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2 hours ago, RandyH000 said:

 transformer  attenuators can  be used for maximum bandwidth potential  -

 

dscn2017.jpg

 

 

 

 

 

 

 

 

1 hour ago, jimjimbo said:

Stop the presses!  Did you hear that Chief?  ALK!  We’re saved!


Call me crazy but I swear “ALK” was part of the above pictured mounted circuit board? Deleted? Why? By whom? 

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5 hours ago, richieb said:

Call me crazy but I swear “ALK” was part of the above pictured mounted circuit board? Deleted? Why? By whom? 

 

No, you're not crazy.  The post was manipulated, not a surprise.  The post originally said something very close to "ALK recommends an Lpad for.......".

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10 hours ago, Chief bonehead said:

Curious......I see a lot people recommend Lpads. Why?  Do L pads reduce the volume equally across the associated bandwidth?

I would say yes, only a resistor network something that Klipsch uses now for attenuation in their speakers. Autotransformers have not been used by Klipsch for years. Where confusion lies is discrete vs variable L-pads. I would say discrete is somewhat better in the long wrong but nothing to lose any sleep over. One could use a variable L-pad to find the right network by measuring and then use a discrete network if you are concerned. 

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r100t2-4.jpg

Fostex R100T2 Transformer Type Attenuator - MONO

The transformer attenuator addresses the challenge of attenuation by using a transformer rather than a resistor to decrease voltage.

 

  • Attenuation 0 to 21 db (1 db step)
  • Input 100 watts (Music)

 

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9 hours ago, RandyH000 said:

I am not familiar with this type but if it works it may be OK but not for me when a couple of resistors do the same thing. Even an autotransformer is cheaper than it. 

 

 

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Seems to me that an lpad, unlike an autoformer, will not result in a consistent voltage drop across the driver at all frequencies. This is because the impedance curve of most drivers is not flat. When the driver impedance increases, the voltage across the driver will also increase.  Likewise, the voltage across the driver will drop as impedance decreases.

 

Although the variations may be small, wouldn't this be considered distortion?
 

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42 minutes ago, mboxler said:

Although the variations may be small, wouldn't this be considered distortion?

 

Not under the classic definition of harmonic or intermodulation distortion, which result from nonlinearities in the system. This would just be frequency response variations.

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Would not call it distortion and the effect of resistance changes may effect the amount of attenuation but at such a small amount not anything audible. Even an autotransformer has resistance as well as capacitance but neither are significant enough to be meaningful. Electrical engineers get down to specifics and tradeoffs and the ones at Klipsch now do not think it meaningful enough to matter by their chose of discrete l-pad networks. There are electrical engineers who participate on this forum who could say more on this subject and specifics of how much and the effects between different ways of attenuation. There are very few speaker manufactures that use anything other then L-pads, either discrete are adjustable for attenuation. I am sure there are exceptions like most everything.  The one negative of an adjustable L-pad is what happens to all controls is that over time they can be a problem but we are talking 15 years and a shot of deoxit cures that. 

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