Count H1 - Reference headphone amplifier

Available for pre-order. Delivery July 2025.

H1 Reference Headphone Amplifier

A reference amplifier with unparalleled transparency and precision, attention to detail, and tremendous performance. For high-end enthusiasts and professional users. Developed and manufactured in Germany.

Reviews

Golden Sound Channel/The Headphone Show - Cameron Oatley

"This is the best possible example of a reference sound. Of all the devices I've tried, this amplifier truly deserves the designation "transparent."

History - Why H1?

Headphones in the professional sector

Today, high-quality products enable applications in the professional field that were once unthinkable. While headphones were once primarily used for recording, they are now also used by sound engineers for reference monitoring during the final mix. It is essential that the reproduction is pure and does not mask or brighten anything.

High-end headphones

Discerning high-end enthusiasts generally want to enjoy music first and foremost. So why shouldn't their headphones or amplifiers make the sound a little more pleasant than it actually is on the recording? Unfortunately, such "embellishment" can't be relied upon. What's beneficial for one recording can be detrimental to the next, and this can also apply to instruments within a recording. If a recording is truly good, a faithful reproduction is always the best option.

Therefore H1

This is where professional users and high-end enthusiasts come to a common conclusion. The H1's power amplifier is extremely powerful and sonically pristine.

The H1 offers all the core features of its sister product, the HM1: the power supply design, the power amplifier with its unique option for switching between different amplifier architectures, and the stereo base control. Its sonic characteristics and playback quality are identical.

For users who do not need the HM1's mixing or A/B comparison function, high and low frequency equalizer, and preamplifier function, the H1 is the perfect choice.

By omitting the equalizer and mixer stages, both of which are highly sensitive to magnetic and electrical interference, the power transformer could be integrated (after being installed in an elaborately constructed Mumetal housing). This benefits handling.

Special features

Unique: Class A performance and even one step further

• Class A power amplifier in its purest form
• switchable negative feedback [“Servo”] while maintaining Class A operation

Stereo basic control

Stereo Base Control lets you adjust the soundstage to your preferences. A precise tool for widening or narrowing the stereo image, or switching to mono.

Three output ports

XLR 4-pin – ¼“ jack – Pentaconn

"The H1 gets the most out of any headphone. It offers the same core technology as its sister product, the HM1."

• Perfect impulse reproduction
• Ultra-wide frequency response
• Extremely low output impedance Precise control of complex loads
• Developed and manufactured in Germany
• Pure analog design
• Consistent dual-mono layout
• Logic circuits without clock generator
• Integrated toroidal transformer with specially developed Mumetal housing
• Linear power supply
• No external power supply required
• Uncompromising selection of components
• Uncompromising interior and exterior construction
  

Details H1 performance level

Class A – H1 version

The H1 power stage offers enormous power reserves, as evidenced by its idle consumption of almost 40 W. The output power is more than sufficient for any application and is significantly increased in the millisecond range. The output resistance is remarkably low.

The optimal operating point of the power stage was first determined theoretically, then determined through measurements on sample devices, and finally fine-tuned in numerous listening tests with experts, especially mastering engineers. The same applies to the selection of components. This careful design largely compensates for the potential disadvantages of Class A, which are described in the following section.

Class A & Servo – H1 implementation

To take Class A a step further, we implemented an idea as simple as it is ingenious: We take the best of Class A and the best of negative feedback amplifiers and combine the two. Class A operation is supplemented by negative feedback ("servo"). Since there is no crossover distortion, the feedback circuit does not have to correct anything.

It simply corrects the errors caused by the interaction between the power amplifier and the headphones. The feedback path is designed so that the correction does not cause artifacts. The output resistance is reduced to a value that is less than the sum of the headphone cables and plugs. This allows for precise control of headphone systems. It's safe to say that with the H1, every pair of headphones sounds as they should.

Why Class A and Class A & Servo?

The previous paragraph might lead you to conclude that Class A & Servo operation is the optimum. So why is there a switchable option? Quite simply, because we judge our circuits by ear. Our Class A amplifier was developed with the highest musical standards in mind.

We found that it doesn't sound exactly like the Servo version, but it sounds just as excellent. Depending on the headphones, music, and personal preferences, the user can make their own choice. Even we were surprised that, despite the significantly different characteristics and measurement results, the listening difference is rather subtle.

A little theory

Class A BenefitsAdvantages: No crosstalk distortion on the output transistors and no artifacts due to negative feedback. Disadvantages: The internal resistance of the output transistors and usually also the emitter or collector resistors are in series with the load.

To put it simply, the material properties of the output stage components significantly determine the sound. And since both the resulting internal resistance of the output stage and the resistance of the load, i.e., the headphones, are complex quantities, the result is also complex: It's certainly possible that certain combinations of even very high-quality amplifiers and headphones don't produce optimal results.Experienced audiophiles know this experience.

Class AB with negative feedback advantageAny output error caused by the effects described above is "corrected" by a negative feedback circuit. Furthermore, unless overloaded, the output impedance of the power amplifier theoretically approaches zero; in practice, it is in the tens of milliohms range. The complex internal resistance of a headphone system is almost balanced by the low output impedance. A headphone system is therefore tightly "led" by the power amplifier.

Disadvantage: Cross-transmission distortion occurs first and is then corrected. Thus, the negative feedback control (at least theoretically) always lags somewhat behind the action, which can lead to artifacts in the signal. However, modern audio power amplifiers with negative feedback are generally not designed purely in Class AB.

Very effective techniques are used to minimize crossover distortion without resorting to costly and power-intensive Class A technology. Certain techniques are used in the negative feedback signal, so that the "lag time" of the correction is almost irrelevant.

Stereo Base Control, a little theory

A special feature is the ability to adjust the stereo width. The perception of spatiality when listening with headphones differs from that when listening with speakers. Instead of a cross-feed circuit, we use our stereo base width adjustment. This is based on the mid/side technique commonly used in professional studios and offers additional advantages.

The stereo signal is converted into a center signal (in simple terms, what L and R have in common) and a side signal (in simple terms, what distinguishes L and R). Summing the center and side signals at a 1:1 ratio creates the original stereo signal. However, if you change the ratio between the center and sides before summing, you change the stereo width. In our circuit, we leave the center signal unchanged. We only adjust the level of the side signal. Lowering the level narrows the stereo image; increasing the level widens the stereo image.

Stereo Base Control, what it does

You have direct access to the perception of spatiality. If a music program sounds too "wide" through headphones, turn the control one or two steps to the left. If you find a recording too "dry" (centered), turn the control one or two steps to the right. The far left position is mono. This is the preferred setting for early stereo recordings, where individual instruments were mixed to the extreme left or right—without any spatial reference.

Professional users use this function to check the spatiality of their mix and thus discover possible problems, especially in the extreme positions.

Also important: The DIR (Direct) button allows you to completely remove this stage from the signal path, thus also taking the purist approach into account.

balance

A precision potentiometer with 21 clicks is provided for balance adjustment. The center position is perfectly calibrated and clearly defined by touch. Left/right volume differences of up to approximately 2.5 dB – caused by the music program, headphones, or individual perception – can be compensated in fine increments.

Headphone outputs/balanced connection

The 4-pin XLR, Pentaconn and 6.3 mm jack plugs are connected in parallel and can be used alternatively.Theoretically, you could use them simultaneously, as the power amplifier is powerful enough. However, for a reference-quality listening experience, we recommend against it.

Ideally, 4-pin XLR and Pentaconn connectors are used in conjunction with balanced wired headphones. In this case, the signal streams from the two power amplifiers are not mixed, eliminating mutual interference. The H1 can achieve its full potential (see also the "Dual Mono Design" chapter).

Dual mono vs. balanced amplifier design

With its dual-mono design, the H1 offers the same advantages as a balanced output stage, but avoids its disadvantages.

The disadvantages of a balanced output stage are the significantly increased number of electronic components – a balanced output stage contains two output stages per channel, operating in phase opposition. Two output stages result in a doubling of the output impedance. More components increase the risk of nonlinearities.

¼-inch jack socket

Another advantage of the H1 architecture is that even unbalanced headphones with a ¼-inch jack plug can be operated without any problems.

INPUT Balanced/Unbalanced

The input can be switched between balanced and unbalanced mode.

• XLR connectors for balanced operation

• RCA connectors for unbalanced operation

Balanced mode behaves like a transformer: hot or cold can be connected to ground without loss. XLR and RCA cannot be connected at the same time.

INPUT Gain

Basic gain rate from input to output: 6 dB

3-position gain switch (-10/0/+10) to decrease or increase the input gain by +/-10 dB allows adaptation to sources with different output levels.

This is also useful for adjusting to headphones with different sensitivities.

Dual-mono design

The idea

The idea behind the strict separation of left and right channels is to keep any interference away from the circuits. A term like "crosstalk" misses the point. Music signals usually have a left/right reference, so an extremely low crosstalk value—which is usually measured with sine waves—doesn't mean much. However, music involves high-energy signal pulses that individually demand high currents from the output stages. In these cases, it is extremely important that there is no coupling via a common power supply or via signal-carrying ground lines. This is the only way an amplifier can deliver absolutely undistorted output signals.

Implementation in H1

In the H1, the power supplies for the left and right channels are separate, both for the preamplifiers and the power amplifiers. The mains transformer features independent, fully isolated windings for each channel. Rectification, filtering, and voltage regulation are performed separately for each channel. There is an additional winding for the logic circuitry and the front panel displays, as well as separate rectification, filtering, and voltage regulation.

The ground potentials of the two channels are connected to each other at only one point, but this only serves to equalize the potential; mixing of the signal currents is impossible.

Optimal output connection

When using the 4-pin XLR or Pentaconn output in combination with balanced wired headphones, the dual mono principle is consistently implemented.

When using the jack output, the ground conductors of both channels are connected to each other in the jack socket and the headphone jack plug. Using headphones with jack plugs is therefore not ideal. However, the H1's optimized ground routing ensures that the adverse effects are minimized.

Technical data

Entrances

Balanced line inputs – impedance 20 kΩ – maximum level +23 dBu

Unbalanced line inputs – Impedance 20 kΩ – Maximum level +23 dBu

Headphone output

Impedance Class A 0.8 Ω, Class A & Servo 0.045 Ω

Maximum level +23.5 dBu (+/-16.5 V)

Output power per side

RMS 4 W/30 Ω; 7 W/15 Ω

Peak power 7.6 W/30 Ω; 11 W/15 Ω; 12 W/10 Ω (18 W for 1.5 ms)

Frequency response

10 Hz ... 30 kHz -/+0.05 dB

1 Hz ... 500 kHz better than -3 dB at the headphone output at +6 dBu

Reinforcement

will be updated shortly...

Rush

equal to or better than HM1

will be updated shortly...

Headphone output THD (total harmonic distortion)

equal to or better than HM1

will be updated shortly...

Power supply

will be updated shortly...

Dimensions and weight

will be updated shortly...