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FISHER X100A LAMBALI AMFI PROJECT Schematic Circuit Diagram

I have recently started working on paper and I have worked on paper for almost 6 months. I have finished my amphitheater based on Fisher x100a. I have.

I have made a very good amplifier by revising some parts of the amplified amphitheater X100A series, which is one of the best El84 lamp configurations of the American brand Fishery, which most of you are not hearing by many of you .

Here this work me to share my goal of guiding friends birnev which is keen on both tube amp, help them in their further studies to increase production of Turkey in the tube amp dinleyicilig a nevica and as an amateur, interest is toplamakd.

After a year and a half ago I shared my single EL EL84 am, and now I share a more powerful and successful EL84 push-pull amp.



The circuit is basically the Fisher X100a push-pull amp. El84, which is easily available as an exit lamp, is made with 12ax7s at the input voltage. The original x100a has tons of control and pre-amp parts. As the pre-amp and tone control should always be separate, the human may have to change the system completely when it listens to a much better pre or tone control in the future.

I think the circuit is an ideal light bulb for the home, especially the treble and the mid of the amphitheater. It is an amphitheater that carries all the features of the lamp amphitheaters.

The original biode of the circuit ( cathode bias ), because my materials are unsuitable for this, I have made a lot of changes on the bias. If I don’t have a 3w potentiometer, I’m going to cancel this part. I added low and high pass filters on the input voltage amplifier. These details are not very important, but the most important is the negative bias. The way will be.

In general, El84 applications negative bias’a not seen, most el34 and 6550, such as the 20-50w between the amphitheater. But in this circuit is a potentiometer such as 5w in the cathode bias line will still need 10w strength resistors will be needed. Because of the cathode resistance, a current flowing from each lamp to Allaha will flow. In order to eliminate all these negativities, I have changed the negative bias -20v ( approx. negative bias voltage -15v of the el84 lamp ). When the desired bias current circuit can be set.

Another change I have made in the time of the feedback line, a little increase in the resistance in the feedback line, and the amphitheum slightly reduced the amount of noise reduction by reducing the gain.

Besides, I designed a new supply circuit for the circuit, I also drew it as a diagram and again it is simple and easy to find materials.




The negative bias voltage of the output lamps is provided by the Lm317 voltage regulator. The negative bias voltage, which is one of the most important voltages, should be free of noise and regulated so that it does not change with the network fluctuations.

amp is very simple bit of push-pull applications as can be seen in the open şemada, simple pieces of resistors and capacitors on the circuit in Turkey market Lamps outside the malzemeler.b can be found very comfortable and can be a bit difficult to find sockets in Turkey but abroad this stuff as I do It will be very easy to procure.

Again, the amphitheater of the most important points in the amphitheater, the output transformers I wrapped myself, as a result of the tests of the high-quality transformers of the transformers I’m convinced that I was close to the high-quality transformers, of course, for similar applications, transformers can be taken abroad.


One of the important points of the circuit is the case, usually in the case of a lamp and other amplifiers I use aluminum. Aluminum is an aesthetic view to the eye and can be found easily to collect the magnetic field of the amphitheater.

The lamp sockets will be mounted on the plate and attached directly to the ceiling of the box together with the plaque.

Again, I designed the input circuit board to be mounted directly to the plate and fastened to the front panel.
The output of the amplifier consists of two options as 4ohm or 8ohm, but due to the limitations of my output terminals, this connection is made manually. The quality of this potentiometer can be called the first factor in determining the sound quality, and the sound is reached through it.




The circuit of the circuit is finished in the circuit, especially in the circuit divider section of the 12ax7 lamp 47kohm resistors with 1% selective resistance from the resistors. .

One of the most important parts is the feedback line. The cable you are going to use on this line should be coaxial or shielded cable, because such circuits will be immediately affected by magnetic field, so the feedback line should be protected.



After switching on the transformer holes of the amphitheater and replacing the transformers, most of the amplifier has been completed.

The supply circuit of the amplifier can easily be made to the plate, but a larger case will be needed as it will take up a lot of space.
In my period, the Lm317 bias regulator was installed externally, but later on, it was easier for me to carry this part to the plaque because of the external installation. My amphitheater was on the casing because I had printed my plaque before doing this revision.

When I talked about the supply circuit, I realized that in my listening tests after the circuit was finished, the charging adapter of my computer made a huge noise. When the adapter is plugged in, there is an annoying whirl in the speakers. Noise is lost without removing the adapter. This information may be affected by your circuits such as your amplifiers.
After the installation of the supply circuit, we went to the connection of the card to the supply stage, where one of the important points is the winding of the supply cables on one of them as shown in the illustration.


This process should be applied particularly and especially on AC lines. As can be seen in my circuit, the transformer’s 220v input is wound up on the switch and the transformer after the mains filter.

Another thing that needs to be done precisely is the filament feeding of the lamps. For partial removal, the filament feed cables should be wound on each other and should be carried as far as possible from the plate. If the distribution of materials is available, the filament cables must be carried from the corners of the frame.

100er ohm resistors connected in parallel to the chassis in the filament feed are of great importance in suppressing noise.
After all these operations are finished amphime. I couldn’t tell you about every stage of this amphitheater, if you have another part attached to it, you can e-mail me about this amplifier or general lamp amps, I try to help as much as I can.


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