This is a mature classic design,New optimization,Double side FR-4 1.6MM PCB Material,Each element from both acoustic and aesthetic point of view to consider,Whole board without jumpers,beautiful and practical! When users in the audio recording,the speaker unit and other equipment place is not necessarily perfect, pure passthrough preamp may not be able to meet the requirements,then add the tone adjustment becomes very important, if you have no extra power supply equipment, Passive preamp tone is preferred. It can adjust the treble and bass frequency effect is very obvious, let amplifier and speakers with more reasonably. Features: 1.Contains 10 times the tone board preamp, and treble, alto, bass, volume control. 2.With op amp IC package socket, flexible, easy to upgrade, suitable for different tastes. 3.Board layout is reasonable, low noise, component layout nice, maximum to meet your critical eye. 4.Components carefully selected areas, the use of cost-effective than high NE5532 op amp, high-quality small potentiometer, Black Edition BP Promise coupling capacitor, 1 % metal film resistors, capacitors, etc Specifications: Model: NE5532 Supply Voltage: AC 12V Size: 100x43.5mm Type: assembled board DIY KIT(Need welding by yourself! Note: Please allow 1-3mm error due to manual measurement. pls make sure you do not mind before you bid Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1set x NE5532 HIFI Preamplifier Control Board