The Я4С-90 is a dual-trace vertical amplifier plug-in for Soviet 7000-series clones. It is roughly analogous to the Tek 7A18.

Vilnius Research Я4С-90
Dual-trace vertical amplifier
Я4С-90 front panel

Compatible with Soviet 7000-series clones

Produced from (?) to (?)


Significant differences to the 7A18 include:

  • has a bandwidth limiting switch like the 7A26

The input connectors are СР50-73 type.

The example in the photos is labelled in German. A version labelled in Russian also exists.

Key Specifications

V/div 5mV/div to 5V/div in 1-2-5 sequence
Vertical modes I, chop, add, alt, II



Comparison 7A18 vs Я4С-90 attenuators