optical
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Post by optical on Mar 16, 2022 14:41:00 GMT
I have received this rather attractive looking power supply from Ali Express. It's to power an Arcam rPhono stage.     It puts out a very stable 12V and should be good for up to 4A. (My phono stage only draws 2A). You can spec it with other values but above 12V the amperage value drops a bit (although it's still likely fine for most DAC's and other low power consumption devices). Proper toroidal in there and the circuit looks very well designed and put together. Even comes in a nice chunky case with a nice umbilical. Oh and it's £35.00 +postage. Came in a week. Here is the link: www.aliexpress.com/item/1005002950848940.html?spm=a2g0o.order_list.0.0.21ef1802QHaBr3 |
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Bigman80
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Post by Bigman80 on Mar 16, 2022 15:27:43 GMT
Bargain!
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Post by alit on Mar 16, 2022 16:36:49 GMT
Indeed, lot of value there. Is it a 230v traffo?
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Post by misterc on Mar 16, 2022 16:46:27 GMT
4 amps planning on using the phono stage as heater Chris  |
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Post by firebottle on Mar 16, 2022 17:00:39 GMT
Very nicely built unit with pass transistors mounted on the case for heatsinking and heatsinks on the rectifier diodes.
Certainly a good price, HOWEVER:
As with virtually all power supplies built in China/far east the specified output current is over specified.
The transformer may well be a 50W (VA) but you can not equate that with the output power directly.
There are losses associated with transformer utilisation and conversion from AC (the transformer output) to DC via the rectifier diodes, plus losses in the regulator.
The maximum output depends on whether it is full wave or bridge rectification but is likely to be 2.5A DC.
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Post by misterc on Mar 16, 2022 18:19:00 GMT
I have at least six here all slighty different cases but virtually the same inside, very basic ac filtration as Alan mentions 2.5amps if you are lucky the most I have seen on the 12Vdc models is 1.8amps before distablising the base voltage. Not unsafe at all, but CE emissions and immuntiy test if a slightly plastered complience testing facility manager is open to a few Kung poo Chickens then maybe lol I have just measured one I had lying around here they are quiet noisy around 25mA's of riple current, while much better than most wall warts, you get what you pay for. As you can see 1.8am CCL its out of its depth and 2 amps the voltages is sagging worse than Matron's juggs on a bath day.
Images below of unit, no load raw volatge, 1mp load no sag, then 2.5 amps dropping like a stone. 1.85 amps is the thresh hold of sag beginning. this is an adjustable psu and can go upto 17Vdc per rail, only signle rail measured
But I will add I can't even produce a matching Tx with our company for the cost of that psu alone!
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optical
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Post by optical on Mar 16, 2022 19:10:14 GMT
Indeed, lot of value there. Is it a 230v traffo? Will check for you tonight Ali |
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optical
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Post by optical on Mar 16, 2022 19:29:47 GMT
Very nicely built unit with pass transistors mounted on the case for heatsinking and heatsinks on the rectifier diodes. Certainly a good price, HOWEVER: As with virtually all power supplies built in China/far east the specified output current is over specified. The transformer may well be a 50W (VA) but you can not equate that with the output power directly. There are losses associated with transformer utilisation and conversion from AC (the transformer output) to DC via the rectifier diodes, plus losses in the regulator. The maximum output depends on whether it is full wave or bridge rectification but is likely to be 2.5A DC. Thanks Alan, Yes I'm not exactly expecting it to perform to spec hence why I went for one which can easily handle much more then my stage requires. To be honest I don't think the stage ever actually draws anywhere near its rating so this will certainly be adequate and then some. I did look at a lot of similar ones around and this one seemed the most sensibly built, especially for the price. |
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optical
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Post by optical on Mar 16, 2022 19:31:52 GMT
I have at least six here all slighty different cases but virtually the same inside, very basic ac filtration as Alan mentions 2.5amps if you are lucky the most I have seen on the 12Vdc models is 1.8amps before distablising the base voltage. Not unsafe at all, but CE emissions and immuntiy test if a slightly plastered complience testing facility manager is open to a few Kung poo Chickens then maybe lol I have just measured one I had lying around here they are quiet noisy around 25mA's of riple current, while much better than most wall warts, you get what you pay for. As you can see 1.8am CCL its out of its depth and 2 amps the voltages is sagging worse than Matron's juggs on a bath day.
Images below of unit, no load raw volatge, 1mp load no sag, then 2.5 amps dropping like a stone. 1.85 amps is the thresh hold of sag beginning. this is an adjustable psu and can go upto 17Vdc per rail, only signle rail measured
But I will add I can't even produce a matching Tx with our company for the cost of that psu alone!
Thanks Tony, I've no doubt you can get better performance but not for similar outlay, that was the brief here, to try out a slightly better supply than a wall wart for beer money. As you say the cost of parts can't be far off the entire cost. |
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Bigman80
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Post by Bigman80 on Mar 16, 2022 19:33:20 GMT
Very nicely built unit with pass transistors mounted on the case for heatsinking and heatsinks on the rectifier diodes. Certainly a good price, HOWEVER: As with virtually all power supplies built in China/far east the specified output current is over specified. The transformer may well be a 50W (VA) but you can not equate that with the output power directly. There are losses associated with transformer utilisation and conversion from AC (the transformer output) to DC via the rectifier diodes, plus losses in the regulator. The maximum output depends on whether it is full wave or bridge rectification but is likely to be 2.5A DC. Thanks Alan, Yes I'm not exactly expecting it to perform to spec hence why I went for one which can easily handle much more then my stage requires. To be honest I don't think the stage ever actually draws anywhere near its rating so this will certainly be adequate and then some. I did look at a lot of similar ones around and this one seemed the most sensibly built, especially for the price. It's fine for your phonostage mate. MrC has high expectations of power supplies, and rightly so, but it's £40 and you can't buy the case for that, so yeah, whilst it may not pull up any trees in that world, it's far beyond the wallwart. It's also made by Teradak, so it won't be as bad as some of them. I reckon it'll be quite decent. Great find. |
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Post by sq225917 on Mar 16, 2022 20:44:52 GMT
Swap the traffo, put voltage up to 15v feed it through 6x lt3045 and hey presto, decently quiet supply.
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optical
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Post by optical on Mar 16, 2022 20:59:45 GMT
Swap the traffo, put voltage up to 15v feed it through 6x lt3045 and hey presto, decently quiet supply. Maybe, and also a much more expensive one.... |
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optical
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Post by optical on Mar 16, 2022 21:44:46 GMT
Indeed, lot of value there. Is it a 230v traffo? Will check for you tonight Ali Ali, it's 230v or 2 X 115v to be exact! |
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Post by pete on Mar 16, 2022 22:30:18 GMT
Be interested to hear how it sounds
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Post by antonio on Mar 17, 2022 8:25:11 GMT
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optical
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Post by optical on Mar 17, 2022 9:59:49 GMT
Be interested to hear how it sounds Better than the wallwart it's replacing! I haven't A/B'd them yet but dynamics are greater and bass is stronger quite obviously. Overall very happy for the outlay. The alternative UK made lpsu for this stage is north of £300..... It's not even my main phono stage I just wanted to see if improvements could be had for very little money. They can. 👍 |
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optical
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Post by optical on Mar 17, 2022 10:06:23 GMT
Swap the traffo, put voltage up to 15v feed it through 6x lt3045 and hey presto, decently quiet supply. I mean to be fair I am a mod-aholic so could well be an option for the future.... Are those regs available for under a tenner?? |
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Post by pete on Mar 17, 2022 10:16:20 GMT
Be interested to hear how it sounds Better than the wallwart it's replacing! I haven't A/B'd them yet but dynamics are greater and bass is stronger quite obviously. Overall very happy for the outlay. The alternative UK made lpsu for this stage is north of £300..... It's not even my main phono stage I just wanted to see if improvements could be had for very little money. They can. 👍 Great outcome then, that is what it all about, an easy and fantastic value upgrade  |
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Bigman80
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Post by Bigman80 on Mar 17, 2022 10:56:19 GMT
Be interested to hear how it sounds Better than the wallwart it's replacing! I haven't A/B'd them yet but dynamics are greater and bass is stronger quite obviously. Overall very happy for the outlay. The alternative UK made lpsu for this stage is north of £300..... It's not even my main phono stage I just wanted to see if improvements could be had for very little money. They can. 👍 Very rarely, if ever, does an improved power supply not make sense. |
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Post by misterc on Mar 17, 2022 11:09:20 GMT
IMHO 90% of all audio is psu with an expectionally small amount of a wierd Sh#t bucking the trend.
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Post by sq225917 on Mar 17, 2022 17:41:59 GMT
Agreed, nothing better than copious amounts of stable voltage, gobs of current, low impedance and vanishing noise.
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Post by alit on Mar 18, 2022 11:19:57 GMT
Will check for you tonight Ali Ali, it's 230v or 2 X 115v to be exact! Thanks. :-) |
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