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a passive boost?

D

DubBeats CB

Jul 18, 2005
180
1
38
Santa Cruz, CA
#1
Is there any pre amp that can do a passive boost....like the bass has no battery but can boost frequencies. I'm not talk ing a relative boost, where everything else is slightly cut to render a desired bost in the desired frequency. Has anyone been able to accomplish this?:confused:
 
#3
DubBeats CB said:
Is there any pre amp that can do a passive boost....like the bass has no battery but can boost frequencies. I'm not talk ing a relative boost, where everything else is slightly cut to render a desired bost in the desired frequency. Has anyone been able to accomplish this?:confused:
Click to expand...

I believe this would violate the known laws of physics. If anyone's done it, I haven't heard about it.

BTW, fender mod, that's a great link. I'll be ordering some stuff from them. Thanks!
 
#4
passive "boost" doesn't exist...as jabberwock777 says, "that would be a violation of physics"...

you could set up a passive tone stack into a gain-only, bypassible preamp...then, when the battery fails, the shape of the tone is maintained, but the level would drop off (depending on the tone-stack and setting, possibly dramatically), but the tone would be maintained.

my latest project will do precisely that, however, I don't perceive the batteries to die, since it will be powered from an AC adaptor (it's an outboard unit). :)
 
#7
Villex is the only one I know of offering something like this. I'm not sure if anyone had an exact idea of how it worked but there was rumour of a tricky little transformer being involved. I've never seen one and apparently its sealed up pretty well, so I can't say on the matter.

It's not so much violating the laws of physics as it's performing a very clever little side-step of the issue.
 
#8
daveze said:
Villex is the only one I know of offering something like this. I'm not sure if anyone had an exact idea of how it worked but there was rumour of a tricky little transformer being involved. I've never seen one and apparently its sealed up pretty well, so I can't say on the matter.

It's not so much violating the laws of physics as it's performing a very clever little side-step of the issue.
Click to expand...

there's no "clever little side-step" for a law of physics....it either is active and "boosts"(or attenuates) and passive and "attenuates"...

you can't get something from nothing...many "clever" people have tried and failed...

often what may appear as a "mid boost" is actually a simultaneous high and low cut...
 
#9
It's flat out not possible to have a passive boost--passive means you take the basic signal and subtract energy from it at some frequency point--active means you ADD energy, it's an active circuit


You can get kind of a relative boost effect. If you cut midrange and treble, you get what the ear hears as more bass. If you cut bass and treble, you get what the ear hears as more midrange. You haven't added any energy to the signal, you've just taken some frequencies away. In some situations cutting bass and treble could sound like a boost, because all the amps power would be going to the punchy mid frequencies.

IMHO boost is not anybody's friend, it starts to sound kind of artificial and to my ears tiring
 
#10
If you lok at that has-sound link you can see he's got a tiny little mini-transformer in there to change--I assume--the frequency range that gets bled to ground. But he doesn't make any claims to boost anything on the passive page
 
#12
Hi guys,
William Villex is here. I anderstand it's hard to belive that
there is way to make that boost. But it's possible!
I have been demonstrating it at this winter NAMM show.
Not only mid bost but also low and high boost.
People who checkd it not a kids and you can't cheet them.
The names are: Stuart Spector (Spector basses), Joe (Fodera), Carl (lakland), Anderson (Modulus), Bob Taylor
(Taylor Guitars), Tom Anderson (Anderson guitars),
Jose (ESP Guitars) Lee Sklar, Jacko III X, And many other top professionals.
Respectfully,
William Villex.
Email me [email protected] and I will answer your questions
 
#13
You can use a trasformer to boost voltage at the expense of current. Since the input of a preamp doesn't care about current, it works. If you then put in passive frequency cuts and simultaneously kick in a transformer to boost voltage, you'll get the effect of a passive boost at the chosen frequencies. You can also use coil taps to kick output up and down, and then put passive filters in.

It's smoke and mirrors, but can work. But why? Passive does not automatically equal better...
 
#14
Rick Turner said:
You can use a trasformer to boost voltage at the expense of current. Since the input of a preamp doesn't care about current, it works. If you then put in passive frequency cuts and simultaneously kick in a transformer to boost voltage, you'll get the effect of a passive boost at the chosen frequencies. You can also use coil taps to kick output up and down, and then put passive filters in.

It's smoke and mirrors, but can work. But why? Passive does not automatically equal better...
Click to expand...

Rick...you're right, of course, about using a transformer to boost voltage...

the main misgiving I have about putting a transformer into a passive electronic circuit is this...FREQUENCY RESPONSE...why muddy the waters with an additional inductive load???

Holy Phase-Shifting, Impedance-Matching Bat Contraptions, Batman!!!


Me...I'll stick to high-quality, low-noise linear amplification circuits, or RC passive filters, as required.
 

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