Effect of an imperfect voltage regulator on a simple vacuum tube preamplifier circuit. Looks at how low the regulator's output impedance should be for it to have a negligible effect on the preamp circuit's performance.
AUDIO AMATEUR 2/1982 [May 1982] (v.13#2) pg. 37
Improved power supply for the Hafler DH-101 preamplifier. Reduce output impedance by substituting two external transformers.
AUDIO AMATEUR 1/1983 [Apr 1983] (v.14#1) pg. 33
Added Info AUDIO AMATEUR 4/1983 [Nov 1983] (v.14#4) pg. 57
Tube preamp audio output turn-on delay circuit (14 second delay).
AUDIO AMATEUR 1/1984 [Mar 1984] (v.15#1) pg. 39
A fail-safe muting circuit for preamps. Protect your speakers from high voltages whenever the power switch is turned on or off.
AUDIO AMATEUR 1/1985 [Jan 1985] (v.16#1) pg. 38
Using a solid-state relay allows your preamp to handle the power amp load (up to 40A).
AUDIO AMATEUR 4/1985 [Oct 1985] (v.16#4) pg. 43
A wideband power supply. Positive and negative versions of a clean, stable, and wideband power supply for preamps.
AUDIO AMATEUR 1/1987 [Jan 1987] (v.18#1) pg. 22
Added Info AUDIO AMATEUR 1/1988 [Feb 1988] (v.19#1) pg. 53
Added Info AUDIO AMATEUR 3/1988 [Aug 1988] (v.19#3) pg. 56
Added Info AUDIO AMATEUR 3/1989 [Aug 1989] (v.20#3) pg. 53
Preamp power supply circuits incorporate three-terminal adjustable voltage regulators from Linear Technology Corp.
AUDIO AMATEUR 4/1990 [Oct 1990] (v.21#4) pg. 47
Added Info AUDIO AMATEUR 1/1994 [Mar 1994] (v.25#1) pg. 36
Added Info AUDIO AMATEUR 2/1992 [Jun 1992] (v.23#2) pg. 54
Improving the "soft" power supplies found in most audio preamps. Modifications for a C-9 hologram generator and a Mitsubishi DA-F20 FM tuner.
AUDIO AMATEUR 4/1991 [Oct 1991] (v.22#4) pg. 24
A quick, simple and effective delay-before-operation timer for an existing preamp to prevent switch-on and switch-off thumps. Uses only inexpensive, non-critical components.
AUDIO ELECTRONICS 6/1997 [Dec 1997] (v.28#6) pg. 26
Switching power supplies for tube preamps.
AUDIOXPRESS Apr 2001 (v.32#4) pg. 16
Added Info AUDIOXPRESS Aug 2001 (v.32#8) pg. 84
Soft start for tubes. Build a two-stage slow (40 second) turn-on circuit for audio preamps to prevent vacuum tube damage. Four LEDs show circuit status.
GLASS AUDIO 2/1989 (v.1#2) pg. 1
Improving the vacuum-tube slow turn-on voltage and constant-current heating circuits in preamp and power amp supplies.
GLASS AUDIO 1/1993 (v.5#1) pg. 38
Resurrection for Lazarus. Modifying the Lazarus Cascade Basic preamp with a four-tube design and separate power supply.
GLASS AUDIO 3/1993 (v.5#3) pg. 6
Correction GLASS AUDIO 4/1993 (v.5#4) pg. 39
A quality preamp power supply circuit for driving a replica of Audio Research's SP10 (or SRPP) phono stage. Can be adapted to most vacuum tube preamps.
GLASS AUDIO 1/1995 (v.7#1) pg. 12
Circuit for a positive feedback 100mA voltage regulator that is intended for preamplifiers or as a screen regulator for power amplifiers. Output voltage can be either 250 or 300 volts.
GLASS AUDIO 4/1996 (v.8#4) pg. 64
Added Info GLASS AUDIO 6/1996 (v.8#6) pg. 66
Correction GLASS AUDIO 3/1997 (v.9#3) pg. 54