Archive for the ‘Amp Settings’ Category

I very quickly drew the negative feedback filter controlled by the presence control when using Vintage mode on a 2001 3 Channel Dual Rectifier.  The red line represents the -3 dB half boost mark from the point of the most filtering.  I tried drawing the entire phase inverter, but it didn’t make a difference on the plots, so I removed it and kept it simple.

R2 is being instructed to act as a variable resistor with 11 points to represent each 30 degrees of travel from 0 -10 on the control.  Anytime a part of the plot goes below the red line, the feedback is lessened by quite a bit and those frequencies pass the phase inverter more easily.  The maroon line on each picture is representing the control being at maximum and a massive amount of the frequency band is passing easily. (more…)

The idea was to take Vintage on Channel 2 and make it sound very similar to Modern on Channel 3.  The results ended up being very close, but I didn’t have the time to completely match the EQ (for the most anal of comparisons).  The overall response was what I was going for and that is achieved.  (more…)

On the back of every Mesa Engineering Dual Rectifier, there are 2 switches to select options for the power supply.  One of these is to select Bold and Spongy and affect overall voltage to the amplifier, with Bold being full power and Spongy reducing power by about 20%.  The other switch is used to select the rectification: Silicon or Tube.  Selecting Tube reduces power by nearly 10%, since the tube has losses when it conducts.  There are 4 options for running the power supply:

  • Bold and Silicon
  • Bold and Tube
  • Spongy and Silicon
  • Spongy and Tube

Before I get to decisions for selecting power supply options, we should cover some facts and history.  Along the way, we’ll learn basic information about the differences between these options. (more…)

Fuzz-Crunch-CleanI’ve been experimenting with making Channel 3 a fuzz tone for a long time, but recently got just the setting I wanted.  This kind of setting gets close to “Dazed And Confused” and sounds good with “Purple Haze”.  Being tube, instead of transistor, it’s a little softer, but the Presence  can dial in the edge a person needs for fuzz bliss.

Faux-Fuzz EQ Setting

Yellow is the Modern setting as described above with no treble and full mids. Green reduces Bass to 11:00.

The way that old, germanium transistor fuzzes would clip is awfully close to the way the cold clipping circuit works in these Marshall/Soldano types of circuits and the Recto has the bottom end to really sound huge.

I found this Channel 2 Raw setting to be a match for the fuzz tone.  It’s bright, with plenty of bottom, and crunches up quite nicely.  Both dirty channels get cleaner as guitar volume is rolled back, but, like a Tonebender, Channel 3 never gets “squeaky clean”, but it does make a nice half-clean sound, since the treble is flattened.

I hope this helps.  Enjoy.

While this is written about a 3 Channel Dual Rectifier with an FX loop modification to serial, the basic idea will apply to any amplifier with a serial loop.  As well, the Nova System can be substituted for another device with a speaker simulation.  The speaker sim is in the Utility menu. (more…)

EQ Schematic

Schematic of tone stacks for Channel 2 and 3.  Note the Presence control circuit and the value differences for its resistors

When Modern Mode is selected on Channel 3 of a Dual Rectifier, an additional capacitor is added to the circuit.  This changes the capacitance value from 500 pf to 680 pf.  By doing this, it moves the frequency from which the treble swings on axis from 1.27 kHz down to 936 Hz.

The effect of this change is twofold: 1) The upper mids receive a greater emphasis in the sound; 2) The overlap of range between the Mid control and the Treble control forces the Mid frequencies to move up in dB, effectively giving a mid-boost throughout the range of the Mid control.  The change also prevents the Mid control from being as scooped at the minimum setting by about a maximum of 2 dB between 600 Hz and 800 Hz.


Here’s an example of the way I’m setting my amp lately.  It utilizes what I’ve learned about the Clean circuit, FX Send, Solo, and other things.   (more…)