Posts Tagged ‘voicing’

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…)

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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…)