← Reference

83

Full-wave mercury-vapour rectifier — the odd tube of the corpus. Where every other rectifier here is a vacuum diode whose drop climbs with current, the 83 strikes an arc in mercury vapour and then holds a nearly constant ~15 V drop from idle to its full 225 mA rating. That is why the tweed 5F6 Bassman runs a stiff, barely-sagging supply — and why the datasheets specify vertical base-down mounting, a condensed-mercury temperature window, and filament warm-up before high voltage.

Basing (pinout)

Bottom view — the socket as you see it from the wiring side. Hover, tap, or focus a pin to name it. Read from the datasheet basing diagram (how to read these →).

1 2 3 4

Hover, tap, or focus a pin to name it.

  • High voltage (B+)

Viewed from below (socket / wiring side) · medium 4-pin · basing 4C

⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.

Datasheets

Primary manufacturer data, via public tube-data archives. The model below is fitted to the tabulated "average characteristics" in these sheets; the datasheet files themselves are linked, never rehosted.

PublisherTypeSource
RCA 83 frank.pocnet.net ↗
General Electric 83 frank.pocnet.net ↗

Circuit Codex model

A CC0 ngspice model in an arc form, fitted here to the published anchor — no parameters copied from other model collections. Methodology →

Anchor
Tube Voltage Drop (Approx.) = 15 V at the rated 225 mA d-c output; peak plate current 1 A per plate
Source
RCA type 83 data sheet, 7-63; corroborated by General Electric ET-T464, 2-47
Note
Exponential arc model (I = IREF·exp((Va−VARC)/VSOFT)), not the Child's-law diode used for the vacuum rectifiers — a struck arc is not space-charge limited. One plate unit; instantiate twice for the full-wave pair. Verified by driving current and reading the drop back: 15.0 V at 225 mA, 14.2 V at 22.5 mA, 15.5 V at the 1 A peak rating.
File
models/83.inc ↗

Maximum ratings

Capacitor-input design-centre maximums. Two of these constrain how the tube may be used rather than how hard it may be run: a minimum total plate-supply impedance of 50 Ω per plate limits the peak charging current into the first filter capacitor (RCA adds that a first capacitor larger than 40 µF may need more), and the condensed-mercury temperature must sit between 20 °C and 60 °C — which is why the tube is specified to be mounted vertically, base down, and given its filament warm-up time before high voltage is applied.

Peak inverse plate voltage
1550 V
Peak plate current per plate
1.0 A
A-C plate voltage per plate (capacitor input)
450 V RMS
D-C output current
225 mA
Total effective plate-supply impedance per plate
50 Ω minimum
Condensed-mercury temperature
20–60 °C
Rating system
Design centre — carries an allowance for manufacturing spread
Source
RCA type 83 data sheet, 7-63 (design-centre system); General Electric ET-T464 tabulates the same design-centre column ↗