A/V Receiver Impedance Selector Switch

[dlaloum]

The Onkyo 876 weighs 24.1 kg not 30 kg. Yes it is still heavy for a 7.1 avr.

Yes you are right .... still more than double the NR7100, or DRX3.4 - and substantially more than the RZ50!

 

[PENG]

Yes you are right .... still more than double the NR7100, or DRX3.4 - and substantially more than the RZ50!

I agree those Onkyo and Integra AVRs are among the heaviest, only heavier by the Yamaha and Denon of the days.

I compiled the following top AVRs of the older days based on their measured output by S&V, you can see that Onkyo and Integra did occupy the top 2 spots based on most (not all) of the measured criteria. You can also see that weight is not always the only indicator to predict output, as the Denon in the 6th spot (I owned that one) weighed a lot less but actually measured higher in the 2 ch output and not far behind in the 5 and 7 channel driven criteria, and at lower THD+N too. That's because while power supply is obviously the key part, the output devices and heat sinks also play an important role.

 

[Trell]

No.

He claimed that "They ALWAYS produce LESS power in the low impedance mode ", but it seems not applying to Yamaha RX-V1070. I believe that RX-V1070 should be able to produce MORE power in lower impedance mode.

You believe?

 

[everettT]

BTW, RX-V1070 weights more than 40lbs with a massive transformer. It handles a pair of 4ohm Altec Lansing speakers easily.

This is really simple, prove your theory by testing it with the proper methodology, it's not hard.

 

[PENG]

I measured more than twice. It make sense to me.
RX-V1070 rated 110wpc / 135wpc (8ohm/6ohm) for front and center channels. Power output higher for 6ohm speakers means the rail voltages for it should be higher.

That's not how the electrical theories work. To see some detailed explanation, please refer to post#76 in which @dlaloum used calculations with numerical examples to make it easier to understand:

A/V Receiver Impedance Selector Switch | Page 4 | Audioholics Home Theater Forums

The funny thing is, you somehow found a diagram that led to believe the 6 ohm setting gives a higher voltage.
I got curious, because that would make no sense at all, so I googled for another Yamaha AVR's service manual and found one for the RX-A3050 and RX-V3079 that have comparable power output rating to the RX-V1070. You can look at another one such as the one for the RX-A3080 and I am sure you will see something similar.

Now take a look:

You will find that there are enough evidence to show/suggest that the diagram you posted had a few typo. So yes, I understand why you were led to believe that the 6 ohm setting gives higher rail voltage, because of the typos in that diagram, when in fact the opposite is true.

 

[richardjhy]

That's not how the electrical theories work. To see some detailed explanation, please refer to post#76 in which @dlaloum used calculations with numerical examples to make it easier to understand:

A/V Receiver Impedance Selector Switch | Page 4 | Audioholics Home Theater Forums

The funny thing is, you somehow found a diagram that led to believe the 6 ohm setting gives a higher voltage.
I got curious, because that would make no sense at all, so I googled for another Yamaha AVR's service manual and found one for the RX-A3050 and RX-V3079 that have comparable power output rating to the RX-V1070. You can look at another one such as the one for the RX-A3080 and I am sure you will see something similar.

Now take a look:

You will find that there are enough evidence to show/suggest that the diagram you posted had a few typo. So yes, I understand why you were led to believe that the 6 ohm setting gives higher rail voltage, because of the typos in that diagram, when in fact the opposite is true.

View attachment 59243

View attachment 59244

You're ridiculous!

I have Yamaha RX-V1070 and measured rail voltages with multimeter for both 6ohm and 8ohm settings and results completely match the schematic diagram. Even more, I compared the circuit boards with the diagram and they match.

Here is the source of RX-V1070 SERVICE MANUAL.

Yamaha RX-V1070 Audio Video Receiver Manual | HiFi Engine

www.hifiengine.com

 

[richardjhy]

Here is my RX-V1070.

 

[gene]

No.

He claimed that "They ALWAYS produce LESS power in the low impedance mode ", but it seems not applying to Yamaha RX-V1070. I believe that RX-V1070 should be able to produce MORE power in lower impedance mode.

Posting an incomplete schematic doesn't prove your point. EVERY Yamaha receiver I've EVER tested produced LESS power with the impedance switch set to 6 ohms or the "lower setting". This is true whether the amp is driving a 8 ohm load or a 4 ohm load.

Yamaha RX-A6A 9.2CH 8K AV Receiver Bench Test Results!

We bench tested the Yamaha RX-A6A 9.2CH 8K 150watt/ch Atmos/DTS:X Receiver to gauge power output and uncover performance issues we discovered. We discuss the proper settings for best power delivery.

www.audioholics.com

Yamaha RX-Z7 7.1 Channel Networking A/V Receiver Review

The Yamaha RX-Z7 offers benchmark performance in virtually every category with all of the latest audio and video processing features, along with a host of multi room and networking capabilities.

www.audioholics.com

The only Yamaha product that wasn't negatively impacted with the low setting for up to 2CH driven is their dedicated 11CH Amp, the MX-A5000 and newer and the old flagships like the RX-Z11. However, I did see a negative impact on power with more than 2CH driven with the impedance switch set to low.

Yamaha AVENTAGE CX-A5000 AV Processor and MX-A5000 Amplifier Review

Review: The Yamaha AVENTAGE CX-A5000 Processor and MX-A5000 11-channel amplifier are for you if you have ever wanted reasonably-priced separates but didn't want to sacrifice features or performance.

www.audioholics.com

You can continue to fetishize the impedance switch if you like but the bottom line is it LIMITS power as it's designed to do so that the product can satisfy heat dissipation requirements to get the 4 ohm UL rating. I not only confirmed this with the product managers but also the design engineers AT Yamaha.

 

[PENG]

richardjhy said:
You're ridiculous!

That seemed ironic for you to say that..

When you said things like the following:

richardjhy said:
RX-V1070 rated 110wpc / 135wpc (8ohm/6ohm) for front and center channels. Power output higher for 6ohm speakers means the rail voltages for it should be higher.

No, it does not always mean that. I am sure you know the basic power formula and should therefore understand power output into 6 ohm will be higher at the same or even slightly lower voltage.

That's why AV receiver manufacturers often provide those impedance selectors to lower the rail voltage (or other methods) to limit the otherwise much increased load current when used with 6 ohm or lower impedance speakers. You said you measured the rail voltages, if they were higher for the 6 ohm selection, then something was not right but I wouldn't want to speculate what could be the causes.

Take a look of another numerical example:

Power = V^2/R (for simplicity, let's use a resistor load for the calculations).

For 8 ohm load, 110 W output:
V = sqrt(P*R)Into an 8 ohm load, Power =110 W, V = sqrt (8*110) = 29.66 V

For 6 ohm load, 135 W output:
V = sqrt (6*135) = 28.46 V, that's lower than that required for the 110 W rated output into 8 ohm, yet the power output is higher, using your RX-V1070's specs for this numerical example.

So please know that higher output into 6 ohm than into 8 ohm does not mean the rail voltage has to be higher, it depends on how much higher.

If you are not going to listen to others points, fine, but there is no need to be rude. We are here to help and/or learn from one another.

Happy holidays!

 

[paveldeg]

I doubt this applies to Denon receivers though - I ran x1700H with KEF Q floor-standers with 8 ohm setting and it sounded miserable, weak bass. All changed once I switched to 4ohm - got deeper bass and punchier sound overall.

 

[isolar8001]

Is it April First already ?
I wish...just skip winter.

 

[paveldeg]

"When using 4 ohm speakers you draw twice the current from the amp. Voltage times ampere are watt and at 4 ohm you will only need half the voltage to produce the same watt as compared to double the voltage using 8 ohm speakers. When the voltage is dropped from the power supply when selecting a 4 ohm setting it has to drop to half voltage to produce the same watt from a 4 ohm speaker as in a 8 ohm setting using 8 ohm speakers, but it is only reduced some 35% so it will be more power available in the 4 ohm setting when using 4 ohm speakers. When using 6 ohm speakers in the 4 ohm setting it will produce the same watt as in 8 ohm setting and 8 ohm speakers.

So in reality the only important thing that change with the speaker impedance setting are how the protection circuit operates."

Denon x3700H Impedance Setting - Different Impedance...

www.avsforum.com

So essentially in Denons switching to 4 ohm stops protection triggering too early, and allows thus producing more power for 4 ohm speakers.

 

[gene]

"When using 4 ohm speakers you draw twice the current from the amp. Voltage times ampere are watt and at 4 ohm you will only need half the voltage to produce the same watt as compared to double the voltage using 8 ohm speakers. When the voltage is dropped from the power supply when selecting a 4 ohm setting it has to drop to half voltage to produce the same watt from a 4 ohm speaker as in a 8 ohm setting using 8 ohm speakers, but it is only reduced some 35% so it will be more power available in the 4 ohm setting when using 4 ohm speakers. When using 6 ohm speakers in the 4 ohm setting it will produce the same watt as in 8 ohm setting and 8 ohm speakers.

So in reality the only important thing that change with the speaker impedance setting are how the protection circuit operates."

Denon x3700H Impedance Setting - Different Impedance...

www.avsforum.com

So essentially in Denons switching to 4 ohm stops protection triggering too early, and allows thus producing more power for 4 ohm speakers.

No, that's essentially wrong. The 4 ohm setting severely limits power and thus current into 4 ohms. The receiver isn't tripping in the low impedance settings bc it never delivers enough power to the load due to limiting it in that setting. You can read every review I've done with measurements on AVRs with the impedance switch to see the results.

I can't believe this is still a topic of debate.

 

[highfigh]

No, that's essentially wrong. The 4 ohm setting severely limits power and thus current into 4 ohms. The receiver isn't tripping in the low impedance settings bc it never delivers enough power to the load due to limiting it in that setting. You can read every review I've done with measurements on AVRs with the impedance switch to see the results.

I can't believe this is still a topic of debate.

This thread is 14 years old- a new indoor record!