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Discussion Starter #1
Can any engineers/physicists out there explain why the reverb is hugely magnified when I run my slightly overdriven, slightly reverbed pedal thru the Overdrive channel (vs. Clean channel)?

It totally crunches up the sound the way I like, but the reverb goes from some 'depth' to the reverb that you hear on "Magic Bus" off "Live at Leeds".

Zoom 505II into a Marshall CDR15 if that makes any difference...
 

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"Let's DWELL on it..."

Killick said:
Can any engineers/physicists out there explain why the reverb is hugely magnified when I run my slightly overdriven, slightly reverbed pedal thru the Overdrive channel (vs. Clean channel)?

It totally crunches up the sound the way I like, but the reverb goes from some 'depth' to the reverb that you hear on "Magic Bus" off "Live at Leeds".

Zoom 505II into a Marshall CDR15 if that makes any difference...
Actually, that probably DOES make a difference!

This is a simple solid state amp with a spring reverb added, as opposed to a digital one. Simple reverb circuits work by tapping off the main (dry) signal, passing it through the reverb spring tank and then recovering it as the "wet" signal and mixing it back with the original. The only control you have is a "mixer" control to dial in how much "wet" echo-y signal is mixed with the dry.

As you might expect, when you do things so simply you are left wide open if the situation changes. Controlling the mix is only part of a spring reverb's sound. It's also affected by how HARD you drive those reverb springs! This is called "dwell" and is the important factor in your question.

Fender pioneered the spring reverb circuit but usually kept to a simple, one control circuit to keep costs down. Only some of their amps like the Vibro series and their stand-alone reverb unit had a "dwell" control to let you adjust the drive into the springs. You could control how hard you made those springs shake and then how much of that signal you mixed in, with an overall tone control as well.

When you add a boost pedal in line with your MGCDR15, you're boosting not only the dry signal but also what's driving into the reverb springs by the same amount. Your less complicated preamp circuit doesn't allow you to reduce the extra gain into the reverb with a dwell control.

Every so often I build up a standalone tube reverb unit similar to the ones Fender, Traynor and Garnet made during the golden years and keep it available for some of my customers to play with. Within a few weeks someone always buys it - especially if that someone is into jazz. Some of the tones you can add with the extra controls are really sweet and just can't be gotten any other way.
 

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Discussion Starter #4
So, if I'm understanding you correctly, the extra-strength reverb is coming from the amp, not the pedal?

That seems reasonable, thanks Coustfan & Wild Bill!
 
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