# 35W Tube Power Amplifier with EL34

This is the circuit diagram of 35W Tube Power Amplifier with EL34. This tube amplifier designed in 1953 and worked from 1954 until 1989. If you’re interested with classic circuit and classic components, then you should try this circuit. The circuit is interesting but i think it is hard to find the tubes.

Schematic Diagram:

Power Supply:

Component List:

 R1 = 470K 0,5W R13-21 = 820K 0.5W C8-9 = 0.1uF 630V R2-5 = 2K2 0.5W R14-22 = 5K6? 0.5W C10-14 = 0.47uF 630V R3 = 150K 0.5W R15-20 = 680K 0.5W C11-13 = 25uF 40V R4 = 220K 0.5W R16-19 = 100K 0.5W V1 = E80CC R6-10 = 56K 0.5W R17-18 = 3K3 1W V2 = E80CC R7 = 3.9K 0.5W R24 = 470R? 2W V3-4 = EL34 R8 = 220R? 0.5W TR1-2 = 470R? 1W Variable (adj. 270O) Rectifier tube =?Z2C R9 = 1M? 0.5W C1-3-6-7 = 0.1uf 630V T1 = Audio Transformer for 2x EL34 Push Pull R11 = 39K 1W C2 = 220pF 600v R12-23 = 180K 0.5W C4-5 = 16uF 550V

It is a classic design of power amplifier 35 W using tube, with two EL34 in connection Push-Pull, by Siemens & Halske, with design date 03/24/1953 and code SV410 / 1. The amplifier worked from 1954 to 1989, whenever and went off, with an average lifespan of 15 hours a day. Showed no particular damage beyond the replacement tubes, resistors and capacitors, resulting from natural wear.

A significant change was the replacement of the rectifier device of lamp diodes. The only problem will be for those who try their construction, will be the output transformer (applies to all tube manufactures), because the code is not helpful. Can be replaced with a conventional output transformer suitable for EL34. During the construction, it is need (applies to all circuits respectively) enough electronic experience and attention to the high voltage, electric shock risk.

source: http://users.otenet.gr/~athsam/Power_amplifier_EL34.htm

## 4 thoughts on “35W Tube Power Amplifier with EL34”

1. eduardo alves barbosa

quantos k tem o trafo de out put ? no primário .

2. ronny liu w.h.

I am interesting in an audio amplifier circuit and the new element ron

3. Arden Barker

What sort of value would we be looking at for C12?

REgards,
Arden

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