• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Simple ECL86 amp

So you salvaged the ECL86's from two HMV Model 2202 taperecorders? In a thread earlier this month you posted the schematic of the HMV 2202. The tubes in it are ECC83, ECL82 and EM84.
I haven't salvaged anything, Columbo. I'm leaving the tape recorders complete. They're not HMV 2202's as I first presumed. They where not yet in my possession when I made that assumption.
Hope that's ok with you ☺️


Disabled Account
2021-07-06 6:56 am
I haven't salvaged anything, Columbo.
Thanks for the compliment!

From your post #1 of this thread:

"I posted another thread on here relating to a similar project salvaging parts from an (sadly broken) old tape recorder. However, it turns out I have different valves than I originally though and so, I have started a fresh with a new thread."

So is it so strange that I thought that you did salvage something?

But don't bother to reply. I'll stay out of this thread from now anyway.
Hi Peacocksuit,
Those tapre recorders probably have a very basic circuit, and probably just need a couple of PSU caps and a coupling cap or two to fix. It could be a good exercise to do a minimal renovation. If you can get them to work as simple PAs (a lot of taperecorders have that feature) then you could have a simple tube practice amp for a guitar enthusiast. Then you should have no difficulty moving them on.

As mentioned, I had fixed a couple of old tape recorders before, and they were surprisingly good as a bluetooth player, propped up on a shelf in front of where I work. It was quite rewarding hearing what a difference a sympathetic renovation had on the sound.

Cheers, Richard


2022-03-26 6:10 pm
A distinctive feature of this lamp amplifier is simply the absence of scarce parts, but at the same time it has a good sound. Due to the ease of setup and high repeatability, this amplifier can be recommended to beginner radio amateurs. The author of this scheme is Anatoly Manakov. The output power of the amplifier is 2.5 W with a coefficient of non-linear distortion of 0.5-1%. The frequency range of the amplifier is from 30 Hz to 20-23 kHz. The amplifier is made according to a two-stage scheme. In each channel of the amplifier it is used on one 6F3P lamp. The 6F3P lamp is combined, it contains two lamps, a triode and a beam tetrode in one cylinder. The 6F3P triode lamp is used for preliminary signal perception, and the tetrode operates in the sensing output stage. The input signal through the consumption regulator consumes the grid of the 6F3P triode, wins and consumes from the anode through the isolation capacitor to the control grid of the output stage. The output stage is made according to a triode circuit, in which the screen grid of the 6F3P tetrode is connected to the anode through a resistor with a resistance of 220 ohms. In contrast to the tetrode mode, in the triode mode, its resistance is reduced several times, and a more linear characteristic of the lamp is applied. The disadvantage is the higher power output. The output stage on the 6F3P tetrode is loaded onto the TVZ-1-9 output transformer from a tube TV. Other output transformers of the TVZ series from tube TVs can also be used in the amplifier. Excellent results can be obtained with Edcor transformers. It is proposed to repeat the circuit of two amplifiers at 6F3P, the first (Fig. 1) - with the installed one, the second (Fig. 2) - with automatic bias of the output stage, a little constructively. Figure 3 shows the power supply circuit of the amplifier.

Схема лампового усилителя на 6Ф3П с фиксированным смещением


Рис.1. Схема лампового усилителя на 6Ф3П с фиксированным

Схема лампового усилителя на 6Ф3П с автоматическим смещением

Рис.2. Схема лампового усилителя на 6Ф3П с автоматическим смещением

Схема блока питания лампового усилителя на 6Ф3П

Рис.3. Схема блока питания лампового усилителя на 6Ф3П

Детали . В усилителе применяются резисторы резистора МЛТ-0,5, разделительный конденсатор С2 типа К71-7, можно применять конденсаторы К78, К73. Блок питания выполнен на силовом трансформаторе от магнитофона «Комета-201». Можно применить унифицированные трансформаторы ТАН-28 , ТАН-29 , в крайнем случае при соединении усилителя с автосмещением можно применить силовой трансформатор ТС-180 от чёрно-белого ТВ, хотя он велик для этой конструкции. Дроссели Др5-0,08 от цветных ламповых телевизоров УЛПЦТ, или применение стандартных унифицированных дросселей Д22 , Д31 .

Электролитические конденсаторы в анодном питании К50-32 100мкФх350В, можно применять конденсаторы других типов на такое же напряжение, или выше-400В. Вместо дросселя можно применить резисторы МЛТ-2 номиналом 250-300 Ом, но ёмкость электролитических конденсаторов в этом случае желательно увеличить вдвое. Электролитические конденсаторы в выпрямителе с напряжением 50-100В.

При работе усилителя на загрузку 8 можно применить выходные трансформаторы ТВЗ-1-1, ТВЗ-1-2, ТВ-2АШ, ТВ-1-Л-1 от чёрно-белых телевизоров. При работе на нагрузку 4 Ом можно применить выходные трансформаторы ТВ-2Ш2, ТВЗ-1-9 от чёрно-белых и цветных ламповых телевизоров. При работе на нагрузке 16 Ом можно применить трансформаторы кадровой развертки ТВК, но при этом АЧХ усилитель может сузиться до 15-17 кГц.

настройка усилителя. При исправной лампе и правильном монтаже первый каскад в настройке не нуждается. настройка второго каскада сводиться к регулировке тока тока тетрода лампы 6Ф3П в пределах 40-45 мА по контролю производительности в катоде. При этом падение напряжения на катодном резисторе номиналом в 1 Ом должно быть в пределах 0,04-0,045 В постоянное напряжение. Для выбора усилителя с автоматическим смещением требуется подборка катодных резисторов так, чтобы ток через лампу на выходе схемы был мощностью 40-45 мА, при этом падение напряжения на этих резисторах будет в пределах 20-24 В.
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Details . The amplifier applies resistors of the MLT-0.5 resistor, the C7-type separator capacitor, C71-7, can be used Capacitor K78, K73. The power supply is made on the power transformer from the Comet-201 tape recorder. You can apply unified TAN-28 transformers, TAN-29, as a last resort, when connecting an amplifier with automotive, you can apply the power transformer TS-180 from the black and white TV, although it is great for this design. DR5-0.08 chokes from Color tube TVs ULPCT, or the use of standard unified chokes D22, D31.

Electrolytic capacitors in anodic power supply K50-32 100MKFH3B, you can use condensers of other types to the same voltage, or above-400V. Instead of throttle, you can apply resistors MLT-2 with a face value of 250-300 ohms, but the capacity of electrolytic capacitors in this case is desirable to increase twice. Electrolytic capacitors in a straightener with a voltage of 50-100V.

When the amplifier is working on loading 8, you can apply TWZ-1-1 transformers, TVZ-1-2, TV-2Ans, TV-1-L-1 from black and white TVs. When operating on the load of 4 ohms, you can apply the TV-2S2S2, TWZ-1-9 from black and white and color tube TVs. When working on a load of 16 ohms, you can apply transformers of frame sweep of TCEs, but at the same time the ACH amplifier can narrow to 15-17 kHz.

Adjust the amplifier. With a good lamp and the correct installation, the first cascade in the setup does not need. Setting the second cascade to adjust the current current Tetrode lamps 6F3P in the range of 40-45 mA to control the performance in the cathode. At the same time, the voltage drop at the cathode resistor with a par value of 1 ohms should be within 0.04-0.045 per constant voltage. To select an amplifier with an automatic displacement, a selection of cathode resistors is required so that the current through the lamp at the output of the circuit is 40-45 mA, while the voltage drop on these resistors will be within 20-24 V.

English please.

dave :cop:
diyAudio moderation team

Note: there seems to be some sort of auto-translate system, shown up since the new BBS sw, that is putting original language posts inso take extr care.