# PA Speakers



## AsRock (Jul 17, 2016)

Is there a way without risk using them on a HiFi type amp ?, i need more though test some really rare YS-115's. 

They are 8 Ohn like the amp is how ever they use 2 jacks per cab which i think requires 2 channels and if that's true maybe i can plug them both in 2 different channels for each speaker although i don't want to fry some thing.

I know they do work but i need to test them long enough before i can even think of selling them.

I am actually waiting on the final piece of info on them from the manufacture, i do know they were made between 1987-1997 how ever they changed the horn tweeter which mine are known by the manufacture as the early ones.  So they are checking if they have the serial numbers in there data base.


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## Bill_Bright (Jul 17, 2016)

I am having a hard time finding information on these speakers. YS-115 keeps taking me to Yorkville Sound speakers, but they keep going to YS-115P, YS-115PW or Y115. The first two "P" models have integrated amps. The Y115 does not have an amp, but not certain it is what you have. And I can find no manual for it. 

My "guess" is the two jacks are for two separate inputs for redundancy. If me, I would try it using one input. Just make sure the gain (volume) control on your amp is all the way down when you power up, then very slowly turn it up.


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## FR@NK (Jul 17, 2016)

AsRock said:


> 2 jacks per cab



Might be for bi amp mode. Can you post a picture of the jacks?


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## Bill_Bright (Jul 17, 2016)

I am quite certain it is for bi-amp, but not to split frequencies - but for redundancy. And I say that because these are "PA" or public address speakers. So the redundant inputs would be in case one mic or amp blew, the audio would continue on with the redundant mic/amp input without the audience knowing anything happened.


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## Recon-UK (Jul 17, 2016)

All that matters is OHM rating and power delivery.

2 jacks? woofer and tweeter separated?


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## Bill_Bright (Jul 17, 2016)

Recon-UK said:


> 2 jacks? woofer and tweeter separated?


Again, that would be a bi-amp configuration to power the bass and upper frequencies with separate amps - or to use a cross-over circuit in one amp and not the crossovers built into the speakers.

That is not uncommon in higher-end stereo, surround sound and home theater audio systems. But it is highly unlikely with PA speakers - which typically are designed for voice for speeches, public announcements, and such.


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## AsRock (Jul 17, 2016)

Bill_Bright said:


> I am having a hard time finding information on these speakers. YS-115 keeps taking me to Yorkville Sound speakers, but they keep going to YS-115P, YS-115PW or Y115. The first two "P" models have integrated amps. The Y115 does not have an amp, but not certain it is what you have. And I can find no manual for it.
> 
> My "guess" is the two jacks are for two separate inputs for redundancy. If me, I would try it using one input. Just make sure the gain (volume) control on your amp is all the way down when you power up, then very slowly turn it up.



Yes there is not much info out there, they don't have much either, how ever i have had good communication about them from there company.

The ones you find in searches and on ebay and such are the same to a degree, later versions were released with square horn tweeters which i was able to check with the guy by the model number.

As you can see the Horn Tweeter is there old one, which on Monday  i am hoping the guy will get back to me about the S\N to actually get a date.


Well, making a connection to just one of the plugs gives sound to both units so with that said i think it's what Bill originally said (redundancy).

Anyways here's the pic.







Here's some other info i have found too though them.

they were in production from 1987 to 1998.
The horn  appearing in the last master material list was
our part no HRN0037 with dimensions listed as 129.4 x 317.5 x 196.5mm.
I also found some cab specs:
Power capacity - 200Wpgm
Imp. - 8 Ohms
Sens - 100dB@1W@1m
Max SPL - 123dB
F/R - 60-16kHz +/-3dB
Woofer - 15", 8R
Horn driver - 1"
X-over - 3kHz

Which made me worried they might be replaced tweeters how ever there was a change as when i gave him the model number of the tweeter confirmed them to be a early version.



Recon-UK said:


> All that matters is OHM rating and power delivery.
> 
> 2 jacks? woofer and tweeter separated?



I believe you maybe wrong on this as when i did just plug one is the sound was not stable so i  unplugged them asap, my amp is more than cable  of delivering 100w per watt a channel.

All so supplied sound to both drive units.

But here's the pic of what you wanted.


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## 95Viper (Jul 17, 2016)

Those are parallel connections... that allows the PA speakers to be connected in a string.

As noted in this Yamaha article:


> However, if speakers are added by connecting them in parallel, the total impedance for the speakers will change, resulting in a different power output. Impedance is a compound resistance value: the greater the resistance, the harder it is for electricity to flow; and the less the resistance, the more electricity flows. The lower the impedance (ohms) (which is the resistance mentioned here), the greater the number of watts output by the power amplifier.
> 
> When two 8-ohm speakers are connected in parallel, the total impedance for the two speakers is 4 ohms. The P3500S power amplifier can be used at 4 ohms, and the output power will increase with reduced impedance.
> 
> The benefits to connecting speakers in parallel are an increase in output compared to just using one speaker per stereo side, as well as the ability to angle the speakers to cover a wide area with sound. Speakers are often added at the live venue in order to enhance the audio system.


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## INSTG8R (Jul 17, 2016)

Damn 95viper beat me to it. But yeah it's for chaining them together.


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## AsRock (Jul 17, 2016)

95Viper said:


> Those are parallel connections... that allows the PA speakers to be connected in a string.
> 
> As noted in this Yamaha article:



Yes i forgot all about seeing that on another pair, So is it to daisy chain them so to speak ?.


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## Bill_Bright (Jul 17, 2016)

But daisy chaining (putting two speakers in parallel) would drop the impedance seen by the amp to 4Ω and that would greatly increase the current through the final stages of the amplification increasing heat significantly, potentially causing a safety hazard. That is not to say there are not amps out there capable of supporting 4Ω loads, but many are not. I would think the speaker would be labeled differently if daisy chaining was the purpose.


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## INSTG8R (Jul 17, 2016)

They are series wired.


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## AsRock (Jul 17, 2016)

Bill_Bright said:


> But daisy chaining (putting two speakers in parallel) would drop the impedance seen by the amp to 4Ω and that would greatly increase the current through the final stages of the amplification increasing heat significantly, potentially causing a safety hazard. That is not to say there are not amps out there capable of supporting 4Ω loads, but many are not. I would think the speaker would be labeled differently if daisy chaining was the purpose.



Well i guess there are amps made for that as the newer ones of what i have. I guess it be another question for the guy, keep on like this going owe him a beer lol.








So i take it you can just run just one speaker but which plug do you use the left or right one ?.

EDIT:
So there is no way to run these correctly unless you have a  PA Amp ?.


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## INSTG8R (Jul 17, 2016)

Well that is parallel wired....


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## Bill_Bright (Jul 17, 2016)

Yeah, that makes sense. Series would raise the impendence to 16Ω (with 2 x 8Ω speakers) and that would result in low SPL (volume) output from the speakers. Your amps won't blow a fuse or breaker but if the folks in back cannot hear, that's not good either.

So parallel "inputs" makes sense as that provides for redundancy. I used to do PA support for military functions (visiting dignitaries, change of command ceremonies, etc.) and the last thing you want is to lose your audio due to a blown amp or faulty mic. So we always had redundant mics, redundant mics and even a backup generator ready to fire up - just in case.


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## AsRock (Jul 18, 2016)

Well he got back to me once again and confirmed their dates being Sept 1987 & Jan 1988, ones really close to start of production with other not to far behind.

Maybe i should just stop trying to use them and actually bag them and put them away for another 10 years unless i drop on a PA amp for cheap to just try them.


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## Bill_Bright (Jul 18, 2016)

Well the horns will be fine but I have seen the flexible materials holding the cones deteriorate with speakers sitting in storage. So if they work now and you don't want them anymore, maybe try to sell them.


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## AsRock (Jul 18, 2016)

Bill_Bright said:


> Well the horns will be fine but I have seen the flexible materials holding the cones deteriorate with speakers sitting in storage. So if they work now and you don't want them anymore, maybe try to sell them.



Only known foam ones and very rare cases rubber ones to decay.

Selling them is the issue, your talking of upwards of $120 just for shipping.


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## Bill_Bright (Jul 18, 2016)

AsRock said:


> Only known foam ones and very rare cases rubber ones to decay.


Sorry, but rubber decays too. It is often called "dry rot" and it is a big problem with tires for example that sit "brand new" unsold on the shelf for 6 or more years. They become unsafe without a single mile on them because they can fly apart.

While certainly it is a bigger problem with foam as you noted, 30 year old (or 40 after another 10 years) rubber is not immune from rot or other damage.

As far as shipping, well, if the buyer want's them bad enough, they can pay for shipping.


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## AsRock (Jul 18, 2016)

Well though the last 30 years i have dealing with HIFI speakers only even had 2 pair that the rubber had failed, i was not saying it don't happen but it stands the test of time much better typically.


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## Bill_Bright (Jul 18, 2016)

Well, I've been into computers since the mid 70s but maintaining audio reproduction equipment was my first love and remains a passion. And I agree that decaying rubber is less likely and if that is what these speakers have, then you are probably okay. But the issue is speakers in storage. The rubber in speakers that are used regularly stay flexible - at least in my experience. Rubber that is not flexed for years gets stiff and can dry rot. In recent years, I have seen old audiophiles dig out their old equipment only to find that while stuffed in boxes in the basement or attic, they have not remained in the same condition as when first put in storage.

If yours are fine now, then great.


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