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Cab Impedence Switchbox


PaulyWally

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Right... I do understand that. But I don't want to be confined to a 2 ohm stereo amp for a given setup.


Maybe it's my lack of commitment. I dunno... ask my ex-wife. I just want the options, man... I'm all about having options.
:deadhorse:

 

 

Then build the box and go have all of the options.

 

I don't see how having one amp that can drive any combination of speaker would be considered confining.

 

I also do not see what advantage there would be in running three cabs in series and presenting a 12 ohm load to an amp. If a situation required three speaker cabs, then more power is also in order.

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To nitpick a little...we're talking about impedance, not resistance, thus:

V = I * Z

Where I=Current, V=Voltage, Z=Impedance. And this technically only applies when there is inductive reactance or capacitive reactance also present in the circuit, not a purely resistive circuit.

...and I'm a finance major... :D

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To nitpick a little...we're talking about impedance, not resistance, thus:


V = I * Z


Where I=Current, V=Voltage, Z=Impedance. And this technically only applies when there is inductive reactance or capacitive reactance



Actually... that's "DC Resistance". And it is V=I*R. Impedence (Z) doesn't quite apply because it's not a measurement of DC resistance, and it changes as the frequency changes.


Either way... I've conceded to you bastages a long time ago. :p:D

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Question (seriously):
How is that speaker-impedence box possible when people say the "AccuSwitch" was impossible?

Mine doesn't have it, so don't really care, but just curious- is it because that box matches it at two points, or what? But an amp automatically "sees" what ohmage it's being fed, so what does it matter?? :confused:

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Question (seriously):

How is that speaker-impedence box possible when people say the "AccuSwitch" was impossible?


Mine doesn't have it, so don't really care, but just curious- is it because that box matches it at two points, or what? But an amp automatically "sees" what ohmage it's being fed, so what does it matter??
:confused:


IIRC, a speaker-impedence box is completely possible, with the use of transformers. I don't know about the AccuSwitch, but it is possible to alter impedances with transformers.

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Mine doesn't have it, so don't really care, but just curious- is it because that box matches it at two points, or what? But an amp automatically "sees" what ohmage it's being fed, so what does it matter??
:confused:



Yes, and if you connect the amp to this miracle box, the amp 'sees' the impedance the box is showing it :)

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We aren't talking about a box that magically converts the perceived load from 4 to 8 ohms, we are talking about a box that, through the use of switches, will enable a user to put the outputs in series or parallel.

 

A transformer can be used for impedance matching, but as power goes up, so must the size of the transformer. That's why the Weber box is only rated for 100 watts.

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We aren't talking about a box that magically converts the perceived load from 4 to 8 ohms, we are talking about a box that, through the use of switches, will enable a user to put the outputs in series or parallel.


A transformer can be used for impedance matching, but as power goes up, so must the size of the transformer. That's why the Weber box is only rated for 100 watts.


Yeah, what he said. :D

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IIRC, a speaker-impedence box is completely possible, with the use of transformers. I don't know about the AccuSwitch, but it is possible to alter impedances with transformers.



The Accu-Switch was said to be able to change a cab's impedence from 8 -> 4 ohms, back and forth, yet there's been so much written on how it's "impossible" to do so, how is this box plausible? I'm quite confused, or they're not trying to do the same thing at all.
:cry:

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We aren't talking about a box that magically converts the perceived load from 4 to 8 ohms, we are talking about a box that, through the use of switches, will enable a user to put the outputs in series or parallel.


A transformer can be used for impedance matching, but as power goes up, so must the size of the transformer. That's why the Weber box is only rated for 100 watts.

 

 

So this changes the load FROM the amp? But doesn't an amp already do that, as I asked before?? I'm lost.

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The Accu-Switch was said to be able to change a cab's impedence from 8 -> 4 ohms, back and forth, yet there's been so much written on how it's "impossible" to do so, how is this box plausible? I'm quite confused, or they're not trying to do the same thing at all.

:cry:


The AccuSwitch is plausible as long as they're using some sort of impedance-switching transformers, like Burdizzos said. But again like Burdi said, more power = bigger transformer. Maybe the AccuSwitch is some sort of series/parallel switch that could change the impedance by rearranging the wiring configuration of the speakers in the cab. Like I said before, I don't know much about the AccuSwitch so I can't say if it's capabilities are true or not. All of that aside, it IS possible to alter the impedance of a cab with transformers.

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We aren't talking about a box that magically converts the perceived load from 4 to 8 ohms, we are talking about a box that, through the use of switches, will enable a user to put the outputs in series or parallel.

 

 

Right.

 

My original idea for this was to have a box that had 4 speaker jacks. With a DPDT switch between each jack, it could select any two to series or parallel.

 

In essence, one would be able to make quick changes in an instant:

 

4 speakers in parallel

4 speakers in series

2 in parallel + 2 in series

3 in series to 1 in parallel

3 in parallel

3 in series

1 in parallel to 2 in series

 

etc...

 

The only caveat is... one would have to know just how much impedence they are sending to the amp.

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The AccuSwitch is plausible as long as they're using some sort of impedance-switching transformers, like Burdizzos said. But again like Burdi said, more power = bigger transformer. Maybe the AccuSwitch is some sort of series/parallel switch that could change the impedance by rearranging the wiring configuration of the speakers in the cab. Like I said before, I don't know much about the AccuSwitch so I can't say if it's capabilities are true or not. All of that aside, it IS possible to alter the impedance of a cab with transformers.

 

 

Weird. All I've ever heard is that according to someone's "physics", it is in fact impossible to switch ohm-loads on a cab, which is why Accu got such a bad wrap by some with their design.

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The Accu-Switch was said to be able to change a cab's impedence from 8 -> 4 ohms, back and forth, yet there's been so much written on how it's "impossible" to do so, how is this box plausible? I'm quite confused, or they're not trying to do the same thing at all.

:cry:

 

It is possible, but it requires big ass transformers with multiple taps.

 

The Accu-switch was a magical black box that contained a capacitor. All it did was change the DC resistance of the cab. Most amps can actually run at lower impedances than the manufacturers claim, so no one blew up am amp as a result of the accu-switch, but it has been proven by independent electronics geeks that it is total bull{censored} and a marketing scheme that blew up in Accugroove's face.

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Right.


My original idea for this was to have a box that had 4 speaker jacks. With a DPDT switch between each jack, it could select any two to series or parallel.


In essence, one would be able to make quick changes in an instant:


4 speakers in parallel

4 speakers in series

2 in parallel + 2 in series

3 in series to 1 in parallel

3 in parallel

3 in series

1 in parallel to 2 in series


etc...


The only caveat is... one would have to know just how much impedence they are sending to the amp.

 

 

Yep, you'd also have to stop playing while changing.

 

Like I said, Loopmaster will build you one, just tell them what you want and they will give you a price. Provided you are using less than 500 watts, a standard footswitch will work. Hell, they could make it with 3PDT switches and give you LEDs to show which outputs are hot.

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