Looking for physical switch for amp outputs to speakers

[HarryK]

I want to A/B/C several pairs of speakers using a single amp.

Is there a device that takes one amp input and can physically switch to several outputs?

It doesn't have to be pretty, and I'm not concerned with effects on the cable signal, assuming it has good conductivity at the switchbox.

Thanks for any suggestions.

 

[XEagleDriver]

Any Speaker Switch should work

Any speaker switch should be able to handle the task. You may need to deselect the first pair as you select the next pair to get your desired result, but that is not difficult.

For instance: this one

Cheers,
XEagleDriver

 

[HarryK]

Hey thanks. I wasn't very clear (it was late and I was tired). I'm looking for a purely physical switch if possible where you move something and it connects one set at a time. I need to push 500W RMS with peaks much higher, and I also don't want any electronics in the path that may alter the amplified signal.

Is this something so strange nobody sells anything like it?

 

[j_garcia]

Your question was already answered. Pretty much all speaker selector switches do exactly what you are asking.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-970

 

[XEagleDriver]

Why so much power?

Hey thanks. I wasn't very clear (it was late and I was tired). I'm looking for a purely physical switch if possible where you move something and it connects one set at a time. I need to push 500W RMS with peaks much higher, and I also don't want any electronics in the path that may alter the amplified signal.

Is this something so strange nobody sells anything like it?

The 500W RMS requirement may severly limit your choices-- be sure to check the specs of any switch you choose carefully.

May I ask what application requires such a high power spec?

Most speaker switches allow you to bypass (i.e. not use) the protection circuitry if you so desire.
- Depending on the resistance rating of your speakers, be careful to deselect the 1st pair, before selecting the 2nd pair to avoid a potential bad result for your amp if you disabled the protection circuit!

XEagleDriver

PS. Neither the switch I nor j_garcia suggested will handle 500W RMS.

 

[HarryK]

Pushing some old ADS speakers that can handle that type of power rating, although in all honesty I don't really like it that loud very often, but sometimes with some music I do. And ADS recommends 10 times the power for headroom so even at 50W I want at least 500W capacity to handle that.

I went back and checked j_garcia's post (thanks for pointing me back there), and I must have looked at 20 different boxes and none of them even come close to that level of power.

Also, I am too ignorant to know, but I don't want anything in the signal path - just copper to copper in a switch. ADS mentions that even passive components alter things like damping factor, and I especially don't want anything electronic that could alter the signal.

Also that Monster box required that you use their special connector. Ideally I would use a banana plug or stranded wire or spade lug (not sure what experts here think of those three, but that's a separate topic).

And yes you are right to point out that if you activate more than one set at a time, the impedance will drop with each set activated and that will put my amps at risk.
But I only want one set at a time active, so I'm ok there.

Thanks again!

 

[j_garcia]

I think you are REALLY over thinking this. 500W is ridiculous. You won't need that much, and the speakers likely won't actually be able to handle it anyway, realistically. A/D/S speakers are nice (my uncle has a set of floorstanders), but few speakers actually require that kind of power, even during peaks. You'd more likely be looking at 5 figure speakers for that kind of power handling.

 

[XEagleDriver]

I think you are REALLY over thinking this. 500W is ridiculous. You won't need that much, and the speakers likely won't actually be able to handle it anyway, realistically. A/D/S speakers are nice (my uncle has a set of floorstanders), but few speakers actually require that kind of power, even during peaks. You'd more likely be looking at 5 figure speakers for that kind of power handling.

+1 on all the above!

 

[HarryK]

I think I'm actually under-thinking it. I just want a simple physical switch. I don't need or want any passive or active components in the physical path.

I also don't think it's ridiculous. I owned a pair of 810s, and used to routinely run 100W Avg levels into this speaker for hours at a time. So this is not a theoretical discussion, I am in the practical realm. Since SPL increases on a logarithmic scale, and ADS points out in their manual that musical peaks routinely are 5 to 10 times average levels, I don't think 500W or even 1,000W capability is "ridiculous".

Also, I think you are overlooking the primary cause of driver failure. It's in using an under-rated amp, not an over-rated amp. That's why clipping is my number one concern, not an "over-rated" amp.

I would suggest a look at the power ratings recommended by ADS themselves:
L910; amp rating of 150W to 300W RMS
L2030: amp rating of 300W to 1200W RMS
L1590: amp rating up to 500W RMS
Those are not speakers in the tens of thousands of dollars.

Finally, one of the reasons ADS recommends biamping is to remove more of the passive components from the physical path. I don't think they were that ignorant of the issues involved when they make such a recommendation.

Please provide practical and factual issues and evidence before calling me "ridiculous".
Thank you.

 

[j_garcia]

Cerwin Vegas say they can handle 500W too and they can be had pretty inexpensively. Get my point? People still blow them, yes usually with too little power because they don't grasp the concept of clipping.

It is a PEAK rating and does not mean you will damage them if you don't have 500 or 1200W on hand (unclipped), because no manufacturer realistically expects you to have that available. Your speakers likely use 10W or less for typical listening, so that 10X peak means 100W of CLEAN (unclipped) peak demand power even for a decent speaker. What the headroom buys you is the ability to turn them UP and hit peaks without clipping, but unless you are listening at deafening levels, yes your request is a bit beyond reality. I am definitely not one to say that more power is a bad thing, but there's a point at which it doesn't get you anything more just like a 1000hp street car. You can drive it, but unless you are at the track, that extra power just isn't doing anything. 500W may mean you will never clip, ever; however for the levels that the average person listens, one probably would not clip even with 200-300 solid watts.

You've put the carriage before the horse, so to speak. If you are using the manufacturer's rating to determine how much power you need, you've probably started in the wrong place. There are plenty of other factors that come in to play. You'll notice that the manufacturer's rating didn't specify the size of room the speakers will be in, whether or not you have treatments or an "active" room, what type of audio you will be playing on them at what level, etc... Which is exactly why their ratings are so broad.

You didn't say anything about biamping. Active biamping requires you to remove the passive crossover completely and thus is unrelated to what you are asking about.

 

[HarryK]

Not sure how this turned into me being "ridiculous" and "not needing" what it is that I think I need.

So does anybody have any suggestions?

I'm starting to feel better that there isn't something like this just sitting around that I missed. But I am sincerely looking. I may go to an electrician or electronics supply store next.

--------------------

JG - you certainly are a font of misinformation, but that's a separate topic.
Comparing CV to ADS? OMG.
(btw, you are not spelling ADS correctly)

 

[j_garcia]

Sorry, forgot the last slash and trademark

It turned that way because what you are asking for likely doesn't exist in an off the shelf package. It may not be a unicorn, but it sure isn't going to be something you will find at Radio Shack When you find it and the holy grail, do let us know though.

 

[HarryK]

Actually that logo you posted is not even close. Like I said...
I'm still shocked that anyone would compare them to CV.
Wow.

I don't know why I'd post my final outcome. I'm the only one weird enough to want one, so I assume I'm all on my own here. That's OK, and sorry for the sniping, couldn't resist.

 

[TLS Guy]

Not sure how this turned into me being "ridiculous" and "not needing" what it is that I think I need.

So does anybody have any suggestions?

I'm starting to feel better that there isn't something like this just sitting around that I missed. But I am sincerely looking. I may go to an electrician or electronics supply store next.

JG - you certainly are a font of misinformation, but that's a separate topic.
Comparing CV to ADS? OMG.
(btw, you are not spelling ADS correctly)

Your problem is too little physics.

First I can assure you those ADS speakers will not handle 500 watts very long. I know those speakers burn out very easily, so be careful.

Now all program has tremendous variation in moment to moment power requirements. Every time you double the apparent loudness, power demands go up 10 fold. Now the average power of any program is quite low, usually less than 10 watts. However the musical peaks require enormous power, especially in classical music. Most systems are actually in permanent recovery mode playing a lot of program, because of peak demand. That is why pros use so much power. I personally use 2.5 KW on my rig, but the average power demand is much less than that.

Now what you are asking for was commonly available until much more powerful amps became available. So why are these units a thing of the past. The reason is voltage.

The power into a load is the square of the voltage across the load, divided by the resistance or in the case of a speaker the impedance.

Now voltages between 40 and 100 volts are common place now.

The next thing you have to understand is the back EMF in inductive loads.

When you break an AC circuit driving an inductive load, the load (in this case the speaker voice coils and inductors in the crossover) resist the collapse in voltage as you break the circuit with your selector switch. This results in a huge increase in voltage as you break the circuit of between 10 and 100 fold depending on the circuit.

So if you happen to flip the switch at low voltage well and good, but if you do in a peak where the voltage is peaking at even 50 volts say, then the switch contacts at circuit break will see probably at least 500 volts and depending on circumstances could be 5000 volts. This will fry the switch contacts for sure, but the speaker voice coils will see that voltage as well and you can generate arcing across the coil windings and fry the speaker.

This is one of many reasons why we always advise to switch off amps and receivers before pulling or inserting speaker plugs into the output socket. We have had members cause many expensive fry ups over the years, by disregarding this rule. The above is just one of the causes of these fry ups.

So to switch speakers at high power really does require electronics to safely control the situation. In any case electronics to level match the speakers is mandatory. A/B speakers teat without level matching are meaningless, as there is such a strong tendency to favor the loudest speaker under these circumstances.

So you need to stop right now, or you will regret it.

--------------------

 

[HarryK]

TLS Guy, thanks for all this info. I'll go off and study it and think it through. I love getting that kind of educational info I can chew on and ponder and question, but in the end I'll be further in my understanding.

I should have said I don't want to do A/B testing, yes I'm fully aware that volume matching is critical for that.
And I should have said I'm willing to turn gain to zero or even turn off the amp before switching.

And I think you strengthened my whole point about wanting a lot of power reserve, and I had already been saying all along that with a logarithmic scale of power increase, that it didn't take many db to reach some high power levels.
I don't think I agree the speaker will not handle 500W, but you didn't what the source material is (of course a signal generator tone would melt them with far far less than that for example), or which speaker. In fact, many of the ADS tweeters can handle far more than 500W, depending on the source and the duration.
I do however, agree with your general statement, and appreciate that you are trying to help me keep from ruining some expensive toys. Thanks.

I have a question? It's a serious one, I'm not being sarcastic.
How do amps and receivers that can connect to 2 or 3 pairs of speakers and switch between them work?
I guess if they work the same as a "speaker selector" box, that would be interesting.

I assume you were better able to understand my concerns about putting even passive components in the path. I never said I was going to biamp, I was using ADS own written comments about biamp advantages to support my concerns (of course you don't have to remove the crossover on an ADS speaker, they have a special design to accomodate this setup without doing that).

Thanks again.

 

[j_garcia]

Actually that logo you posted is not even close. Like I said...

I guess you will have to post actual pics then, because that was their logo until they went out of business. You didn't happen to buy them out of a white van did you? Or maybe you are just a troll?

I'm still shocked that anyone would compare them to CV.
Wow.

You're shocked because you clearly missed the entire POINT, which is not surprising at all based on all that you have said.

Is your "special design" a jumper? LOL!

Active Vs. Passive Crossovers

 

[TLS Guy]

I have a question? It's a serious one, I'm not being sarcastic.
How do amps and receivers that can connect to 2 or 3 pairs of speakers and switch between them work?
I guess if they work the same as a "speaker selector" box, that would be interesting.

I assume you were better able to understand my concerns about putting even passive components in the path. I never said I was going to biamp, I was using ADS own written comments about biamp advantages to support my concerns (of course you don't have to remove the crossover on an ADS speaker, they have a special design to accomodate this setup without doing that).

I have not examined a modern receiver, and the companies do not release circuits.

However on older receivers it was a simple switch and they often did give trouble if the owner used the facilitie a lot.

I suspect that modern receivers may well be the same, however they are not high powered certainly not in the 500 watt class.

For a 100 watt amp you have an RMS voltage of 20 volts and a peak voltage of 30 volts. So if you break the circuit at peak into an inductive load, the peak back EMF voltage would typically be 300 volts, and no harm done. In any event that would be absolutely worst case to switch right at peak RMS voltage. Chances are most switching would take place at a point way below peak voltage. If the speaker presented an unusually inductive load, then you could be unlucky and get up to 3000 volts. So the chance of damage is low but not non existent.

Now if you break a 500 watt amp at peak voltage you will have a back EMF voltage of typically 900 volts at peak and on the outside 9000 volts. Now those voltages, either one could easily spark through the insulation on voice coil wire, and certainly destroy switch contacts.

You could minimize it by bypassing the contacts with a cap, but the cap would be relatively large and I bet they don't do it on receivers because of space.

A/B switches are a bad idea anyway, and another of my many gripes about receivers. I have never seen A/B switches on beefy amps.

There is no circuit that allows active bi-amping without removing the passive crossover in a speaker from the circuit.

 

[STRONGBADF1]

TLS Guy is correct on ADS speakers burning out easily. They are know for this. They are nice speakers (and have quite the following) for vintage speakers but the tweeters are very fragile. I have a pair with blown tweeters around here someplace... Be careful with how much power you push them with. that big of an amp if great, you'll have plenty of headroom so as long as you don't push it you'll have clean power. you need clean power for those delicate vintage tweeters. Too much clipping and they'll go quick. Too much volume and they'll go quick. Get a good switch and turn the volume all the way down when selecting a different set of speakers.

Good Luck!

 

[jonnythan]

At 500 watts, those speakers will be pumping out about 120 dB.

 

[HarryK]

I guess you will have to post actual pics then, because that was their logo until they went out of business. You didn't happen to buy them out of a white van did you? Or maybe you are just a troll?



You're shocked because you clearly missed the entire POINT, which is not surprising at all based on all that you have said.

Is your "special design" a jumper? LOL!

Active Vs. Passive Crossovers

Actually I sense troll myself. You keep commenting as if expert on speakers where you literally can not spell A-D-S.

You said "Active biamping requires you to remove the passive crossover completely". Not true on ADS speakers, and no it's not a jumper. Clearly you have never seen one of these speakers.

As for all your other misinformation, I'll just let it float on by on the wild world of the internet.

btw, if it was me, I would have already asked what the difference is between ADS and what you keep posting. But then again, I prefer to learn rather than post/blast away blindly...