High performance headphone amp User manual ALHANZZ
Contents
1. Optoma mE smiS HA200 High performance headphone amp mSisojmeic User manual ALHANZZ NuForce HA 200 Headphone Amplifier FCC Notice Declaration of Conformity Information This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures e Reorient or relocate the receiving antenna e Increase the separation between the equipment and receiver e Connect the equipment into an outlet on a circuit different from that to which the receiver is connected e Consult the dealer or an experienced radio TV technician for help WARNING Only peripherals complying with the FCC class B limits may be attached to this equipment Changes or modifications made to this equipment not expressly approved by us or parties authorized by us could2. O0ptoma com
3. void the user s authority to operate the equipment This device complies with part 15 of the FCC Rules Operation is subject to the following two conditions 1 This device may not cause harmful interference and 2 this device must accept any interference received including interference that may cause undesired operation NuForce HA 200 Headphone Amplifier INTRODUCTION The NuForce HA 200 is a high performance Single Ended Class A Headphone Amplifier engineered to satisfy the requirements of the most devout headphone enthusiast As personal music listening and headphone use has become an ever greater part of the audio market the desire for uncompromised headphone amplification among devout enthusiasts has increased accordingly The HA 200 was developed to specifically meet this need by uniting the most musically accurate technology available along with renowned NuForce value As an ultimate high performance headphone amplifier the HA 200 starts out with Class A design and then combines that with a constant current output topology Furthermore when it is operated in classic Stereo Mode it also offers true Single Ended SE output performance As a valuable plus two units can easily be combined to provide true Balanced Headphone Mode operation which quadruples the available output power 2X voltage 4X power while increasing transient speed and dynamic control over the music Features Class A Topology The Class A topology is w
4. START GUIDE WARNING Do not connect your headphones to the XLR output when the RCA inputs are used Use the XLR output only when you combine two HA 200 units in Balance Mode Product Overview Front Panel Back Panel 0 MODEL 0 A VOLTAGE FUSE F500mAL 250V FOR 230V FIAL 250V FOR 115V XLRINPUT O FA Gun O 55 g R RCATNPUT e To power on the unit please turn on the rear AC switch Connections e Input 1x XLR input 1x RCA input e Output 1x XLR output 1x 6 3mm headphone output Note e Headphones earphones differ greatly in their impedance and efficiency For safety please make sure that the volume knob is adjusted to the lowest position setting before plugging your headphones earphones into the 6 3mm headphone output Then to avoid damage gradually increase the volume to your desired listening level NuForce HA 200 Headphone Amplifier SPECIFICATIONS Frequency Response 10 20K Hz THD N 0 0005 Rated Power Output 393mW 16 ohm 747MW a 32 ohm 383mW 100 ohm 129 300 ohm 70mW a 600 ohm Max Power Output 600mW 16 ohm Normal stereo non balanced mode 937mW 32 ohm 530mW 100 ohm 180mW 300 ohm 96 3mW 600 ohm SNR gt 116 dB Dimensions Depth x Width x Height 44mm 1 73 inches 217mm 8 54 inches 231mm 9 10 inches Weight 2 2 Kg 1 pound Optoma www
5. along with a Balanced headphone cable available from your local or online Headphone Specialty Stores for connecting the headphones In Balanced Mode four completely separate amps 2 per unit are utilized to drive the four phases of the music signal right normal right inverted left normal left inverted Please keep in mind though that this is NOT the same technique as mentioned above in the push pull Class B scenario In Balanced Mode all transistors are biased in Class A so as to conduct current at all times only the phase is inverted 180 degrees in the case of the left amp right inverting amplifiers The primary benefit of such a design is that the available output voltage is doubled so the actual output power is quadrupled It also doubles the effective slew rate the maximum change in voltage per second that an amplifier can achieve as both amplifiers are operating in opposite phase to increase the dynamic realism of the music While technically not a pure SE design since Balanced Mode remains in full Class A operation at all times it can be thought of as a dual SE architecture that retains the best of SE performance with the added benefits of higher power and better dynamic control Sonically the resulting sound is completely grain free the soundstage is wide and deep while instruments and voices are reproduced with extreme clarity and purity of tone The incredible power and dynamic control over the music simpl
6. e loads and or headphones exhibiting erratic electrical impedance across the frequency spectrum The Constant Current topology has the ability to constantly adjust output voltage as the headphone impedance changes with frequency which is more common than not with most all headphones to some degree Constant Current operation avoids the extreme performance and available volume variations that often plague other amplifier topologies and ensures consistently good performance regardless of headphone type and or impedance Listeners that use differing types of headphones will greatly appreciate this feature NuForce HA 200 Headphone Amplifier Other HA 200 Features A single output gain stage only 1 op amp and 1 output device in the signal path e A high performance Alps volume control e XLR connectors for operating in Balanced Headphone Mode see above e A linear power supply comprised of a custom made toroidal transformer and extensive capacitor reserves To be sure the HA 200 is not a headphone amplifier for the common man or woman Developed specifically for the devout headphone enthusiast it s comprehensive design and pristine audio performance is reserved for those that demand nothing less than the very best Jacks Plugs HA 200 Left i Left HA 200 Right Right In the Balanced Headphone Mode simply use the XLR input one on each HA 200 and output NuForce HA 200 Headphone Amplifier QUICK
7. idely recognized as being the purest form of amplification and this is because other topologies such as Class B and Class AB require that two output devices be operated in push pull fashion in order for each to handle one half of the musical waveform At the point where a given device hands off to its opposing counterpart it must turn off or stop conducting current until the waveform polarity ultimately returns to that which the device was assigned to handle Then and only then will that device begin to conduct current again while in turn the opposing device must now stop conducting This sharing of polarity behavior leads to what is commonly termed crossover or notch distortion Due to the battery like type of charge storage within them and their inherent speed limitations the transition between opposing output devices can never be perfectly aligned in time to produce a seamless flow of electrical current Typically a small discontinuity or notch at the zero crossing crossover point can always be observed by an oscilloscope connected to the output terminals of the amplifier This notch represents distortion and is of a static nature meaning its amplitude remains the same at all signal levels Therefore this distortion represents an ever increasing percentage of the total output as power levels are reduced and contributes to a grainy sound that is particularly audible and quite irritating at low listeni
8. ng levels Conversely in Class A operation the output device is never completely shut off so there is no turn on or turn off time requirement per se Hence there are no issues with charge storage or any ensuing crossover distortion Class A designs generally offer better high frequency performance and over all feedback loop stability This second point is especially important because all amplifiers produce some distortion but compared to other topologies Class A s superior feedback loop stability means that fewer high order distortion harmonics are generated The result is a more natural and harmonically accurate reproduction that is significantly less fatiguing Single Ended SE Design One unique advantage of Class A design is the ability to employ only a single output device with the technique commonly referred to as Single Ended design Quite simply such a configuration guarantees that there is no opportunity for the generation of crossover distortion and therefore is considered by many to be the purist form of amplification possible The HA 200 operates in full SE Mode when used in its stock stereo configuration NuForce HA 200 Headphone Amplifier Balanced Headphone Mode Unique to the HA 200 is its ability to quadruple output power by simply adding a second unit and operating them together in Balanced Headphone Mode For this configuration all that s needed is to use the XLR inputs and outputs on each HA 200
9. y must be experienced to be appreciated Class A s Modest Disadvantage The one slight disadvantage that Class A amplifiers have is that transistor bias current must be set such that the output transistor continually operates in the center of its linear region which simply speaking is the midpoint between its fully on and fully off limits Therefore regardless of the actual audio power being used Class A amplifiers continuously consume their full rated output power and dissipate that power in the form of waste heat Now in some cases this might be a serious efficiency issue but mostly in those applications involving loudspeaker amplifiers capable of delivering several hundred watts of power With headphone amplifiers this is less of a concern due to their need for significantly less output capability Nevertheless while in operation the HA 200 will continuously consume 24W of power In fact that value actually exceeds the idle power consumption of a NuForce Reference 18 amplifier The upshot is that in order to benefit from the superlative performance that the HA 200 has to offer one must be willing to accept its somewhat lower power efficiency In our opinion that s a relatively small price to pay for such a great reward and we believe that many will agree Constant Current Output In addition to the Class A Single Ended and Balanced Mode advantages the HS 200 s Constant Current output feature allows it to drive difficult headphon
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