Two receivers one speaker each?

[swechsler]

Not sure what kind of speakers you have, but you could look into bi amping. One receiver would drive the woofers, another the tweeters. You would need a crossover though.

This receiver lacks preamp out/power amp in connections, so this would be impractical to do. Even passive biamping would be difficult without some way of tying the volume controls together.

 

[swechsler]

Not many hifi amps have bridge mode capability.

And even fewer receivers have it.

 

[StimpyWan]

Would this be similar to running mono-block amps? Would the OP enjoy the same benefits that mono amps provide? Channel isolation, with better stereo separation. Plus, as mentioned, since both amps channels aren't being stressed, distortion should be lower too. With better current delivery capability. So, while the gains wouldn't be huge, theoretically sound quality could improve.

Now, do the receivers in question, require a load on both channels, for normal operation? Any chance of damaging anything by not utilizing both channels?

 

[MushroomHunt]

OP, here. It’s not necessarily that I want to listen louder. I do have a higher power amp that I’ve used with these speakers in the past..I find, with more power, even at the same decibels I can notice the dynamics more and it just sounds better...I’m not a Pro, but I am a musician with a decent ear. Am I imagining this? Anyway, I was gonna trade one of the receivers, but then I got thinking, that I might be able to get creative so I could own a system w/ more power. Thanks for all the replies and suggestions.

 

[MushroomHunt]

If you need more power - assumedly so that you can drive your speakers louder - get a different receiver (or integrated amp, or preamp+power amp), OR, get more sensitive speakers.

And keep in mind that it takes twice as much power to get a 3dB increase in loudness (3dB is generally defined as the smallest change in volume to be clearly noticeable...a 10dB change = twice as loud, and requires 8 times as much power).

Your 680, like any stereo amp, has two amps - one for the right channel, and one for the left. In the 680 (and most receivers), the power supply for the amps is shared. Each of these amps is rated to be able to deliver 30 watts of continuous output into an 8 ohm load.

Whether you use two receivers or one, the power available for each speaker is therefore the same....30 watts, assuming 8 ohm speakers (slightly higher with lower impedance speakers).

While true that by using two receivers the common power supply is not shared, this will not provide an appreciable difference in output.

 

[bowtie427ss]

So, while the gains wouldn't be huge, theoretically sound quality could improve.

The cruxt of the issue is that while measurable with highly resolving test equipment in a laboratory setting, the differences with the subject gear at hand are likely to remain well below the threshold of audibility, or at least marginal to the degree that they don't warrant the cost/effort of the exercise.

 

[MushroomHunt]

If you need more power - assumedly so that you can drive your speakers louder - get a different receiver (or integrated amp, or preamp+power amp), OR, get more sensitive speakers.

And keep in mind that it takes twice as much power to get a 3dB increase in loudness (3dB is generally defined as the smallest change in volume to be clearly noticeable...a 10dB change = twice as loud, and requires 8 times as much power).

Your 680, like any stereo amp, has two amps - one for the right channel, and one for the left. In the 680 (and most receivers), the power supply for the amps is shared. Each of these amps is rated to be able to deliver 30 watts of continuous output into an 8 ohm load.

Whether you use two receivers or one, the power available for each speaker is therefore the same....30 watts, assuming 8 ohm speakers (slightly higher with lower impedance speakers).

While true that by using two receivers the common power supply is not shared, this will not provide an appreciable difference in output.

Thanks, this

An amplifier's ability to drive power into a load is determined by the available voltage swing (provided it can also supply the necessary current to meet that swing). P=V^2/R

The amplifier power supply is at a fixed voltage (except in some esoteric classes of amplifier). The amplifier can only swing the output within the range of its power supply.

A stereo amplifier has two amplifier circuits, one for left, one for right. Both swing the output within the range of the power supply. An amp rated for a given power can drive both channels with that power; the power supply is capable of providing current to do that.

If you don't use one channel, the power supply voltage is still the same. The amplifier cannot swing the output any further. It cannot drive any more power into the single load. The only change is that you don't take as much current from the power supply.

The only way to increase the output power with the same power supply is to use the two channels in bridge mode, where the input to one channel is the inverse of the signal fed to the other channel, and the speaker is connected across the outputs of the two amplifier channels. This doubles the effective swing seen across the load.

Not many hifi amps have bridge mode capability.

thanks this is useful

 

[StimpyWan]

In audio mastering, I've made level changes to a section of a song, as small as 0.1dB. This to adjust level balance within the song, and as compared to the other songs on the project. While subtle, it was audible to my client, and myself. While not the same as a 3dB change in amp power, it still applies. Subtle can be obvious. Otherwise, why do we do this?

 

[spark1]

OP, here. It’s not necessarily that I want to listen louder. I do have a higher power amp that I’ve used with these speakers in the past..I find, with more power, even at the same decibels I can notice the dynamics more and it just sounds better...I’m not a Pro, but I am a musician with a decent ear. Am I imagining this? Anyway, I was gonna trade one of the receivers, but then I got thinking, that I might be able to get creative so I could own a system w/ more power. Thanks for all the replies and suggestions.

At the same loudness, with the same speakers, your 30 watt amp is delivering precisely the same power a 1000 watt amp would be, assuming it is not clipping.

If the more powerful amp sounded better, it is because either a) it is a better amp or b) it was not clipping (or was clipping less). Or both.

Unless you are running speakers of high sensitivity, it is pretty easy to push a 30 watt amp into clipping (with accompanying distortion of the signal).

 

[cpt_paranoia]

In audio mastering, I've made level changes to a section of a

That's relative level. We can do relative level. It's absolute level we're not good at judging.

 

[quiet]

Can each receiver be set to mono and the L and R be joined from that receiver and be sent to one speaker? And the same with the other receiver for the other channel?

No.

Or more accurately, yes, if he wants to create a high likelihood of damage to his receivers.

In addition, this arrangement would not provide stereo output (for the few moments before one or both amps melt down). It would be mono.

I have a pair of Lafayette LR 1500ta receivers. I'm gonna give it a go and see if the smoke comes out.
The only remarkable thing about these receivers is the amp protection system.

Please report back with your findings.

OK, preliminary results, no smoke.
I used a Toshiba SA-620 set to mono. I split the R channel source from computer into the L/R aux input of the 620. Then connected both of the 620 L/R channels speaker A outputs to one speaker.
It does play louder than one speaker channel out connected to one speaker. Same SQ, maybe.
But the balance "must" be centered "and" both L/R aux inputs "must" be connected from the R channel splitter from the computer out. Or the protection relay does it's job.
It was not necessary to center the balance to avoid the protection on FM. Just more volume when centered. Same SQ, maybe.
Ran test for 1 hour. I'm confident the 620 has now passed the abuse test.

 

[spark1]

I stand (sit) corrected.

OP can apparently turn his rwo SX680s into a pair of 60 watt mono amps.

I assume care would need to be taken with speaker impedance. Seems like the current draw when "bridged" would be double...so 8 ohm speakers, for example, would draw as much current as 4 ohm speakers in normal configuration (not bridged). Maybe not?

Personally, I would not do it....but what do i know? Apparently not much

 

[quiet]

I see all kinds of problems.
I wouldn't do it. Not without knowing how to go inside the receivers and make any needed changes.
I think the impedance to each channel was 4 ohms. The Realistic Nova 8 speaker is 8.
The 50 watt sacrificial 620 was clearly not happy.

 

[62caddy]

OP, here. It’s not necessarily that I want to listen louder. I do have a higher power amp that I’ve used with these speakers in the past..I find, with more power, even at the same decibels I can notice the dynamics more and it just sounds better...I’m not a Pro, but I am a musician with a decent ear. Am I imagining this?

Probably.

The speakers have no way of knowing, nor will they perform any differently whether x volts are being supplied by a given amplifier or another that is much larger (all else equal). All that matters is the amplifier is not being overdriven.

It is common fallacy that amplifier A can perform better than B by simple virtue of one having greater output capability than the other (assuming each is driven within its operational limits). Note emphasis on capability - which is not the same as actual usage.

 

[E-Stat]

What about the main power supply. Would it not be taxed less?

Yes, but I doubt going from 16 to 32 joules would have much effect on its dynamics.

 

[Sam08861]

This receiver lacks preamp out/power amp in connections, so this would be impractical to do. Even passive biamping would be difficult without some way of tying the volume controls together.

Yes, a preamp or source selector w/volume control into the crossover would be required. The volumes could then be balanced 'set and forgot' on the two receivers.

Other complexities would be remembering to turn on the pre/crossover first before the receivers and shutting off the amps (in this case receivers) before the pre/crossover.

 

[cpt_paranoia]

It does play louder than one speaker channel out connected to one speaker.

I am surprised. Neither channel is able to increase its output voltage swing (parallelling does not change the power supply voltage). Therefore, it should not be possible for the volume to increase, unless each channel on its own is incapable of driving adequate current into the load (i.e. your speakers are too low impedance for the amp).

In general, parallelling of amplifiers is a bad idea, because any small variation in channel gain between the channels (due to manufacturing tolerances) will cause one amp to drive into the other amp; they fight for control of the common connection.

 

[quiet]

Definite increase in volume. That much was obvious. But maybe no more than running one speaker on each channel both channels driven.

It was very sensitive to the balance control.

The test was a total smokeless fail.

 

[spark1]

Definite increase in volume. That much was obvious. But maybe no more than running one speaker on each channel both channels driven.

It was very sensitive to the balance control.

The test was a total smokeless fail.

Increase vs what?

 

[quiet]

One receiver L "and" R channel "bridged?" into one speaker was much louder than L "or" R channel into one speaker. All at full volume. Indicating two receivers with only two speakers would be louder than one receiver with two speakers. Till she blows. And I think that was the OP's speculation. But would it be louder than one receiver with four speakers?

In any case there would be no reason to do it with 30 watt receivers because 60 watt receivers are very affordable. If a person had a pair of 80 watt receivers handy the game may change, because 160 watt receivers aren't free. But then the integrated units look like the best buy for that.

Maybe someone else will offer up a lamb and give it a go. As stated in post #37, the 620 was fitting itself if not balanced.

If I'm still not clear just hit me again.