Archive for June, 2015

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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Nchannel depletion mode Mosfet exampleI’m thinking of a way to mute the dry signal from the parallel loop in my Mesa Dual Rectifier Solo 100.  There are already a few widely distributed mods, but none keep the functionality completely intact.

The depletion mode mosfet is a closed circuit when no power is applied to the gate.  When the bias voltage appears on the gate (at the same time it opens up the jfets), the channel between source and drain will pinch off, muting the dry signal.  I’m not sure exactly how to do it, but this is an idea I’m working on.

(EDIT)  Since beginning this, I found it practically impossible to get the correct Mosfet to implement this idea as it is.

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