lovinthehd

lovinthehd

Seriously, I have no life.
To be any good speakers pretty much have to be 4 ohms, unless they are small bookshelves. The reason is the BSC compensation. If the speaker is passive then the BSC compensation drives the impedance down in the power range. In a passive speaker the only way to get more power out of the amp in that range is to drop the impedance. There is no other way of doing it, unless we are going to make 16 ohm drivers again. Then the amps would be voltage limited in the upper range instead. That would also have the effect of lowering the sensitivity spec, which the marketers would not tolerate.

Since 16 ohm drivers are a thing of the past, all my speaker designs are effectively four ohms. In addition four ohms really is the sweet spot for the load of a properly designed amplifier. So yes, an amplifier not comfortable with a four ohm load, in my opinion is not fit for purpose.

Hopefully the system in question will work for awhile as the owners are comfortable not blasting it. Within those limits it does not get over hot and sounds good. Start to push it and its another story. If it becomes a problem for them, we will just add more power for the front three. Really good speakers are everything, and it is ridiculous to have power amplification in receivers limit your choice of speakers.
Hmmm that so about 4 ohm? Why particularly? Seems a silly range to design for, especially nominal ratings. Even many consumerl amps aren't all that great below 4 ohm. Buying an avr with low impedance speakers in mind seems sillier....
 
Gmoney

Gmoney

Audioholic Samurai
You guys still up? TLSGUY, LTHD, When was the last time a AVR or amp made in the USA? I’m old 61 but maybe not old enough to remember.

Oh wait you two are on Pacific time I’m Central standard time.
 
langbecker

langbecker

Audioholic Intern
Hmmm that so about 4 ohm? Why particularly? Seems a silly range to design for, especially nominal ratings. Even many consumerl amps aren't all that great below 4 ohm. Buying an avr with low impedance speakers in mind seems sillier....
I think it's silly that manufacturers design something and say can push 4ohm but then when you try to do it,it overheats.

Sent from my SM-N960U using Tapatalk
 
langbecker

langbecker

Audioholic Intern
To be any good speakers pretty much have to be 4 ohms, unless they are small bookshelves. The reason is the BSC compensation. If the speaker is passive then the BSC compensation drives the impedance down in the power range. In a passive speaker the only way to get more power out of the amp in that range is to drop the impedance. There is no other way of doing it, unless we are going to make 16 ohm drivers again. Then the amps would be voltage limited in the upper range instead. That would also have the effect of lowering the sensitivity spec, which the marketers would not tolerate.

Since 16 ohm drivers are a thing of the past, all my speaker designs are effectively four ohms. In addition four ohms really is the sweet spot for the load of a properly designed amplifier. So yes, an amplifier not comfortable with a four ohm load, in my opinion is not fit for purpose.

Hopefully the system in question will work for awhile as the owners are comfortable not blasting it. Within those limits it does not get over hot and sounds good. Start to push it and its another story. If it becomes a problem for them, we will just add more power for the front three. Really good speakers are everything, and it is ridiculous to have power amplification in receivers limit your choice of speakers.
It's funny you should say that I actually have 2 emotiva t2+ Arriving today quite afraid to even run them on my AVR due to the fact of all the horror stories I've been hearing about 4ohm on marrantz.

Sent from my SM-N960U using Tapatalk
 
TLS Guy

TLS Guy

Audioholic Slumlord
Hmmm that so about 4 ohm? Why particularly? Seems a silly range to design for, especially nominal ratings. Even many consumerl amps aren't all that great below 4 ohm. Buying an avr with low impedance speakers in mind seems sillier....failure problem.
We have been over this before. This is the issue, to really produce the output required in that all important 80 to 400 Hz range requires a drop in impedance unless the speaker is active. That is just the way it is. There is no way round it.

So here is the problem. If you drop impedance, then you will have higher current and more heating in the output device. And don't forget that the heat increase is not linear, but goes up by the square of the current. So why not increase the impedance? That means increasing the voltage and so the impedance then becomes higher above the half space/full space transition. That means the voltage has to increase. And again it is all against us. The voltage again has to increase by its square. Now modern output devices especially, have thinner semiconductor layers. This improves performance. However it makes them more vulnerable to the voltage punching holes through the semiconductor layers resulting in output device failure. It is far easier to deal with the heat problem, than the voltage failure problem. So actually 4 ohms below the transition frequency does turn out to be optimal and not eight. So the sweet spot is in that four to six ohm range for a speakers impedance. Now of course the speakers impedance is varying with frequency. That means a speaker manufacturer can quote any impedance he feels like. 90% are fiction, may be more. The only impedance that matters is the impedance across the power band. For most speakers that is four ohms and not eight. Unfortunately for most speakers the impedance rating is totally dishonest, or their are no third party measurements available. You will do not wrong however assuming any speaker with more than one bass, or bass/mid driver is actually a four ohm speaker no matter what 'nominal' impedance is claimed. The latter being totally meaningless.

So this really stacks the deck against the poor receiver. One power supply trying to drive multiple power amps in a small case. So current is limited, the output devices are too small and vulnerable the heating from high current and also vulnerable to excess failure from higher voltage.

The receiver really is a very bad concept from and engineering point of view.

Peter Walker of Quad who was a great mentor to me understood this instinctively. He was absolutely obsessed that his products have long life and very, very low failure rates. Despite his marketers begging for a receiver in the line up, he always refused, and that was when there were only two channels!

Probably 90% of his production is still in use. Old Quad units going back 50 years or more are easy to find in eBay. They continue to command prices above their original purchase price. I note in these difficult times the prices for those old units are actually increasing as people run for safety so to speak.

Now do you wonder why there are so many receiver failures and that they are not as group known for longevity?

There is an escape route, that is going away from class AB and going class D. However making them robust and reliable is not inexpensive. You also have the potential for RF radiation to high gain circuits and increased noise. But really getting the power amps out of the "receiver" really is the best solution.



Now if you understand this you come to understand why a receiver is a really, really bad concept. As you add channels it gets worse.
 
P

PENG

Audioholic Slumlord
You guys still up? TLSGUY, LTHD, When was the last time a AVR or amp made in the USA? I’m old 61 but maybe not old enough to remember.

Oh wait you two are on Pacific time I’m Central standard time.
I think it is his wishful thinking. China, Vietnam, Taiwan, like Japan 40 years ago has to go through their learning curves. It won't be long before they can produce reliable electronic gear like the USA and Switzerland did, or will do in the future. They could land on the moon too so they could do if they want to.. As the moment, I would actually trust electronic gear that are made in Japan a little more than I would trust those made in the USA, obviously TLSG thinks otherwise.:D My old Admiral and RCA TV sets didn't seem to be more reliable than my Toshiba and Mitsibishi either. My made in Japan Marantz preamp and power amp are still working after close to 40 years.
 
Gmoney

Gmoney

Audioholic Samurai
I think it is his wishful thinking. China, Vietnam, Taiwan, like Japan 40 years ago has to go through their learning curves. It won't be long before they can produce reliable electronic gear like the USA and Switzerland did, or will do in the future. They could land on the moon too so they could do if they want to.. As the moment, I would actually trust electronic gear that are made in Japan a little more than I would trust those made in the USA, obviously TLSG thinks otherwise.:D My old Admiral and RCA TV sets didn't seem to be more reliable than my Toshiba and Mitsibishi either. My made in Japan Marantz preamp and power amp are still working after close to 40 years.
PENG, the last TV I had I believe was made in the USA was a Magnavox. 25” color all wood cabinet it had a Ping-pong game built into it. It went out in less than 3 months. The Family owned store I got it from was also the repair guy he came out to my home in the early 80’s to replace a Resistor that went out. Never had a issue with it for years after that.
 
P

PENG

Audioholic Slumlord
PENG, the last TV I had I believe was made in the USA was a Magnavox. 25” color all wood cabinet it had a Ping-pong game built into it. It went out in less than 3 months. The Family owned store I got it from was also the repair guy he came out to my home in the early 80’s to replace a Resistor that went out. Never had a issue with it for years after that.
Yeah, the thing is, I do feel proud and good of buying Canadian products and that's the main reason why I bought my Bryston and Anthem amps. I also think in order to compete well we have to recognize the strength of competitors, not just their weakness. Many of the top rated external DACs measured at ASR were made in China, just case in point.
 
Gmoney

Gmoney

Audioholic Samurai
Yeah, the thing is, I do feel proud and good of buying Canadian products and that's the main reason why I bought my Bryston and Anthem amps. I also think in order to compete well we have to recognize the strength of competitors, not just their weakness. Many of the top rated external DACs measured at ASR were made in China, just case in point.
Interesting, them ESS Saber DAC Pro chips that Yamaha uses in the flagship line come from China?
 
AVUser001

AVUser001

Full Audioholic
My 2 cents , we're not going to survive , by alienating countries as a whole. Lots of breakdowns everywhere , misplaced priorities and spending.. multi-billion$$$ spending on some things globally.., that could have been spent more wisely on R&D, Healthcare, Education, Infrastructure modernization, Safety & Security etc..

Anyways, from electronics perspective, country of origin shouldnt be a prime factor. If the best product comes from China or Japan or Canada or USA or wherever...,I'll take it , as long as the company stands by its products , not just the limited manufacturer warranty, but beyond that as well .., product itself is reliable( Engg design, build quality, QA) , committed customer service and has local dealers who'd actually service you.

Few of my recent purchases..., MiniDSP SHD from China , Bryston 4B Power Amp from Canada - 20yr warranty , Focal Electra from France ...
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Yeah, it doesn't matter where things are made as long as they have top Quality, Reliability, and Support.

Yamaha electronics are made in Malaysia. But I would take a Yamaha over other brands - even if they are made in Japan, USA, Canada, or wherever.
 
TLS Guy

TLS Guy

Audioholic Slumlord
I think it is his wishful thinking. China, Vietnam, Taiwan, like Japan 40 years ago has to go through their learning curves. It won't be long before they can produce reliable electronic gear like the USA and Switzerland did, or will do in the future. They could land on the moon too so they could do if they want to.. As the moment, I would actually trust electronic gear that are made in Japan a little more than I would trust those made in the USA, obviously TLSG thinks otherwise.:D My old Admiral and RCA TV sets didn't seem to be more reliable than my Toshiba and Mitsibishi either. My made in Japan Marantz preamp and power amp are still working after close to 40 years.
I agree we have lost high tech manufacturing capability. We have to get it back. It is a matter of national security. This national security issue is becoming left right and center in the UK.

I hope to post on this later as it applies to the Covid 19 pandemic.

The UK just received 3.5 million test kits from China all of them dud. They are demanding a refund, and have cancelled an order for 17.5 million more.

The Dutch have also reported receiving a bunch of dud test kits from China. Unlike the UK they did not validate them and this has caused the Dutch to now loose the good control of the outbreak they had.

Good news is that Porton Down say they may well have an answer to this by mid fall. Usually everything there is top secret but the UK have allowed limited information out to the press. News is breaking now that intelligence services have known about this virus since November. Apparently fever pitch work has been going on to understand this virus at the top secret biological and Chemical warfare unit at Porton Down for at four to five months. Questions are now being asked about the origin of this virus in high places. I will post more about that later.

The point is that we can absolutely not trust a country with a President for life and an unelected Politburo! That is an absolute bottom line going forward no matter how good their electronics might be.
 
lovinthehd

lovinthehd

Seriously, I have no life.
You guys still up? TLSGUY, LTHD, When was the last time a AVR or amp made in the USA? I’m old 61 but maybe not old enough to remember.

Oh wait you two are on Pacific time I’m Central standard time.
Did McIntosh ever make an avr? Can't think of anyone else that might have. 2ch receivers, some. I'm west coast, TLS is in Minnesota.

I think it's silly that manufacturers design something and say can push 4ohm but then when you try to do it,it overheats.

Sent from my SM-N960U using Tapatalk
Did it overheat or run very warm? What temperature was it? OTOH Marantz didn't actually rate it at 4 ohm either.
 
lovinthehd

lovinthehd

Seriously, I have no life.
We have been over this before. This is the issue, to really produce the output required in that all important 80 to 400 Hz range requires a drop in impedance unless the speaker is active. That is just the way it is. There is no way round it.

So here is the problem. If you drop impedance, then you will have higher current and more heating in the output device. And don't forget that the heat increase is not linear, but goes up by the square of the current. So why not increase the impedance? That means increasing the voltage and so the impedance then becomes higher above the half space/full space transition. That means the voltage has to increase. And again it is all against us. The voltage again has to increase by its square. Now modern output devices especially, have thinner semiconductor layers. This improves performance. However it makes them more vulnerable to the voltage punching holes through the semiconductor layers resulting in output device failure. It is far easier to deal with the heat problem, than the voltage failure problem. So actually 4 ohms below the transition frequency does turn out to be optimal and not eight. So the sweet spot is in that four to six ohm range for a speakers impedance. Now of course the speakers impedance is varying with frequency. That means a speaker manufacturer can quote any impedance he feels like. 90% are fiction, may be more. The only impedance that matters is the impedance across the power band. For most speakers that is four ohms and not eight. Unfortunately for most speakers the impedance rating is totally dishonest, or their are no third party measurements available. You will do not wrong however assuming any speaker with more than one bass, or bass/mid driver is actually a four ohm speaker no matter what 'nominal' impedance is claimed. The latter being totally meaningless.

So this really stacks the deck against the poor receiver. One power supply trying to drive multiple power amps in a small case. So current is limited, the output devices are too small and vulnerable the heating from high current and also vulnerable to excess failure from higher voltage.

The receiver really is a very bad concept from and engineering point of view.

Peter Walker of Quad who was a great mentor to me understood this instinctively. He was absolutely obsessed that his products have long life and very, very low failure rates. Despite his marketers begging for a receiver in the line up, he always refused, and that was when there were only two channels!

Probably 90% of his production is still in use. Old Quad units going back 50 years or more are easy to find in eBay. They continue to command prices above their original purchase price. I note in these difficult times the prices for those old units are actually increasing as people run for safety so to speak.

Now do you wonder why there are so many receiver failures and that they are not as group known for longevity?

There is an escape route, that is going away from class AB and going class D. However making them robust and reliable is not inexpensive. You also have the potential for RF radiation to high gain circuits and increased noise. But really getting the power amps out of the "receiver" really is the best solution.



Now if you understand this you come to understand why a receiver is a really, really bad concept. As you add channels it gets worse.
I was asking more about the speakers as to why they tend to be lower impedance....
 
TLS Guy

TLS Guy

Audioholic Slumlord
I was asking more about the speakers as to why they tend to be lower impedance....
Well, I hope I explained it. You absolutely can not consider speakers and power amps in isolation. Technically they are joined at the hip. If electronics was as reliable as Quad, there would be no argument that speakers should be active. That absolutely has overwhelming advantages. The barrier is too much junk electronics, because people don't want to ditch their speakers if an internal speaker amp or crossover fails.

So current output devices work optimally around the 4 to 6 ohm range. Lower impedance requires higher current and therefore more heat is generated. Raising impedance of speakers requires increase voltage which is a worse problem for output devices.

So that fact is that if you want a really good system then I do not know of a current receiver that really fits the bill. That is the way it is.

So in my view if finds are limited a two channel receiver that is easily 4 ohm comfortable is a far, far better solution than a ton of lousy amps from one power supply in one box. A good 2.1 system can get you 95% plus of the loaf, and is far preferable to a poorer multi channel system. I have one of those and it sounds very, very good.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
a two channel receiver that is easily 4 ohm comfortable is a far, far better solution than a ton of lousy amps from one power supply in one box. A good 2.1 system can get you 95% plus of the loaf, and is far preferable to a poorer multi channel system. I have one of those and it sounds very, very good.
Why compare a "Good" 2Ch receiver to a "Lousy" and "Poorer" MCH AVR?

Why not get a good MCH AVR and use it for 2Ch?

For example, the Yamaha RX-A3080 AVR (you can even get used older models for cheaper if funds are limited) can output almost 300W x 2Ch RMS into 4 ohms.

I just sold my Denon AVR-5308CI to someone for $900. It can output about 340W x 2Ch RMS into 4 ohms.

How many 2Ch AVR can output 300W x 2Ch RMS into 4 ohms?
 
P

PENG

Audioholic Slumlord
It's funny you should say that I actually have 2 emotiva t2+ Arriving today quite afraid to even run them on my AVR due to the fact of all the horror stories I've been hearing about 4ohm on marrantz.

Sent from my SM-N960U using Tapatalk
I am not aware of any receiver rated for 4 ohms without some sort of output limiting gadget such as the so called impedance switch. So they are not at fault, the users are more to blame for not reading the owner's manual.

Also, in theory any well designed AVR can drive 4 ohm speakers, you just have to discipline yourself on the volume. For example, your Marantz AVR is rated 100 W into 8 ohms, 2 channels driven simultaneously, so if you use it to drive 4 ohm nominal speakers you should de-rate to 50 W and you will be fine. Practically speaking, that (i.e. self de-rating) is not always necessary if you use it for movies and typical jazz, pops and classical music enjoyment. If you use it for highly compressed music for extended period of time, then you do need to remind yourself that for truly 4 ohm rated speakers, the AVR should be de-rated from 100 W to 50 W.

It is too bad that the audio world went down the road of "watts", instead of voltage and current. That has created so much avoidable confusion and misconception among the less technically informed consumers. Guys like TLSGuy will know exactly why I say that, I think... I hate to say this sort of thing, and I am doing it now only out of frustration.
 
AVUser001

AVUser001

Full Audioholic
It is too bad that the audio world went down the road of "watts", instead of voltage and current. That has created so much avoidable confusion and misconception among the less technically informed consumers. Guys like TLSGuy will know exactly why I say that, I think... I hate to say this sort of thing, and I am doing it now only out of frustration.
Becos
Power in a AC circuit like speaker
P = Vrms * Irms * PowerFactor
where PowerFactor = Cos(Phase angle between Current and Voltage)

Which do you think the consumer is going to easily absorb...a single measure Power in watts or a multiple factors( voltage , current and the phase angle) ;-)

jk , you know what I mean...
 
TLS Guy

TLS Guy

Audioholic Slumlord
I am not aware of any receiver rated for 4 ohms without some sort of output limiting gadget such as the so called impedance switch. So they are not at fault, the users are more to blame for not reading the owner's manual.

Also, in theory any well designed AVR can drive 4 ohm speakers, you just have to discipline yourself on the volume. For example, your Marantz AVR is rated 100 W into 8 ohms, 2 channels driven simultaneously, so if you use it to drive 4 ohm nominal speakers you should de-rate to 50 W and you will be fine. Practically speaking, that (i.e. self de-rating) is not always necessary if you use it for movies and typical jazz, pops and classical music enjoyment. If you use it for highly compressed music for extended period of time, then you do need to remind yourself that for truly 4 ohm rated speakers, the AVR should be de-rated from 100 W to 50 W.

It is too bad that the audio world went down the road of "watts", instead of voltage and current. That has created so much avoidable confusion and misconception among the less technically informed consumers. Guys like TLSGuy will know exactly why I say that, I think... I hate to say this sort of thing, and I am doing it now only out of frustration.
What you say is absolutely true. In retrospect I should have left that receiver at the lower ohm setting. I really have never weighed in on this issue before as it has not really concerned me. But the WRONG advice, at least now, is being given on these forums. We should tell people to downgrade their receivers in pretty much all circumstances, especially with the new crop of receivers. That is true even if a speaker manufacturer says his speakers are 8 ohm. Unless you can find an impedance curve for those speakers or the manufacturer at least quotes a minimum impedance value, then assume your speakers are actually 4 ohm, as they likely are. The best rule of thumb if a minimum impedance is quoted to add 10% and take that as the true impedance.

So the reality is that for the current crop of receivers you have to divide the specified power ratings by a factor of 2. So they are in fact overrated by 100%. Doing that will reduce the chance of your receiver failing significantly.

There is evidence from Quad back to 1969, from the Quad 303 power amp. This was the first solid state amp to be robust with many still in service. So the output stages were tripled and the amp guaranteed stable under all loads. It was honestly specked at 45 watts per channel into 8 ohms, and 22.5 watts per channel into 4 and 16 ohm loads. Peter Walker was not one to dodge difficult issues, or hide them. So its back to 1969 now for the current receiver crop.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Why compare a "Good" 2Ch receiver to a "Lousy" and "Poorer" MCH AVR?

Why not get a good MCH AVR and use it for 2Ch?

For example, the Yamaha RX-A3080 AVR (you can even get used older models for cheaper if funds are limited) can output almost 300W x 2Ch RMS into 4 ohms.

I just sold my Denon AVR-5308CI to someone for $900. It can output about 340W x 2Ch RMS into 4 ohms.

How many 2Ch AVR can output 300W x 2Ch RMS into 4 ohms?
I don't follow the receiver market that closely, but that receiver does have a 4 ohm rating in 2 channel, but 6 ohm in multichannel. However the cost is virtually identical to a pre/pro and a 2 channel power amp of equivalent power. With the latter you have the option to add power amps over time. I suspect that the latter solution would actually prove to be the better option.
 

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