The amplifier is very easy to get on the board, and an innovative tone defeat. Rather than disabling the sound system completely, they are massively de-sensitized, and defeated the  have a maximum range, . This can be increased if desired, so that you can have two settings of tone, a rising standard of 10 dB and a cut and the other with a very subtle 3dB boost and cut – that’s enough (surprisingly) a very minor adjustments to the way you need for day-to-day hearing.

Otherwise, the design is fairly conventional, with a great advantage over other models that require almost no cable. Transfer of the source is as you want – I suggest you bring a rotary switch on the rear of the enclosure, and a shaft extension with the tree in front. This leads to a minimum of wiring and reduces crosstalk from other active inputs.

Picture 1 - A and tone controls

Circuit Description

The input stage is shown with a gain of 2 times (6dB), configure and also acts as a buffer circuit for tone control. The tone control is a fundamental type Baxandall, but the addition of R117, 118 and 119 provide the flexibility and ease of reconfiguration, which is not the traditional arrangement.

Picture 2 - Balance, volume and output stages

R119 is the hard part of this circuit (which is unique, too

- I have not seen before, this technique is used). As it is 100k, which limits the range of tone control to a reasonable + /-10dB. To increase more and cutting, R119 (R219 and receive) can be omitted altogether. Conversely, reducing the value of a small area, will also, with about 6 dB at 20 Hz and 20 kHz to 7.5dB with 22K.

The sound system (and overall) performance is shown in Picture 2 (in increments of 10% of pot), and it appears that the midrange is hardly affected. This is in contrast with the majority of drawings in which the controls are aligned to 1 kHz, and it is a very audible in the media. For those who want absolutely no use of tone controls, I suggest that the  both without tone controls are designed and in line with true minimalist design.