The Zishan dsd's corner

[Merlin-PT]

@Ivan TT
Do you mind sharing the capacitors you use in the DAC VREF?

It's difficult to find high capacity and low size.
I found this but the drawback is they are rated for 40C, 40C seams too low...
https://www.arrow.com/en/products/t490b337m006ate800/kemet-corporation

 

[kookaudio]

@Ivan TT
Do you mind sharing the capacitors you use in the DAC VREF?

It's difficult to find high capacity and low size.
I found this but the drawback is they are rated for 40C, 40C seams too low...
https://www.arrow.com/en/products/t490b337m006ate800/kemet-corporation

Kemet tantalum are ok, don’t think 40° is a problem.

 

[Merlin-PT]

I'm used to caps always being rated >80C and with good ones up to 125C or more.

 

[Ivan TT]

Do you mind sharing the capacitors you use in the DAC VREF?

Here you go:
6.3ZLQ680MEFC6.3X11
https://www.arrow.com/en/products/6.3zlq680mefc6.3x11/rubycon

 

[Merlin-PT]

Thanks!

I'll have to see where I'll fit those.

I'm also considering trying to fit 2 of these each side to use less space:
https://www.arrow.com/en/products/t55b227m6r3c0025/vishay

The size of these is also interesting:
https://www.arrow.com/en/products/f950j337kbaaq2/avx
https://www.arrow.com/en/products/f950j477mbaaq2/avx

 

[Ivan TT]

I'm also considering trying to fit 2 of these each side to use less space:

Yes, I also have two tantalum caps side to side (vertically compared to normal placement), but I now think it’s a bit of overkill, especially using TI LDO (long story, but modern LDOs can supply current on demand much faster but capacitors kind of fool them into not reacting fast enough, not sure if anyone compared the effects using proper techniques and equipment).
Having said that paralleling caps gives lower ESR, so they can supply more current on demand, as far as I understand.
The only location I found for Rubicon is per photos I posted, it’s a tight fit because of the geometry of the digital board above it.

 

[Themilkman46290]

Anyone figured and easy way to extend these contacts from board to board?

 

[Merlin-PT]

^When I built the extension cable, I saw that connector pin pitch is 2.00mm.
You'll have to google image search for something like "5x2 pin pcb header 2.00mm pitch".
You'll need to know what is the extension size you want, because the connectors occupy space.

You can replace one of the boards connector with a taller one or you can make a rigid extension or a cable.

Yes, I also have two tantalum caps side to side (vertically compared to normal placement), but I now think it’s a bit of overkill, especially using TI LDO (long story, but modern LDOs can supply current on demand much faster but capacitors kind of fool them into not reacting fast enough, not sure if anyone compared the effects using proper techniques and equipment).
Having said that paralleling caps gives lower ESR, so they can supply more current on demand, as far as I understand.
The only location I found for Rubicon is per photos I posted, it’s a tight fit because of the geometry of the digital board above it.

In the last photo here you have 2 tantalum vertical and nothing more, but you say you added 2 more 680uF there...Well they recommend 2200uF in the datasheet.
I think I'm going to have only 2 tantalum in each side of DAC VREF to use less space.

BTW, I think I've found a DC-DC converter that is pin compatible and with delivery stock :
https://www.arrow.com/en/products/adp1612armz-r7/analog-devices
I still need to read rest of the datasheet.

 

[Ivan TT]

In the last photo here you have 2 tantalum vertical and nothing more, but you say you added 2 more 680uF there...Well they recommend 2200uF in the datasheet.

Ah, sorry
Life is getting in a way, will try to take updated photos soon, hopefully.

Spoiler

Black cap above 5V LDO:

AD1612 is a nice find, seems to be pin-compatible, nice!
FB Voltage is slightly different, I think this will produce slightly lower voltage if used as a direct MP1542 replacement.
MSOP is fun to solder too
Why not AD1613 though?

 

[Merlin-PT]

Thanks, there's much going in your PCB and I missed you were talking about the 1 cap in LDO legs.
I'll be only using 2 of these in each side, I'm going to order 4 and see if they fit the space:
https://www.arrow.com/en/products/t55b227m6r3c0025/vishay

Yes, I mean AD1613 with 2A like the original, it was a typo.
Yes, maybe the rest of the components need to be changed and I'm not sure if it works with 4.7uH or needs 10uH, I'll have to read the datasheet before I consider doing anything. I'm not very comfortable changing this, because the over voltage will damage the caps and the opamps and testing it out of the board will be more work.

 

[Draknodd]

I just changed lpf opamp with ad8620 and lower the output resistors value.
But when I tried I noticed a problem: left channel was missing, BUT If i press down the jack of the headphone it worked; so I think it's a problem of loosen female jack connector. What should I do? replace it? If so can someone know where to find a replacement similar or equal to the one mounted in the zishan?

 

[silverfishla]

I just changed lpf opamp with ad8620 and lower the output resistors value.
But when I tried I noticed a problem: left channel was missing, BUT If i press down the jack of the headphone it worked; so I think it's a problem of loosen female jack connector. What should I do? replace it? If so can someone know where to find a replacement similar or equal to the one mounted in the zishan?

Did you just try tapping the connections with some solder? My 2.5mm side came undone with a bad solder joint as well as a leg on one of the original caps.

 

[kookaudio]

Some good old wima here!

 

[kookaudio]

I just changed lpf opamp with ad8620 and lower the output resistors value.
But when I tried I noticed a problem: left channel was missing, BUT If i press down the jack of the headphone it worked; so I think it's a problem of loosen female jack connector. What should I do? replace it? If so can someone know where to find a replacement similar or equal to the one mounted in the zishan?

Checking solders should be the first thing to do.

 

[Draknodd]

Sorry I haven' t mentioned this. I already checked the solders. In fact, only by pulling down (with a certain amount of force) the sound come back on the left side. If you pull down the jack, with the same force you'll "rise" up the inner extremity of the female connector on the pcb, pulling up the jack socket, another reason why it should not be a soldering contact problem.