The Relentless Preamplifier combines inventive power supply and audio circuitry, an elegant architecture, and a suite of innovative features. The complex design requires the use of three separate chassis – a dedicated audio chassis for each channel and a separate power supply centred between the two to keep the power supply feeds as short as possible.

The three chassis' interlock through unique mechanisms in the mounting feet of each chassis. Thirty pin interlocking 20-amp, gold plated connectors eliminate any linking cables. This distinctive construction isolates the audio signal completely, both physically and electrically, from the power and digital control sections. This monaural structure also separates the two audio channels from each other, ensuring the ultimate channel separation.

Extensive electrical and magnetic shielding is used to keep radiated interference out of critical preamplifier circuits. According to the company, internal line conditioning circuitry filters RF noise on the AC power and compensates for asymmetric power waveforms and DC on the mains. Two 150 VA toroidal transformers are utilised – one dedicated to the analogue circuitry and one for the digital and control circuitry.

The audio circuit topology starts with a completely unique new discrete differential FET input stage featuring a voltage input signal capability of an extraordinary 30 volts. With an input impedance of over 1 MOhm, the Relentless Preamplifier's front end is immune to source related electrical issues. Developed specifically for the company's Relentless Preamplifier, a unique circuit maintains a stable bias so that temperature-related anomalies are offset and said to "preserve performance during extended listening."

Only balanced XLR inputs are employed on the Relentless Preamplifier. At the same time, all signal gain is realised in the current domain using proprietary multiple-output current mirrors, "with nearly 30 times the linearity of other designs". Executed with four-layer circuit boards for superior signal quality, the use of four-layer boards dramatically reduces distortion and propagation levels as compared to the more commonplace, two-layer boards, says D'Agostino.

Utilising no negative feedback anywhere, core D'Agostino circuit concepts include a signal path that is fully complementary, direct-coupled, and balanced from input to output, achieving a frequency response flat to 120 kHz.

Dan D'Agostino, Co-Founder and Chief Engineer said:

The new Relentless Preamplifier is a major moment in our pursuit of making audio components that deliver the most musical presentation possible. It has been a more than four-decade pursuit and the Relentless Preamplifier is a crowning jewel of my career.

Inputs include five pairs of Balanced XLR connectors, while there are two pairs of Balanced XLR connectors outputs - one for each zone. The Relentless Preamplifier can simultaneously control the switching and volume of two sources in two separate rooms or zones. This may be two analogue sources or when equipped with the optional digital streaming module, one digital source and one analogue source.

The Relentless Preamplifier remote control, housed in machined aluminium and copper, is a comfortable design, operated via touchpad. Bluetooth Six technology extends the usable range of the remote control and eliminates the line of sight issues that plague conventional infrared designs. New bi-directional remote functionality reflects all adjustments made on the Relentless Preamplifier front panel to the remote control's display screen, including input, volume, and balance selections.

New to D'Agostino, this product is the first to offer an optional Digital Streaming Module (DSM). This DSM adds connectivity for legacy sources, USB functionality, and streaming capability. The DSM adds SPDIF coaxial, Optical, USB-A, and RJ-45 and Wi-Fi network inputs. For latency-free playback of high-resolution network content, 10/100/1000 Gigabit Ethernet is supported.

Customised apps for iOS devices provide easy control of music collections, streaming content, and unit control. Subscription streaming services TIDAL, Qobuz, and Spotify, are native within the app. With appropriately encoded music files. The Relentless Preamplifier is also MQA decoding capable and is Roon Ready.

Available now, the D'Agostino Relentless Preamplifier sells for £165,000 including VAT and installation.

For more information visit Dan D'Agostino