Yes, it should be fine. It might get warm but Aleš has a neat heatsinking arrangement with an aluminium block that couples the regulator device to the chassis. Selecting the right transformer so that the regulator doesn't have to burn of excess volts will help with heat management too.
I keep meaning to try a battery supply but have never quite got around to it. If you search the power supply section of the site I'm sure you'll turn something up.
Ray
Doing the maths contained in the manual suggests a transformer secondary of 7.7VAC (assuming 500mV for dropout over the regulator). Unless you have a transformer custom wound, the nearest stock transformer above 7.7VAC will be 9VAC. If you want 1A out I suggest your transformer needs to be capable of delivering 9VAC @ 2A, which is 18VA - nearest stock transformer is likely to be 25VA.
I think heat dissipation might be a problem at 1A output though.
Where do you get the 2A figure? The regulator is 1A.. sorry confused. Are you talking about using a transformer that has dual secondaries and only using one of the secondaries instead of running them both together in parallel?
Basic electronics. The rectifiers will give a DC voltage that is 1.414 times the AC voltage from the transformer so if the voltage is increasing the current must decrease - you can't get something for nothing! If you double the transformer current you give yourself a good margin as you don't really want to run the transformer at full load all the time.
Whether you use two secondary windings in parallel or a single secondary you need sufficient current.
Ales, also sells his power supplies on ebay, though it looks as if he only has the upgraded version listed at the moment;
Ultra Low Noise HiFi Power Supply TPS7A4700 DIY Preamplfier DAC Raspberry Pi PSU | eBay
The upgraded version has a CL (capacitor/inductor) pre-filter that should make the regulator even quieter.
Surprisingly he doesn't mention anything about a heat sink on the ebay page. So I wouldn't know what heat sink to buy. I am sure I'd end up getting the wrong one that didn't fit right or cool well enough.
I've just taken delivery of two of these supplies and the heatsink blocks were included. The heatsinking is an aluminium block that is sandwiched under the PCB so it sinks the heat itself but also couples to the chassis.
Oh okay thanks. So I should just go ahead and buy this board from ebay? Like you say it's better -- less noisy.
It's for a linear regulated power supply for SMSL M8 DAC which requires a 9V 500ma input. (It comes stock with a switching power supply wall wart -- yuck.) So I figure a 25VA 9V antek transformer with the regulator jumpers set to 9V output. Should be a nice power supply no? Much better than the one SMSL is trying to sell for $100 (the P1).
Hold fire for a short while. The inductor will drop some voltage but I'm not sure how much as I don't recall the specs. I've mailed Ales asking him whether a 9V transformer would still be sufficient for 9V DC out.
Oh darn it, because I just ordered the 9V transformer from Antek earlier today.. I suppose I could email them now and ask them to put it on hold.
For those that use the reg at 5V or 6V DC output: I have a quantity of excellent quality Rcore transformers 6V 3A with 2 x 115V primaries. These give 6.8V unloaded and have enough juice for 5V or even 6V DC output of LDO regs at full load. I used them for my own PSU Group Buy but I have some leftovers. If someone wants one of those please send me a PM. I was thinking of a rerun of my SBT PSU but decided not to do it as I have other priorities at the moment.
These are relatively small, they are absolutely silent, produce no hum and they have a very low stray field. All features we like a lot in audio devices. Even at full load they don't heat up much. They are way better than toroids.
These are relatively small, they are absolutely silent, produce no hum and they have a very low stray field. All features we like a lot in audio devices. Even at full load they don't heat up much. They are way better than toroids.
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Hi Jennifer,
here is the calculation for transformer voltage.
First we will calculate ripple voltage after the capacitors:
Ripple with 2 x 3900uF:
Uripple (50Hz mains Europe) = 1A / (2*50Hz*2*3900uF) = 1.282V (50Hz mains)
Uripple (60Hz USA) = 2.273V (60Hz mains) = 1.068V
Upeak = 9V * 1,41 - 1V = 11.728V
9V is AC voltage of transformer, 1.41 is actually value of sqrt2 and 1V is voltage drop on schottky diodes.
"Usable" voltage is then 11.728V - 1.068V = 10.66V
Since the output of the regulator will be 9V DC, and his voltage drop is 307mV , needed voltage on the regulators input is 9.307V.
9V AC transformer is, according to calculation, OK!
Best Regards,
Aleš
here is the calculation for transformer voltage.
First we will calculate ripple voltage after the capacitors:
Ripple with 2 x 3900uF:
Uripple (50Hz mains Europe) = 1A / (2*50Hz*2*3900uF) = 1.282V (50Hz mains)
Uripple (60Hz USA) = 2.273V (60Hz mains) = 1.068V
Upeak = 9V * 1,41 - 1V = 11.728V
9V is AC voltage of transformer, 1.41 is actually value of sqrt2 and 1V is voltage drop on schottky diodes.
"Usable" voltage is then 11.728V - 1.068V = 10.66V
Since the output of the regulator will be 9V DC, and his voltage drop is 307mV , needed voltage on the regulators input is 9.307V.
9V AC transformer is, according to calculation, OK!
Best Regards,
Aleš
Would a 12v possibly sound better over the 9V for this application? Would it generate too much heat at 500 ma to 1a?
Antek cancelled my order and refunded me. So I can reorder the right now based on your feedback.
12V AC transformer would be better regarding ripple voltage.
My kit is supplied with aluminum heat bridge, which was proven to be very good solution to dissipate heat from regulator. Though you must note that you should attach it to bigger cooling area.
Best Regards,
Aleš
So I can probably drop in one of the new 'Pro' version boards to replace a standard version; 5VDC output from a 6VAC secondary. I'll give it a try.
Ray