The Zishan dsd's corner

[Merlin-PT]

With this thing open, I can hear high freq. noise coming from somewhere in the power section, right part of the DAC/amp board.

This noise is related to the PWM LCD brightness circuit, because if I lower the brightness a lot or put it at full brightness or the lcd turns off, the noise disappears.

I can't hear this noise in the music, it's a component that resonates in the audio board. If I only power the LCD board, there's no noise.
If I can identify the component I'll replace it. I can only hear this very low volume and very high freq. noise in complete silence with the screen on, I can't hear it in the audio, so no big deal.

I replaced all the 10uF and 11uF ceramic caps (SMD 1206) in the analog board, with a known brand X7R 10uF ceramic multilayer caps.
While I was at it, I also replaced all the 0.1uF ceramic caps (SMD 0603) with a known brand X7R 0.1uF ceramic multilayer caps.
I went for the lowest price, X7R, good precision, >=16V, from the known brands available.
The vibration noise that I could hear with the screen on is completely gone.

 

[kookaudio]

Thanks to Dbaldock9 for suggesting the 2 lme49710ha, they are my favorites so far

Did you compare the 49710ha to cheaper ones like the 49710MA or so...?
And, anybody please knows where I can find a battery like the one in the zishan dsd?

 

[kookaudio]

?

 

[DBaldock9]

Did you compare the 49710ha to cheaper ones like the 49710MA or so...?
And, anybody please knows where I can find a battery like the one in the zishan dsd?

Haven't had my DSD open in the last week - does it use a standard 3.7V Li-Ion battery?
If so, there are quite a few vendors on eBay & AliExpress, selling that style of battery.
I do know that with the changes in airline and import safety regulations, it's more difficult to order Li-Ion batteries to be shipped to the USA.
You'd need to check with the vendors, or the Italian regulators, to see how easy it would be for you to order batteries from Asia.

 

[kookaudio]

I already had other lithium battery delivered to Italy from Aliexpress, just had to wait a few more days for customs inspections but everyrging went ok...
I was mainly asking about these 49710MA instead of the HA, but probably there’s no reply about that.
Thanks.

 

[DBaldock9]

I already had other lithium battery delivered to Italy from Aliexpress, just had to wait a few more days for customs inspections but everyrging went ok...
I was mainly asking about these 49710MA instead of the HA, but probably there’s no reply about that.
Thanks.

None of the Dual Mono (LME49710NA / HA) to Stereo DIP-8 adapters will fit in an unmodified DSD.
The actual op-amp die is the same in both package styles (Plastic DIP-8 and Metal TO-99), so there's not likely to be very much difference in audio performance - but there could be better RFI rejection by the metal can.
However, having to add wires to extend the socket, so that a pair of LME49710HA can be connected, might negate the advantages of using the TO-99 package.

 

[Ivan TT]

And, anybody please knows where I can find a battery like the one in the zishan dsd?

545476 3.7V 3100MAH
https://s.click.aliexpress.com/e/bPXHbe5x

 

[kookaudio]

None of the Dual Mono (LME49710NA / HA) to Stereo DIP-8 adapters will fit in an unmodified DSD.
The actual op-amp die is the same in both package styles (Plastic DIP-8 and Metal TO-99), so there's not likely to be very much difference in audio performance - but there could be better RFI rejection by the metal can.
However, having to add wires to extend the socket, so that a pair of LME49710HA can be connected, might negate the advantages of using the TO-99 package.

We could use 2 soic ones

 

[DBaldock9]

We could use 2 soic ones

I thought that TI had "End of Lifed" the LME49720 / 49710 family, and didn't realize they were selling a SOIC-8 version.

There is a custom short pin, without a shoulder, available on the BrownDog 020302 Dual SOIC-8 to DIP-8 adapter.
If you're careful about centering the chip on the bottom, and remove a bit of the inside plastic on the DIP socket, the adapter will plug in far enough that it's no taller than a standard DIP op-amp.

 

[kookaudio]

I thought that TI had "End of Lifed" the LME49720 / 49710 family, and didn't realize they were selling a SOIC-8 version.

There is a custom short pin, without a shoulder, available on the BrownDog 020302 Dual SOIC-8 to DIP-8 adapter.
If you're careful about centering the chip on the bottom, and remove a bit of the inside plastic on the DIP socket, the adapter will plug in far enough that it's no taller than a standard DIP op-amp.

I know, but I make my own adapter using a simple dual soic to dip board and some copper.
I’ll show you one. making it takes minutes

 

[kookaudio]

1)You solder the 2 opamps, perfectly centered.
2)Use some solid copper wire like this.

2)You trim the socket till the board sits flat to it, with the bottom opamp lying “into” the socket.
3)You solder 8 short copper wires to the board after inserting them in the socket, like this. You cannot have a more flatter adapter, guaranteed. Only thing to pay attention to is not to solder the biard directly to the socket, but it’s very easy, just pay a little attention.

 

[Merlin-PT]

I thought copper was too soft for legs, so I didn't try using copper.
Let us know if they bend or lose the alignment with use? Don't they oxidize with time?

I'm using these pins for legs, I saw @Ivan TT recommending them and bought some:
https://www.aliexpress.com/item/10p...-dual-row-Male-straight-gold/32721243961.html

They work very well and I also recommend them.
To be perfect they should be round (needle type) pins, but their face is square type, not a problem because the pins are very small, so the square is almost a round surface. I couldn't find round pins with this diameter and length.

 

[kookaudio]

I thought copper was too soft for legs, so I didn't try using copper.
Let us know if they bend removing or with the use? Don't they oxidize with time?
.

Copper in the right diameter is perfect, you simply care when insering the adapter or removing it, but simply the same you do with any opamp. And you can trim the adapter at the lowest possible position in case space is an issue like in our present case.
It is also very easy to use since you just cut it after soldering at the lenght you need.

 

[Merlin-PT]

So they don't bend?
There's also the oxidation problem.

 

[kookaudio]

The legs of every opamp bend if you do not pay attention.