Enleum Amp 23-RMH Headphone Amplifier

The Enleum HPA-23RMH is a compact, reference-grade headphone amplifier built for listeners who want serious drive capability without giving up the flexibility of a battery-powered design. Based on Enleum’s acclaimed HPA-23RM platform, the HPA-23RMH is the High Power version, adding a reworked and enhanced power supply that increases current output while keeping the same slim, precision-machined form factor.

That makes the HPA-23RMH especially compelling for difficult headphones that need current, control, and headroom. It carries forward Enleum’s dual-output amplifier concept, with separate voltage and current headphone outputs, allowing it to work across a wide range of headphones and IEMs. Use it on a desktop, run it from battery power, or keep it connected to a USB-C charger for continuous listening.

High Power HPA-23RMH vs HPA-23RM

The standard HPA-23RM was already Enleum’s most compact high-power headphone amplifier, delivering performance comparable to the legacy HPA-21 in a chassis less than a quarter of the size. The HPA-23RMH takes that same foundation and pushes the current output further.

The key difference is power. The HPA-23RM delivers 1W from its current output, while the HPA-23RMH increases current output to 1.35W. Voltage output remains the same at 500mW at 30 ohms. That 35% increase in current output makes the HPA-23RMH the better choice for more demanding headphones, especially current-hungry planar designs.

Voltage and Current Outputs

The HPA-23RMH effectively contains two amplifier approaches in one compact chassis. Its 1/8-inch voltage output uses a MOSFET output stage inherited from Enleum’s AMP-23R architecture, with a simplified version of the JET2 Bias circuit. This output is well suited for IEMs, portable headphones, and headphones that pair better with a conventional voltage-drive amplifier.

The 1/4-inch current output uses a bipolar transistor-based circuit descended from Enleum’s HPA-21, updated with more modern circuit refinements. This is the output that defines the HPA-23RMH. It gives demanding headphones more current delivery, stronger control, and a more authoritative presentation than you would expect from an amplifier this thin and transportable.

Ensence Module and Lossless Variable Gain

At the input stage, the HPA-23RMH uses Enleum’s Ensence module, the same core concept found in the AMP-23R. This all-discrete transistor circuit uses zero negative feedback and is designed for ultra-fast, ultra-wideband performance. It also enables Enleum’s lossless variable gain, helping preserve sound quality across different gain and volume levels.

That matters in daily use because the HPA-23RMH is built to work with a wide sensitivity range. Whether you are using sensitive IEMs or power-hungry headphones, the amplifier is designed to keep its performance intact rather than feeling optimized for only one narrow use case.

Advanced Battery Power Supply

Enleum has a long history with battery-powered amplification, and the HPA-23RMH continues that approach with a compact, high-efficiency power supply design. It uses a 1.2 MHz SMPS power supply and ultra-low-noise regulators, allowing Enleum’s reference circuits to run from a small internal battery system without the size and heat of a traditional desktop amplifier.

Battery operation gives the HPA-23RMH a clean, self-contained power environment for portable and transportable use. For desktop listening, it can also run continuously from a USB-C charger or battery pack, making it easy to use as a fixed amplifier without treating it like a temporary travel solution.

Precision Machined Design

The HPA-23RMH carries Enleum’s design language forward from the AMP-23R, with machined waveform side panels, a faceted volume knob, and a minimalist control layout. The chassis is not just about looks. Its internal structure and side heatsinks are part of the thermal management strategy, helping the amplifier handle meaningful output power in a chassis that measures only 22mm tall.

It is also a design with real recognition behind it. The HPA-23RM platform won both the Red Dot Design Award 2022 and iF Design Award 2023, reflecting the level of mechanical finishing, proportion, and industrial design Enleum brings to the product.

Key Features

• High Power version of Enleum’s HPA-23RM reference headphone amplifier
• 35% increase in current output compared to the standard HPA-23RM
• 1.35W current output for demanding headphones
• 500mW voltage output at 30 ohms for headphones and IEMs
• Dual amplifier design with separate current and voltage outputs
• Current output descended from Enleum’s HPA-21 circuit
• Voltage output inherited from AMP-23R MOSFET output stage with simplified JET2 Bias
• Ensence module with all-discrete transistors and zero negative feedback
• Lossless variable gain for consistent performance across volume levels
• Advanced battery power supply with 1.2 MHz SMPS and ultra-low-noise regulators
• Solid state relay attenuator with precision resistor network
• RCA and 1/8-inch mini jack analog inputs
• 1/4-inch current output and 1/8-inch voltage output headphone jacks
• Continuous operation with USB-C charger or battery pack
• Precision-machined chassis with integrated side heatsinks
• Red Dot Design Award 2022 and iF Design Award 2023 winning platform

Technical Specs