I have considered the Mac Mini power supply options and concluded that the SR5 power supply would likely suit most Mini audio server applications. If you are planning on using your Mac for gaming or video editing then you really need a larger power supply like the SR7 or SR7EHD. I have chosen the SR5 for this “Group Buy” project because it is more rugged and gives better sound quality than the SR3 so you are unlikely to get problems if you configure your audio server with a higher power overhead than the SR3 can provide. Of course, if you are going lean on the configuration like Bob Lloyd has, and your budget is limited, you can use the SR3 which does cost less than the SR5.
The SR5 will be set up to allow 4 amps continuous current delivery and it should easily deliver 40-50 amps transient while still remaining in regulation. There should be no boot up or run problems with this power supply provided you use the Mini for the designated task of audio server.
There are two AC versions of the SR5 to cover the various Mac Mini supply requirements. This is necessary because dialing the 18v5 version down to 12v would increase the power dissipation in the output stage and the heatsink would exceed 70 degrees C. I like to keep heatsink temperature to less than 50 degrees C where possible to ensure reliable operation and a long life. The case size for the AC input versions is W 224mm x H 80mm x D 220 and the back panel heatsink protrudes a further 40mm. The output connector is via a 4 pin XLR with silver plated pins and the mains input version has a silver plated fuse holder, mains voltage selector and an IEC mains inlet.
The most convenient battery solution for the DC input version is two 12v batteries in series to give 24v so I use a larger heatsink for this supply to allow dialing the power supply output voltage down to 12v without excessive heatsink temperature. This also requires a larger case to suit the heatsink and this case size is W 224mm x H 120mm x D 220 and the back panel heatsink protrudes a further 40mm.
The DC version will have a 4 pin XLR input connector with silver plated pins, allowing you to connect the battery to the power supply. The battery voltage, for the DC input version, needs to be a minimum of 5 volts higher than the output voltage. I fit an additional module to this supply that provides reverse polarity protection and soft start. Connecting low impedance batteries to uncharged low impedance capacitors can cause spectacular transient current delivery generating electrical arcs. Without the protection of the soft start these electrical arcs would burn and oxidise switch and connector contact surfaces destroying the electrical integrity of the contact. Once again I like my products to have a long life.
I normally sell this version of the SR5 AC input for £450 and the SR5 DC input for £450. The SR3 is usually £270 and the DC3C is normally £35.
The PR3iHD regulator module can be used for DIY power supply build and this currently costs £120 for either the AC input version or the DC input version with the additional battery protection module. You will be responsible for sourcing case, transformer and hardware yourself for a DIY build. The module is fully built and tested and is easy to apply.
I am sure there will be plenty of questions about application so feel free to discuss this on the thread.
Rather than set up a Group Buy, which could take time to accumulate enough interest to start the ordering and it would likely increase the administration, I have decided to just give a sizable discount on the normal price. This discounted price pays for materials and the cost of production for 30 units but does not include any business profit. I am going to stick a limited quantity and finite order window on this project, as I would not be able to sell the power supplies at this price continuously, as any business does need to have some profit to allow further product development, expansion and financial security. The quantity limit will be 30 units and the order window starts now and closes on the 30th November 2012. Then it is back to the normal prices.
Audiocircle members discount price.
SR5-12 AC input and SR5-18v5 AC input £350
SR5-12 DC input and SR5-18v5 DC input £350
SR3-12 AC input and SR3-18v5 AC input £220 (only available as an AC input power supply)
PR3iHD-12 or PR3iHD-18v5 £095
DC3C OFC DC cable 1 metre length for the 12v Mini £025
DC3C OFC DC cable 1 metre length for the 18v5 Mini will have to be sourced from the Mac power supply or Carnetix. You will have to supply these. I am prepared to modify these for a cost of £15 if required.
Insured carriage and packing will depend on destination and I will have to quote for this once the destination is known.
All of my products are custom built to order. Orders are placed in the build schedule on receipt of cleared funds. The build schedule lead-time is normally 35 to 48 working days for this product. Working days are Monday to Friday excluding national and personal holidays. Also circumstances beyond my control, such as component sourcing problems, weather related delays like power failure, and absence from work due to illness can affect lead times.
Payment can be via PayPal by sending funds, with 3.5 % added to cover the Paypal fees, to
[email protected] in GBP. Please remember to include details of what you are ordering and ensure that a delivery address is also included.
Alternatively payment can be by bank transfer, adding £6 for the Barclays processing fee. Payment can also be made with no additional fees, either over the counter at any branch of Barclays in the UK, or via the “Fast Payment” bill payment scheme that some banks now operate in the UK. If any of these methods of payment are chosen I will forward details of the bank collection account to enable payment.
My worldwide guarantee covers parts and labour for three years from receipt of goods, subject to correct application, and is transferable should you decide to re-sell at a later date.
I also give a 56 day, return if not satisfied guarantee for standard products. This allows a reasonable burn in period before appraisal.
If I can be of further help let me know.
Regards
Paul
