Adcom GFA-545 power amp

Adcom GFA-545 represents the most advanced thinking in audio amplifier design. At 100 watts per channel, the GFA-545 offers an exceptional value; superior performance at a reasonable price.

Some of the outstanding features of this amplifier are:

100 watts per channel, 20 Hz - 20 kHz, into an 8 Ω  load with both channels driven with less than 0,09% Total Harmonic Distortion.

The ability to drive low impedance loads

Large Heat sinks to dissipate heat from the power transistors

External and internal fuses which are designed to protect your loudspeakers from possible damage and also to protect the amp itself under all but the severest abuse of operating conditions.

A thermal cutoff is also employed to protect the amplifier under high temperature conditions.

Instantaneous Distortion Alert which indicates when distortion products are above the 1% level.

 

The instantaneous Distortion Alert is a unique distortion detection circuit which reads all forms of distortion - T.H.D., Intermodulation DIstortion, Slew Induced, and DC-offset, peak LEDs, one per channel, will glow when distortion is above 1% regardless of the load impedance or reactance in use, the LEDs may occasionally flicker under high volume listening. It they glow brightly or are on most of the time that you are listening, you are overdriving your equipment and should turn down your volume control.

 

The GFA-545 is a truly significant contribution to the advancement of sound technology. To ensure that the quality of construction is on par with the quality of the sonics, (a much neglected area in many other amplifiers) the GFA-535 has been carefully developed with computer controlled metal fabrication techniques that maintain 0,005 of an inch tolerances throughout. Full electrical inspection of each and every circuit board, sub-assembly , as well as the finished amplifier, provide a mechanically and sonically superior product for your enjoyment.

 

Specifications

Continuous Power Output (both channels, 20 Hz - 20 kHz, less than 0,09% T.H.D.):

100 watts/channel at 8 Ω

150 watts/channel at 4 Ω

Signal-to-Noise Ratio (A-weighted, Full output):  better than 106 dB

Input Impedance:  22 k Ω

Input Sensitivity

For rated Output :  1,3 Volt

For 1 watt :  130 mV

Damping Factor (20 Hz - 20 kHz):  better than 130

Dynamic Headroom (at 4 Ω ):  2,6 dB

Available Voltage:  120 V at 60 Hz, 220 V at 50 Hz

Dimensions (W x H x D):  432 x 140 x 318 mm (17" x 5-1/2" x 12-1/2")

Shipping Weight:  12,2 kg (27 lbs)

 

Adcom GFA-535 power amp

Adcom GFA-535 represents the most advanced thinking in audio amplifier design. At 60 watts per channel, the GFA-535 offers an exceptional value; superior performance at a reasonable price.

Some of the outstanding features of this amplifier are:

60 watts per channel, 20 Hz - 20 kHz, into an 8 Ω  load with both channels driven with less than 0,09% Total Harmonic Distortion.

The ability to drive low impedance loads

Output for 2 pairs of speakers

Two additional AC outlets for a CD Player, Tuner, or other audio components up to 100 watts maximum

Instantaneous Distortion Alert which indicates when distortion products are above the 1% level.

The instantaneous Distortion Alert is a unique distortion detection circuit which reads all forms of distortion - T.H.D., Intermodulation DIstortion, Slew Induced, and DC-offset, peak LEDs, one per channel, will glow when distortion is above 1% regardless of the load impedance or reactance in use, the LEDs may occasionally flicker under high volume listening. It they glow brightly or are on most of the time that you are listening, you are overdriving your equipment and should turn down your volume control.

The GFA-535 is a truly significant contribution to the advancement of sound technology. To ensure that the quality of construction is on par with the quality of the sonics, (a much neglected area in many other amplifiers) the GFA-535 has been carefully developed with computer controlled metal fabrication techniques that maintain 0,005 of an inch tolerances throughout. Full electrical inspection of each and every circuit board, sub-assembly , as well as the finished amplifier, provide a mechanically and sonically superior product for your enjoyment. At the time of its design, no other product on the market which offered the design and construction quality of the GFA-535 at anything close to its selling price.

 

Specifications

Continuous Power Output (both channels, 20 Hz - 20 kHz, less than 0,09% T.H.D.):

60 watts/channel at 8 Ω

100 watts/channel at 4 Ω

Signal-to-Noise Ratio (A-weighted, Full output):  better than 106 dB

Input Impedance:  22 k Ω

Input Sensitivity

For rated Output :  1,0 Volt

For 1 watt :  130 mV

Damping Factor (20 Hz - 20 kHz):  better than 130

Dynamic Headroom (at 4 Ω ):  3 dB

Available Voltage:  120 V at 60 Hz, 220 V at 50 Hz

Dimensions (W x H x D):  432 x 83 x 318 mm (17" x 3-1/4" x 12-1/2")

Shipping Weight:  10 kg (22 lbs)

 

Onkyo Icon Series M-80 power amplifier

Icon Series M-80 Power Amplifier

 

Refined Style You Can Feel

Just as your favorite music resonates on an emotional level, premium design is felt instinctively. Intuitively. The Onkyo Icon Series is meticulously designed for simplicity and balance, blending an elegant form factor with classic hi-fi details. Carefully selected materials and tactile buttons and knobs elevate the user experience to something greater than the sum of its parts.

 

Superior Sound Starts with Onkyo

Sophisticated circuitry, elevated design choices, and next-generation tech are weaved into every millimeter of Onkyo’s new Icon Series. Our dedicated engineers believe everyone deserves an exceptional listening experience with all the nuance, detail, and emotion that the artists or players intended. The content played through any of our Icon Series products isn’t just heard – it’s felt.

 

Powering The Music That Moves You

The M-80 uses a three-stage Inverted Darlington Amplifier. The three-stage Inverted Darlington Amplifier has a very low output impedance and drives speakers powerfully with a large current. Also, by keeping NFB (Negative Feedback) low, it is not affected by noise from the speaker. It offers a powerful yet highly resolving and informative sound. The M-80’s output stage transistors are in parallel configuration, which provides excellent instantaneous current supply capability, further enhancing the rise of sound and the sense of power. The driver stage of the M-80 amplifier uses DIDRC (Dynamic Intermodulation Distortion Reduction Circuitry). Reducing beats generated signals(noise) in the ultra-high frequency band by DIDRC’s high slew rate designand helps produce the natural sound of an analog record.

 

Cutting Edge Compomentry for Captivating Playback
The M-80 housing consists of two aluminum side panels and a steel top panel. The three-piece construction of the housings increases rigidity and improves seismic resistance. Various vibrations are suppressed and sound quality is improved.

 

Create Your Perfect System

The M-80 has an output power of 130w(FTC, 8Ω, 20Hz - 20kHz, THD 1%, 2ch driven) / 200w(4Ω, 1kHz, THD 0.7%, 2ch driven) which allows it to powerfully drive large speakers and bring you dynamic acoustic information. For example, Klipsch Forte speakers paired with the P-80 and M-80 would maximize the dynamic and extended sound of the Forte.

 

From Onkyo Academy: The Benefits Of A Power Amplifier

A power amplifier receives the signal from your pre-amp and literally powers it into your speakers. Think of your pre-amp as a brain, and your power amplifier as the muscle. Separating your amplifiers into pre- and power gives you ultimate flexibility in audio playback. Since they are not affected by each other’s circuits, they can provide high-resolution sound quality through even cleaner signal transmission. Audiophiles are well-known to prefer specific power amps and the way they impact sound quality and coloration. The M-80 is a power amplifier that reproduces the full range of artists or players’ intentions in their music and drives you into a world of emotion.

 

Specifications

Output Power:

130 W (FTC 8 Ω, 20 Hz - 20 kHz, THD 1%, 2-ch driven)

200 W (4 Ω, 1 kHz, THD 0.7%, 2-ch driven)

Amplifier Channel:  2 Ch

Amplifier Type:  Class AB

Frequency Response:  5 Hz ~ 100 kHz (+1/-3 dB)

Speaker Impedance:  4 - 16 Ω

Analog Audio Input
RCA (Unbalanced) x 1pair

XLR (Balanced) x 1pair

12 V TRIGER Input (1/8” (3.5 mm) Jack)

Power Consumption: 445 W, 51 W (idle), Less than 0.3 W (Standby)

Dimensions (W X H X D):  435 x 135 x 345 mm (17.1” x 5.3” x 13.6”)

Weight:  13.5 kg

Finish:  Black or silver

 

Kyocera B-901 power amp

 

MOS FET Power Amplifier

Incorporating Direct Coupled Triple Push-Pull MOS FET Power Output

 

Features

Powe Switch

Protection Indicator

Peak Indicator

Input Jack

Input sensitivity switch

Power Indicator

Speaker terminals

 AC outlet

 

Specifications

Power Amplifier

Power Output

130 W + 130 W at 8 Ω , 20 Hz - 20 kHz

180 W + 180 W at 4 Ω , 20 Hz - 20 kHz

Total Harmonic Distortion

0,01% at 8 Ω , 20 Hz - 20 kHz

0,02% at 4 Ω , 20 Hz - 20 kHz

Frequency Response

20 Hz - 20,000 Hz +0 -0,2 dB

5 Hz - 100,000 Hz +0 -1,0 dB

Signal-to-Noise Ratio:  -120 dB

Hum and Noise:  0,2 mV

Damping Factor (8 Ω , 50 Hz):  80

Input Sensitivity/Impedance"  1,5 V; 3,0 V /30 k Ω

Power Supply:  AC 120 V, 60 Hz

Power Consumption:  500 W

Dimensions (W x H x D):  18-7/16" x 7-3/16" x 15-11/16"

Weight:  48,4 lbs

 

Quad 405-2 power amplifier

More than 60,000 Quad 405 current dumping amplifiers are in use around the world providing the "closest approach to the original sound" in the homes of serious music listeners, in recording and broadcasting studios and for sound reinforcement where quality is of prime importance.

The Quad 405-2 exploits improvements in component technology to provide more VA into a wider variety of loads than the original Quad 405 without compromising performance and reliability.

The Quad 405-2 will produce perceptibly higher sound pressure levels from the majority of loudspeakers than the original Quad 405, which will be of significant benefit with the increased dynamic range of modern programme sources.

The 405-2 uses "current dumping", a Quad invention based on feedforward error correction which eliminates many of the problems traditionally associated with transistor amplifiers.

"feedforward error correction" was first proposed by Harold Black in 1928, in which a derived error signal is added to the output signal of an amplifier in exactly the right amount to cancel the distortion produced by the amplifier. While it is relatively easy to add error current to signal current without interaction, as in Black's invention, it is very much more difficult to do so in voltage terms. Loudspeakers require a stiff source and so "feedforward" has found no successful application in audio amplifiers.

What Quad has done - not quite as easy as it sounds - is to produce a current controlled amplifier, apply a special type of feedforward current error correction and then apply overall voltage feedback to convert the whole to a voltage amplifier. There is in effect, both a low powered very high quality amplifier and a high powered heavy duty amplifier, the current dumpers. The low power amplifier controls the loudspeakers at all times, calling upon the high power section to provide most of the muscle. The small amplifier which carries the error signal is so arranged that provided the large power transistors get within the target area of the required output current, it will fill in the remainder accurately and completely.

The quality is solely dependent upon the performance of the low powered high quality amplifier together with four passive components. When correctly designed, all distortion in the output stage is reduced to zero.

With this technique it is possible to produce an amplifier of very high performance without using carefully matched relatively fragile output devices. There are no crossover biasing problems, no alignment or adjustment is required to obtain optimum performance and nothing can go out of alignment during life. In the event of component failure, replacement can be effected and performance restored without realignment.

 

Specifications

Power Output:  the amplifier is intended for use with loudspeakers of 4 - 16 Ω  nominal impedance.

Power and distortion for various frequencies

Continuous sine wave into 8 Ω , resistive load

100 Hz any level up to 100 watts : less than0,01% Dtot

1,100 Hz any level up to 100 watts : less than0,01% Dtot

10,100 Hz any level up to 100 watts : less than0,05% Dtot

Output Internal Impedance and Offset:  3,3 µH is series with 0,03 Ω . Offset 7 mV max

Frequency Response:

Ref. 1 kHz

Low frequency -1 dB at 20 Hz. Filter attenuation as curve.

High frequency -0,5 dB 20 kHz -3 dB 50 kHz

Signal Input Level:  0,5 V rms ±0,5 dB for 100 watts into 8 Ω . Amplifier loads th input by 20 k Ω  in parallel with 220 pF

Signal Input Slew rate Limit:  0,1V/µS.

Provided the rate of change of input voltages does not exceed this figure which is about ten times the maximum slew rate on a gramophone record and the amplifier is not driven into clipping, then the total of all distortions appearing in the audio range (20 - 20,000 Hz) due to transient or repetitive waveforms with frequency components inside or outside the audio range will be at least 80 dB below full rated power. If the major portion of the input energy is wanted signal then -80 dB (0,01%) represents the maximum possible distortion on programme.

Signal Input Overload:  Instantaneous recovery up to =20 dB overload

Crosstalk (Input loaded by 1 k Ω ):

80 dB at 100 Hz

70 dB at 1 kHz

60 dB at 10 kHz

Hum and Noise:

"A" Weighted:  -96 dB ref full power

Unweighted:  -93 dB ref full power

(15,7 kHz measurement bandwidth)

Protection

The Quad 405-2 is suitable for use under the most arduous music conditions and is electrically protected by current limiters; 8,5 ampers peak current into any load reducing to 3,1 amperes steady state into a short circuit. Shorting both outputs simultaneously for an extended period will result in overheating and eventual breakdown

Stability: Unconditionally stable with any load and any signal

Power Input:  100-120-130 V, 220-230-240 V 50/60 Hz, 30 - 350 watts depending on signal level

Dimensions (W x H x D):  340 x 115 x 195 mm (13,4" x 4,5" x 7,7"). Allow an extra 38 mm (1,5") for plug and socked

Weight:  9 kg (20 lbs)

 

Hafler DH-120 power amplifier

The DH-120 may shatter the illusions of some audiophiles in their search for perfection with ever larger, heavier and more costly amplifiers. It demonstrates once again that quality, not quantity, is the deciding sonic factor. Engineered for adequate power, proper headroom and excellent overload characteristics, together with conservative ratings, the DH-120 surpasses in sound quality many amplifiers of substantially higher advertised output.

To the technically knowledgeable observer, the DH-120 is quite elegant. Its novel drive circuit is extraordinarily linear. Its very low distortion is achieved with relatively little negative feedback. The oversized heat sinks and power supply, the careful selection of critical components for their sonic attributes, and the evident product quality demonstrates our commitment to excellence.

The most important design element is the utilization of power MOSFET output devices MOSFET advantages include self-stabilization  robustness linearity, high speed, vaccum tibe-like characteristics and they require no thermal compensation. Because MOSFETs can handle heavy currents current limiting circuits are not required.

The audio enthusiast will appreciate the extra features which make the DH-120 more versatile than conventional amplifiers. Independent level controls on each channel are valuable for such applications as bi-amplification. For those needing higher power in a small package a back panel switch converts to a bridged mono mode which uses both channels to deliver in excess of 125 watts. If separate speakers are to be used in another area, a second set of speaker terminals is provided. Alternatively, these terminals can be switched to power rear speakers to add ambience recovery to the main system.

Hafler ingenuity has developed a uniquely simple and effective means of recovering heretofore inaccessible sonic details which have been hidden in many recordings and broadcasts. These elusive signals consist of reflected and reverberant sounds which contribute the sense of space and depth in the recording location. When these sounds are reintroduced through loudspeakers placed behind the listener using the Hafler Ambience Recovery System you will find a new sense of immediacy and involvement emerging from many of your familiar recordings.

 

Specifications

Power rating:  less than 0,009% Total Harmonic Distortion at any power level up to 62 watts continuous average power per channel into 8 Ω  at any frequency between 20 Hz and 20 kHz with both channels driven.

Intermodulation DIstortion (SMPTE): less than 0,005% from 1 watt in 62 watts each channel into 8 Ω

Total Harmonic Distortion : 0,002% (8 Ω , 1 kHz)

Frequency Response (at 8 Ω )

At 1 watt :  4 Hz - 200 kHz -3db

At 62 watts :  10 Hz -40 kHz +0 -1/2 dB

Typical Channel Separation: 

20 Hz :  better than 75 dB

1 kHz :  better than 85 dB

20 kHz :  better than 65 dB

Signal-to-Noise Ratio (Unweighted):  exceeded 103 dB referred to 62 watts into 8 Ω

Input Impedance:  22,000 Ω

Input Sensitivity:  11 volts rms for 62 watts into 8 Ω

Damping Factor:  100 to 1 kHz into 8 Ω ; 50 to 10 kHz into 8 Ω

Rise Time:  10 kHz, 45 volts peak to peak square wave, 10% to 90%, 2 µs

Slew Rate:  10 kHz, 45 volts peak to peak square wave, 30 V µs

Semiconductors:  22 Transistors; 4 Power MOSFETs; 23 Diodes; 8 Zener Diodes; 1 Diode Bridge

Power Consumption:  62 watts both channels into 8 Ω , 300 VA

Dimensions (W x H x D):  15-3/8" x 3-1/2" x 9"

Weight:  18 lbs Net

 

Hafler DH-220 power amplifier

A State of The Art. Power Amplifier

The DH-220 follows in the path of the widely acclaimed DH-200 amplifier which has had highly laudatory reviews and widespread consumer acceptance. Like the DH-200 amplifier, this 115 watt per channel amplifier is available either in easy-to-assemble kit form or factory assembled. Either way it is a highly reliable piece of equipment which can satisfy the most hyper-critical listener, including the audiophile with the most difficult loudspeaker load. And, in kit form the DH-220 provides a significant cost saving for a pleasant few hours of assembly time, using factory pre-assembled and tested audio modules.

The DH-220 utilizes all polypropylene capacitors in the circuit path. All electrolytic are bypassed by polypropylene capacitors. This results in a clarity of sound unusual in an amplifier of this size.

Two completely assembled and fully tested amplifier modules comprise all of the kit's active circuitry, leaving just a handful of parts for the builder to complete the mechanical assembly and power supply wiring. This makes your job simpler and faster, and assures that your finished kit will easily meet all of its specs, and provide the ultimate in listening pleasure.

 

The DH-220 employs a unique circuit configuration using all discrete transistors, operating the very latest output devices, power MOSFETs, in a conservative array. The result is that the benefits of Class A output stages are obtained - such as high speed, minimal crossover distortion, and decreasing distortion at lower signal levels - without the disaddvantages of high cost, high heat, low efficiency and thermal instability that are a part of conventional Class A operation. Like other Hafler products, this new power amplifier has a completely symmetrical, mirror-image complementary push-pull circuit from input to output.

 

Exceptionally low distortion is apparent on reading the specifications, but such figures cannot detail the unit's true capabilities. The significance of achieving orders of magnitude reduction in total harmonic distortion and intermodulation distortion lies in the correlative elimination of other distortion products. Presently recognized test standards are seemingly unable to quantify to many listeners. The DH-220's characteristics of vanishing distortion at lower signal levels, and minimal indication of any forms of transient distortion, such as slew induced distortion, as observed at all power levels of square waves, tone bursts and pulse tests, will, we are confident, maintain its superiority as new standards and tests become applicable.

 

Specifications

Power Rating:  less than 0,02% T.H.D. at any power level up to 115 watts continuous average power per channel into 8 Ω  at any frequency between 20 Hz and 20 kHz with both channels driven.

Intermodulation DIstortion (SMPTE): less than 0,005% from 1 watt to 115 watt into 8 Ω

Typical Total Harmonic Distortion at 115 wats into 8 Ω :

1 kHz :  0,0015%

10 kHz :  0,005%

20 kh :  0,012%

Frequency Response (into 8 Ω ):

2 Hz to 160 kHz at 1 watt (-3 dB)

6 Hz to 60 kHz at 115 watts (-0,5 dB)

Typical Channel Separation:

20 Hz :  75 dB

1 kHz :  85 dB

20 kHz :  65 dB

Signal-to-Noise Ratio (Unweighted): better than 100 dB at 115 watts into 8 Ω

Input Impedance:  47,000 Ω

Input Sensitivity:  1,55 volts rms for 115 watts into 8 Ω

Damping Factor:

300 to 1 kHz into 8 Ω

60 to 10 kHz into 8 Ω

Rise Time:  10 kHz, 60 volts peak to peak square wave, 10% to 90% :  2,5 µs

Slew rate:  10 kHz, 60 volts peak to peak square wave :  30 V/µs

Semiconductors:  26 Transistors; 8 Power MOSFETs; 29 Diodes; 4 Zener Diodes; 1 Diode Bridge

Power Consumption:  Quiescent 125 VA, 115 watts into 8 Ω  ; 580 VA

Dimensions (W x H x D): 16" x 5-1/8" x 10-1/2"

Weight: 26 lbs net

SAE 2200 power amplifier

 

Stereo Power Amplifier

The new SAE2200 Power Amplifier achieves the ultimate. It combines performance and value with aesthetic balance and beauty. Delivering 100 watts rms/channel from 20 Hz to 20 kHz at less than 0,05% Total Harmonic Distortion, the 2200 shares the SAE engineering heritage which includes fully complementary circuitry, high slew rate and low transient distortion. The 2200 package also includes a 15 LED/channel power display which instantly indicates the amount of power being delivered to your speakers, and because of the quality of material and components that go into every SAE, the 200 offers a Free transferable 5 year Service Contract.

 

Fully Complementary Circuitry

The 2200 is completely balenced from input to output utilizing full complementary dual-differential inputs, full complementary drivers and full complementary output stages. This design approach offers inherently low steady-state or transient distortion while assuring accurate reproduction of complex musical waveforms.

 

LED Power Display

This display can instantly inform you of the power output to your speakers, channel imbalance and other information pertinent to the proper performance of your system. Utilizing 15 light Emitting Diodes per channel the amplifier's average power (peak responding) is constantly displayed from 20 mW to full rated power. Amplifier overload is also indicated. The circuit is analog in nature and displays power output in 3 dB increments over its full range, making it the most accurate indicator of its type available in the industry today.

 

Amplifier Protection

Three means of circuit protection are included in the 2200;

-A VI limiter which senses load impedance below 2 Ω  without being affected by reactive loads (i.e. electrostatic speakers) which are rated at 4 Ω  or greater

-A thermal cutout device shuts down the amplifier should the heatsink reach an abnormal high temperature

-An AC line fuse for overall protection

 

Loudspeaker Protection

Should subsonic pulses or ±DC Voltages, which could damage your speakers, appear at the amplifiers outputs, a relay circuit will automatically disconnect the speakers from the amplifier. The circuit is also used during turn-on/off to prevent annoying transients. This relay circuit incorporates many features unique to SAE products, the most important of which alleviates high frequency distortion developed by the relay due to "contact diode effect"

 

Plug-in Board Design

Easily accessible input-drive, relay-power, and meter boards make the 2200 consistent in performance from one amplifier to another in production, and simple to service.

 

Monocoque Construction

Utilizing technology developed in our other amplifier designs, the 2200 mechanical package is constructed in the form of a box, offering structural rigidity and integrity, plus high strength to weight coefficient,

 

Premium materials

Only the finest materials have been used in the construction of the 2200. among the components used you will 5% carbon deposit resistors throughout, military grade glass-epoxy circuit boards and high-grain iron-ore laminations in the transformer. These efforts to use quality materials throughout insures that the 2200 will deliver superior performance and reliability in any application.

 

Precision Construction

No effort has been spared in taking these raw materials to manufacture the highest grade audio components available. It was because of this goal that our 36,000 sq,ft, primary production facility was built. This plant was designed exclusively for the manufacture and assembly of audio components. Further, critical parts unique to SAE products, such as metal work, toroid inductors and circuit boards are produced at our facilities. As a testimonial to SAE thoroughness, our metal shop fabricates all parts with a tolerance of 0,005 in (,013 cm) for proper fit. All front panels are hand brushed for proper aesthetic appearance, and all aluminum parts are mil-spec anodized for long life and easy upkeep. This attention to detail is the hallmark of SAE Components.

 

Specifications

RMS Continuous Power Output per Channel (20 Hz - 20 kHz, both channels driven into 4 or 8 Ω ):  100 Watts at 0,05% T.H.D.

Total Harmonic Distortion (from 20 Hz to 20 kHz at 250 mW to rated power into 4 or 8 Ω ):  0,05% max

Intermodulation Distortion:  0,05% max.

Frequency Response at Rated Power:  20 Hz - 20 kHz ±0,25 dB

Noise:  Greater Than 100 dB below rated power

Transient Response of Any Square Wave:  2,5 microseconds rise and fall time

Slew Rate:  40 Volts/microsecond

Stability:  Unconditionally stable with any type of load or no load including full range electrostatic loudspeakers

Damping Factor:  150 Min (100 Hz)

Input Sensitivity:  1,5 Volts RMS

Input Impedance:  50 k Ω

Overload Protection:

Low impedance electronic-sensing circuit limits with output current below 2 Ω  without limiting with 4 Ω  or higher (or reactive Loads)

Thermal sensing of inadequate ventilation.

Loudspeaker Protection:

Relay circuit protects loudspeakers from low frequency oscillations and plus or minus DC output.

Five second turn on disturbances

Power Requirements:  110 - 120 V, 50 /60 Hz. 75 Watts at idling to 600 Watts at rated poer

Dimensions (W x H x D):  483 x 133 x 21,6 mm (19" x 5,25" x 8,5")

Weight:  11,4 kg (25 pounds) shipping

Denon POA-800 power amplifier

Stereo-Monaural Power Amplifier

 

 

Specifications

Rated Power Output

Stereo

50 W per channel, min. RMS, at 8 Ω  from 20 Hz to 20 kHz with no more than 0,05% T.H.D.

90 W + 90 W (4 Ω , 1khz, T.H.D. 1%)

Monaural

120 W channel, min. RMS, at 8 Ω  from 20 Hz to 20 kHz with no more than 0,08% T.H.D.

150W (4 Ω , 1khz, T.H.D. 1%)

Dynamic Power

Stereo

130 W + 130 W at 4 Ω

150 W +150 W at 2 Ω

Monaural

180 W at 4 Ω

190 W at 2 Ω

Total Harmonic Distortion (-3 dB at rated output , 8 Ω ) 

Stereo :  less than 0,008%

Mono :  less than 0,007%

Intermodulation Distortion (60 Hz/7 kHz : 4/1 at rated output , 8 Ω )

Stereo/Mono :  less than 0,03%

Power Bandwidth:  10 Hz - 50 kHz (8 Ω , T.H.D. 0,1%)

Frequency Response:  1 Hz - 100 kHz +0 -3 dB at 1 W

Input Sensitivity/Impedance: 

Stereo :  1 V/ 25 k Ω

Mono :  0,85 V/ 25 k Ω

Output Impedance:  0,1 Ω  (1 kHz)

Signal-to-Noise Ratio (A weighting)

Stereo :  120 dB

Mono :  114 dB

Output Terminals

Speakers :  4 Ω  Min.

Power Requirements:  AC 110, 120, 220, 240 V 50/60 Hz

Power Consumption: 150 - 160 W (3 A in USA, Canada)

Dimensions (W x H x D):  434 x 120 x 300 mm

Weight:  6,8 kg

 

Hafler DH-200 power amplifier

Both ears and instruments attest to the excellent quality of the DH-200 power amplifier. It has both superior test specifications and the listening quality to satisfy the most critical listeners, including those for whom price is not a limitation.

The DH-200 follows in the path of the widely acclaimed DH-101 preamplifier which has had highly laudatory reviews and wide spread consumer acceptance. Like the preamplifier this 100 watt per channel amplifier is available either in easy-to-assemble kit form or factory assembled. Either way it is a highly reliable piece of equipment which can satisfy the most hyper-critical listener, including the audiophile with the most difficult loudspeaker load. And, in kit form the DH-200 provides a significant cost saving for a pleasant few hours of assembly time, using factory pre-assembled and tested audio modules.

Two completely assembled and fully tested amplifier modules comprise all of the kit's active circuitry, leaving just a handful of parts for the builder to complete the mechanical assembly and power supply wiring. This makes your job simpler and faster, and assures that your finished kit will easily meet all of its specs, and provide the ultimate in listening pleasure.

The DH-200 employs a unique circuit configuration using all discrete transistors, operating the very latest output devices, power MOSFET's in a conservative array. The result is that the benefits of Class A output stages are obtained - such as high speed, minimal crossover distortion, and decreasing distortion at lower signal levels - without the disadvantages of high cost, high heat, low efficiency and thermal instability that are a part of conventional Class A operation. Like the Hafler preamplifier, this power amplifier has a completely symmetrical, mirror-image complementary push-pull circuit from input to output.

Exceptionally low distortion is apparent on reading the specifications, but such figures cannot detail the unit's true capabilities. The significance of achieving orders of magnitude reduction in Total Harmonic Distortion and Intermodulation DIstortion lies in the correlative elimination of other distortion products. The footnote at the end discusses this in detail.

 

The DH-200's characteristics of vanishing distortion at lower signal levels, and minimal indication of any forms of transient distortion, such as slew induced distortion, as observed at all power levels of square waves, tone bursts and pulse tests, will , we are confident, maintain its superiority as new standards and tests become applicable.

T.H.D. and Intermodulation Distortion (both SMPTE and CCIR measurements) are below the threshold of the finest test equipment - from one-tenth of a watt to beyond 70 watts. Measured with the Sound Technology Model 1701A analyzer, typical mid-band distortion at full power into 8 ohms averages 0,0015%

Another limiting factor in correlating sound quality to measured performance is that conventional amplifiers may measure well on the standard resistive test loads, but exhibit distortion when confronted by the complex reactive loads of the loudspeaker and its crossover network. The Hafler DH-200 has the power reserves to handle mismatched loads (it can deliver 150 watts into 4 ohms, and 100 watts into 2 ohms), but more important, it can handle the back - EMF from the loudspeaker cone without generating interfacing distortion components.

With no need for special protective circuits which may compromise sonic performance, the self-protective design of the DH-200 output stage prevents the thermal runaway which is a threat to other designs.

For applications requiring extraordinary power, the DH-200 may also be bridged to convert it to 300 watt (at 8 ohms) monophonic amplifier, with similar distortion specifications. As a modestly priced, versatile "no frills" design, operating premium quality components conservatively for extended life, this new Hafler amplifier is the audio perfectionist's answer to state of the art. Performance at affordable prices.

 

Specifications

Power Rating:  less than 0,02% T.H.D. at any power level up to 100 watts continuous average power per channel into 8 Ω  at any frequency between 20 Hz and 20 kHz with both channels driven.

Intermodulation DIstortion (SMPTE): less than 0,005% from 1 watt to 100 watt into 8 Ω

Typical Total Harmonic Distortion at 100 wats into 8 Ω :

1 kHz :  0,0015%

10 kHz :  0,005%

20 kh :  0,012%

Frequency Response (into 8 Ω ):

-3db, 1 Hz to 100 kHz at 1 watt

±0,5 dB, 10 Hz to 40 kHz at 100 watts

Typical Channel Separation:

20 Hz :  66 dB

1 kHz :  66 dB

20 kHz :  60 dB

Signal-to-Noise Ratio (Unweighted): better than 100 dB at 100 watts into 8 Ω

Input Impedance:  22,000 Ω

Input Sensitivity:  1,5 volts rms for 100 watts into 8 Ω

Damping Factor:

150 to 1 kHz into 8 Ω

50 to 10 kHz into 8 Ω

Rise Time:  10 kHz, 60 volts peak to peak square wave, 10% to 90% :  2,5 µs

Slew rate:  10 kHz, 60 volts peak to peak square wave :  25 V/µs

Semiconductors:  26 Transistors; 8 Power MOSFETs; 24 Diodes; 4 Zener Diodes; 1 Diode Bridge

Power Consumption:  Quiescent 100 VA, 100 watts into 8 Ω  ; 370 VA

Dimensions (W x H x D): 16" x 5-1/8" x 10-1/2"

Weight: 26 lbs net