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Post by danielquinn on Jul 14, 2014 15:07:30 GMT
I have a phono amp which uses a wall wart .
Remembering the AOS wall wart wars which saw the frustrated retreat of Jez Arkless  [ hey jez join here ]
Amongst my many cost effective projects , I am keen to try out the efficacy of regulated linear dc power supplies over wall wart , while I save up for a new amp and moving coil or wait for my four children [ 11,9,7, and 7 months ] to piss off and find a job . Which ever comes first .
Now this issue seems to inflicted with the hifi disease , ie charging £100's for what can be had for £'s . Ebay is full of regulated linear dc power supply bargains cause they have a plethora of professional applications .
Additionally , words like regulated and linear don't seem to actually mean anything , as it would seem all ac to fixed dc convertor power supplies are regulators and linear [ on this I could be wrong as I rely on my understanding of Wikipedia ]
So my question is what is a hifi power supply giving me that one designed for professional use is not ?
For example , there are 100 on ebay at the moment bankrupt stock for £19 which were part of traffic control system . They can even be run of 12v batteries , thereby adding additional spice to my investigations .
p.s - is it wall wart or wort ?  |
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Post by Dr Bunsen Honeydew on Jul 14, 2014 15:15:50 GMT
What is not understood is that most product use Wall Warts because by doing so they can claim munufacture to Class III regs Class III "A Class III appliance is designed to be supplied from a separated/safety extra-low voltage (SELV) power source. The voltage from a SELV supply is low enough that under normal conditions a person can safely come into contact with it without risk of electrical shock. The extra safety features built into Class I and Class II appliances are therefore not required. For medical devices, compliance with Class III is not considered sufficient protection, and further more-stringent regulations apply to such equipment." en.wikipedia.org/wiki/Appliance_classesThis is done for cheapness and to get around have to meet the onerous safety regs of Class I and Class II. So by adding a after market proper power supply you render your product illegal. But it doesn't seem to stop people doing it or selling these power supplies, so fill yer boots. |
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Post by Deleted on Jul 14, 2014 15:59:37 GMT
For example , there are 100 on ebay at the moment bankrupt stock for £19 which were part of traffic control system . They can even be run of 12v batteries , thereby adding additional spice to my investigations .
p.s - is it wall wart or wort ? any chance of a link? |
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Post by danielquinn on Jul 15, 2014 9:34:54 GMT
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Post by MartinT on Jul 15, 2014 10:13:19 GMT
There is additional complexity in order to get the full picture. Wall warts come in three different types:
- Low voltage AC
- Unregulated low voltage DC
- Regulated low voltage DC
Of the items in 3 above, there are two kinds:
- Linear regulated voltage
- Switched regulated voltage
So now you have 5 types on sale. Be careful that you know what you need and what you are buying.
As for the regulation itself, a regulator can vary from a simple transistor or three-pin IC regulator like an LM317 (variable) or 7812 (fixed 12V), all the way up to extremely complex power supplies from the likes of Nick Lurcher and Paul Hynes. These latter offer very stiff regulation, large reservoir storage, low noise and large instantaneous current delivery. Ultimately, you get what you pay for and the cheap Chinese wall-warts that are frequently provided with equipment can often be improved upon, with consequent improvement in sound quality.
Witness Stan Beresford, who supplies a decent switched 12V supply with his DACs but positively encourages users to experiment with batteries and linear power supplies.
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Post by yomanze on Jul 15, 2014 10:23:14 GMT
My phono stage has an AC wall wart for sonic reasons i.e. keep the transformer well away from the phono stage electronics. Funny how they do seem to have a bad reputation, but really it's just a form factor, and anything can be inside it.
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Post by danielquinn on Jul 15, 2014 10:34:19 GMT
Ultimately, you get what you pay for and the cheap Chinese wall-warts that are frequently provided with equipment can often be improved upon, with consequent improvement in sound quality.
Witness Stan Beresford, who supplies a decent switched 12V supply with his DACs but positively encourages users to experiment with batteries and linear power supplies.
This is of course what i want to put to the test as it is by no means an accepted fact of hifi . my flummixing IS why do some for professional use power supplies cost £40/£80 quid and yest the same thing with the same specs and same components but with the word audiophile on them cost £200 to £500 ? I do have some experience of this conundrum , I have an origin live advanced motor kit , when i modified my PT at the cost of a fully functioning thumb  , I experiemented with motor controllers and motors . Eventually I got a variable output dc linear regulated bench power supply and a motor direct from Maxon total price £220 and the motor was £150 . Now this is vastly superior to the origin live in every way , but in terms of the power supply only , it doesn't fluctuate over time which the O/L did often during the course of a couple of hours and the whole speed integrity is much better to my ears . |
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Post by Dr Bunsen Honeydew on Jul 15, 2014 10:37:18 GMT
A Wall Art or AC adapter is specifically a very simple cheap AC to DC low voltage power supply built into a mains plug. Anything more complex that that is not a Wall Wart.
Its purpose is so that the unit being powered doesn't have to have a mains lead or a built in power supply, so it can be built far more cheaply outside of the safety regs of Class I and Class II appliances. The other primary designed use is to replace batteries and the cost of replacing them, or to charge those batteries.
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Post by Dr Bunsen Honeydew on Jul 15, 2014 10:39:27 GMT
my flummixing IS why do some for professional use power supplies cost £40/£80 quid and yest the same thing with the same specs and same components but with the word audiophile on them cost £200 to £500 ? It is very simple, it is because people in this industry want to rip you off, and they have found some idiots who will give them the money. |
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Post by Deleted on Jul 15, 2014 10:41:06 GMT
thanks DQ that particular unit has surprisingly high ripple figure in the spec(25mv). I know with these things(wall warts) this figure is not usually specified, but I would usually be aiming for way under that figure with a linear supply. Having said that, the ripple on the SMPS units is way up in the 20k-40khz range and even if significant is not usually bothersome. Others may have a different view on this... |
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Post by MartinT on Jul 15, 2014 10:48:53 GMT
Having said that, the ripple on the SMPS units is way up in the 20k-40khz range and even if significant is not usually bothersome. Injecting 20k - 40kHz switching noise into my system components, or back into the mains, is something I have spent a great deal of time and money eliminating, to advantageous sonic effect.
My house is a 'quiet zone' in as much as I have control over it.
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Post by Deleted on Jul 15, 2014 11:00:37 GMT
Injecting 20k - 40kHz switching noise into my system components, or back into the mains, is something I have spent a great deal of time and money eliminating, to advantageous sonic effect.
My house is a 'quiet zone' in as much as I have control over it.
quite so... I use some of the larger 12v 20amp switchers for heater supplies on some valves and I've found they're totally unacceptable without running through a regulator as well. Having done a lot of measurement/testing with various SMPS over the years I've found that the PC power supply units are very much cleaner than the standard wall wart devices, though using the same fundamental mechanisms. This must be an example of getting what you pay for. |
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Post by danielquinn on Jul 15, 2014 11:18:24 GMT
my flummixing IS why do some for professional use power supplies cost £40/£80 quid and yest the same thing with the same specs and same components but with the word audiophile on them cost £200 to £500 ? It is very simple, it is because people in this industry want to rip you off, and they have found some idiots who will give them the money. That is my preliminary opinion , but it nice to listen to the case for the defence [ if there is one ] before casting judgement |
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Post by MartinT on Jul 15, 2014 11:23:38 GMT
It's the same with hi-fi equipment as it is in the educational market. Always look for the exact same thing in different markets - this is where eBay and the likes are so useful. You won't always find it, but it's worth a look.
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Post by gazjam on Jul 24, 2014 19:29:31 GMT
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Post by Eduardo Wobblechops on Jul 24, 2014 19:46:54 GMT
Which phono stage is that Gaz?
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Post by gazjam on Jul 24, 2014 19:59:52 GMT
Firebottle Plus MM/MC
Helluva step up from the Yaquin mate...its very very good.
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Post by Eduardo Wobblechops on Jul 24, 2014 20:10:25 GMT
Cool. What are you powering?
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Post by Firebottle on Jul 24, 2014 20:19:01 GMT
Glad you appreciate it Gaz, how noticeable was the difference from wall-wart to Maplin linear?
Cheers, Alan
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Post by gazjam on Jul 24, 2014 20:24:18 GMT
Cool. What are you powering? This mate. (though it looks a bit different now   Picked it up at Owsten. Vinyl rocks! |
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[ hey jez join here ] 
, I experiemented with motor controllers and motors . Eventually I got a variable output dc linear regulated bench power supply and a motor direct from Maxon total price £220 and the motor was £150 . Now this is vastly superior to the origin live in every way , but in terms of the power supply only , it doesn't fluctuate over time which the O/L did often during the course of a couple of hours and the whole speed integrity is much better to my ears . 
