Broughton SV-Pre

Preamp

The SV-Pre is a JFET preamplifier that has been modeled after the preamp section of the 70s SVT. Each gain stage has been carefully designed to capture the feel of warmth and breakup found on the original amp. Coupled with a cab sim, you could have the monstrous tone of the classic bass amp stack without the challenge of transporting 250 pounds of gear.

In addition to the gain stage design, the EQ and tone switches have been designed to give the same response as those on the original amp. The Bass and Treble controls are the standard James stack configuration, having a shelving response of the lows and highs. The eq is flat when at noon.

The middle control uses a simulated inductor to emulate the same frequency response and width of the mid control on the SVT. Instead of three fixed frequencies, the frequency knob continuously varies from 220 to 3k Hz. The mid eq is flat when at noon.

The Low toggle switch uses the same circuitry as the three-way Ultra lo switch on the SVT. With the toggle to the right, a 2-pole high pass filter is applied, and allows for a more natural drive tone. With the toggle in the middle position, the low end is unaffected. With the toggle in the left position, a slight scoop is applied, emphasizing deep lows and treble frequencies. The Bright toggle switch applies a treble boost, and is more pronounced at lower gain settings.

A Master volume knob has been added on the output to set the overall level. Use the Gain knob to set the desired amount of warmth and overdrive. The Gain knob is equivalent the the Volume knob on the 70s SVT.

The pedal requires a 9V DC power supply (not included). Do not exceed 9V as this will damage the pedal. The DC supply should be a standard Boss style connector, center negative polarity. The current draw is approximately 20 mA.

Power Supply Notes

The JFETs are sensitive to power supply noise. Ideally you should use a clean power supply that is isolated from other pedals (i.e. not daisy chained). Some switch mode power supplies tend to be more noisy and should be avoided. Use a good quality, isolated supply and the SV-Pre will perform with very low noise.

The SV-Pre has a true bypass switch.

Dimensions: 4.77" long x 2.6" wide

https://www.broughtonaudio.com/product-page/sv-pre