Posts Tagged ‘eq’

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…)

HarmonicI like this boosted filter.  The 400 Hz peak is accompanied by a 3.2 kHz peak of a smaller amplitude.  This accents the 4th Harmonic, which is consonant.   (more…)


Basics of the Signal Path

The input to the Boss GE-7 Graphic EQ has a buffer which is active at all times.  There is a slight emphasis around 2 kHz to help the guitar sound stand out.  Immediately after the buffer is the amplifier for the level control.  It’s a differential type with only one source voltage split with the level’s sliding potentiometer.  This slider will either boost or cut the whole signal when it is moved from the zero line.  From here, the signal is split; one path goes to the EQ section and one part goes to the positive input of another differential amp.  The EQ section feeds the negative input of the differential amp. (more…)

I had just a few thoughts come to mind regarding modifying amps, modifying EQ, or creating your own.

It’s a fact that Mesa Engineering uses two modified forms of the Marshall tone stack for their Dual Rectifier series.  Compared to a classic Marshall tone stack, the Vintage/Raw tone stack moves the center of the “Mid” control down in frequency and has more attenuation.  This carves out some of the meatier part of the guitar frequency to make room for the massive lows and a high-mid emphasis.  The tone stack enabled for Channel 3 Modern has boosted upper-mids, but has a very similar, low-to-low-mid frequency response. (more…)

I put together a rudimentary representation of the effect on filter curves when setting a graphic EQ.  It isn’t exact.  Use it to get a general idea for the way a graphic EQ shapes the signal. (more…)

Blank Settings Form For Boss GE-7

Using an equalizer to boost the guitar’s input signal makes a lot of sense.  It provides a clean gain and a lot of headroom.  Aside from boosting the signal, it can, of course, be used to carve out specific frequencies.  Unlike most overdrive pedals, an equalizer has the ability to be very precise with multiple frequency bands and can create special effects.

The downside to this specific pedal is noise.  It uses cheap tantalum capacitors in the signal path.  This creates a hissing sound when the sliders are moved away from the zero mark.  The MXR 10 Band EQ is reputedly better, but I don’t own it and can’t comment about it further. (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.

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…)

ACDCPlexi VintageCleanThese settings are for an approach to getting some vintage tones from a Mesa Boogie Dual Rectifier.  The Clean uses the ideas I’ve been developing about a higher gain setting against a lower Volume setting.  It also has less Bass dialed in.  This made the moderate use of Mid and Treble possible to control sizzle and distortion.  The Presence is just an extra treble control, because Channel 1 has no negative feedback in the power amp.  This setting is very full through the mids and has enough bass and treble to sound good, without either dominating.

The Dirty setting is copping a nice late-70s AC/DC tone.  It sounded really good for many Classic Rock tunes that aren’t fuzzed up.  Raw has a lot of top and bottom rolled off.  It only needs a little nudge to move into Plexi territory, though it could take some more Mid if a person wished to do so.  The Solo is engaged and dialed-in just enough to change the top frequency response.   (more…)