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Speaker switching box and "protection mode" ...?

RunOutGroove

RunOutGroove

Addicted Member
OK... I've upgraded my stereo so that I'm running a two sets of 6 ohm speakers from my trusty old Marantz 2270 recover rather that a couple of pairs of 8 ohm speakers that I was running in the past. In the interest of not damaging my Marantz receiver, I took folks' advice here and haven't been running my two pairs of 6 ohm speakers together as I don't want to damage my amp (I have no interest in an excuse to upgrade the Marantz; it's might just be the last amp I'll ever buy). Not a deal killer by any means but I do sometimes miss having both sets of speakers on together and filling my whole house up with sound. I see that there are speaker switcher units for sale that have a "protection mode" feature on them, and I'm wondering if that protects the amp that it's plugged into from straining too much with lower impedance speakers? If this would allow me to safely run two sets of 6 ohm speakers at the same time, what if any is the tradeoff? Is there going penalty in sound quality and then how so?
 
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In any case, the answer to your questions are:

Yes, as regards impedance. The protection function uses resistors or autoformers to assure that impedance does not drop below a specified point (often 4 ohms, but sometimes 5 or 6 ohms...see specs of the units being considered). This allows multiple pairs of speakers to be used safely.

As regards sound quality, some folks seem not to notice any, while many others report minor loss of quality....especially in the case of the resistor-based units (which are far more common, and less expensive).

If you go this route, consider a used unit. There is not much to go wrong with them, so they are a fairly safe purchase.
 
spark1 said:
In any case, the answer to your questions are:

Yes, as regards impedance. The protection function uses resistors or autoformers to assure that impedance does not drop below a specified point (often 4 ohms, but sometimes 5 or 6 ohms...see specs of the units being considered). This allows multiple pairs of speakers to be used safely.

As regards sound quality, some folks seem not to notice any, while many others report minor loss of quality....especially in the case of the resistor-based units (which are far more common, and less expensive).

If you go this route, consider a used unit. There is not much to go wrong with them, so they are a fairly safe purchase.
Click to expand...

Thanks for your advice... I did actually see one of these used in the ads. I wonder if the degradation in sound quality only happens if you have both sets of speakers on at once? I guess that I could live with that, but if there's likely to be an issue with the quality of the sound if only one set of speakers is running at a time, it doesn't really seem worth it...
 
Any degradation would be less with the protection function turned OFF. In this case, the signal should be impacted only by running through an extra set of terminals and switches.

So, you can run one pair at a time with minimal impact on SQ.
 
Personally, I would avoid units with volume control, unless that is something you are specifically needing/wanting. However, this can be a useful function if the sensitivity of your two different pairs of speakers is significantly different from one pair to the other (which of course results in one pair being noticeably louder than the other).

It is also unclear to me as to what impedance is maintained by that unit. I am guessing 4 ohms, but it's not clear.

All of that said, Niles is one of the market leaders in such devices. Verify that it can handle the output power of your amp, and that it can handle the gauge of speaker wire you plan to use.
 
spark1 said:
Personally, I would avoid units with volume control, unless that is something you are specifically needing/wanting. However, this can be a useful function if the sensitivity of your two different pairs of speakers is significantly different from one pair to the other (which of course results in one pair being noticeably louder than the other).

It is also unclear to me as to what impedance is maintained by that unit. I am guessing 4 ohms, but it's not clear.

All of that said, Niles is one of the market leaders in such devices. Verify that it can handle the output power of your amp, and that it can handle the gauge of speaker wire you plan to use.
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The specs I read on it say that it works for 100 watts at 8 ohms but I don't know how that translates to my 2270 and the two pairs ot 6 ohm speakers that I'd be running with it..? I don't really care too much about matching the volume between the two sets of speakers so I don't really need those volume controls and maybe those things do degrade the sound a bit. I'd guess that on a purely technical level they do but I have to wonder if it's enough to translate to anything that most would ever notice...
 
That spec is referring to the rated output capability of your amp into an 8 ohm load, which I believe is 70 watts for your receiver.
 
Two pairs of 6 ohm speakers in parallel means your amp will be driving a 3 ohm load - which isn't a great idea. For $50 I'd guess that box simply puts a 4 ohm resistor in series with whatever is connected to the box so even if the speakers were shorted out the amp would see a 4 ohm load and thus be "protected". However a 4 ohm resistor in series with 3 ohm loudspeakers means the resistor will be dissipating more power than the speakers! Also, the damping factor of the amp is effectively reduced from maybe 100 down to about 1. You may well hear the difference.
 
Some of the boxes favor the primary position over the rest and it will play that pair louder. This is done to make the large family room louder than the smaller bedrooms when used for house distribution. The cure is to not use the primary position.
My question is, why can't these 6 ohm speakers be run in series for a 10 to 14 ohm load?
 
quiet said:
Some of the boxes favor the primary position over the rest and it will play that pair louder. This is done to make the large family room louder than the smaller bedrooms when used for house distribution. The cure is to not use the primary position.
My question is, why can't these 6 ohm speakers be run in series for a 10 to 14 ohm load?
Click to expand...

If I do that then don't I have to have both sets of speakers on all of the time?
 
rothwellaudio said:
Two pairs of 6 ohm speakers in parallel means your amp will be driving a 3 ohm load - which isn't a great idea. For $50 I'd guess that box simply puts a 4 ohm resistor in series with whatever is connected to the box so even if the speakers were shorted out the amp would see a 4 ohm load and thus be "protected". However a 4 ohm resistor in series with 3 ohm loudspeakers means the resistor will be dissipating more power than the speakers! Also, the damping factor of the amp is effectively reduced from maybe 100 down to about 1. You may well hear the difference.
Click to expand...

A link to the specs is here: https://www.crutchfield.com/S-u2ffNKD1iAL/p_190SVL2/Niles-Audio-SVL-2.html

I'm not sure though how much this tell you about the thing... As for the price, there's none listed on the Crutchfield site as it's a discontinued item, but I'd bet that it went for well over $50 brand new. That being said though, I see that it's available used for even cheaper than $50 online.
 
The load match boxes do work. I think you would be happy for a long while. I don't like the theory but need the utility to play with my 18 pair of speakers at will.
So I except the necessary evil. I don't have a problem with the sound other than the #1 position plays louder.
 
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