INSTRUCTIONS FOR

THE HAFLER DH-222AMPLIFIER BRIDGING KIT

FOR THE DH-220

The DH-222 may be installed in a Hafler DH-220 power amplifier to enable easy conversion to a high power monophonic amplifier, bridging the two conventional chan- nels to a single floating output which can deliver in excess of 400 watts into an 8 ohm load. Its rated power output is 350 watts across the audio band.

When switched to monophonic operation (UP), signal input should be provided to the LEFT input jack only, and the output should be connected only to the two center BED ( +) terminals. No connection of the load is to be made to the black output terminals. Because of the floating output, neither side of the load may be grounded. Thus it is unlikely that stereo speaker switching boxes, or headphone adapters may be used, as these often have a common ground between the left and right chan- nels.

The speaker fuses may be replaced with higher values than the 2-5 ampere range suggested for stereo operation, if de- sired, depending on the degree of protection for the speaker which is intended. The graph shows the nominal sustained power output limit of a 7 ampere standard fuse, which is the maximum recommended value. Smaller values will provide more protection for the speakers; larger ratings are at the user’s risk.

Both speaker fuses should be the same value. If one speaker

fuse blows in mono operation, both should be replaced, for it is likely that the second has been weakened. For equivalent load impedance, each speaker fuse provides the same power output protection as in stereo operation.

With the internal conversion switch DOWN, the amplifier functions as a conventional stereo amplifier, with normal input and output connections. The minimum recommended load impedance, which is limited only by thermal factors (abil- ity of the heat sinks to dissipate high energy levels), is 6 ohms in mono; the usual 3 ohms in stereo. The amplifier circuit can safely accommodate lower impedance loads, of course.

The conversion, which takes less than an hour, involves only changes to the input wiring, and installation of the switch with its mounting bracket and one resistor. These instructions assume familiarity with the usual kit building descriptions, and reminders. For more details in this regard, see the con- struction section of your DH-220 amplifier manual. You must be certain you have made a good solder connection wherever one is called for, not only to the wire you have attached, but to any others already connected to that point. The notation ( S) indicates a soldered connection; (S-2) denotes that there are two wires to be soldered. Use only 60/40 rosin core solder. Be careful not to let the soldering iron touch adjacent components on the circuit board: excessive heat could change their opera- tion, with the possibility of damage to the amplifier.

KIT PARTS LIST

Switch, DPDT

sz114

Mounting bracket

MS183

Indexing washer

HW123

Lockwasher

HW122

Nut, switch mounting

HK125

Nut, 6-32 KEP

HK112

Screw, machine, 6-32

HA116

Resistor, 3000 ohms

FLzo17

Wire, red, 22 gauge

 

Wire, green, 22 gauge

 

Wire, black, 22 gauge

 

 

 

I

 

 

1

I

I

I

6

12

16

RESISTIVE LOAD IMPEDANCE - n

LIMITED WARRANTY

The parts in the DH-222 are guaranteed against defects for one year from the date of purchase. Installation in a DH-220 amplifier is the owner’s responsibility. In the event of difficulty with the completed unit, charges for service, if any, will be in accordance with the warranty provisions for the amplifier, if it was purchased as a kit. If it was purchased as a factory assembled unit, there is the further stipulation that faults incurred as a result of improper installation of the DH-222 are the owner’s responsibility, but in other respects the original warranty applies. This warranty gives you specific legal rights. You may also have other rights which vary from state to state.

5910 CRESCENT BOULEVARD, PENNSAUKEN, NJ 08109.609/662-6355

LM056

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Hafler DH-200 manual Limited Warranty

DH-200 specifications

The Hafler DH-200 is a well-regarded power amplifier that has earned a dedicated following among audio enthusiasts since its release in the early 1980s. Known for its excellent performance and reliability, the DH-200 has become a staple in many home audio systems.

One of the key features of the DH-200 is its high power output, delivering 100 watts per channel into 8 ohms and 200 watts into 4 ohms. This robust power handling capability makes it suitable for driving a wide range of speakers, from compact bookshelf models to larger floor-standing designs. The amplifier's low distortion and high current output ensure that it can reproduce dynamic and intricate musical passages with clarity and precision.

The DH-200 utilizes a unique circuit topology that incorporates a high-performance, complementary push-pull output stage. This design minimizes crossover distortion while providing excellent linearity and frequency response. The frequency response extends from 20 Hz to 20 kHz, matching the full range of human hearing and allowing for a natural reproduction of both low and high frequencies.

Another notable technology in the DH-200 is its use of a toroidal transformer, which contributes to the amplifier's efficiency and low noise operation. Toroidal transformers are known for their compact size, reduced electromagnetic interference, and improved power supply regulation, which translates into cleaner audio performance.

In terms of build quality, the Hafler DH-200 features a rugged chassis and a minimalist front panel design. The amplifier is a two-channel unit, with individual volume controls for each channel, allowing for precise adjustments. The rear panel is equipped with standard RCA input connections and binding posts for speaker outputs, making it compatible with most audio sources and speaker systems.

The DH-200 is also praised for its thermal management, featuring multiple heat sinks to dissipate heat effectively during extended use. This design helps to ensure long-term reliability, even under demanding listening conditions.

In conclusion, the Hafler DH-200 is a power amplifier that stands out for its exceptional sound quality, powerful performance, and robust build. Its combination of advanced technologies, such as a complementary push-pull output stage and toroidal transformer, make it an enduring choice for audiophiles seeking a reliable and high-performing amplifier for their home audio systems. Whether for casual listening or critical listening sessions, the DH-200 has proven to be a versatile and gratifying component in any audio setup.