Strange DS display blinking issue...when theres no power to the unit?!


#1

Noticed this earlier today, when I disconnect the power cord the display flashes?
No power to the unit so thought maybe it was stored power in caps maybe, but kept going for a few minutes?
Put power back on, dac initializes and all is well.

Anyone seen this before>
Display flash?


#2

Did you turn off the unit using the back switch before disconnecting the cord? (I assume so).

Does it flash with the power switch turned to “off?”


#3

Yup,
Was switching it off at the rear switch to swap out a cable when I noticed the display flashing.

With power cord removed it still flashes, whether the switch is at On or Off.
Absolutely fine when the dacs switched back on.

a weird one!


#4

Truly odd. Perhaps PS Audio has a clue.

I have a little concern there is some type of small failure, such as the capacitors are not bleeding off properly (if they are designed to do so with resisters across the caps.)


Getting Oppo DSD Output to the Direct Stream Dac
#5

You are probably proving power on an I2S input (pin 18). Don’t :slight_smile: You are basically tying the DS’s 5V to your source’s 5V.


#6

Intriguing. Thanks, Ted.


#7

Not on purpose! :slight_smile:

An interesting one, guess my main question was where did the power for the flickering screen come from?
Betting it would stop if I took the hdmi cable out.

Not doing the dac any harm ?


#8

Tying the power supplies together defeats a lot of the theoretical benefit of using I2S in the first place, you might as well use S/PDIF or AES3…

If both supplies are nominally 5V and neither one can sync current (e.g. most LDO’s including the one in the DS) then the one that puts out the greatest voltage (if only slightly) powers the boxes on both sides, I suspect that your source can’t power all of the 5V needs in the DS and so it’s under strain when the DS is off. The DS has a poly fuse on the 5V I2S line so if the device on the other end of the HDMI cable draws too much current (more than, say, 100mA) the poly fuse will open the circuit, but it will close again later when it cools down. You really want to cut the power off from pin 18 on one side or the other. If you are handy with the soldering iron you can remove the poly fuse in the DS (F60 and F61) or do what you need to on the other end.


#9

Thanks Ted, very informative.
More likely to make a change at the source end than the dac if I need to.

Disconnecting pin 18 on the cable linking source and dac would do it?
(If its academic, in that the issue only occurs when the dac is powered off then I’ll leave as is)

I keep my dac powered on all the time Ted, so the circumstances that enable this doesn’t ever occur.
(Aside the very rare time I switch it off)

Playing music normally with the dac on, do I still “lost the i2s theoretical advantages” or is it academic?
i2s sounds noticably better than coaxial connection in my system.

Just trying to understand better :slight_smile:


#10

Does I2s still sound better than coax (or XLR) if you disconnect the I2S cable when listening to the coax/XLR? Are you testing I2S and coax (or XLR) from the same source?

Anyway, tying the power supplies together isn’t a good idea, but you’re unlikely to hurt the DS.


#11

i2s does sound better than coax when the i2s cable is removed yes.
Using the modded oppo in both cases, same volume etc etc.

Can confirm flashing display issue goes away when I disconnect the i2s cable from source.

Recently upgraded firmware in source, dont think I did a factory reset this time, will do that see if it affects anything.

Thanks.


#12

My experience in SQ is the opposite of gazjam’s. With both types connected, I find the coax more top to bottom balanced, though not as spacious sounding. But I’m not sure if the difference and the latter is I2S per se or the current PSA I2S cable, which has that diffuse quality to it. Have to check.

But if pin 18 or whatever it is on the HDMI to I2S board is in the way, then I’d like to hear the difference without it. I just ordered an Oppomod I2S conversion board, so if I could improve things without it, that would be good.


#13

HDMI cables can sound quite different when used between the Oppo and DS I’ve found?

Had a trial of 3 cheaper ones that had good write ups and all quite different.
An amazon one: (Good)

Bluejeans cable (Better)
https://www.bluejeanscable.com/store/hdmi-cables/hdmi-cable.htm

Best one of the bunch for me was an “Apollo AV” flat HDMI cable, silver plated. (Best)


Quite a lot of DS users have been happy with the Wireworld Platinum Starlight 7?
Its expensive, but now I’ve narrowed down the “best of the rest” I’ll see if I can get a chance to try one in my system.

WIll need to be night and day better for me to swap out the Apollo AV, its very very good.


#14

FWIW: I have encountered this issue as well once or twice when using the Chinese HDMI to I2S board. It happens when you turn off the power to the DS, and yet keep the Oppo connected via one of these boards.

It scared the crap out of me the first time that I encountered it. It does look like the card does backfeed power into the DS. I had the cover off of my DS one time when this occurred, and some of the internal power LEDs were lit.

The only sure fire way to keep this from happening is to disconnect the I2S input from one of these cards before powering down the DS.


#15

I’ll remember to do that when I power the dac down.
Teds suggestion earlier is worth thinking about too.


#16

Which of the Bluejeans cables did you try (FE, Series-1 or Tartan)? I have the FE and I have been happy with it.


#17

I have the FE cable, which comfortably trounced the Amazon cable, and was very happy with the sound.

The Apollo AV is noticably better To me.

Ite the best of the non “boutique” cables Ive had in my system.
I’d like to compare it to a very expensive (anf highly thought of by DS owners) Wireworld Platinum Starlight cable.
I’ll buy it if its night and day better, but its too expensive for a little but better, wiser to spend thst money on PS Audio AC5 power cables, which really improved whatever was powered by it!


#18

gazjam, what position do you have SW1 in? The diagram on the board shows positions for Int and Ext power, with 1-2 being the latter. Does the problem with the DS flashing occur with that position? It doesn’t for me, but does in 2-3.


#19

was flashing in 2-3, swapping over to 1-2
No flashing in this position, improved sound quality.

So SW1 jumper 1-2 was the right setting all along

As per Teds earlier comments, happy i2s can do its thing properly now.


#20

Got one that works today. Sounds robust and within a touch of as sweet as I like it out of the box. Give it two to three weeks to refine and I’ll report back.