richardnau Posted January 9, 2024 Posted January 9, 2024 This is a well-made linear power supply with output suited to many applications (12V / 6A). I used this to power my Burson Playmate (Class A headphone amp) for a year or so, but relocated the gear to an enclosed space not suited to the higher heat generation of a linear power supply. Could be used for any device requiring 12V and drawing up to 6A. Unit can still be bought new on eBay, for around AUD307 landed. https://www.ebay.com.au/itm/122728397679 From the eBay listing: Single-pass, series regulator design. No IC (integrated circuits) are used. This allows complete design control over all operating points and parameters for superior performance. Low noise, high PSRR A constant-current source feeds a zener diode as a stable voltage reference. A low-pass filter (with a corner frequency of 1.6Hz) prevents zener noise from being introduced into the error amplifier. This is an effective yet lower-cost alternative to expensive voltage reference ICs. The low-pass filter also provides a soft-start characteristic. The output noise (unloaded) is less than 13µV at 24VDC output (measured using a Tangent LNMP (low-noise measurement preamplifier) and a Fluke 187 50000-count DMM in ACmV mode). The output noise is even less when the output voltage is lower. This is much better than the noise of an IC regulator based PSU tested under identical conditions. The error amplifier is a discrete implementation of an opamp with a high open-loop gain of 102.5dB. The voltage supply to the error amplifier is isolated with capacitance multipliers to boost its PSRR (power supply rejection ratio). This greatly improves the line regulation performance of the PSU. A long-tailed pair differential amplifier with current mirror and constant current source forms the first stage of the error amplifier. The second stage is the voltage amplification stage (VAS), also with constant current source load. The 3rd stage is comprised of the power MOSFET output devices configured as a source follower. High-current MOSFET pass transistors Two paralleled high-current, highly reliable MOSFETs (rated at 18A each) serve as the "pass" transistor. The high current rating provides a very high safety headroom against overcurrent damage. The use of paralleled MOSFETs divides the heat dissipation, simplifying thermal management. Onboard heatsinks can be used which would allow the this PSU to supply up to 1A continuous (with much higher peak currents). More sustained currents are possible by using larger, offboard heatsinks. The negative temperature coefficient of MOSFETs prevents damaging Fully functional, in great condition. Well-made, in anodized cabinet with ample heatsinks on the sides for the voltage regulators. Substantial toroidal transformer and other electronics inside. Comes with IEC mains cable, braided DC cable fitted with plug to suit Playmate. Easily changed to whatever you require. I have no packaging. Pickup preferred. Can post at your expense. Weighs a few kg.
richardnau Posted January 10, 2024 Author Posted January 10, 2024 Hi all. I have had a huge number of replies. Working through them in order. Will reply to each one. Probably sold. Obviously my price was too low!
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