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jrwalsh33 10th October 2012 06:29 PM

Basic Question
 
Hey,

I would like to have one input into my guitar cab that would send the signal to a three position On-On-On switch that would allow for sending the signal to either the open-back pair, the closed-back pair, or all four simultaneously. Will the multiple wires from the input/switch to the various destinations degrade the signal or are there any other problems/solutions to consider?

Thanks,

Joe

Loudthud 10th October 2012 07:23 PM

The only problem is the lower impedance the amp sees when the both position is used. Most amps will tolerate the change, even many tube amps, unless you play with extreme overdrive. In that case tube life may be shortened and they may fail without warning.

jrwalsh33 10th October 2012 07:37 PM

Thanks
 
Thanks, Loudthud,

I will be matching impedance with a selector on the head for all speaker combinations. My real concern is just the effect of multiple lengths of wire attached to the same input/switch and going to various locations in terms of signal quality.

Thanks again,

Joe

ChrisA 10th October 2012 10:53 PM

Quote:

Originally Posted by jrwalsh33 (Post 3196745)
Thanks, Loudthud,

I will be matching impedance with a selector on the head for all speaker combinations. My real concern is just the effect of multiple lengths of wire attached to the same input/switch and going to various locations in terms of signal quality.

Thanks again,

Joe

No. That has zero effect in audio frequencies. It starts to matter if you get into VHF radio antennas but if you are sending audio even a 1,000 foot difference is "nothing". The audio signal travels at about one foot per nanosecond in wire. So a 1,000 foot difference means a micro second delay.

If you jump over to the HiFi forums there are "audiophools" who think they can hear the difference if they remove a fuse from its holder, reverse it, and put it back in "backwards". these guys will spend days deciding which direction sounds best. I think the same people swap speaker cable end for end too.

The wire length difference has an effect similar to fuse direction, nothing. Although like fuse direction there are people who think they can hear it.

gingertube 10th October 2012 11:19 PM

Lets apply some theory.
To have a barely noticeable effect on the sound the the resistance of the wire would need to be 10% of the speaker impedance. Say you have 4 Ohm speaker impedance, that means 0.4 Ohms max wire resistance.
For speaker wire you would use 16 gauge minimum. for 0.4 Ohms resistance that would require 100 feet of 16 AWG. (30 meters for those who use sensible units of measurement).
Don't worry about it.
Cheers,
Ian

jrwalsh33 11th October 2012 12:24 AM

Thanks
 
Wow, this site is great! Thanks so much ChrisA, ginger tube, et al.

So, I now understand that the length of good wire is insignificant. Just to quell my ignorance-based paranoia, is it equally insignificant to have one input signal, then divided into multiple signal paths (i.e. several wires), some of which terminate at a switch while others pass through the same switch to other switches and/or speakers?

Thanks!

Keriwena 11th October 2012 01:21 AM

Even more insignificant. Current only flows in a closed loop. It will take the shortest path to ground and ignore any dead branches.



Just be sure the switch you use is rated for some serious amperage.

jrwalsh33 11th October 2012 01:39 AM

Thanks again
 
Thanks, Keriwena...this site rocks!


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