Scratch and Rumble Filter 2

The purpose of this filter is to undermine the very low frequency noise and very high. Because the cues in the stride frequency is generally large amounts of harm than good to the overall sound cues. Another consideration of this circuit is to mamandangnya sabagai pass filter is very wide path for the line that contains the most important part of the sound spectrum. The layout is so simple as it consists of two pieces of filter rows, a pass-over was followed by a pass down. Each filter comprises a pair of second-order filter stage stratified (cascade), to obtain the characteristics of a steep 24 dB / octave. Frequency of 11.8 Hz and the stopper is in 10.7 KHz with the components shown here. Adequacy of this point depends on the application and not too difficult to change it. Blockage of 11.8 Hz can be shifted up by reducing the value of the capacitor C1, ... C4, or can be facilitated by increasing its capacity.  This Capacitors  must all be of equal value. Pass filter frequency of the plugs can also be modified to change the value of resistor R5 .... R8. Like the capasitors, the fourth resistor should be worth it all together. This value can be reduced to increase the frequency of stoppers or enlarged to lower frequencies. Op-amp low noise dipergunaken merupaken type and there are two in each of the IC packaging. Therefore we need two ICs for each channel. Canals discharging currents around 20 mA each.

Simple Stereo Synthesizer

There are two common methods for generating a pseudo-stereo effect from a mono signal, the mono signal to both speakers play out of phase, and the use of frequency selective techniques, which usually consists of directing lower frequency signals in a single channel and higher frequency signals in the other. This circuit uses the second technique, but it can also antiphase signals that can give a better effect, especially when using headphones.

Q1 is used an emitter follower buffer stage, which provides two filter networks quagmire of its production is driven low impedance source. If they were driven directly to the input, it is quite possible that they would receive food source impedance of a few ohms or more pounds, which would be more than enough to change their properties effectively.

Both filters are formed by R4 and C3 (low pass), and C6 and R8 (step height). Wind in the price is not essential in this application and the rate of attenuation of 6 dB per octave filters simple as that RC is perfectly adequate. The-3dB point of each filter is about 800 Hz and mixed, therefore, gives an almost flat response, with significant peaks or troughs.

Q2 is connected as an emitter follower buffer stage, which ensures that there is minimum load on the low-pass filter. Q3 also ensures that there is minimum load on the high-pass filter, but this device can also serve as a phase separator. With SW2 switched to the output of the transmitter third quarter, Q3 acts effectively as an emitter follower and makes no phase inversion. With SW2 switched to exit in the third quarter of collectors, Q3, thus effectively act as a common-emitter stage with negative feedback of 100% (and a unity voltage gain) due to R11. 1t also provides a phase change of 180 °, so the two output signals are in phase opposition. A phase conditions are necessary to give a good stereo image center and use of anti-phase signals tend to give an impression of greater separation channel.

Stereo recording in an orchestra, it is normal for the violins from the left channel, with cellos and basses in the right way. Therefore, the high frequency signals are routed to the left channel and low frequency signals are routed to the right channel so that the device gives a similar effect (although this will obviously work well with the outputs connected both ways ).

Simple Scratch and Rumble Filter

This is 12 dB per octave and the beginning of the add-on Rumble filter, which can be connected to "Tape" or the institution responsible for the amplifier.

And 'the usual quadratic filter circuit having a passive high pass filter formed by the ability of C3 and C4 series and parallel resistor R2 and R3 (the latter is also used to bias the transistor Q1 source follower). Passive filter of this type gives only very slowly to the original roll, and the final reduction was only 6 dB per octave. Boot Strapping resistance is then used to improve performance. Above the cutoff frequency, where profit is the district would otherwise drop slightly, R1 is the effect of strengthening the signal. Well below the cutoff frequency, the loss of C4 leads to the signal emitter of Q1 is significantly below the junction of C3 and C4. This leads to some of the signals at the intersection of C3 and is pushed through the R1 and R1 with C3 effectively forming a second network-pass filter. This eliminates the sluts, the number of the original film (in fact, is a small and insignificant in a maximum of about 05dB above the cutoff frequency) and accelerates the depreciation rate for a nominal 12 dB per octave.

The low pass filter works the same way that the high-pass, except, of course, the elements of R and C of the filter have been implemented to provide the correct action of the filter.

With the component values ​​specified for Rumble filter response drops below unity at about 45 Hz, where -6 D13 just above 30 Hz, then drops to a nominal 12 dB per octave. The filter response from zero to unity gain points around 6k5Hz time 6dB points at about 10 kHz, then drops to a nominal 12 dB per octave.