Active vs Passive EQ?

[Gamera]

What's the difference on a practical level?

I have a Genz Benz 60 combo amp and have been in a love/hate relationship with for the last couple years. Only recently did I learn (or maybe it just sunk in) that the bass/mid/treble controls are active vs passive. I did some googling to try and figure out what that meant. A post on the Les Paul forum was helpful and basically stated:

A passive EQ amp delivers 100% pure tone when all knobs are at full(10). Any thing lower than that cuts the volume of that frequency.

An active EQ amp delivers 100% pure tone when all knobs are at mid(5). Anything lower than 5 reduces the volume of that frequency. Anything higher introduces gain to that frequency? This is where it gets a little wobbly to my brain.

In a sense it sounds like the active is saying "but these go to 11" without providing any practical explanation of what that means.

Anyone care to school me?

 

[Gamera]

Re: Active vs Passive EQ?

I think you got it.

Active - Cut/boost

Passive - is like a faucet.

So then that "boost" is essentially gain?

If this is the case it gives me new incentive to sit down with that amp and attempt to dial in a sound. Again. This time hopefully with a better understanding of what I'm doing.

 

[Funkfingers]

Re: Active vs Passive EQ?

In order to be able to offer the cut/boost capability, active EQ is powered.

By comparison, passive EQ is simple subtractive filtering via resistance within frequency ranges determined by capacitors.

 

[Van Noord]

Re: Active vs Passive EQ?

Yup, think of an active eq dial's range like an integer line. (Halfway on the dial is zero)

-5 < -4 < -3 < -2 < -1 < 0 > +1 > +2 > +3 > +4 > +5

Increasing the dial past halfway will introduce more output to the preamp.

 

[Gamera]

Re: Active vs Passive EQ?

Increasing the dial past halfway will introduce more output to the preamp.

So I guess this "increased output" is what I'm having trouble wrapping my mind around. This "output" isn't just more volume, no? Not sure what the point of that really would be. Is that increased signal somehow being colored other than just a volume increase? Should I expect some amount of gain or perhaps breakup here?

Sorry if this sounds like a dumb question but I know to my ears it'll just sound like it's louder. So in a practical sense it would be acting identically to a passive EQ. Other than pointless bragging rights saying "but it goes to 11."

Thanks for the replies.