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
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