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Discussion in 'DIY (Do-It-Yourself) Discussions' started by clieos, Jun 26, 2013.
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?
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, 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?
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.
Yes, relay for headphone-out.
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.
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...
Just did the mod right now, sounds much cleaner than the original AD8397. Thanks OP.
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
I so wish i had the skillset to do this mod. Looks awesome.
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 )
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.