Audio-GD – HE1 – Regenerative PSU Balanced Preamplifier (RCA, XLR, ACSS)

REVIEW

UPDATES

– Single polarity FET buffer stages in input and output, which is had a bit lower distortion and improve on the sound quality. The Single polarity FET stages have non feedback design (Toshiba K170)
– Power supplies imporvements; lower noise floor resuluting in a darker background.
– Users can enable/disable the “shorten” input signal now.

KRELL CAST

• A cable is available to connect HE-1 ACSS outputs to a KRELL CAST amplifier input. KRELL amplifiers have lower gain versus audio-gd HE series amplifiers when using the CAST connection, so customers can custom order the HE 1 to have higher ACSS output gain if expecting to connect to KRELL amplifiers.

SUMMARY

• Built-in top class discrete regenerative power supply
• Fully balanced design built by discrete analog stages without any OPA or coupling caps in the signal channels.
• Non- feedback ACSS analog output stage .
• Uses three R-core transformers (135W total), separate power supplies for the digital components, right and left channels.
• More than 50,000uf audio grade NOVER capacitors are used to ensure ample and smooth power supply.
• A total of 9 groups class A PSU’s  are used to purify the power supply. To achieve a high S/N ratio, the control circuit is powered with separate regulators.
• Uses high-grade parts and exactly matched transistors.
• Four channel 99 steps digitally controlled relay-based volume control avoids channel imbalance and improves sound quality.

INPUTS

• 1. XLR balanced
• 2. RCA single ended
• 3. XLR balanced
• 4. RCA single ended
• 5. ACSS balanced (mini xlr)

OUTPUTS

• Balanced (XLR)
• Balanced ACSS (4-Pin XLR)
• Single ended (RCA / Cinch)

HIGH PRECISION VOLUME CONTROL

Volume control consist of relay-controlled attenuators. Fully-independent, fully-balanced stereo volume controls. The volume controls feature consist of high-precision 0.05% tolerance film resistors and golden contact relays. Buffered inputs and outputs.There 4 channels volume boards are built in the unit to achieve ultimate balanced volume control. They are controlled by a digital signal controlling the high quality relays switching the precision resistors in analog area.

Quality of volume control is very important in balanced applications . It have to effectuate the four channels to work as synchronous as possible to keep the balanced signal in perfect shape. In traditional volume controls the balanced output will introduce distortion which will negatively influence sound quality and performance and might even get worse than a single ended setup and waste the advantages of balanced designed solution.

REGENERATIVE POWER SUPPLY

An integrated regenerative power supply is a proprietary electric generator built into the unit to avoid any noise from main power and deliver ultra-low noise and clean AC wave to feed the preampIt will regenerate the main power and block noise from the power line, this way the preamp is able to reproduce the most neutral and analog sound you can imagine.First a transformer converts main voltage. DC conversion is done by class A PSUs power supplies.A discrete balanced regenerative wave generator produces the new ultra-low noise wave form at 400Hz. The 400Hz frequency was chosen because they have better efficiency compared to traditional 50Hz and at this frequency, 400Hz, it will boost the sound to reproduce real and pleasant analog sound.

The balanced gain amps with powerful output stages are driving the regenerative transformers to produce the extreme clean AC power. The extreme regenerated clean AC power is send to separate class A PSUs power supplies for both left and right channel.The discrete class-A DC power supply with high input impedance will avoid any noise and allow the amplifier stages to have low output impedance at very high speed and linear at frequency spectrum.