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Tektronix Type H
15 MHz amplifier plug-in
Tek Type H

Compatible with 500-series scopes

Produced from 1958 to 1971

(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix Type H is a single-channel, 15 MHz plug-in for 500-series scopes. It provides two inputs and has a switch to select between them.

A design compromise, Type H is not as fast as Type B, but it is DC-coupled on all ranges.

Type 53/54H was introduced in 1958, along with the 533 and 543, renamed Type H in 1959, and dropped after 1970.

Key Specifications

Bandwidth DC to 15 MHz
Rise time 20 ns
Deflection 5 mV/cm to 20 V/cm


The input is switched via a frequency-compensated attenuator network which is controlled by the Volts/cm switch.

Later Type H models use a turret attenuator. Type H with S/N less than 10,000 have ordinary rotary switches.

Input is then coupled to the paraphase amplifier or phase inverter made up of two 12AU6 pentode tubes, V3854 and V4854. This stage converts the input signal to a differential push-pull output. Output of this stage is then passed to the first cathode follower, made with a 12AT7 dual triode, V3863A and V3863B. The output from this cathode follower is then passed to the main amplifier made with a pair of 12AU6 pentodes, V3874 and V4874. The final output to the scope chassis is driven via final cathode follower with a 12AT7 dual triode tube, V3893A and V3893B, which drives pin 1 and 3 of the connector to drive the vertical amplifier inside the chassis.

The tubes are heated from the +75 VDC heater supply available at pin 15 of the plug-in connector. This is to avoid any interference/hum from the regular AC heater supply at 60 Hz.

The chassis is shock-mounted to reduce microphonics.



Some Parts Used in the H

Part Part Number(s) Class Description Used in
12AT7 154-0039-00 Vacuum Tube (Dual Triode) dual high-gain triode 161 180 310 310A 315 316 360 502 502A 511A 512 513 513D 514 514AD 514D 516 524 529 RM529 544 546 547 556 565 570 3A2 75 3A75 1M1 A B C G H K L ML M N K R S Z
12AU6 154-0040-00 Vacuum Tube (Pentode) RF pentode 81 112 1L10 1L20 1L60 3L10 512 556 575 545 547 549 581 585 A B C G K H L ML M N O R S Z