Posts Tagged ‘Presence’

I don’t have time to type right now, but here are the images from the analysis for a 2 Channel Orange, 3 Channel Vintage on ch 2, and 3 Channel Vintage on ch 3.  The responses of the 2 Channel Orange and 3 Channel Vintage on ch 2 are very close.  Other factors could influence the differences between them.

2ch voicingandpresencevintageorange

2 Ch Orange

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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…)

Tonight, I tried some different setups between my Recto and a Line 6 Pod X3 Live.  I was trying to get a good headphone mix for silent playing.  The “Slave Out” was making noise and I switched to using a send from my Nova System to the X3.  I found the similarities between the modes to be quite minimal.  It was striking, really. (more…)

This is in regards to the Presence circuits for a 3 Channel Dual/Triple Rectifier and the Roadster/Road King.  I do not have information on the Reborn or miniature versions, though I suspect they kept it pretty much the same.

Mesa came up with a clever Presence circuit for the 2001 3 Channel Rectos, which carried over to the Road King and Roadster on their relative channels.  For the sake of flexibility, the Presence pot is flanked by relays to swap the function between modes.  The modes are used to determine power amp response due to negative feedback and the amount of distortion it is capable of producing.  From most to least: Modern, Vintage, and then Raw.

Using Modern, the negative feedback is disconnected and treble frequencies are being attenuated by an RC filter connected between the the Presence pot and the wiper of the Treble pot.  Using Vintage, negative feedback is being fed from the transformer to the PI.  The amount of feedback is controlled by the Presence pot, which also sets the frequency cutoff; it has dual functions as a resistor divider and a filter.   Raw is a special case and is discussed on its own below.  I will be using Channel 2 for the examples, but I will contrast the circuit differences with channel 3. (more…)

  1. Input Stage
  2. Stage 2: Go With The Flow
  3. Stage 3: Clean It Up
  4. Skip The Nerd Talk: Putting It All Together
Introduction

I’ve been thinking a lot of about modifications recently and I’ve been going over the schematic for the 3 Channel Dual Rectifier on a regular basis for quite awhile.  I was recently thinking back to when I was starting out and how it was difficult to understand why or what a part of the amp was doing.  I don’t consider myself an expert.  I was taught solid state theories in school and had to buy books and read websites regarding tubes and how they apply to guitar amps.  I wished there was more information about the design concepts.  So, I thought I’d break down the preamp for the Dual Rectifier into the stage circuits and just talk about the general, overall concept of what each does on its own and together with its neighbors.  This might help the users with tones and circuit designers and hobbyists with ideas and insight. (more…)

(11/15/15: Edited information about the Presence and Treble)

Modern, high gain, guitar amplifiers generate much larger signals than vintage amps, hence high gain (high increase).  Compared to a vintage amp, modern amps can produce much more distortion and saturation.  In addition, the low frequency content of a Recto is fairly great.  Stages 1, 2, and 4 of the dirty channels are shunting the lows at about 88 Hz, -3 dB.  While the amp voicing is another topic, it’s important to have an idea of what is coming into the tone stack if you wish to shape it.  Since I own a Dual Rectifier, I’m using it as the example, but these concepts and this tone stack are applicable to many amplifiers.  I’m focusing on the Vintage mode of the Orange Channel.

Our topics for this discussion are: target frequencies, response of individual controls, the interaction of the controls, and dialing in useful tones more easily.  Some of the information is simplified for clarity.

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Convention, hype, and a confused amp tech’s handwriting have mucked up the exact nature of the Presence control settings on the Dual Rectifier 3 Channel amp.  For the non-geeks, I will say what the real nature is and then dive into detail afterward.

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My current main gear is a LTD AX-2E and a 2006 Mesa Dual Rectifier.  I’ll speak briefly about each:

The LTD was second-hand and had EMG 81/85 when I acquired it.  I later swapped the EMG out for Duncan’s JB/Jazz set.  This is probably the best “cheap” guitar I’ve ever owned.  It’s odd shaped, but the ebony fretboard with neck-through design is awesome.

The Mesa DR is their original three channel design.  It’s often vilified as a less desirable amp than the 2 channel originals; especially now that the new design is out.  My amp is not modified, but I may jump the effects loop to make it serial.  I use Clean, Raw, and Modern with Bold and Vacuum settings.  It’s a trade off.  In a few years, I might switch to a Reborn Recto, just to have silicon on the Modern mode and 50W on the Raw. (more…)