[Themilkman46290]

Thanks guys, turns out my suspicion was right glad i didnt turn it on, guess i will meed to take it back and hope the get it right

 

[HeyManslowdown97]

Thanks guys, turns out my suspicion was right glad i didnt turn it on, guess i will meed to take it back and hope the get it right

Give them hell for almost killing your baby.

 

[Merlin-PT]

Thanks guys, turns out my suspicion was right glad i didnt turn it on, guess i will meed to take it back and hope the get it right

I'm not sure if my notes are correct or not, I need to double checked them.
I'll open Z2 and look for those SMD markings:
DE=A1D
4BMD
And measure them with the multimeter.

Problem is that SMD markings are different from part numbers.

EDIT:
OK, I confirmed they are correct, Z2 has one DE=A1D and it measures 3.3V in the output.

Did you bought the LDOs yourself?
The markings on those sometimes are different from the part numbers.

 

[HeyManslowdown97]

As a really simple mod it wouldn’t hurt to replace the stock 5V LDO with the TPS73250 apparently it “rocks” and it’s a Soic so it’s like replacing the stock Op275s sans trashing your board. It’s only 2 bucks US Lol.

It may or may not improve sound but it would make the board a lot healthier. I like to try lots of all changes incrementally like replacing the buck booster converters (the boxes with “47”??) and the power caps but I’d like to do It slowly and with gradual increments so I can assess my progress better and not overwhelm myself with mods. I have a second Zishan coming in the mail for A/B testing. Stoked!

Does anybody have any recommendations for an upgrade to the stock input voltage regulators chip that rocks? Thanks

http://www.ti.com/product/TPS73250-EP

 

[Themilkman46290]

Yeah, ordered them, waited for ever to get them, glad i didnt turn it on

Thinking about getting a rework station, looking at the yihua 858d, read that it needs to be modded a bit and properly ground it

Anyone got better suggestions in this price?

And how difficult is it to use, i can use soldering iron bit never tried a hot air station

 

[HeyManslowdown97]

Yeah, ordered them, waited for ever to get them, glad i didnt turn it on

Thinking about getting a rework station, looking at the yihua 858d, read that it needs to be modded a bit and properly ground it

Anyone got better suggestions in this price?

And how difficult is it to use, i can use soldering iron bit never tried a hot air station

Yep I thought about it too it’s a two in one and can use Hakki tips (forgot brand name)

I would I use the Hot Air to start a new PCB by put small stuff resisters, etc doing it sections. I’m sure I’ll overheat some stuff but that’s the “catch” with hot air. You will just have replace the damage ones. The “Payoff” is you can do entire sections in very little time. You’d probably have to solder the ones you damaged though.

You first have to preheat the board apply flux paste and slip the components into the place. That’s it!

I got a killer magnifying glass work station in my wish list in AliExpress so it’s in the works!

I subscribed to the “Great Scott” channel on YouTube and I learn a lot from that that guy. He’s German and dry but he’s style is a great contrast to my rapid fire impulsiveness and the guy knows his stuff!

There’s a great tutorial on hot air and soldering on his page that would have post but don’t want to get in trouble with the secret police. Lol.

 

[HeyManslowdown97]

For anyone needing to recase your Zishan because of human error or just to put bigger amps I found a great video on how you make one by yourself with simple steps!

I want to make my own clone Zishan and design my own case using Fusion 360 software which have plenty of tutorials on YouTube but for me that’s way into the future

 

[HeyManslowdown97]

@Themilkman46290

There’s a 2 in 1 for the same price!

2in1 8786D SMD Soldering Rework Station Hot Air Gun Solder Iron Welder LCD Display (YIHUA 8786D) https://www.amazon.com/dp/B00XTK1JLC/ref=cm_sw_r_cp_api_i_i9TDCbQXASX8D

 

[Merlin-PT]

@Themilkman46290
I never had used hot air before, but it's the correct way to do change SMDs or soic opamps. I don't find it more difficult than using a soldering iron for the soldering iron work. For doing SMDs hot air is much much easier than a soldering iron.
Requirements are steady hand and good close range eye sight, but I manage to do the work.
If you right handed, tweezers will go in that hand.

Some advises:
Watch some videos.
Train in a old board.
Use low fan speed or the components will fly.
Use precision tweezers (don't need to be expensive)
If needed take photos before the work.
If needed, make some small heat shields from copper foil (I isolate the copper foil with kapton tape) or any other material to protect other components, plastic parts or wires in the PCB. It will be very hot both sides of the PCB, be careful with the other PCB side, don't allow batteries to take any heat.

When you start to heat the PCB needs to get hot and takes some time, move the air in the component area, after that solder from surrounding components can also be melted, so you need a steady hand or others can move from place.

Biggest problem I found is a 603 size SMD jumping from the tweezers before it was soldered and never to be found again.
Now I apply lower tweezers force.

You need to use something bellow the PCB to protect the table from heat.
I reuse the solder already in the PCB and finishing with the iron and flux if needed, but this is a shortcut not the correct technique.
With the soldering iron I'm using a water based flux that leaves no residue.
Video tutorials are the best to learn this, my advises are from my learning curve.

 

[HeyManslowdown97]

@Themilkman46290
I never had used hot air before, but it's the correct way to do change SMDs or soic opamps. I don't find it more difficult than using a soldering iron for the soldering iron work. For doing SMDs hot air is much much easier than a soldering iron.
Requirements are steady hand and good close range eye sight, but I manage to do the work.
If you right handed, tweezers will go in that hand.

Some advises:
Watch some videos.
Train in a old board.
Use low fan speed or the components will fly.
Use precision tweezers (don't need to be expensive)
If needed take photos before the work.
If needed, make some small heat shields from copper foil (I isolate the copper foil with kapton tape) or any other material to protect other components, plastic parts or wires in the PCB. It will be very hot both sides of the PCB, be careful with the other PCB side, don't allow batteries to take any heat.

When you start to heat the PCB needs to get hot and takes some time, move the air in the component area, after that solder from surrounding components can also be melted, so you need a steady hand or others can move from place.

Biggest problem I found is a 603 size SMD jumping from the tweezers before it was soldered and never to be found again.
Now I apply lower tweezers force.

You need to use something bellow the PCB to protect the table from heat.
I reuse the solder already in the PCB and finishing with the iron and flux if needed, but this is a shortcut not the correct technique.
With the soldering iron I'm using a water based flux that leaves no residue.
Video tutorials are the best to learn this, my advises are from my learning curve.

I've reuse it to in PCB. it's necessary a bad idea but maybe frowned upon by a profressional.

“Water based flux” I’ll have to try it too!

I’m left-handed and it much harder for some reason and certain situations have had to use my right hand which isn’t that stable. Helping hands to put the board are also great.

With soldering I found less is more and practicing how to control the solder on with various tips and locations on the iron just to get a feel for it off board. It’s very easy to lose track of your concentration especially when you wear magnifying gogles to accidentally melt pieces so concentration is Paramont.

Also, I’ve notice that I make more mistakes with mental fatigue so I need to take breaks! I Believe this improves when you become better at it.

*****

I don’t want to beat a dead horse just want clarify something don’t mistaken style with intent. Someone may be polite don’t mean he isn’t trying to charm or persuade you to do something you don’t want to do.

There were no ad hominem attacks it was always reference to some concept or idea or limited belief that’s been debunked. We must an agree on objective reality not urban myths.

 

[HeyManslowdown97]

Was doing some reading and I believe that in the Zishan DSD a low noise precision op amplifier works best in the lpf since the gain the balance is +6 dB.

This would explain the “spike in high frequencies” they also improve DC circuitry along replace the stock 5V LDO with the should make the Zishan more stable with DSD.

LNA’s
“Achieve lower distortion and higher performance with ultra-low noise amplifiers“


I, by chance dropped the Opa2107 which I believe is a low noise precision op amp in lpf and it sounds great with the dual Opa627bp in the 3.5mm

I have to say I’m biased since I like the burr brown sound. It’s really analog, very Warm sound not everyone’s preference.

With a low noise figure, an LNA must have high gain. An LNA without high-gain allows the signal to be affected by LNA circuit noise; the signal may become attenuated, so the LNA's high gain is an important parameter. Like noise figures, LNA gain also varies with operating frequency.

http://www.ti.com/amplifier-circuit/op-amps/precision/overview.html

 

[HeyManslowdown97]

@Merlin-PT I want to apologize for pouncing on you over “Sibilance.” I was so caught up in my argument that I didn’t realize what you stating was your problem and I was focused on the word “Sibilance” and somehow it was lost in translation which may mean something different in your native tongue.

Read up on the different amps and with main functionality are and see if you helps your sound. (If you haven’t fix it already)

I should have taken into account that English isn’t your first language I am sorry.

 

[Merlin-PT]

No need. It's normal to have different opinions and points of view. The word means exactly the same and we understood all arguments.
As much I would like, I don't have enough free time to reply to all post. I also don't want to monopolize the thread and must give time for others to reply and participate.

 

[LaughMoreDaily]

I mainly listen to 16 bit wav files and some 24 bit wav files so I guess I dont need the best of the best but the AK4497 sounds like the best option? I do have an AK4490 Z3 but its busted. I need to get it fixed.

 

[Themilkman46290]

I mainly listen to 16 bit wav files and some 24 bit wav files so I guess I dont need the best of the best but the AK4497 sounds like the best option? I do have an AK4490 Z3 but its busted. I need to get it fixed.

Well i have the ak4490 and the ak4497, i have also heard the ak4495, the ak4495 has the most synergy with high and low impedance headphones, the ak4490 version is the best if you have mainly iems or low impedance (use it with my he4xx and it gets louder and has less distortions, better sub bass etc etc) the ak4497 version is not that great with sensitive iems, but pushes my samsaras beautifully and i tried them with some dt770 pro 250ohm and they sound marvelous, as loud as needed and very well controlled, it also is the only version which is th 2.5 balance jack, the other 2 versions have a line out instead