
 Here:
  


clieos said:


> Roughly speaking, I'll say they are about on par with each other. My modded X3 has a slightly cleaner treble, where X3 II has a slightly wider and more 3D soundstage. Otherwise I'll say they very close.


----------



## imackler

clieos said:


> Here:


 
  
 Epic fail. Thanks for the reply! Sounds like that would be an awesome way to go if I can find someone to do help with the upgrade!


----------



## Jnjy

@ClieOS would you happen to know (perhaps in passing, from Fiio guys) if the X3 1st gen has a dual rail supply? Or just a single rail supply?
 Still looking for other chips that might work.


----------



## ClieOS

jnjy said:


> @ClieOS would you happen to know (perhaps in passing, from Fiio guys) if the X3 1st gen has a dual rail supply? Or just a single rail supply?
> Still looking for other chips that might work.


 
  
 It has been awhile since I measured it, but IIRC, it is dual rail +/-5V.
  
 p/s: Found it, here it is:
  


clieos said:


> ...Supply voltage in X3 is around +/-5V ~ +/-5.5V....


----------



## Jnjy

clieos said:


> It has been awhile since I measured it, but IIRC, it is dual rail +/-5V.
> 
> p/s: Found it, here it is:




Oh great. That's a wide operating range for a portable.
Thanks!


----------



## BETEP 9

Is its possible solder another DAC in it ?


----------



## Mmet

betep 9 said:


> Is its possible solder another DAC in it ?


 
 Don't think so .... way complicated !


----------



## puppyfi

I finally mod my X3. 
 AD8692 to ADA4841-2
 AD8397 to AD8620
 ( But I have no exact idea on the other capacitors mod as suggested in the erji thread.)
 This now sounds like a new toy and should keep me busy listening to my collection for some time.
 Many thanks to this thread, thanks to erji, thanks to ClieOS.


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## djbaneatwebde (Sep 8, 2017)

Hey hello there, i did my conversion to 8620 today. Changing the amp wasn't that hard. BUT when i put it back together celebrating myself that i was in fact able to solder this on my own i discovered something disturbing: the balance was out of order. so i reopened the case and checked every leg again. i disconnected the resistor of channel b - input oO... maybe it was a bad angle with the iron... those things are tiny... 3 hours later now i gave up, this thing is so small it stuck to the iron or to my knife i was holding it down with... my solution was actually pretty simple. i desoldered a - aswell, so now the gain is very low but at least it's coming from center again AND it's still loud enough for the pair of etymotics 4xr. could it be, that it's affecting gain only or does it create any harmful currents? sounds better than the old amp though, like less muddy but no world of difference?.


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