Amplifier Global Feedback
The Art of Control
At CH Precision, every technology is pursued to solve a real problem that high-end audio has left unanswered. Our work is never about features for their own sake, but about finding original solutions that remove obstacles between the listener and the music. Few challenges are more demanding than the amplifier’s role as the bridge between source and loudspeaker. Loudspeakers present complex, reactive loads—shifting impedance, difficult phase angles, and energy fed back through the cable—all of which place exacting demands on an amplifier’s stability and fidelity.
Our culture of innovation has always embraced the union of software precision with analog purity. This approach lets us set and adjust critical variables—such as cartridge loading or amplifier global feedback—with exactitude, while ensuring that once adjustments are made, the software layer is completely removed from the signal path and galvanically isolated from the gain stages. Supporting control circuits are powered independently, so they never intrude on the purity of amplification. This philosophy reaches its fullest expression in our proprietary adjustable global feedback system, which gives listeners direct control over the balance of local and global feedback. It is a uniquely CH solution: precision that adapts to the system, always in service of more realistic musical reproduction.
What is Feedback?
An amplifier’s global feedback directly affects its relationship with the loudspeaker. More global feedback lowers output impedance, raising the damping factor and giving the amplifier greater control. Less global feedback raises output impedance, reducing that control. While this might suggest that more global feedback is always better, it comes with tradeoffs: excessive global feedback can blur timing cues, flatten dynamics, or impose an artificial character on the sound. In theory, the purest solution would be no feedback at all—removing the loop for the most direct and unmediated signal path. But zero global feedback can only succeed if the underlying gain stages are intrinsically stable and linear, supported by a power supply with the speed and reserves to remain composed under any load. This is precisely how CH amplifiers are designed, which is why they deliver excellent control and authority even with no global feedback applied.
Still, the real world is never ideal. Certain loudspeakers—such as low-impedance designs or models with high-mass woofers that feed significant back-EMF to the amplifier—and rooms with heavy bass response can benefit from the additional control that carefully applied feedback provides. Loudspeakers are not uniform, and neither are the rooms they inhabit. This variability makes a single fixed global feedback setting a blunt tool.
For most manufacturers, global feedback is a necessity, locked in place with little or no flexibility. CH Precision takes a different view. Because our amplifiers are already stable into any load, with damping factor preserved by oversized, high-speed power supplies, we can treat global feedback not as a crutch but as a tool—adjustable with precision, so the amplifier can be tuned to the system and always serve the music with greater realism
The CH Approach
Because no loudspeaker, room, or system is ever the same, CH Precision amplifiers give listeners direct control over global feedback. Our proprietary circuitry allows the ratio of local to global feedback to be adjusted continuously from 0% to 100%, transforming what is fixed in most amplifiers into a flexible tool. In the I1, adjustments are made in 20% steps; in the A1.5 in six steps 0% to 100% (0, 10, 20, 40, 70, 100%); the M1.1 in 10% steps (ten steps from 0% to 100%); and in the M10 Reference in 1% steps in single-percent increments. This refinement gives listeners unprecedented authority over how the amplifier interfaces with both the loudspeaker and the acoustic environment.
Just as important is how we implement this flexibility. Software is used only as the interface for making adjustments—once set, the software layer is completely removed from the circuit, and the control functions are galvanically isolated from the gain stages. Even the supporting control circuits draw power from dedicated supplies, ensuring they never intrude on the purity of amplification. The result is an adjustable feedback system unique to CH: precise, stable, and musically transparent.
Control in Service of Music
The ability to adjust global feedback from 0% to 100% is more than a technical feature—it is a practical tool for shaping how an amplifier integrates with the loudspeaker and the room. By varying the ratio of local to global feedback, listeners can directly influence the amplifier’s damping factor, adjusting how firmly it interacts with the loudspeaker’s drivers. This is particularly valuable with designs that use high-mass woofers, which can return significant back-EMF to the amplifier, or in rooms with “loose” or “heavy” bass response, where subtle adjustments can restore balance and clarity.
Because every system is unique, CH amplifiers allow each channel to be set independently in bi- or tri-amped systems. Differential feedback values can be applied to specific frequency ranges to help compensate for room asymmetries or non-linearities. The result is not generic control, but finely tuned integration that makes the amplifier an adaptable partner to the system as a whole. By giving listeners this precision, CH turns global feedback into a creative tool—one that serves both the music and the environment in which it is played.
Finesse. Balance. Realism.
Adjustable global feedback is one of the defining attributes of CH Precision amplifiers, transforming what is fixed in most designs into a finely tunable parameter. Rather than treating feedback as a corrective necessity, CH employs it as a means of system-level optimization—allowing the amplifier’s behavior to be precisely matched to loudspeaker load, room interaction, and system architecture. Whether controlling demanding woofers, shaping low-frequency balance, or optimizing complex multi-amplifier configurations, adjustable feedback provides authority and precision without sacrificing signal purity.
This approach reflects a broader CH Precision philosophy: engineering challenges are not constraints, but opportunities to serve music more faithfully. In the context of amplification, feedback becomes a tool of refinement rather than compensation—an instrument of control that preserves bass definition, dynamic stability, and musical realism while allowing the system as a whole to perform at its highest level.