There are two adjustable resistors on the board, close to the input to adjust the input sensitivity, 300K (500K) adjustable resistance is to adjust the light band closed.

Another 6E2 is Shanghai's early annual production inventory tube, some surface atomized white, some of the top has black spots, but does not affect the use. This circuit consists of tuning instruction tube 6E2 (also known as electro-eye tube) and related circuits, the signal is taken from the front stage or amplifier output voltage, after the pressure-lowering rectification drive the tube's electronic target. 6E2 screen light-emitting area and signal size proportional, no signal when the light-emitting area is smallest, strong signal time-shift light band from both sides to the center expansion until overlapping. Under the signal-change signal, 6E2 electric eye with signal changes, green electric eye lifelike, for the amplifier color added a lot. Economy. Not only does it display the size of the amplifier output power at any time, but it can also display problems with the amplifier circuit, power supply, and load. If the electric eye fluctuates greatly and the horn is low, the load is too light impedance mismatch.
Electric eye has a display and the horn is silent to indicate that the load open, electric eye has light but does not with the signal fluctuationmeaning for the amplifier or input signal problem;
Tuning indicates that the power consumption of the tube 6E2 is only about 2W, will not pose a burden on the amplifier power supply, enthusiasts are interested in this, you can use this "VU table" on the amplifier. It is also very simple to adjust the r and L channel output level indication size and balance by first giving a channel input signal (the mid-treble signal in a signal generator or CD audio test dish) under load, and adjusting the volume to make the amplifier output rated.
Then adjust the W so that the two luminous tube bands of the 6E2 nearly contact or slightly overlap can be done, the same method to adjust another channel this work is done. Affirmation: The components on the finished board vary depending on the assembly batch, and some components will use slightly different types, brands, models, specifications. The components and parameters assembled on the received board will prevail! The finished plate is tested for normal sale.

Package including:
6E2 Magic Eye Tube Audio Level Indicator Music Spectrum Fluorescence Display