HC6S Headphone Amplifier

HC6S Headphone Amplifier

The Rane HC6S is one of the most indispensable products in today’s audio industry. Featuring six stereo headphone amplifiers, the HC6S performs a number of necessary tasks, not all of which are headphone related.

The HC6S provides Master stereo Inputs which can be used to drive any or all of the 6 stereo headphone amplifiers. A Mono switch on the front panel drives both channels of all 6 amplifiers from a common mono source. Six individual unbalanced stereo Inputs are available to drive any individual amplifier from a separate stereo source. These Inputs can be converted to mono balanced Inputs through internal jumpers if required. Outputs for all six channels are provided on the front panel and on the rear panel so that headphones may be connected on either side. Two pairs of headphones may be driven from each channel, one pair connected to the front and one to the rear.

The HC6S is capable of delivering up to 500 milliwatts into headphones with rated impedances between 32-600 Ω. The precise amount of power depends on the exact impedance of the headphone in use and the number of headphones connected to the unit. Under most conditions, the HC6S produces sound pressure levels in excess of 120 dB, more than adequate for most listeners.


  • 6 independent stereo headphone amplifiers
  • Master balanced or unbalanced stereo inputs with Master Level
  • Six unbalanced stereo Inputs can drive each amplifier
  • Front and rear Output jacks
  • Six Output Level controls
  • Stereo / Mono switch

HC6S Headphone Amplifier

At first glance the HC6S looks like any other headphone distribution amplifier. Indeed, it performs superbly all the basic functions of such an instrument. Two balanced Inputs provide a master stereo signal to six stereo headphone amplifiers, with individual stereo Level controls. The Master Level control allows adjustment of the main stereo Input level for proper matching to any source. In addition, a Stereo/Mono switch converts the stereo Inputs to mono operation when required.

However, several unique features of the HC6S allow performance well beyond the limits of standard headphone distribution amplifiers. Besides the stereo Master Inputs, the HC6S provides separate stereo Inputs for each of the six headphone amplifiers. Whenever a signal is plugged into the individual stereo Input, the Master stereo signal automatically disconnects from that amplifier, allowing the remaining stages to be fed either from the Master stereo Inputs or likewise from another separate input. This feature opens new applications for the HC6S, allowing operation as either a standard distribution amplifier or as six separate amplifiers, or any combination of both. By connecting the six Inputs to a monitor mixing console, or to sub-master sends, or even to a patch bay, the HC6S converts any size studio to a custom headphone monitor mixing system. You now can give each vocalist more of their voice for increased clarity; or add more kick drum to the bassist (without giving everyone else a headache); or let the producer monitor the straight mix all at the same time. This feature proves equally valuable to broadcast facilities, video production studios, language labs and other educational facilities.

The HC6S provides Output jacks on both the front and rear panels. The front jacks (paralleled with the rear jacks) add considerable flexibility and ease of operation. This feature allows permanent rack-mounting while maintaining instant access to any of the Outputs. Cueing becomes a snap; a must for monitor mix adjustments, and allows additional monitoring or routing without the use of a patch bay. Or, for language labs and other demo purposes, this feature means up to 12 headphones may be driven simultaneously.

The HC6S makes a valuable tool for any band wanting to practice anywhere, anytime, at any volume, without disturbing a soul. By connecting the HC6S directly to the mixer outputs and using headphones instead of amps and speakers, the entire band can perform at ear shattering levels, with no feedback, with amazingly cleaner, clearer sound. The HC6S is a very cost-effective alternative to renting a practice studio for every rehearsal.

Note: headphones with an impedance of less than 32 Ω are not recommended for use with the HC6S.

Block Diagram

HC 6S Block Diagram

Understanding Headphone Power Requirements

Much confusion abounds regarding headphone power requirements. This note is intended to disperse some of the mist surrounding headphone specifications and hopefully give you a clearer understanding of how much power is really needed for your application.

Headphone Sensitivity

Headphone manufacturers specify a sensitivity rating for their products that is very similar to loudspeaker sensitivity ratings. For loudspeakers, the standard is to apply 1 watt and then measure the sound pressure level (SPL) at a distance of 1 meter. For headphones, the standard is to apply 1 milliwatt (1 mW = 1/1000 of a watt) and then measure the sound pressure level at the earpiece (using a dummy head with built-in microphones). Sensitivity is then stated as the number of dB of actual sound level (SPL) produced by the headphones with 1 mW of input; headphone specifications commonly refer to this by the misleading term dB/mW. What they really mean is dB SPL for 1 mW input.

Think about these sensitivity definitions a moment: headphone sensitivity is rated using 1/1000 of a watt; loudspeaker sensitivity is rated using 1 watt. So a quick rule-of-thumb is that you are going to need about 1/1000 as much power to drive your headphones as to drive your loudspeakers since both of their sensitivity ratings are similar (around 90-110 dB-SPL). For example, if your hi-fi amp is rated at 65 watts, then you would need only 65 mW to drive comparable headphones. (Actually you need less than 65 mW since most people don't listen to their loudspeakers at 1 meter.) And this is exactly what you find in hi-fi receivers. Their headphone jacks typically provide only 10-20 mW of output Power.

Take another moment and think about all those portable MP3 players. Ever hear one? They sound great, and loud. Why you can even hear the headphones ten feet away as the teenage skateboarder that ran over your foot escapes.

Power output? About 12 mW.

This RaneNote is discontinued because most of the models described in it are obsolete. Because we still get requests, you can get the PDF here.

HC6S Power Output Specifications

Parameter Specification Limit Units Conditions/Comments
Power Output: 1 Channel Driven Max average rms power, 20-20 kHz
  500 5% mW 32 Ω headphones
  500 5% mW 50 Ω headphones
  500 5% mW 100 Ω headphones
  300 5% mW 200 Ω headphones
  200 5% mW 300 Ω headphones
  120 5% mW 600 Ω headphones
  6 Channels Driven      
  250 5% mW 32 Ω headphones
  250 5% mW 50 Ω headphones
  250 5% mW 100 Ω headphones
  200 5% mW 200 Ω headphones
  100 5% mW 300 Ω headphones
  120 5% mW 600 Ω headphones
(Note: Above values produce loudness levels of 120 dB in most headphones)
Headphone Impedance Range 32-600 10% Ω For best performance
Inputs: Type Active Balanced/Unbalanced      
.....Connectors 1/4" TRS     Balanced
.....Impedance 20k 1% Ω  
.....Maximum Level +20 1 dBu  
Outputs: Type (6) Stereo Amplifiers     (6) Outs front + (6) Outs rear
.....Connectors 1/4" TRS     Tip = Left, Ring = Right
.....Impedance 0.25 typ. Ω Headphone Outputs
Overall Gain Range Off to +20 1 dB  
LED Threshold: Signal Present -20 1 dBu Input Level
Ultrasonic Filter 20 kHz, 6 dB/octave 5% Hz Linear phase
Frequency Response 20-20 kHz +0/-3 dB  
THD+Noise @ 1 kHz 0.002 .002 % 150 mW / 200 Ω
THD+Noise 20-20 kHz 0.02 .01 % 150 mW / 200 Ω
IM Distortion (SMPTE) 0.03 .01 % 60 Hz / 7 kHz, 4:1, 150 mW / 200 Ω
Signal-to-Noise Ratio -96 2 dB re 150 mW / 200 Ω, A-weighted
Mean Time Between Failure 20,500   Hrs Mil Hdbk-217D, Section V
Unit: Conformity CE, FCC, cULus      
Unit: Line Voltage 100-240 VAC, 50/60 Hz   VAC 12W Max Power
Unit: Construction All Steel      
.....Size 1.75"H x 19"W x 5.3"D   (1U) (4.4 cm x 48.3 cm x 13.5 cm)
.....Weight 5 lb     (1.9 kg)
Shipping: Size 4.25" x 20.3" x 13.75"   (1U) (11 cm x 52 cm x 35 cm)
.....Weight 9 lb     (4.1 kg)
Note: 0 dBu = 0.775 Vrms

User Review

HC6S Literature

Each unit is shipped with a booklet containing all of the above, the RaneNote "Sound System Interconnection," Declaration of Conformity, and Rane's 2+ Year Warranty information.

HC6S Support

When I use the direct inputs I lose the signal from my master. Can I mix both through the unit simultaneously at the same output?

No. You you need an external mixer to be able to hear both. Each input is either a direct headphone amp, or fed from the masters, but not a mix of the two signals. You can use any number of direct inputs and the remaining inputs will still receive signal from the master section.

How loud is the HC6S?

It can be extremely loud, but it depends on your headphone impedance and sensitivity. There is a list of popular headphones from the '90's (now out of date) and the SPL expected from each, in this PDF Understanding Headphone Power Requirements.

If the above doesn't answer your question:
Phone the Rane Factory at 425-355-6000, 8:30 AM to 5 PM PST, Monday to Friday.
Email is answered most weekdays from the Rane Factory Contacts.

HC6S Headphone Amplifier