Author Topic: New linear 5V USB Power Supply for RED  (Read 3315 times)

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Offline miraculon

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New linear 5V USB Power Supply for RED
« on: August 30, 2013, 01:05:13 PM »
I just received my new power supply from A&B Systems, a TeraDak U9VA w/USB. I was using a re-purposed Moto phone USB-mini charger supply, but I know that it was a switcher. To help keep noise down, I was looking at the "audiophile-grade" USB supplies. This one wasn't crazy expensive (maybe it was, depending on your point-of-view) at $45USD.

It took a couple of weeks to come from Hong Kong. They provide nice USB A-B and 9V cables, but I didn't use them. You have to provide your own IEC cable. Be sure to specify 115VAC for US.



Out of the box, the 9V is running a bit low, but it is easily adjusted by an internal potentiometer. Since I am not using it, it doesn't matter. Importantly, the USB voltage is at 4.7V. While this might seem low, it is exactly what I was looking for to feed the display. Everything on the STM32 discovery board that runs from 5V are just regulators and there is plenty of headroom for them. The Atmega8 is OK as are the PGAs on the amplifier board. So far, I have not seen any unusual behavior for waveforms, etc.

Since it is a linear power supply with a transformer and linear regulator(s), it does run slightly warm, but is all contained in a nice aluminum box. The noise RMS voltage was about 1mV on my DMM (didn't put a scope on it). I expected it to be quiet, since that is the claimed benefit.

Greg H.


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Offline Jumpin Joe

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Re: New linear 5V USB Power Supply for RED
« Reply #1 on: September 06, 2013, 04:51:02 PM »
Greg,

Looks like you have had this power supply for a week or so. Is it working as you hoped/expected?

Thanks,

Joe

Offline miraculon

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Re: New linear 5V USB Power Supply for RED
« Reply #2 on: September 06, 2013, 06:04:05 PM »
So far, so good. It is still working fine. That's a plus.
The regulation seems OK, judging from the GUI "Input Voltage" display.

I would say that it has not made any difference in noise as picked up by the antennas.
The switcher USB supply doesn't seem to have been a noise contributor.

It runs slightly warm, but not anything to worry about.
The red LED is very bright.
I think that the major advantage has been the lower voltage to keep the display happy.

Greg H.




Blitzortung Stations #706 and #1682
CoCoRaHS: MI-PI-1
CWOP: CW4114 and KE8DAF-13
WU: KMIROGER7
Amateur Radio Callsign: KE8DAF

Offline Jumpin Joe

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Re: New linear 5V USB Power Supply for RED
« Reply #3 on: September 06, 2013, 08:46:22 PM »
So far, so good. It is still working fine. That's a plus.
The regulation seems OK, judging from the GUI "Input Voltage" display.

I would say that it has not made any difference in noise as picked up by the antennas.
The switcher USB supply doesn't seem to have been a noise contributor.

It runs slightly warm, but not anything to worry about.
The red LED is very bright.
I think that the major advantage has been the lower voltage to keep the display happy.

Greg H.







Thanks for the update.

Joe

Offline Jumpin Joe

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Re: New linear 5V USB Power Supply for RED
« Reply #4 on: November 29, 2013, 02:55:49 PM »
So far, so good. It is still working fine. That's a plus.
The regulation seems OK, judging from the GUI "Input Voltage" display.

I would say that it has not made any difference in noise as picked up by the antennas.
The switcher USB supply doesn't seem to have been a noise contributor.

It runs slightly warm, but not anything to worry about.
The red LED is very bright.
I think that the major advantage has been the lower voltage to keep the display happy.

Greg H.







Thanks for the update.

Joe

I do now. Thanks .... I guess that's what happens when you turned 29, 30 plus years ago.  :lol: