Heathkit SP-2717A HVPS
Overview
The Heathkit SP-2717A (1982, Heath-Zenith era) is the later, solid-state-reference generation of the same Heath regulated-HV-supply circuit as the IP-32 — NOT a higher-current sibling. Both deliver the identical 0–400 V B+ @ 100 mA continuous (125 mA intermittent), 0 to –100 V bias @ 1 mA, and dual metering. It keeps the tube series-pass element (two 6L6GC) but modernizes everything around it: a 6AU6 control amp, a stack of ten zener diodes (ZD1–ZD10) replacing the IP-32's 0A2 VR tubes, and all-silicon rectifiers (no 6X4, no selenium). Adds a 12.6 V @ 2 A filament option (with 6.3 V @ 4 A, ≤25 VA total). Insulated/floatable output posts.
Context
Together with the IP-32, this is the bench-supply pair that lets any tube circuit be breadboarded without building the supply rail first — the two are the same 0–400 V/100 mA supply, ~20 years apart (a generational pair, not low/high-current). Common service issues (from the manual + restorer reports): a shorted 6AU6 kills regulation; shorted zeners in the ZD1–ZD10 stack (they run hot against the PCB — stand them off to cool) shift the –150/–300 V references; the electrolytics (esp. C2/C3, the 68 µF ≥450 V doubler reservoirs) age; the C– pot (R19) can be burned by loading the bias output; HV nodes arc if flux-contaminated. Cal pots: R10 ZERO VOLTAGE ADJUST + R14 400 VOLT ADJUST (they interact — iterate). (The scaffold's "~3 revisions / changed current-limit + bleeder" is unverified/likely false — see the deep dive.)
