i have a receiver that reads at 120W is that enough to drive 2 speakers a tweeter and an external subwoofer ?

i have a receiver that reads at 120W is that enough to drive 2 speakers a tweeter and an external subwoofer
the receiver says on the back 120V 120W 60Hz 170VA  so im guessing it runs at 120W per channnel at 8 ohms so would i risk blowing the amp or speakers if i plug an external subwoofer to the speakers and tweeters
the recever does not have a sdubwoofer channel so would i damage anything at all with it in the channel as well
by external subwoofer i mean it has its own power source its own crossover its own amp it has an rca in put or you can use the terminal plate it has as well

this is the JVC RX 212

Picture of i have a receiver that reads at 120W is that enough to drive 2 speakers a tweeter and an external subwoofer ?
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MariusS12 years ago

I greet with respect to all who have the pleasure of using a very old tuner like

JVC RX-212. I found on a website technical details of the receiver. It says that the RMS power is 40-50W per channel. For very detailed information, search for them on http://elektrotanya.com/jvc_rx-212bk.pdf/download.html

I am very pleased with the receiver. With all due respect, marius_seeker

MariusS12 years ago
pkveazey5 years ago
Re-design is getting you there. The wattage on the back is what it pulls from the wall. You will never get that much power out to the speakers. The best rule of thumb is about 30% of the wall power can be delivered to the speakers.

I have a JVC 212 and the output power is 25 watts RMS per channel. The way they can get twice the normal power is by using the first half wave of the input power to power one channel and the second half wave to power the second channel. The output impedance is 4 to 16 ohms. I have mine hooked up to 4-15's, 2-10's, 4-5's, 2-3's, 2-13'" horns, and 2-6" horns. I'm using both, the A and B speaker outputs. 25 watts RMS per channel is actually a lot of power. I can rip the roof off the house with mine.

Just a side note: If you see any wattage rating other than RMS(root/mean /square) ignore it. Music power and Peak power are instantanious just like a flash camera and those figures are worthless.

fastcar123 (author)  pkveazey5 years ago
Good point. I've come to realize that it's more about the speakers that are used rather than the power to them.

May I ask how exactly you have your system hooked up? I plan on building a guitar amplifier using proaudio kits, but you seem to have an enormous load on your receiver. How did you do that exactly?
I hit reply and I think my reply went to the website. If you got it that's great but if you didn't, here's the short version. On your RX212 set you have A and B speaker outputs. They are looking for a load of 4 to 16 ohms. Just make sure you stay inside that range and all will be well. If you parallel a bunch of speakers and the load drops to lets say, 2 ohms. The amplifier will try to produce twice as much power as it was intended and you will burn up your amp if you turn the volume up too high. Speakers are rated by running a 1000 cycle tone through them. Whatever ohmage reads out, that's the impedance they put on the speaker. In reality, music sends all sorts of different frequencies to the speaker so the impedance constantly changes. Don't worry it all averages out and the speaker and the amplifier are happy. If you run a bunch of speaker and can't calculate the load, just ask an electronics tech to calculate it for you. Running speakers in parallel drops the impedance and running them in series increases the impedance.
fastcar123 (author)  pkveazey5 years ago
So you've precisely calculated the impedance to run around 4 speakers per channel. Something like running a parallel circuit into a series circuit to even it out. I have to give you credit on that, that's an ingenious design. On my JVC I can't seem to run both A and B channels at once. I tried using 2 speakers one on leftA and the other right B, but I wound up with no sound at all
Whoa!!! The A and the B are not left and right. You have a left and right output for the A and a left and right output for the B. Just plug one pair of speakers in the A side and then push the button on the front of the amp that says 1. If you want to run a second set of speakers, just plug the second set into the B inputs on the back and push the button on the front that says 2. You can then choose to use one set or the other or both sets at the same time. You probably already know where the 1 and 2 buttons are but just in case they are on the front immediately to the right of the PHONES input. When the buttons are in, the speakers are on and when the buttons are out, the speakers are off. That's so you can turn the speakers off when you are using the headphones. I hope this helps.
fastcar123 (author)  pkveazey5 years ago
I know that each channel has a left and right makeing the reciver a 4 channel system. i simply used that design to test the outputs of the system. seeing as how my dads friend was throwing it in the trash i assumed there was something wrong with it and i planned to use it for spare parts if it didnt work. knowing that its does work i just need to find a second set of speakers (or an external subwoofer with built in crossover)to run on channel B the problemn is tyat when i triwed that i got no audio period
I understand what you mean by 4 channel system but it is actually 2 stereo outputs. All you really need is the A output. The B just gravy. It was the forerunner of surround sound. You could put 2 speakers in front of you and 2 behind you and get a nice effect but it wasn't really surround sound. You don't need the subwoofer if you've got large speakers in your enclosures. The subwoofer thing came along when bookshelf speakers were being used and there was no bottom end. Since Bass is not very directional, they just used one amplified speaker enclosure. Personally, I'm not a fan of subwoofers and bookshelf size speakers. I do like true surround sound as long as there is no subwoofer. With surround and a subwoofer, the sound can slowly circle all the way around you but the Bass will always come from one spot. With 4 large speakers everything can slowly circle around you and you'll get a true surround sound.
You can't run an amplified subwoofer from the B output. You will overload the subwoofer's amplifier and blow it up. You should be able to feed an amplified subwoofer using the signal from the tape recorder output left and right jacks. If the subwoofer has left and right inputs.
fastcar123 (author)  pkveazey5 years ago
It sounds like I need to switch my speakers back to the A channel rather than running on B. I ditched channels to see if it would fix a problem I have with it now that makes the left speaker cut out or reduce volume drasticly. That didn't work but I never got around to switching it back, even though it's only been this way for a day or two

My external sub woofer has RCAs for input so I will use that. The speakers I am using have a 1.5" tweeter, 6" mid range, and 6" sub-mid so they are specifically built to have little bass response, which is why need a subwoofer
OK, I'm getting a bit confused, but you might have found the reason your Dad's friend threw it out. If you are feeling froggy, try opening up the enclosure and tighten every screw on the circuit boards. You might be losing your ground connection and that may be why the volume drops or cuts out. I have also used a wooden stick to tap on the electronic components while music is playing, just to see if something that is loose needs to be re-soldered. Don't touch anything with your fingers. You might also try hooking up your speakers to the B side and see if the volume problem is also on that side. If the problem is on both sides, your pretty much out of luck. If it only occurs on the A side, then just don't use that side.

Just remember, if you are going to try to use the Subwoofer, do not hook it up to the A or B speaker outputs. Hook it up to the RECORD OUT or LINE OUT. As best I remember, it definitely has a RECORD OUT. I'm not sure about it having a LINE OUT.
fastcar123 (author)  pkveazey5 years ago
It may be a ground issue. If I push the A and B channels repeatedly on and off or if I power it off then back on it will work fine for a while. I'll go in and re tighten the screws for the mother board and the screws for the case ground.

And yes the RX212does have a tape out put that would be perfect to use for the subwoofer
Glad I could help. I'm going to add a picture of mine. I run mine on my computer because I do a lot of music recording and its great for playback. Ain't that a stack?
fastcar123 (author)  pkveazey5 years ago
thats exactly what i se my system for. id love to see yours
OK, I'm going to try to send the picture again but I don't hold out much hope since it didn't send last time. The enclosures stand 6-1/2 feet tall. and they are located left and right of my desk. I hope the picture uploads for you.
What is the rating of your tweeters + 2 speakers + sub combined ?
( i mean rated )
fastcar123 (author)  Thereyouhaveit7 years ago
the 2 tweeters and 4 speakers total each have a rating of 8 ohms the subwoofer has no rating written on it because its self contained and external from a system all together
If your amp has a limit of 8 ohms on each line , that's fine .

Your amp should have a LPF for the tweeter line ,
HPF for the subbie .

Try getting a info on your subbie .
fastcar123 (author)  Thereyouhaveit7 years ago
actually its a bit older so it has no tweeter line or sub line
frollard7 years ago
If the sub is powered, you can't really hurt the amp by feeding the sub the same signal -- somewhere on the back will be audio 'monitor out' -- if you dont have a subwoofer out it should do. if its 120v 120W 170VA then its 120 total watts.
fastcar123 (author)  frollard7 years ago
so your saying that the amp wont be at risk and no problems will come if I connect the sub right into the same place my speakers are plugged into
NO!!! I'm saying feed the amp and the sub the same signal. Never feed a sub's signal level inputs with amplified 'speaker' level power.
fastcar123 (author)  frollard7 years ago
it has a terminal plate for that so it can use high voltage un less im mistakin so if that not how i do it then what is?
The terminal block might be for amplified out -- I have 2 powered subs and both take signal in, and spit out a) sound/bass, and b) amplified l/r channels.
fastcar123 (author)  frollard7 years ago
so what do you recomend
What EXACTLY does it say, better yet, can you attach a picture? Feed the SOURCE signal to the rca jacks.
fastcar123 (author)  frollard7 years ago
so i just need a splitter for RCAs right?
fastcar123 (author)  frollard7 years ago
i have 2 subs on that is used with a set of computer speakers that have a crossover and i have a sub that is seperat from anything else they both have a power souce in them they both have a volume control the stand alone sub has a frequency control on it but it gets hot the other one doesnt have a frequency control but it stay fairly cool which one is the right one
The 120 watts is total power used and isn't related to the power of the amp. 120 volts x 120 watts is 168 va. (Unless I did the calc. wrong.)
volt-amps are watts in the simplest sense, they just account for the power factor that many inductive devices tend to have.
fastcar123 (author)  Re-design7 years ago
actually 120V 120W 60Hz 170VA is exactly what its says on the back of the receiver i really only know what volts are the other stuff i really dont know so how do i figure the power of the amp
Re-design7 years ago
I found the manual here, and you can get a copy there for free.

According to the manual your amp is 110 watts per chan. into 6 ohms.  So it should be able to drive most any speaker you put on it as long as it 6-8 ohms.

Now you just need to make sure you don't overpower your speakers.
fastcar123 (author)  Re-design7 years ago
6 ohms it says 8 ohms back there thats odd hmmmmmmmm but it would definaltly work with no damage to the speakers or amp
Well, didn't know the receivers would be that different with similar numbers.

After going thru 20 pages of links I only found two usable references.  One in a review said the 212 didn't power speakers that need 30 watts very well, and a very short review on one for sale said 40 watts but didn't spec. if that was total of per channel.  I would assume it was total just so I wasn't disappointed.

They spec 6 ohms probably because they came with speakers as a set and they designed the speakers that way.
fastcar123 (author)  Re-design7 years ago
ok i was reading around and i found that my particular model was about 15 years old so it will be michharder to findi will post a pic if i can find one
fastcar123 (author)  Re-design7 years ago
umm that close to my model but not exactly the same so i wil just trust the amp runs at 110 watts per chann
Re-design7 years ago
More likely that's how much power it consumes. There may be more info somewhere else. What is the brand and model number?
fastcar123 (author)  Re-design7 years ago
it is a JVC RX-212 it is more of an older model so it may hard to find any info on it