Sugden Audio has released a Sapphire Series comprising a DAP-800 ‘Digital Analogue’ preamplifier and FBA-800 ‘floating bridge’ ‘Pure Class-A’ stereo power amplifier.
The analogue and digital sections of the DAP-800 Digital Analogue preamplifier are completely self-contained, with their own power supplies and voltage regulation, and on completely different PCBs. The analogue stage has a 50-watt toroidal transformer and the digital stage a 15-watt E-core transformer.
The DAP-800 analogue stage incorporates a Sugden ‘VCV’ circuit in its most developed advanced form. This circuit has a high impedance input section, and the current gain stage drives a folded cascode stage into a Class-A output stage. The DAC facility to interface with digital products includes inputs for USB, Optical and coaxial S/PDIF signals. The DAC is a non-oversampling, digital filterless type where the digital interface transceiver is a Wolfson Micro electronics device. The DAC also includes Post Conversion Filtering in the analogue output stage. The USB signal received is converted via a circuit including a Texas Instruments Universal IC whose SPDIF output signal is re-clocked and de jittered by the Wolfson interface transceiver.
Sugden refers to the circuitry inside the FBA-800 Power Amplifier as a ‘floating bridge’ circuit that operates in Pure Class-A output mode. Power output is rated at 40-watts per channel. According to Sugden, the Class-A operates in bridged mode with the output earth floating. Each channel consists of two amplifiers working as voltage amplifiers driving an output stage of bridged power transistors. ‘The advantages of this circuit include a low noise floor, better power output relative to the voltage rails (×2) and with the fixed current of the Class-A mode, low output impedance and better load tolerance,’ said George Neophytou, of Neophonics, which distributes Sugden in Australia. ‘The power amplifier is d.c. coupled, with a servo lock, ensuring excellent low frequency detail, but the amplifier has a d.c. protection circuit that is statically switched using extremely low-impedance MOSFETs. This same circuit also ‘soft-switches’ the power amplifier on and off.’
The 350VA power supply is a low impedance design with a single custom made bifilar wound transformer, with four separate windings. The main smoothing capacitors for the output stage are specially developed for professional audio applications with excellent ripple characteristics and long life. The four power transistors per channel in the output stages are multi-emitter devices with an output capability of 26-amps per device. The FBA-800 operates in the full balanced mode from the input of the unit to the output.
‘Sugden’s main objective in developing the Sapphire Series has been musical performance coupled to a practical user interface, pride of possession and product longevity,’ Neophytou told Australian Hi-Fi Magazine. ‘For example the DAC configuration used in the DAP-800 was adopted only after many hours of auditioning of a wide sample of DSPs. The auditory perception/musical performance in terms of dynamic balance, tonal balance, voice and emotion, are so much more satisfying and Sugden’s preference.’
All Sugden products they are designed and manufactured by Sugden on its own premises in West Yorkshire, England. In Australia, the Sapphire DAP-800 retails for $5,950 and the Sugden Sapphire FBA-800 for $9,350.
For further information about Sugden, please contact Neophonics
Pictured Above: Sugden FBA-800 ‘Digital Analogue’ preamplifier; Below: Sugden FBA-800 ‘floating bridge’ ‘Pure Class-A’ stereo power amplifier.