Posts Tagged ‘Distortion’

In some of the articles, I made statements regarding a possibility of mild power amp drive, because I had not had time to really dig into the power amp to confirm or deny it, and due to the sound of Modern mode.  The power amp does not overdrive.  If you come across anything relating to this, any descriptions should be discarded if they contradict the following paragraphs.

Modern has some distortion present, but it isn’t clipping distortion; It’s regular ol’ harmonic distortion, which is otherwise known as “the tube sound”.  I don’t have time or energy to get into it, but the power amp is designed to stay as clean as possible, but tubes do not always amplify in a “linear” way.  This adds curvature to the sound waves, distorting them by bending (coloring the sound). (more…)

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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…)

The purpose of the article about changing the anode resistor value was to improve the clean channel and smooth the dirty channels.  That is exactly what it will do, but I wanted to talk about conceptual ideas regarding this change.  I’m going to use pedals for illustration and then translate that over to tube amplifiers.

Analogy

I used to build guitar pedals and I’ve spent a lot of time cascading circuits into each other.  While transistors and op amps react differently than tubes, the overall result on dynamics is similar from one component to another. (more…)

Where We’ve Been

So far, we’ve looked at the input stage and Clean mode, and the voicing and Gain controls for Channels 2 and 3.  When we left off, the signal had been filtered, dropped down, filtered again, and was exiting the Gain pot by way of a 475 k grid resistor into Stage 2 (V2a).

Grid Resistor

V2aDRAside from controlling incoming current, the grid resistor serves to adjust the highest frequency allowed to enter the amplification stage by creating a filter due to the tube’s internal capacitance (around 1.6 pf).  Additionally, this stage has a 20 pf capacitor in parallel to the tube.  This increases the total capacitance to 21.6 pf. (more…)

I already covered the input stage and clean channel.  I’m not going to repeat the information about the input, except for applications to the dirty tones.

The input stage is followed by a coupling cap and a 2.2 M load resistor in parallel with the voicing circuit and gain pot.  Most amps made prior to the Recto place the grid resistor between the coupling cap and the load.  The load is usually a potentiometer to control gain.  I think Mesa made this change to better enable the changes to the voicing circuit which control the load and blocking resistances. (more…)

Classic RockBefore the mass application of  post-preamp master volume controls, old amps had to be cranked up to get distortion.  The distortion of the power amp is what gave those old amps their defining overdrive characteristics.  Modern, master volume, amps rely on preamp distortion more than the power amp to create crunch and chunk without a person’s ears bleeding from the high SPL.

The 3 Channel Dual Rectifier (non-multiwatt) has an extremely cold biased power amp at full power.  This allows it to amplify the preamp distortion with a minimum of additional overdrive being created, if any is created at all.

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Raw as a Marshall-y

Jimmy Page-inspired settings.

 

(Updated 12/26/15: Second example added)

These are settings I use for classic rock.  The Presence and Treble should complement the other by having one to the lower setting if one is higher. (more…)

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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90s Heavy

The Clean is about what I use normally with the tube rectifier and sounds good with the other settings.  The Soundgarden setting in Channel 2 is based on Fell On Black Days (turn your guitar volume down) and Let Me Drown.  It’s more of a setting for Cornell, since he did the rhythm on his songs and Outshined sounds pretty good on it, too.  Channel 3 sounds pretty close to Tool’s Stinkfist, H, 46+2, and Third Eye.  All the channels compliment each other pretty well and would work as a basis for finding a personal tone.

Let me know what you think of this.

PNP Fuzz

Posted: February 24, 2014 in Effects
Tags: , , , ,

PNP FUZZ

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