Matching Devices — Nelson Pass / 1993

After you acquire the devices, you will need to test them. You might consider running lots of tests on these transistors, but only one is essential: measuring gate-source voltage versus current. The greatest variations occur here, and it is necessary to do some matching to get proper performance. This test will also tell you whether or not the device is broken. The test is simple and requires a power supply, a resistor, and a DC voltmeter. Figure 12 shows the test hookup for N- and P-channel types. The supply source resistance (R1) is nominal, and is found from I =… More...

Speaker Cables — Nelson Pass / 1980

AUDIOPHILES RECENTLY BEGAN re-examining the performance of every link in the audio playback chain, and before long their attention turned to the lowly loudspeaker cable. In response to demand, a number of companies are producing or distributing new and exotic cables claimed to improve audio power transmission from amplifier to speaker. Pointing to lower resistance and inductance, proponents of the newer cables insist they sound significantly better ("better than an expander!"); however, the subject is controversial, and some hi-fi notables claim performance increase is negligible and the higher capacitance of some new cables can cause amplifier instability and damage.1-4 Neither… More...