13-Jul-2016, 10:31
Here are some highlights from Paul Hynes. Some stuff is skipped, very specific to my TT etc., but the SR3 looks like a bit of a bargain if you are just after a decent mR PSU.... Then spend some more, and thing get even better.....
I usually sell the SR3-7 single rail supply for the microRendu but in view of your requirement for the best performance for the microRendu, plus the option of additional rails for your other equipment, I would be more inclined to recommend the SR5MR2 or the SR7MR3 as both of these supplies have space for the additional rails and offer a higher level of performance. The regulator rails are also galvanically isolated, so there will be no ground return current earth loops causing intermodulation distortions that result from having multiple regulator rails driven from the same master supply with a common ground point.
The SR3, SR5 and SR7 power supplies all use the same ultra low noise, high speed, wide operating bandwidth, discrete component regulator circuit topology.
Typical specifications are:-
The error amplifier devices have a noise spec of 0.5 nanovolts root Hz and the low noise voltage reference is noise filtered to reduce its noise contribution to the regulator output.
The operating bandwidth of the regulator circuitry exceeds 300MHz.
The output impedance of the regulator circuitry is less than 3 milliohms from DC to 100 KHz.
Power supply line rejection is greater than 80 dB from DC to 100 KHz
Transient response and settling time is less than 100 nanoseconds for load current changes.
The SR3 is now my entry level power supply and this uses the best of the off the shelf 50VA mains transformers available in the UK, with Schottky barrier rectification to avoid diode switching reverse recovery transients and low ESR energy storage capacitance. The small physical size of this power supply restricts the power rating and limits how much energy storage capacitance can be fitted.
The SR5 uses a 160VA mains transformer custom built to my specifications on an over sized core and wound to avoid core saturation in use and run quietly, both electrically and mechanically. These are usually problems with off the shelf or poorly designed transformers that have their cost cut to the bone to remain financially competitive. Higher power ratings are possible in the SR5 format as there is more space and an additional heat sink can be fitted to the chassis. SR5 can be configured to provide up to 2 galvanically isolated supply rails with one high power rail up to 6A and one low power rail up to 3A or two 3A rails.
The SR7 uses my custom designed mains transformers with ratings from 250VA to 400VA depending on the number of rails and power requirements of the equipment to be powered. The SR7 can be configured to provide up to 4 galvanically isolated supply rails with one high power rail up to 10A and 3low power rails up to 3A, or four 3A rails.
The cost of the power supplies :-
SR3-07v5 for the microRendu - £300
SR5MR2-07v5/09v with 3A ratings for the MicroRendu and the Ethernet switch - £700
SR7MR3-07v5/09v/15v with 3A ratings for the MicroRendu, the Ethernet switch and the Project turntable - £950
The 1 metre DC3C annealed copper with Teflon insulation 3A DC lead costs £50 each. An alternative upgrade is the 1 metre DC3FS annealed fine silver with Teflon insulation 3A DC lead, which costs £85 each. Power supply internal wiring from regulator module output to the chassis DC socket can also be fine silver and this would cost £10 for the SR3, £30 in total for the two rails in the SR5 and £60 in total for the three rails in the SR7.
I usually sell the SR3-7 single rail supply for the microRendu but in view of your requirement for the best performance for the microRendu, plus the option of additional rails for your other equipment, I would be more inclined to recommend the SR5MR2 or the SR7MR3 as both of these supplies have space for the additional rails and offer a higher level of performance. The regulator rails are also galvanically isolated, so there will be no ground return current earth loops causing intermodulation distortions that result from having multiple regulator rails driven from the same master supply with a common ground point.
The SR3, SR5 and SR7 power supplies all use the same ultra low noise, high speed, wide operating bandwidth, discrete component regulator circuit topology.
Typical specifications are:-
The error amplifier devices have a noise spec of 0.5 nanovolts root Hz and the low noise voltage reference is noise filtered to reduce its noise contribution to the regulator output.
The operating bandwidth of the regulator circuitry exceeds 300MHz.
The output impedance of the regulator circuitry is less than 3 milliohms from DC to 100 KHz.
Power supply line rejection is greater than 80 dB from DC to 100 KHz
Transient response and settling time is less than 100 nanoseconds for load current changes.
The SR3 is now my entry level power supply and this uses the best of the off the shelf 50VA mains transformers available in the UK, with Schottky barrier rectification to avoid diode switching reverse recovery transients and low ESR energy storage capacitance. The small physical size of this power supply restricts the power rating and limits how much energy storage capacitance can be fitted.
The SR5 uses a 160VA mains transformer custom built to my specifications on an over sized core and wound to avoid core saturation in use and run quietly, both electrically and mechanically. These are usually problems with off the shelf or poorly designed transformers that have their cost cut to the bone to remain financially competitive. Higher power ratings are possible in the SR5 format as there is more space and an additional heat sink can be fitted to the chassis. SR5 can be configured to provide up to 2 galvanically isolated supply rails with one high power rail up to 6A and one low power rail up to 3A or two 3A rails.
The SR7 uses my custom designed mains transformers with ratings from 250VA to 400VA depending on the number of rails and power requirements of the equipment to be powered. The SR7 can be configured to provide up to 4 galvanically isolated supply rails with one high power rail up to 10A and 3low power rails up to 3A, or four 3A rails.
The cost of the power supplies :-
SR3-07v5 for the microRendu - £300
SR5MR2-07v5/09v with 3A ratings for the MicroRendu and the Ethernet switch - £700
SR7MR3-07v5/09v/15v with 3A ratings for the MicroRendu, the Ethernet switch and the Project turntable - £950
The 1 metre DC3C annealed copper with Teflon insulation 3A DC lead costs £50 each. An alternative upgrade is the 1 metre DC3FS annealed fine silver with Teflon insulation 3A DC lead, which costs £85 each. Power supply internal wiring from regulator module output to the chassis DC socket can also be fine silver and this would cost £10 for the SR3, £30 in total for the two rails in the SR5 and £60 in total for the three rails in the SR7.
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