Paul Hynes SR4 power supply update

[Paul Hynes]

I originally designed the SR4 as a low cost option for upgrading the Technics SL1200/SL1210. The SR4 design has also been set up to provide power for other items of equipment with different voltage and current specifications. The SR4-12 has been used with the V DAC providing a nice upgrade in sound quality over the stock power supply. It also works well with the SB3 and SB Touch. I have used it with the Altmann Attraction DAC for the main 12v supply. The SR4 is comfortably beating typical low cost wall warts, both linear and switching, and giving a very good account of itself musically.

The SR4 can be set up for use with any of the following items of equipment :

Squeezebox SB2, SB3, Duet and Touch
M2Tech Hiface, Hiface II and Hiface DAC (with breakout cable)
M2Tech EVO Spdif interface, EVO Clock, EVO DAC, Young DAC, Joplin ADC.
DacMagic, Chord Qute, Caiman DAC, Weiss INT202, Antelope DAC.

There are many more items of equipment that the SR4 can power as long as their power requirements are within the voltage and current range of the power supply. When set up within the output voltage range of 5v to 12v the SR4 can deliver up to 1.8 amps and set up for 15v to 18v it can deliver 1.6 amps and set up for 21v it can deliver 1.4 amps.

All SR4 sales enquiries should be via ACS Ltd.

David Webb can be contacted at :-

Advanced Camera Services Ltd
Unit 10 Linmore Court
Threxton Road Industrial Estate
Watton
Norfolk IP25 6NG

T 01953 889 324
F 01953 880 086
ACS_2005@BTconnect.com
www.advancedcameraservices.co.uk
Opening Times 9.30am–5.30pm Mon–Fri

If we can be of further help let us know.

Regards
Paul and ACS

[Paul Hynes]

Following requests for further information and pricing for the SR4 power supply.

High performance for a given cost is a must for any product I design, so I have spent some time on the circuit R&D over the last year and arrived at a nice discrete component regulator circuit, that is a considerable improvement sonically over the typical three terminal regulator offerings currently available.

There are several important areas that require consideration for power supply performance and I paid particular attention to the following parameters.

Low output noise is provided by the use of high quality, low noise components used in a low noise circuit configuration.

High supply line rejection achieved by driving the low noise voltage reference, and the regulator error amplifier, from the regulated output voltage, rather than the unregulated input voltage. This increases the supply line rejection considerably giving >80 dB rejection from DC to 100 KHz with around 50 dB rejection at 10 MHz. For comparison the LM317 regulator supply line rejection is around 80 dB from DC to 1 KHz but it falls above 1 KHz to the point where it reaches zero at around 10 MHz which allows more RFI interference through due to poor rejection ability.

Fast transient response and settling time, together with wide operating bandwidth, is essential when dealing with varying load currents that can extend to frequencies considerably higher than the audio bandwidth, for example with digital circuitry. This is important to maintain the output voltage regulation with dynamic loads. The error amplifier devices have an operating bandwidth of >150 MHz and the output device can swing from a few milliamps to the full rated output in <500 nanoseconds. This is a factor of 10 better than a voltage regulator based on an LM317 typically used in general purpose linear regulators.

Low output impedance is also important as, this will dictate how much regulator output voltage fluctuation will occur for a given change in load current. The regulator output impedance is <5 milliohms from DC to 100 KHz ensuring tight regulation under large dynamic load current swings.

The output stage is fully protected against short circuit and thermal overload. The power supply comes complete with an IEC mains lead and a high quality DC lead.

The SR4 costs £195 including VAT. The power supply can be shipped worldwide and insured carriage and packing in the UK costs £12. International shipping costs can be quoted once the destination is known. Payment can be via Credit or Debit card (excluding AMEX), Bank Transfer or Paypal. Cheques accepted subject to clearance.

The product 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.

There is also a 56 day, return if not satisfied guarantee for standard products. This allows a reasonable burn in period before appraisal.

The SR4 is the first product to be designed and manufactured via the new manufacturing partnership of Paul Hynes and ACS LTD and it will be manufactured at the ACS facility in Norfolk. Sales enquiries should be directed to David Webb at ACS.

David Webb can be contacted at :-

Advanced Camera Services Ltd
Unit 10 Linmore Court
Threxton Road Industrial Estate
Watton
Norfolk IP25 6NG

T 01953 889 324
F 01953 880 086
ACS_2005@BTconnect.com
www.advancedcameraservices.co.uk
Opening Times 9.30am–5.30pm Mon–Fri

If we can be of further help let us know.

Regards
Paul and ACS