Hickok 800 test settings

HICKOK ELECTRICAL INSTRUMENT CO. / MODEL 800

Audio valve test settings

Choose a valve to see its verified tester setup, reference mutual conductance and special testing notes.

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Include valves awaiting verified Hickok settings

How to read this guide

Two uses of SHUNT

English/SHUNT is the number from the Hickok tube chart. It produces the GOOD/REPLACE indication. To read micromhos, use the SHUNT dial's range mark near 73, 86 or 92 instead.

The seven selectors

The positions run left to right: FIL · FIL · GRID · PLATE · SCREEN · CATHODE · SUPPRESSOR. Each character below is one tester selector position, not a valve pin number.

Average is not minimum

The listed mutual conductance is the Hickok chart average, not a universal replacement threshold. Compare the valve under the indicated Hickok settings.

Before testing, carry out the manual's LINE-adjust and shorts/leakage checks. Rectifier and diode sections are emission tests and have no micromho target. Never press P4 on a rectifier. Original source images and full special-test instructions take precedence over this lookup.

Sources: owner's photographed Hickok Model 800 roll chart; scanned Hickok foreign/European supplements (each linked with its setting); Hickok Model 800 User Manual, printed pp. 2-4. Data corresponds to the workbook's Verified audio settings tab. Some related types are listed with settings intentionally withheld until verified.

Additional tests from the Model 800 manual

These are supplementary checks for amplifier-valve sections. First use the correct chart setup, adjust LINE TEST with the valve fitted and warm, and complete the leakage test. Follow any special warning printed for the particular valve.

Gas test Section 8, printed p. 4

1. Set SHUNT to 73.
2. Press and hold P5. Adjust BIAS until the pointer shows 100 µmhos on the 0-3,000 scale.
3. Keep P5 pressed and also press P6.
4. Watch for an upward movement of the pointer. A movement of no more than one scale division is satisfactory by the manual's criterion.
5. If gas is suspected after warming, allow the valve to heat for several minutes and repeat the check.

Exception: If the BIAS control cannot bring the pointer down to 100 µmhos (the manual gives type 45 as an example), set BIAS to 100 and perform the P5/P6 check. Do not perform this test when the tube chart says MAKE NO GAS TEST.

Valve life-reserve test Section 13, printed pp. 6-7

1. Measure the valve's mutual conductance in the normal way, using P4.
2. While pressing P4, adjust SHUNT to position the pointer at 2,000 on the 0-3,000 scale, in the green GOOD sector.
3. Keeping the other controls unchanged, reduce the FILAMENT voltage to the lower setting shown below.
4. Read the meter again. If the pointer remains in the green GOOD sector, the manual describes the valve as having a large reserve of life.
5. Restore the correct filament voltage after the check.

Common audio examples: 6.3 V to 5.0 V, and 12.6 V to 10.0 V. This is a comparative stress check, not a prediction of remaining hours.

Show the full filament-voltage reduction table

Normal filament	Reduce to
1.5 V	1.1 V
2.0 V	1.5 V
2.5 V	2.0 V
3.0 V	2.5 V
5.0 V	4.3 V
6.3 V	5.0 V
7.5 V	6.3 V
10.0 V	7.5 V
12.6 V	10.0 V
35.0 V	25.0 V
50.0 V	35.0 V

These P4-based measurements are not rectifier tests. Do not press P4 while testing rectifier valves. Refer to the manual for the full procedure and exceptions.

Resources and links

Open valve datasheets (Google Drive) ↗ Open Hickok Model 800 user manual (Google Drive PDF) ↗ this is a guitar-adjacent blog ↗

Manual references above use the printed page numbers (PDF pages 9, 11 and 12).

Use at your own risk. This guide is a convenience reference. Check settings against the original Hickok chart and manual before testing; no guarantee is made about the accuracy of transcriptions or the condition of any tester or valve.