Tone control low noise here is not without noise, but most low-noise between the tone control on the market, for example Ronica 4 transistors, TL-084, TC-2 LM833 etc.
Jump to the explanation of each component ...
Potentiometer 1 serves to adjust the intensity / level of the incoming signal is assisted Potentiometer 2 as balance / balancer. 2 pot is still mounted regular and an optional component. R1 is actually a capacitor 1-2uF / 250V branded,
but I prefer to replace it with a resistor 1K / 5% are common for a reason to avoid hum and interference-sensitive. R2 R3 minimize the interruptionw adjusts thhilee impedance OP-amp 1. R4 and R5 serves to raise strengthened by 1.3 times. Pre amplifiers typically use a standard reinforcement by 2 times, but by most of us consider this noise. So I chose a value of 1.3 times, but the most minimal noise from the signal volume is enough to light up the lamp peak.
For low noise ...
The cause nois in Op amp 1, audio apex even eliminate this stage. Can
This step is also used as a buffer (jumper R5), strengthened by 1 times. Lower the value of R5 or increase the value of R4 with consequent gains to be less, but remains at a value above 1 time for input to take the path of non-inverting, so that the signals can and nois reduced. R4 can also be replaced with a 10K trimpot and get into the middle leg adjuster bass circuit (resonant bass).
C1 and C6 as a filter to reduce the treble / high frequency of excessive or often called oscillation prevention. R6 is actually an optional component that little help adjust the system impedances. Ideally R7 together with R8 to facilitate
give the sign value gain on potensio panel tone control. C2 and C3 form a series circuit filter treble (high pass filter), its value is greater then the noise is passed increasingly mid. C4 and C5 assisted by R9 and R10 form a low pass filter (filter bass), the greater the value of C is a bass sound that is passed will be more tender / low (maximum 47nF), the smaller the value of c is the bass signal that is passed will further dip ( dig-dig, c4 = c5 = 22nF). A suitable value for this is 27-33nF and not 47nF (depending on taste). Pot 3 & 4 pot set treble and bass levels, the greater the value of the pot is getting bigger gains (bass & treble included Potentiometer volume). R11 adjust the output impedance, while R12 and red LED as an indicator showing that the peak has been given a full signal amplifier.
Supply 15V maximum. IC can TL074, but in designing a PCB, IC can be
replaced with 2x TL072 / NE5532 / 4558.