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The Power Supply

Safety Warning

The RPSU supply module has been designed to work with isolated low voltage AC inputs only. 
Connection to any alternating current supply is done at your own risk. Low voltage is classified as 
being less than 25V with respect to the ground potential. Voltages above this level can, and often 
are, lethal to living creatures.

Oakley Sound Systems will not advise on building or modifying this board to allow for direct 
connection to the mains, or other high voltage sources, further to what is provided in this document.
Please do not ask me for additional information pertaining to direct mains connections or using 
internally mounted transformers as I will not give it.

For safety and legal reasons I cannot recommend powering this board from any other supply 
than low voltage AC output mains adapters.

Oakley Sound Systems are not liable for any damages caused by the misuse of this product. It is 
your responsibility to use this product safely. If you have any doubt about installing a safe power 
supply, then please do not attempt to do so.

Single Phase AC output wall wart supply

These are the most common AC output power adapters but increasingly they are getting harder to 
find particularly at higher output currents. Most wallwart supplies produce DC (direct current) 
voltages which means they are not suitable for use with the RPSU. Ensure that when you buy a 
wallwart type adapter it does actually output an AC (alternating current) voltage. Some DC output 
adapters are confusingly called AC adapters simply because they plug into your AC mains supply.

The SRE330 requires around 650mA or 0.65A from a single phase 15V AC supply. That means 
you need to find one with 

at least

 this capability. A 15V 1A device would be perfect, but a 15V 

0.5A would not. An 18V AC supply would also work but again at least 0.65A is required.

Quite often you will find power supplies not rated in amps but instead given an overall maximum 
power rating, or wattage. The maximum amount of current that can be taken is worked out by 
dividing the power rating in watts by the voltage output. The problem is that you don't often know 
the exact voltage the device is producing since it does vary a lot from what it says on the device. 
For example, a 15V supply may well be producing 18V even when at full load. Even so a 15W 15V
AC device should work fine. A 10W 15V one however, although in theory should work, in practice 
it may not.

Ultimately, the proof of whether it works is twofold. It must firstly produce the correct voltage so 
the RPSU can actually create a /-15V when driving the SRE330. And secondly, the adapter 
must not get overly warm in use. If you've bought what should be a good adapter but it gets hot or 
hums loudly when powering the SRE330 then it is not suitable. Another solution must then be 
sought.

Содержание SRE330

Страница 1: ...Oakley Sound Systems Stereo Ensemble SRE330 Main Board Issue 2 Builder s Guide V2 10 Tony Allgood Oakley Sound Systems CARLISLE United Kingdom...

Страница 2: ...ation regarding where to get parts and suggested part numbers please see our useful Parts Guide at the project webpage or http www oakleysound com parts pdf For general information on how to build our...

Страница 3: ...er is solely designated to 0V A four layer design although expensive to produce gives better performance than standard two layer board designs It is however imperative that when soldering and especial...

Страница 4: ...U is a power supply module designed specifically for the SRE330 although it is likely that other future Oakley Sound rack projects will use this module too It generates 15 3V at up to around 1A given...

Страница 5: ...copper traces on the board Unlike the issue 1 RPSU board there are no trimmers to set the voltages to exactly 15 00V The SRE330 main board s circuitry is not bothered whether the voltage is exactly 15...

Страница 6: ...ts List Resistors All resistors should be 1 0 25W metal film resistors except for R57 which can be 5 metal film or carbon 22R R40 75R R37 R36 R203 R257 R181 R227 120R R38 R39 R52 220R R34 R33 R29 R35...

Страница 7: ...C20 C29 C102 C27 C142 C165 C113 C101 C137 C121 C15 C188 C136 1nF C0G 2 5mm ceramic C93 C182 C156 C123 1n5 100V polyester C158 C97 C117 C185 C91 C128 2n2 100V polyester C139 C191 C111 C100 C167 C106 1...

Страница 8: ...17 U53 U28 78L09 9V regulator 100mA U29 U36 U41 U49 The Belling BL3207 or Panasonic MN3207 may be used instead of the Coolaudio V3207 IC sockets are recommended for the V571D V3102D V3207D and LM13700...

Страница 9: ...RIO board then you do not need to fit this IDC header Instead you will wire the sockets to the appropriate solder pads where the header would normally be fitted Miscellaneous Mounting hardware for the...

Страница 10: ...position LK3 must be left empty Capacitors 100nF axial multilayer ceramic C1 2u2 63V electrolytic C2 22uF 35V electrolytic C3 Discrete Semiconductors 1N4004 diode D1 BC550C NPN transistor Q1 Q2 Interc...

Страница 11: ...1N4004 D1 D2 D3 D4 D5 D6 1N5401 D7 D8 D9 D10 D11 and AC LED are not fitted D9 and D10 do not need to be fitted if you are using a single phase wall wart or line lump although they won t cause any pro...

Страница 12: ...ting of U1 and U2 to panel Heatsink paste For mounting of U1 and U2 to panel if using mica plates Suitable power switch Suitable power socket A suitable length of 24 0 2 insulated cable for all power...

Страница 13: ...an use 47K in place of a 50K pot When constructing the board temporarily fit the pot brackets to their pots by the nuts and washers supplied with the pots Now fit the pot and pot bracket assembly into...

Страница 14: ...tted in the location marked MODE Make sure the switch body is flat against the board Now solder all the pins on each of the switches including the two securing pins to the front You may need to trim t...

Страница 15: ...printed circuit board with copper strips on one side and perforated by a 0 1 grid of holes into which you put the component leads through You can cut it to size by using a knife to score along the hol...

Страница 16: ...are pushed into their panel holes Care must be taken to ensure that the board to board connector does not foul the resistor R39 just behind it Using stripboard to make the LED connections The stripbo...

Страница 17: ...ich means they are not suitable for use with the RPSU Ensure that when you buy a wallwart type adapter it does actually output an AC alternating current voltage Some DC output adapters are confusingly...

Страница 18: ...e mains via your local mains connector They will be different types depending on the country you need them for It comes with a handy three way plug at the low voltage end that you can use with an appr...

Страница 19: ...n It is worth therefore measuring the resistance between parts of the case If you have no connection ie you have a resistance over 10K between the lower panel and the rear panel it will be worth fitti...

Страница 20: ...supplies simultaneously They only need the terminal s AC1 and 0V1 wired to the power socket AC2 and 0V2 are left unused D9 D10 and F1 are not needed to be fitted to the RPSU although it will do no har...

Страница 21: ...r AC2 The 0V should go to the 0V1 terminal The 0V2 terminal is left unused Connecting to a linelump wiring with centre tapped output eg Yamaha PA 20 The front panel switch is a double pole single thro...

Страница 22: ...ual secondary or 18 0 18 single tapped secondary Power At least 25VA This will give you a power supply that should be theoretically capable of providing just over 400mA to each rail assuming your heat...

Страница 23: ...ons required in their own country It is essential that everything you build that has both live mains inside and a metal case or panels has a safety earth fitted UK legislation requires that any metal...

Страница 24: ...Mains wiring diagram For experienced builders only...

Страница 25: ...and fit the power devices to the board by poking their legs up through the bottom of the board Do not solder them but fit the board back into place Use the hole in each regulator to mark out where yo...

Страница 26: ...he power devices Do not tighten them too much as this will crush the insulating pad Once secured you can solder the regulators leads from the top side of the board and clip off any excess lead lengths...

Страница 27: ...the connectors in the photograph above they both point right The red edge denotes the pin one connection Here I have used connectors that have a strain relief fitted which requires the cable to be fol...

Страница 28: ...The power on LED should light up and stay on for as long as the unit is switched on Check that the power supply is still producing between 15V and 15 5V Leave the unit on and check that no device is g...

Страница 29: ...ts used and my time at 25GBP per hour Most faults can be found and fixed within one hour and I normally return modules within a week The minimum charge is 25GBP plus return postage costs If you have a...

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