HiFi Stereo Tube Amp Schematics

In older post I wrote about unified soviet tube audio amplifier. This is from “high class” device. Today, I found the schematics of “highest class”, the HiFi audio device: AM/FM radio, record player. The output is 6W of pure tube power with lowest distortion. This device was manufactured in 1964 and schematics published in popular radio magazine in 1965. With some our days modifications it is possible to build quite cool power amp with quite popular tubes.

HiFi stereo tube amp schematics
The circuit diagram of audio amp for printing

HiFi stereo tube amp schematics
The circuit diagram of power supply for printing

Transformer description
Number Winding count Wire thickness Core
TR1, TR2
3-4 1000 ПЭЛ 0.14 Ш20
4-5 300 ПЭЛ 0.14
5-6 300 ПЭЛ 0.14
6-7 1000 ПЭЛ 0.14
9-1 82 ПЭЛ 0.69
1a-3a 0-458-530 ПЭЛ 0.64 TC-135
1b-3b 0-458-530 ПЭЛ 0.64
5a-5b 505x2 ПЭЛ 0.41
7a-7b 29x2 ПЭЛ 1.20
9a-10a 14 ПЭЛ 0.90
9b-10b 14 ПЭЛ 0.90
11a-14a 0-30-60-100 ПЭЛ 0.31
н-о-к 0-2890-2950 ПЭЛ 0.16 Ш16x16, >3.5H

Tube data:
Л1, Л2, Л3: 6Н2П, ECC83, 12AX7 (but with heater modification)
Л4, Л5, Л6, Л7: 6П14П, EL84, 6BQ5, 7189A

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2 Responses to HiFi Stereo Tube Amp Schematics

  1. Bill says:

    I have been looking at the HIFI Amplifiers that you have posted on your Brain Dump page and would like to know how to translate the Transformer Wire size to english. Could you help me? I will appreciate it or any link that would allow me to enter these values and translate them
    Example: wire thickness ПЭЛ 0.14 and core Ш20.
    I have searched for a way to translate these to no avail.
    Thank you,

  2. Ш20 means, that transformer’s metal core is in the form of “E” (just rotate to get “Ш”) and number “20” is width of the central part (where winding is). There is missing another parameter- thickness of the transformer (толщина пакета).
    About the wire: ПЭЛ 0.14 – the diameter of copper wire is 0.14mm, characters ПЭЛ means “Провод с Эмалевым Лакостойким покрытием масляно-смоляные эмаль, лаки на основе полимеризованных растительных масел” just the type of wire varnish. Any decent copper wire will be better that old russian ПЭЛ.

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