Are u sure? I compared several and the D pins are open. I think that is the common situation. How did you determine this? Would be very interested to see if I missed something. I have several barrel to USB adapters and the Dpins are all open. I had to make a custom cable to short the D pins.
Test WIIM pro+ with different power supplies
- Thread starter D1N0
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I am sure. I've tested 2 adapters, one coming with Sbooster and another with Nirvana SMPS, using a breadboard and multimeter - D pins were shorted. The same thing with the stock Pro charger and few other wall chargers.
In all these cases the charge mode was identified as at least DCP1.5A (or Apple 2.4A when voltages were indicating it) by my Ruideng TC66C tester. It won't work like this when the stock Pro cable is used due to the lack of D wires, charge mode is reported as 'unknown'.
Thank you. I got a cheap tester RD TC64 and for all the dumb type supplies it read Samsung, whatever that means. With an appl charger it read Apple 2.4A and with my custom cable where D cables shorted it read QC2.0. I have on order a Finsri tester, which is supposed to be much better.. When I test with barrel to USB C adapters, it reads Samsung. It never reads DCP1.5A
It seems from what you say, many companies short the D cables. But if you use the stock pro cable, with the stock power adapter it doesnt report as 1.5A?
It seems from what you say, many companies short the D cables. But if you use the stock pro cable, with the stock power adapter it doesnt report as 1.5A?
No, stock Pro cable has no D wires at all.
This makes me confused because if one connects the stock charger with the stock cable to the Wiim Pro, then according to what you say, there are no D wires and therefore it defaults to 5V .5A connected to the Wiim Pro. Why would Wiim have a 1.5A charger but only have it communicated to the Wiim to provide only .5A?
I never get DCP1.5 except at the beginning before reverting to Samsung.
There are no D wires so the Pro is not aware of PSU capabilities. I assume it simply tries to receive the current it needs.
Because the Pro obviously doesn't care about any communication with the charger? Its usb port acts like a simple 2 wires barrel port.
BowsAndArrows
Senior Member
yes i think @onlyoneme is right. they recommend (and provide 1.5A) because of tolerances they don't want someone to buy a 0.6A rated charger (that only delivers say 4.2V at load for example) to then have issues with the wiim unit not receiving enough power
According to the USB protocols, if there is no D wires the protocol defaults to 5V .5A. There is no protocol under USB where it acts as a simple 2 wire barrel port. That was the whole point of my exercise, to determine if the Wiim negotiated under USB protocols the voltage and current it receives. I am sure it negotiates the voltage and therefore does not act as a simple 2 wire barrel port. If Wiim wanted to do that, they would have put a 2 wire barrel port instead of a USB C connector.
What makes you so sure here? There are devices on the market which use the USB port for charging only and they lack any data wires. You've never seen a USB c ports for DIY with 2 wires only?
If WiiM wanted a voltage negotiation, they wouldn't attach a cable without D wiring.
Here is the logic (which could be faulty) - I attached a PD power supply and it connected up as a AAPL 2.4A, 5V supply. How would it know to put out 5V if it wasnt polled to do so? My conclusion was that the Wiim Pro was polling the capability. That was the logic.
That said, there was a sure fire way to make sure, I opened up the case and started looking for a USB C controller power chip like the TI TPS2511. Something that was a USB charging port controller and current limiting switch near the USB C port. It would be a 8 pin SMD. There was no chip nearby the USB C port. That supports your theory in part. If I look at the USB port traces on the board, D+ and D- are connected to some components marked ED, so there are connections to the data wires (lines 7 and 8), but are passive. If I measure the resistance between the D+ and D- pins with the Wiim unpowered, I read an open. If I measure the voltage between D+ and D- with th Wiim powered, using the USB C meter and a dumb supply with a barrel it reads D+ is 1.17V. I have no idea where the D+ voltage comes from if the D lines are open!
BTW, thanks for your input. i am trying to learn what is going on, so your comments are helpful!
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I have never seen a commercial device (non-DIY) that uses a USB port with 2 wires only and does not negotiate any protocols. That is why I am confused, I did not know these existed. These certainly do not follow the USB-IF standards.
Im using the P50 and felt it made a difference to my sound. It also has more than enough power even when running both USB slots, one for the Wiim Pro Plus and they other is running a fan to cool my amp. No issues with lack of power supply at all.
BowsAndArrows
Senior Member
Thanks for the feedback. I figured it would be the same for me.
Have you paired the p50 with an upstream AC regenerator or a DC blocker? I'm worried that my mains grid would be too noisy for the transformers in the p50 and cause them to hum...
I haven't tried it with any Regenerator or AC blocker, my power seems to be pretty clean and stable where i live.Thanks for the feedback. I figured it would be the same for me.
Have you paired the p50 with an upstream AC regenerator or a DC blocker? I'm worried that my mains grid would be too noisy for the transformers in the p50 and cause them to hum...
Ian
Member
I'm intrigued by the idea of using linear power supplies etc
If I'm honest, I don't get it.
Surely all of the Wiim devices use switching regulators anyway?
It would be nice to see schematics of the Wiim devices. I imagine these to closely follow reference designs from chip manufacturers?
If I'm honest, I don't get it.
Surely all of the Wiim devices use switching regulators anyway?
It would be nice to see schematics of the Wiim devices. I imagine these to closely follow reference designs from chip manufacturers?
BowsAndArrows
Senior Member
This is a very nice talk by Rob Watts. Thanks for posting. I particularly liked his comment about noise being deliberately injected to make a cable sound better, or more detailed and listening fatigue being an arbiter of that. I completely agree. I have listened to many components that sound initially better and more detailed, only to fail the listening fatigue test months later. Lack of Depth is also a telltale sign of distortion.
The problem is that there are very few people who design high quality SMPS, and most of the SMPS wall warts are awful. A cheap regulated LPS beats a cheap SMPS (note the regulated word) for low power. Benchmark uses high quality SMPS in their products and evidently so does Chord.
When I Iooked at the Wiim Pro Plus circuit board, there did not seem to be any voltage regulators on the boards. In particular, the digital board did not have any large caps, seemed to just use the power provided thru the USB C connector. So it would seem that a Linear Regulated power supply would be better sounding than the stock SMPS.
The problem is that there are very few people who design high quality SMPS, and most of the SMPS wall warts are awful. A cheap regulated LPS beats a cheap SMPS (note the regulated word) for low power. Benchmark uses high quality SMPS in their products and evidently so does Chord.
When I Iooked at the Wiim Pro Plus circuit board, there did not seem to be any voltage regulators on the boards. In particular, the digital board did not have any large caps, seemed to just use the power provided thru the USB C connector. So it would seem that a Linear Regulated power supply would be better sounding than the stock SMPS.
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