Old version Video
Old Version VacTubAmp. Vacuum tube amplifier with EL34
VacuTub2 In progress, project name VacuTub2306. 2.Push-Pull ultra linear vacuum tube amplifier
Two (four) power vacuum tubes (JJ Electronic EL34) are used to amplify phase-inverted copies of the same signal..
The output power depends on the output transformer, only the recommended current and voltage values for the EL34 anode are allowed !!!
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Example of wiring diagram
PCB
Wiring PCB
Example of a functional Implemented amplifier
Bill of materials (Some resistors depend on the parameters of the tubes)
changes in the values of the components
| Component | Old value | New value |
| Trimer R16 | 10k | 22k |
| Resistor R18 | 18k | to trimer 10k (position cca 2k7) |
| Resistor R21 | 47k |
Bill of materials
Super linear tap 50W push-pull output transformer
5000 Ohm 50W
Measured waveforms (JJ Electronic EL34). Project commissioning
Ia = 80mA, S=cca 7mA| Input signal (Ch2) 2V Output signal 20V (cca 50W/8 Ohm) File 0_1 |
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Input signal (Ch2) 0.5V 1kHz Output signal >6V (cca 5W/8 Ohm) The Rezistor R1 in the centre Feedback is not engaged !!! UaEL34 500V. Manufacturer JJ Electronic All other measurements for this level |
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| On the rezistor R41 (Ch1) On the rezistor R43 (Ch2) File 1 |
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On the grid EL2/2 (Ch1) On the grid EL2/7 (Ch2) File 3 |
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| Input signal (Ch1) 2.5V Output signal 16V (cca 65W/4 Ohm) File 5 |
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| Feedback connected Trimer R8 to left 1/4 Input signal (Ch1) 6V Output signal 25V 1kHz from the Out.Transformer File 6 |
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Feedback connected Trimer R8 to centre Input signal (Ch1) 4V Output signal 25V 1kHz from the Out.Transformer File 7 |
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| Feedback connected Trimer R8 to right 1/4 Input signal (Ch1) 2V Output signal 25V 1kHz from the Out.Transformer File 8 |
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Feedback connected Trimer R8 to centre Input signal (Ch1) 2.4V Output signal 15V 10kHz from the Out.Transformer File 9 |
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| Used old TESLA EL34 Feedback connected Trimer R8 to right 1/4 Input signal (Ch1) 2.5V Output signal 20V 1kHz from the Out.Transformer File 10 |
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Used old RFT EL34 Feedback connected Trimer R8 to right 1/4 Input signal (Ch1) 2.5V Output signal 20V 1kHz from the Out.Transformer File 10 |
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| Used old TESLA EL34, after cathode regeneration! Feedback connected Trimer R8 to right 1/4 Input signal (Ch1) 2V Output signal 20V 1kHz from the Out.Transformer File 12EL |
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TESLA EL34, after cathode regeneration! File 12BM |
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