Quick Power Amp Question

[ferocity02]

I am looking for something to power my loudspeakers - each one contains a tweeter, mid-range, and 12" sub. They fried my old JVC RX-315 (110W/ch) and I am looking into getting a Sony STR-DE 197 this afternoon. However, this receiver is even smaller than the RX-315 so do I need a power amp of some kind?

Also, do I need a receiver that has AV audio outputs, or will one with the positive/negative channel outputs work too? The Sony has two output channels but I don't know if it has AV outputs. Any help would be appreciated, thanks!

 

[fmw]

I am looking for something to power my loudspeakers - each one contains a tweeter, mid-range, and 12" sub. They fried my old JVC RX-315 (110W/ch) and I am looking into getting a Sony STR-DE 197 this afternoon. However, this receiver is even smaller than the RX-315 so do I need a power amp of some kind?

Probably not but nobody can answer the question intelligently without knowing the efficiency of the speakers, size of the room and your listening habits.

 

[mtrycrafts]

I am looking for something to power my loudspeakers - each one contains a tweeter, mid-range, and 12" sub. They fried my old JVC RX-315 (110W/ch)

Can you expand on this? How and when, what conditions did it fry it under?

 

[ferocity02]

Can you expand on this? How and when, what conditions did it fry it under?

I have a pair of Wharefdale W60E loud speakers. Each one contains a small tweeter, a mid-range speaker, a 12" subwoofer, and a 3-way crossover. They were built a long time ago so I have little specs on them. The original subs in the boxes eventually fell apart, so I rebuilt the boxes and put in JL Audio 12w1v2-8 subwoofers, which I think are JL's low-line subs but they sound amazing. According to JL, the recommended power rating(RMS) for the these is 50W to about 300W, with "optimum" being around 130W.

For the past couple months I've been using an old JVC RX-315 receiver to power the speakers without trouble. The back of the receiver says 220W, and there are four outputs for speakers. I was only using two obviously. The other day I pushed the receiver a little too hard and within a couple seconds the sound flickered/crackled and finally died away. I took it apart and didn't smell or see anything burnt. However there were four resistors that were getting very hot even with just the receiver on and not playing any music. Around these resistors the circuit board was a little darker than normal from the heat. The receiver still turns on and operates as normal except no sound comes out.

The room they are in is 20'x20'x15' roughly. I am not that big into audio, I just need a setup that will handle these speakers reliably. I don't need Dolby surround sound, anything fancy. All I use them for is playing the radio and hooking up an iPod or computer.

If you need any more info at all let me know, thanks so much!

 

[mtrycrafts]

I have a pair of Wharefdale W60E loud speakers. Each one contains a small tweeter, a mid-range speaker, a 12" subwoofer, and a 3-way crossover. They were built a long time ago so I have little specs on them. The original subs in the boxes eventually fell apart, so I rebuilt the boxes and put in JL Audio 12w1v2-8 subwoofers, which I think are JL's low-line subs but they sound amazing. According to JL, the recommended power rating(RMS) for the these is 50W to about 300W, with "optimum" being around 130W.

For the past couple months I've been using an old JVC RX-315 receiver to power the speakers without trouble. The back of the receiver says 220W, and there are four outputs for speakers. I was only using two obviously. The other day I pushed the receiver a little too hard and within a couple seconds the sound flickered/crackled and finally died away. I took it apart and didn't smell or see anything burnt. However there were four resistors that were getting very hot even with just the receiver on and not playing any music. Around these resistors the circuit board was a little darker than normal from the heat. The receiver still turns on and operates as normal except no sound comes out.

The room they are in is 20'x20'x15' roughly. I am not that big into audio, I just need a setup that will handle these speakers reliably. I don't need Dolby surround sound, anything fancy. All I use them for is playing the radio and hooking up an iPod or computer.

If you need any more info at all let me know, thanks so much!

Well, we are getting a little closer understanding what happened.
So, your old 12" drivers broke and replaced them with JL drivers? Perhaps that driver is causing the overheating as it may not be a compatible driver for the old one, even though it sounds great. This could fry another amp, or if you get a more capable amp and drive it hard, the smaller drivers will go up in smoke perhaps?

Have you tried another speaker at low volume with this receiver just in case?

Is there a fuse for the speakers someplace, in receiver or in the speaker?

 

[ferocity02]

Well, we are getting a little closer understanding what happened.
So, your old 12" drivers broke and replaced them with JL drivers? Perhaps that driver is causing the overheating as it may not be a compatible driver for the old one, even though it sounds great. This could fry another amp, or if you get a more capable amp and drive it hard, the smaller drivers will go up in smoke perhaps?

Have you tried another speaker at low volume with this receiver just in case?

Is there a fuse for the speakers someplace, in receiver or in the speaker?

I'm not sure about the compatibility issue. Although I had ran the speakers with the JL subs for months without issues, but the other week I decided to push the receiver a little too hard. I did hook up other speakers to the receiver and nothing comes out. There is only one fuse that's next to the main transformer and it's ship shape. Nothing looks or smells burnt.

Either way, I already bought that Sony receiver and hooked the speakers to it. It sounds great, but I'm not going to push it too far. It's a 190W while the RX-315 was a 220W.

SO guess the next question is... will a power amp work into my plans, or am I going to have to do something else? I know of other guys running loudspeakers bigger than this (4 drivers and a 15" sub for example) without issues, but I don't know how they are doing that.

Thanks again guys.

 

[mtrycrafts]

I'm not sure about the compatibility issue. Although I had ran the speakers with the JL subs for months without issues, but the other week I decided to push the receiver a little too hard. I did hook up other speakers to the receiver and nothing comes out. There is only one fuse that's next to the main transformer and it's ship shape. Nothing looks or smells burnt.

Either way, I already bought that Sony receiver and hooked the speakers to it. It sounds great, but I'm not going to push it too far. It's a 190W while the RX-315 was a 220W.

SO guess the next question is... will a power amp work into my plans, or am I going to have to do something else? I know of other guys running loudspeakers bigger than this (4 drivers and a 15" sub for example) without issues, but I don't know how they are doing that.

Thanks again guys.

The power you stated is not the per channel power capability of that receiver. So, it certainly looks like you exceeded the amps capability thinking that that 300 watt driver will take it. It did, the amp didn't

The size of the speaker doesn't determine the power it can handle or the volume level it will produce but other factors do.

You may be able to connect an external amp but you could be in the same boat as before, trying to over drive it. If the receiver has pre amp outputs, then you can attach those outputs to an external amp input.

If you are after high spl, a cause for concern for hearing loss, you may need to find speakers that are more sensitive and capable of delivering the needed spl then an amp to drive that speaker load.

 

[Highbar]

I don't know a ton about speaker internals and crossovers and all but I wonder if you changed the load of the speaker (read that as Ohms) that the receiver sees. In that case you could have dropped it to the point where you will blow just about any receiver or amp if you turn it up. When modifying speakers it's not as simple as taking out one part and putting in whatever you want. Be careful with the Sony and don't turn it up too loud or my guess is that the same thing is going to happen. An amp may help but I don't think that Sony has preamp outs.

 

[ferocity02]

So, you MUST have pre-amp outputs in order to run a power amp?

I've been powering the loud speakers with the Sony today and it works well. The Sony has a built in protection thing so it should be harder to fry it unintentionally.

 

[mtrycrafts]

So, you MUST have pre-amp outputs in order to run a power amp?

I've been powering the loud speakers with the Sony today and it works well. The Sony has a built in protection thing so it should be harder to fry it unintentionally.

Yes, you do need a pre amp output on a receiver to use the preamp and processor but an external amp as well.

Why not just proceed with that receiver and just watch how loud you play it.
Might retain your hearing to old age

 

[fmw]

Yes, you do need a pre amp output on a receiver to use the preamp and processor but an external amp as well.

Why not just proceed with that receiver and just watch how loud you play it.
Might retain your hearing to old age

In a nutshell, given your speakers and room size you aren't likely to use more than 20 watts per channel even on loud peaks. Your receiver will handle it with power to spare.