Audiocom SUPER-REGULATOR 3 Ultra Low Noise 7805 LM317

The Audiocom Super-regulator 3 is an extremely low noise, High PSRR direct pin replacement for generic 78xx & 79xx fixed voltage regulators found in audio equipment. The regulator is designed to match the pin output of 7805, 7812, etc with the same pin pitch to conveniently replace the family of 3-terminal TO-220 regulators.

About Regulators

Almost every OEM product we encounter uses generic, 3-terminal voltage regulators to provide regulated, lower voltage DC to the circuits. The problem here is these 3-terminal regulators are quite noisy in the audio band. For a 7805 (5V)  typical Ripple Rejection Ratio (PSRR) is 80 db (f = 120Hz, load = 100 mA), and noise is in the region of 40µV. Move upwards of 120Hz and the PSRR worsens considerably, at 10 KHz PSSR drops to 60 db, 100 KHz to 50 db. At higher voltages these regulators performance is worse again, a 7815 used for most audio analogue output stages has more than twice the noise figure of 90 µV, PSSR is very poor, approx. 40db at 10KHz.

What this means for any audio circuit using these devices is noise riding on the DC rails and arriving at the inputs of the DAC chip, digital filter, input receiver, I/V converters, etc. The sonic result of this is a loss in resolution, dynamics, smeared detailing, unwanted glare, edginess and compression to the sound.

The solution is to use regulated power supplies designed for audio which provide ultra-low noise, wide bandwidth to these sensitive circuits. To meet this criteria Audiocom have developed their own bespoke discrete regulators. These regulators feature (1) very wide bandwidth (2) ultra-low noise (3) high PSRR. The new regulators design means noise is rejected at the input so the circuit being powered is "isolated" from input noise (noise contribution from the Switch Mode Power Supply /SMPS). Compared to the best standard regulator which at best offers 80db rejection, the Super-regulator 3 will provide a PSRR of 120db across a wide bandwidth. With the new discrete regulated power supplies installed the sense of openness and detailing is incredible; the leading edges of instruments are precisely defined and focused without any blurring. Bass depth and speed is captivating with low and upper bass never becoming muddled through sudden dynamic changes.

This newly designed regulator uses 23 highest grade components packed on to a 4-layer, Gold plated PCB. The extremely low noise performance is achieved with an ultra-low noise voltage reference and 2.1nV/rtHz gain stage amplifier which cancels noise by using a closed loop monitoring system.

Note: The super-regulator 3 is designed to replace 78xx, 79xx & LM317 series without heatsinks and cannot be mounted to a heatsink.

Features:-

• Drop-in pin replacement for TO-220 78xx and 79xx generic voltage regulators.
• Advanced, extremely low noise, wide bandwidth closed loop monitoring system.  
• High Speed, 4-layer PCB design for shortest signal path.
• Ultra-low noise gain amplifier, 2.1nV/rtHz.
• 23, high grade, precision Surface Mount Components (SMD).
• Gold plated, 70 Micron Copper PCB for reduced skin effect, lowest resistance.
• High stability under peak current demands.

The Super-regulator 3 can be supplied in any of the following voltages;

The Super-regulator maximum current rating is 100mA. For higher current applications use the Invisus series 2.

As a guide to replacing a positive fixed voltage regulator, the digits for manufacturers part number LM7805CT can be specified as, LM = manufacturer, 78 = fixed positive (79 = fixed negative), 05 = 5 volts.

 © Audiocom International Ltd 2008