Hafler DH-101

Name: Hafler DH-101
Brand: Hafler

The Hafler DH-101 is a stereo preamplifier sold both as a kit and factory-wired. The kit was $199.95 with a metal cabinet. A custom-wired, tested version was $299.95. Those same prices show up in a 1978 test report and again in an Audio advertisement (November 1981, p.87), so the price held for several years.

The measurements come from the period reviews. HI-Fi-Stereo-Buyers (September 1978, p.65) measured frequency response at +1.2/-0.1 dB from 20 Hz to 20 kHz, with distortion no higher than 0.035% THD at any frequency. Phono hum and noise measured 72 dB, and stereo separation was 66 dB. The tone controls gave +11/-13 dB at 50 Hz and +9/-10 dB at 10 kHz. With the subsonic filter engaged, response was down 2.5 dB at 20 Hz.

The same magazine's earlier report (June 1978, p.52) covered the day-to-day design: a tone-control bypass that took the tone circuits completely out of the signal path, a power switch that controlled two of the four rear AC outlets (the other two stayed live), and phono input capacitance of roughly