# Speaker cables for plugging an attenuator?



## Salokin (Nov 10, 2008)

Hi there,

I've just received my Alex's attenuator to use with my BF Vibrolux! I'm new with that kind of gear and I'm not sure what I'm better to do for connecting it? Should I grab some good speaker cables? Does it really makes a big difference? Am I better to keep the speaker cable that is going to the speakers of my amp and just buy another one? I've always had combos amp and not being used with speaker cables. What I have to know about that? I' ve read that there are females and males cables, which one do I need?

Thanks for help!


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## GuitarsCanada (Dec 30, 2005)

You should always use speaker cable when running to a cabinet. Not instrument cable


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## blam (Feb 18, 2011)

any non-shielded speaker cable will work fine. you can make your own with a lamp cord if you wish. you won't hear any difference.

I run an attenuator on my AC15. it does not have jacks. what i did was hardwired a 1/4" female to the speaker and one to the amp. 

this is what I did. attached the existing wire to some 1/4" jacks and mounted them to the back of the amp. when i use the amp sans attenuation, i use a short patch cable. when i use the attenuator i just plug it in with 2 longer speaker cables. I can also use my AC15 as a speaker cab this way just by turning it off and attaching a head to the speaker jack!

the 1st image is the stock amp. 2nd is the added jacks and a short patch. 3rd is with attenuator.


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## Sneaky (Feb 14, 2006)

You should also make sure the Alex is a 4 ohm model. I think they are mostly for 8 and 16 ohm cabs.


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## Salokin (Nov 10, 2008)

blam said:


> I run an attenuator on my AC15. it does not have jacks. what i did was hardwired a 1/4" female to the speaker and one to the amp.
> 
> this is what I did. attached the existing wire to some 1/4" jacks and mounted them to the back of the amp. when i use the amp sans attenuation, i use a short patch cable. when i use the attenuator i just plug it in with 2 longer speaker cables. I can also use my AC15 as a speaker cab this way just by turning it off and attaching a head to the speaker jack!
> 
> the 1st image is the stock amp. 2nd is the added jacks and a short patch. 3rd is with attenuator.


Great idea!





Sneaky said:


> You should also make sure the Alex is a 4 ohm model. I think they are mostly for 8 and 16 ohm cabs.


With the Alex's attenuator, you can use an 8 Ohm with a Vibrolux. I had a couples of emails communications with Alex and he told me that he was using an 8 ohm attenuator with his BF Vibrolux without any problems. He explained why but I'm really not an expert concerning impedance, so I didn't understood everything! But Alex assure me that the 8 ohm model was all good for a vintage 4 ohm Vibrolux.


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## Davestp1 (Apr 25, 2006)

BF Vibrolux's output trannies require a 4 ohm load but Fenders "apparently" can tolerate a mismatch in either direction (2 ohm or 8 ohm). However, it's your vintage amp if it has the virtually irreplaceable original output tranny, I would think twice but that is just me. I have a 4 ohm hotplate with mine.


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## Salokin (Nov 10, 2008)

Here's an explanation of Alex:

With my attenuator the speaker impedance is not critical and here is why. As long as the amp matches the attenuator and you don't bypass the attenuator the impedance will be closer than you might think. At the most minimum attenuation level -3db using an amp set at 8 ohms and using an 8 ohm attenuator and a 16 ohm cab your amp will see less than 12 ohms. At -6db the amp will see 10 ohms, at -9 db it will see 9 ohms, at -12db it will see 8.5 ohms nearly a perfect match with a 16 ohm cab. The math works the opposite way as well so if you use a 16 ohm attenuator and the amp set to 16 ohms and an 8 ohm speaker with the attenuator set at -3db the amp sees 12db. At -6db the amp will see 14 ohm, at -9 it will be 15 ohms, at -12 it will see -15.5 ohms and the farther you turn the volume down the closer it gets to 16 ohms. The reason is the attenuator is taking a larger and larger percentage of the load as the volume is turned down and it gets closer and closer to 16 ohm. Another thing to remember that the impedance rating is not fixed it fluctuates. That rating is arbitrary for comparison purposes. And only reads the rated impedance at 400hz. The actual impedance fluctuates from 6 to 80 ohms on a 16 ohm speaker depending on the frequency. Now what is important about this is the amp is constantly affected by this altering impedance and that is what is meant by a reactive load and why a reactive load sounds much more natural than a resistive load. And why the UA or HO attenuator uses a resistive load of 30 ohms trying to get an impedance that sounds closer to the average then most resistive loads typically do.


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## Davestp1 (Apr 25, 2006)

While that explanation may make sense (I have no idea), it is coming from someone trying to sell you something (not saying he is incorrect or suspect though). 

A BFVR amp puts out 4 ohms and the speakers are wired up looking for 4 ohms. In my case I decided not to fool around with stuff I don't understand and just got a 4 ohm hotplate, hooked it up with a pair of good quality speaker cables and forgot about it.


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