I have a Sure 4 channel amp 4x100W @ 4 Ohm TK2050 Class-T Digital Audio Amplifier Board 320-302
I need a power supply for it. (the amp is unregulated, it NEEDS 24-30v to really work well)
Can I use a computer power supply? How can I modify the power supply to 24 or even 30 volts??
I need a power supply for it. (the amp is unregulated, it NEEDS 24-30v to really work well)
Can I use a computer power supply? How can I modify the power supply to 24 or even 30 volts??
You may not be able to.
Most manufacturers will use parts that are slightly over rated for their purpose.
Most likely the capacitors in the Computer P/S would be 16-24V capacitors.
Beyond that the modern switching supplies are very type specific in order to get the high efficiencies.
You may be better off building an unregulated supply for your purposes.
Notice also printed on the board it says DC 6-26V in.
Most manufacturers will use parts that are slightly over rated for their purpose.
Most likely the capacitors in the Computer P/S would be 16-24V capacitors.
Beyond that the modern switching supplies are very type specific in order to get the high efficiencies.
You may be better off building an unregulated supply for your purposes.
Notice also printed on the board it says DC 6-26V in.
If you have an ATX 2.x supply most of its output is on the 12 V . By loading the 5V with a couple of amps you can draw power from this 12 V .
Then build your own 12=> + - whatever voltage you need, ie a car audio power converter. Several topics cover this.
If it is a high Q supply ouput noise can be surprisingly low already to start with.
Then build your own 12=> + - whatever voltage you need, ie a car audio power converter. Several topics cover this.
If it is a high Q supply ouput noise can be surprisingly low already to start with.
a computer PSU will not avail to you the type of transformer you need to build a linear PSU.
the "+-20mF" was referring to using a 20000uF cap per rail (pos. & neg.) of a linear PSU.
if you need so much power you must pay the price and the linear PSU is probably the quicker/cleaner/cheaper way of doing it.
the "+-20mF" was referring to using a 20000uF cap per rail (pos. & neg.) of a linear PSU.
if you need so much power you must pay the price and the linear PSU is probably the quicker/cleaner/cheaper way of doing it.
+-20mF could be assembled from a pair of 10000uF//10000uF, i.e. four 10mF caps to give +-20mF.
Can you see why it's easier to use m instead of 1000u?
all computer PSU outputs are referenced to earth-ground which makes it rather problematic placing two of them in series to get 2x12=24. However, modern ATX PSUs can provide enormous amperage at 12 volts and thus amplifier bridge configurations into 4 ohms or lower can yield large output power.
You're right, I forgot about that earth issue as I'm more used to floating outputs on the PSUs I deal with.
I think I would first look to see if I could find a good "surplus" switching supply instead of modding a PC PSU. A linear supply will probably be big bucks. Marlin P. Jones has a 24V 10A switcher for $50 on page 3 of the catalog they just sent me, PN 18436-PS.
edit: Clicked my own link, and MPJA has a 28V 10.8A switcher for only $29.95. PN 18927 PS, right on their home page.
edit: Clicked my own link, and MPJA has a 28V 10.8A switcher for only $29.95. PN 18927 PS, right on their home page.
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I've done exactly that, serially connected 2 PSU using 12volt lines to get a 24volt line. I've been running it for over a year now without problem.
see the box on the left
No, they are definitely not.
The output on all computer PSU I have ever seen is transformer coupled and completely floating. The floating ground of the PSU is connected to power cord ground at the motherboard; the case of the PSU is grounded, and this is in electrical contact with the PC case, so the motherboard (via mounting screws) and all other components touching the case become grounded as a result. If you install the PSU separately from a PC case, you can connect the floating output in any manner you wish, including putting two 12V outputs of two supplies in series.
Armed with this knowledge, you can easily break ground loops in a PC/audio system, just separate the PSU from the case using some type of gasket and use nylon mounting screws. The PC case itself doesn't need to be grounded, only the PSU case does.
Yes, it's very do-able but you (in the general sense, not you obviously) need to be very confident in your understanding of electrical safety aspects to tackle this in the right manner.
Dem is correct.
Mac is wrong.
To prove to myself I pulled a computer PSU off the shelf and measured it.
It has 14 black insulated wires feeding the various plugs to power the PC.
ALL 14 of these black insulated wires are connected to PE and to the PSU chassis.
I don't know who Mac is trying to kid, but I'm not one of them.
Unfortunately we have some Members who will read his completely misleading post and believe what Mac has said.
Even worse these same Members may act on the information given.
Mac's post should either be removed in total, or the Moderators should add an Safety addendum pointing out the wrong information in post14
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a computer switchmode PSU is designed and built to have earth connection
it works without earthing, but noise could be a problem
a switchmode PSU are widely known to be unreliable, and the first to fail in many electronic devices
missing earthing is said to be one major reason for this
at least thats what I have been told by experts
and btw, in bigger commercial setups all computers will have their own dedicated earth connection, seperated from all other electronic devices
its very tricky, and special wall plugs are used to prevent anything else being connected
a have a friend who works offshore, and he knows about earthing problems too
it works without earthing, but noise could be a problem
a switchmode PSU are widely known to be unreliable, and the first to fail in many electronic devices
missing earthing is said to be one major reason for this
at least thats what I have been told by experts
and btw, in bigger commercial setups all computers will have their own dedicated earth connection, seperated from all other electronic devices
its very tricky, and special wall plugs are used to prevent anything else being connected
a have a friend who works offshore, and he knows about earthing problems too
This is incorrect as already pointed out and can be fatal in case of a failure inside the supply.
The power supply ground on secondary side (low voltage) is connected to the casing of the supply, usually by the mounting screws of the PCB to the casing , and casing is also connected to Earth in the power inlet socket via wiring. Only the high voltage (Live/Neutral) connected to the mains are floating, but usually connected with X/Y caps to Earth. Ie the primary side is floating.
In most countries this is so because an unprotected metal casing (metal chassis of the computer) needs to be connected to Earth for safety reasons by regulations(Law and order) , in case of a insulation failure which would make the casing/chassis live at say 230VAC which could be fatal for the user. Or lead to severe damage to other components connected.
Also, the earthing of a metal chassis parts helps reducing EMI from the swithing power supply unit. Running it bare in the open spreads A LOT OF EMI, as most cheap ATX power supplies are quite low quality therefore cost savings have lead to removal of filter parts, or just bad layout and crappy design in general. Also, it is not easy to manage the EMI problem in such power supplies.
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