I built up two boards with different parts and got different results. I'd thought the Epcos B41231 would be a quality choice and put two in series with a resistor for a CRC topology. That didn't work well from an SQ point of view. Removing the good resistor from that resulted in a noticeble improvement, and replacing the Epcos snapins with a single Kemet screw terminal gave a significant increase in SQ. I prefer the resulting sound with Kemet and the big can has 2.5x the ripple rating of a B41231 which are no slouches. Just laid it on its side with a zip tie hold down and 20mm (1") leads. I also found other factors to improve SQ further.
I’ve run into an issue with one of these that I’m hoping someone can help with.
I bought and built one of the original dual design units from AliExpress to drive a WiiM mini and a topping E30 off either "side". I had a spare 30VA r-core transformer with dual 9V secondaries at 1.66A and I’ve got a perfectly stable 5V out of each DC output but neither device powers up properly.
I can only assume I’m short on current but the E30 is designed to run off a computer‘s usb so should not require more than 500mA or so (as far as I’m aware) and all I could find on the WiiM mini is it needs between 150mA in idle and 220mA in use.
is there something I’m missing? Does the current drop off out of the PSU like the voltage does? I see from the thread that there is something in the circuit that limits current but I cant map the solution onto the circuit that I built (this one https://www.aliexpress.com/item/4000263328504.html)
very grateful for any assistance 🙂
I bought and built one of the original dual design units from AliExpress to drive a WiiM mini and a topping E30 off either "side". I had a spare 30VA r-core transformer with dual 9V secondaries at 1.66A and I’ve got a perfectly stable 5V out of each DC output but neither device powers up properly.
I can only assume I’m short on current but the E30 is designed to run off a computer‘s usb so should not require more than 500mA or so (as far as I’m aware) and all I could find on the WiiM mini is it needs between 150mA in idle and 220mA in use.
is there something I’m missing? Does the current drop off out of the PSU like the voltage does? I see from the thread that there is something in the circuit that limits current but I cant map the solution onto the circuit that I built (this one https://www.aliexpress.com/item/4000263328504.html)
very grateful for any assistance 🙂
An example of the better v1.2 board: https://www.ebay.com/itm/275224317734?var=575496726403
The opamp is soldered in without an adapter though.
The opamp is soldered in without an adapter though.
Hi, if you buy a bare board of the LPS they are selling you can easily solder an adapter there, I have done so.
https://www.aliexpress.com/item/100...order_list.order_list_main.266.af761802284Sqv
Cheers
I ended up putting in a 60VA toroidal and it works beautifully so I guess it was just under-current
Hi, i have a problem with this STUDER900 v1.2 board: https://www.ebay.com/itm/353965460852
I want the output to be 5V and have feeded it with small 9V output toroidal transformer like the seller has stated in description. And the RB resistor is also 1kohm. But the output is 12.8VDC, i tried to change the RB resistor to 10kohm to see what happens and then i got 13.0VDC output.
Any suggestions?
I want the output to be 5V and have feeded it with small 9V output toroidal transformer like the seller has stated in description. And the RB resistor is also 1kohm. But the output is 12.8VDC, i tried to change the RB resistor to 10kohm to see what happens and then i got 13.0VDC output.
Any suggestions?
Yep, DIY pack, soldered all myself and was double-checking all the caps and resistor values too.
Mooly is absolutely right, witthout a schematics we are shooting in the dark. Generally after the foor diodes you have to get 9 x 1.41 = 12.69 VAC which has to move here and there in the schematics to reach the required VAC /lets say 5 VAC ultra linear one with 1 KO on pos. R8. In my case it went the right way but is it really linear I do not know.
Re-check all the components/not easy/
Cheers
Re-check all the components/not easy/
Cheers
Okay got it, one led was missing in the kit and i did not populate it at first... didnt know it was needed to work properly 🙂 Now installed it and got the 6.6VDC reading minimum. It's kinda useless anyway because I was planning to use it with my Primare NP5 streamer but it seems the streamer is not working with 6.6VDC.. maybe it has some protection or something.
If an LED is used as a voltage reference the type and colour will be important because of the volt drop each develops. Measure the voltage across the supplied one and compare with the voltage across your replacement.
You have there one variable resistor, please make some turns when connected to the muticet and see whether the volatage is changing. Be patient, it is changing very slow and try to get to 5 VDC. In case there is no change somethig is wrong.
Cheers
You need the schematics of this board . If you look to my schematics in the pdf attached to post #328 of this threat, you see that in the "old" board the output on the PIN 1 of the first OP Amp is compared to the Voltage drop given from R14 connected to Pin6 and the positive voltage. The voltage drop depends on the current flowing through R14, which you can change with R11, R16 and R18 or a combination of them (parallel resistor).
At the end with R11 of 2.2 k
Ohm you are in the range of 5V output and you can then fine adjust the voltage with the 10KOhms Potentiometer.
Now looking at the images of the board in ebay it seems the the position of the op amp are inverted.
If I have read right the tracks of the ebay board, you should try to replace the 3.3k resistor marked in red in the picture with 3,3k+2,2k resistor ca 5.5k. If you have 5.6 k better , but it does not matter.
If it does not work maybe try with the one marked in yellow. But I am quite sure is the one marked in red.
Hi,please advise where to get a schematics of the variant 1.2 which is different from the "old" board ?
Thanks
The schematic is identical with the pdf of my post. The only difference is that the position of the opamp is switched.
The other difference is that know there is no place for an additional resistor to set up the range of the output voltage.so you have to substitute 3k3 with what you need.
The schematic of this regulator has never changed.
Thanks, I am not very familiar with schematics /lawyer/ but will try to read it. The opamp does not matter when we do not change anything I suppose /just the resistor value/??
Thanks your assistance
Ignat