Yes, as long as it's rated at 20VA or more. Separate supplies for the RPi and DAC should give better sound though, if that matters.
Thanks for your help. Of course it does, along with cost, size, complexity, etc. I’ve got to work out where I’m comfortable compromising. I appreciate your useful advice, though
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Thanks for your help. Of course it does, along with cost, size, complexity, etc. I’ve got to work out where I’m comfortable compromising. I appreciate your useful advice, though
You can buy a 5V 'Studer' supply in a case for not a lot more than the cost of a board plus transformer. You could later consider buying another, or just using a cheap switching 5V supply for the RPi (which you probably have already) and using the 'Studer' for the DAC. Just a thought.
I might have another look at that but I like the idea of putting one together and shipping is cheaper and quicker for a kit than with a transformer. I have noticed the studer PSUs seem to come with a Bingzi rather than Talema transformers, unlike the Weiliang PSUs that have the option for either
Do you have a reckon on the delta between the two brands of transformers? The Talemas seem to be about twice the cost
No, I haven't compared them. For a better quality transformer I would look for an 'R core', there are Chinese ones on eBay. If you get one with at least two 0-9V windings you could still use it if you add another board later.
The cheaper Bingzi serves its purpose though - I have a 5V supply that uses one.
Going back to first principles, my goal is to put my raspberry pi with dac hat into a neat case with the power supply inside that I can just plug in to mains. I’d like it to sound as good as is practical but it’s ultimately going to end up in a secondary system so it doesn’t have to be turbo-charged and it will never get better than the boss Allo dac hat which is good but its not going to give DCS any sleepless nights.
I initially started looking sat one of these https://m.aliexpress.com/item/32920...ser_id=46cc1e52047a45169625fc835376fe9a&is_c=
...and got carried away with the possibilities. If i want to drag myself back down to earth and just buy one of these Weiliang dual output ones, will I derive any benefit from the dual outputs to the pi and dac or is it just more wire?
I initially started looking sat one of these https://m.aliexpress.com/item/32920...ser_id=46cc1e52047a45169625fc835376fe9a&is_c=
...and got carried away with the possibilities. If i want to drag myself back down to earth and just buy one of these Weiliang dual output ones, will I derive any benefit from the dual outputs to the pi and dac or is it just more wire?
Yeah, I’m dubious. I’ve just pulled the trigger on the dual studer900 based board from Aliexpress. For a transformer i can go either this
30W 30VA Primary Input 0 115 230V SCN Secondary Output 9V 12V 15V 18V 24V R core Transformer Audiophile|Transformers| - AliExpress
Or this
9V-0-9V 20VA Toroidal Transformer - Low Profile | eBay
The r-core is not much more. Is it the right type?
No. The sketch shows a +/-24VDC configuration. The PCB has 2 floating DC outputs that allows you to get the +/-24VDC when connected correctly.
On the other hand, you can use the 2 circuits separately and get 2 positive or 2 negative DCV outputs.
This one works with the Studer900 board. It has 2 independent windings for the output.
No, a centertaped transformer does not work with the Studer900 board.
Both a R-core or a toroidal transformer can work. But it must have 2 independent, identical windings.
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I assumed that Bo needs a +/-24VDC PSU since he used a center tapped transformer. My suggested hookup will give a +/-24VDC PSU. It is pretty standard practice.
If he needs 2 separate +24VDC PSU's, he still need a dual winding transformer. But he should not tie the low voltage out to the 2nd high voltage out at ground. How did you figure out that Bo wants 2 x 24v positive rails instead of +/-?
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Hi Keilau, the NAC152 clone pre-amp board that I specified I am trying to power requires 2 x +24V rails. I was using that transformer because I had it available and believed that it would do the job, based on something I'd read online.
Thanks for your input.
Cheers,
Bo
Hi, As advised in the 1st post I have tried several trans with this board, one of which was an 18 VAC trans. The problem of unstable DC output voltage remained no matter what trans I use. Anyone any idea what could be causing this. Again have measure the output voltage of all trans & they are all stable.
Ant suggestions, Thanks
How much current is your board supplying?
In your case, use only ONE of the white tap from the transformer together with the black tap. It will work with the Studer900 board, but not enough voltage to get +24VDC. You can use this to check out the functioning of your board.
If you use both white taps from the transformer, and ignor the black tap, the AC voltage will be too high for the Studer900 board and you run the danger of damaging the board.
Your best solution is get a transformer with 2x 22VAC output. The Studer900 has a higher voltage drop from the input to output of the regulator. You want at lease 28-30VDC at the rectifier out across the filter capacitors.
You need a multimeter in current mode connected in series between the Studer board and whatever you are supplying.
Alternatively, look up the specified current requirement of the target board.
Hi Keilau, thanks for your advice. I've got a twin secondary transformer on order now so hopefully that's arrival will enable me to move forward with the amplifier.
Cheers,
Bo
300mA at what voltage out? This regulator can certainly supply a lot more current than that at 5V, say.