CH Precision I1 Integrated Amplifier

The I1 integrated amplifier is possibly the most complex project that CH Precision has ever undertaken – and the most versatile product we have ever produced. Imagine the core qualities and capabilities of the C1.2 DAC Controller and A1.5 Amplifier combined in a single box. Now throw in the choice parts of the L1 Line-stage and add the option of a P1 phono-stage, all combined in a single, standard CH chassis and you begin to get the picture.

The I1 is supplied in standard form equipped with four digital inputs (CH-Link HD, AES/EBU, S/PDIF and TosLink – although a second identical digital input board can be added in the spare chassis slot if you need the extra connections) one set of balanced and two pairs of single-ended analog inputs.

The factory fitted Ethernet Control Board, which allows the unit to be remotely accessed, configured and controlled via the CH-Control Android App, can be replaced with a full network streaming capable Ethernet input and a separate, asynchronous USB input card can be added to enable connection of computer sources for file replay. All digital inputs are fully MQA compatible, while our latest proprietary, fixed-point PEtER spline filtering and updated DSP deliver accurate and musically natural digital decoding.

The discrete, fully-complementary analog input boards can be fitted with additional internal circuit blocks that allow owners to convert either or both of the RCA analog inputs into current-sensing MC phono-inputs, complete with switchable replay EQ settings for RIAA, eRIAA, Decca, Columbia, EMI and Teldec (DGG) curves.

Finally, a Clock- Sync board allows you to slave the I1 to external master clocks, or designate its internal clock as the system master. Dominating the interior of the I1 chassis, you’ll find a massive 1000VA transformer that’s more than capable of supporting the 100 watt/channel into 8 Ohms rated output; in combination with the 100,000uF of reservoir capacitance it allows the output stage to handle awkward loudspeaker loads with ease.

How did we pack so much functionality into a single chassis? By leveraging the power of sophisticated software control, modular construction and advanced digital processing.

The I1’s volume control is a remarkable hybrid design, that uses an R-2R resistor ladder in the analog domain for setting coarse levels, with fine adjustment taking place in the digital domain, a combination that allows incredibly precise level control without eroding bit depth, resolution or dynamic range.

Likewise, the I1’s advanced analog-to-digital conversion stage allows us to set overall cartridge gain and replay EQ in the digital domain, providing unparalleled phono replay flexibility, accuracy and features in an integrated unit. You mean we turn the analog inputs into digital? Yes – but if you don’t tell your friends they’ll never know.

Indeed, many listeners swear that the I1’s phonostage delivers some of the finest analog sound they’ve ever enjoyed! Which tells you that its digital replay is pretty impressive too…

Features

• AES/EBU, coaxial S/PDIF and optical TOSlink digital inputs
• I2S proprietary CH Link HD digital input
• Balanced XLR and single-ended RCA analog inputs
• Current-sensing RCA phono input, ideal for MC cartridges, RIAA, eRIAA, Emi, Columbia, Decca and Teldec EQ curves, optional
• RJ-45 Ethernet audio input, UPnP, Tidal, Qobuz and Web radio compatible, optional
• USB class 1.0 and 2.0 audio input for direct connection to a computer, optional
• Proprietary CH-PEtER synchronous spline-based data upsampling, converting any incoming audio stream to DXD resolution
• Resolution enhancement for audio material of less than 24 bits
• Two ultra low jitter digitally controlled VCXO oscillators, one per time domain
• Individual multibit Delta-Sigma converter per channel
• Pure class A, fully symmetrical analog design
• Fully discrete, ultra low noise, high slew rate design
• Hybrid digital and analogue volume control
• Tight tolerance high-grade metal film resistors
• 120dB range in 0.5dB steps
• Volume pre-trimming on each analogue input
• Phono input adjustable gain
• Post volume control stereo balanced line-level analogue outputs
• Pure class A ultra low noise driver and class AB pure follower power stage
• Feedback Ratio adjustable from 0% – local feedback only – to 100% – global feedback only – in 20% steps
• ExactBias circuitry
• Power transistors and heat sink temperature monitored
• No output relay
• Customized Argento loudspeaker binding posts
• Shielded 1000VA power transformer
• Hyper fast soft recovery diode bridge rectifiers
• Total of 100’000uF reservoir and filtering capacitors
• Made in Switzerland