Heathkit IP-32 HV Power Supply
Overview
The IP-32 (1962–1967) is Heathkit's regulated tube-circuit lab supply: simultaneous 0–400 V B+ (100 mA continuous, 125 mA intermittent), 6.3 V AC filament (4 A), and 0 to –100 V negative bias (1 mA). Dual front-panel meters (B+ voltage + current). It is fully TUBE-regulated: two 6L6 series-pass tubes driven by a 6BH6 control/error amplifier, referenced to two 0A2 gas-VR tubes, with a 6X4 tube bias rectifier and a silicon B+ voltage doubler + two selenium screen rectifiers — no transistors. Sold as a Heathkit kit. The defining utility is being able to design and breadboard tube circuits at the bench without building the whole power-supply section of a chassis first.
Context
Heathkit's tube-era lab supplies (PS-4, IP-32, IP-17, IP-2717) were the bench supplies in countless university and industrial labs through the 60s and 70s. The IP-32 and the SP-2717A are the same 0–400 V @ 100 mA supply, two decades apart — a generational pair, not a low/high-current one. Common service issues: the 6L6 pass tubes and 0A2 references drift → B+ regulation/set-point drifts (use 6L6GC, 30 W, for full ratings); a leaky ~0.047 µF coupling cap breaks the zero/400 V adjust (a classic IP-32 fault); the selenium screen rectifiers age (restorers replace with silicon + series R); the filter/reservoir electrolytics need recap; the meters may need re-zeroing; the power transformer is somewhat under-rated — don't sustain overcurrent.
