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Maximum allowed impedance for Yamaha receiver.

Wharfedale Diamond 11.1 & 11.2 Speakers

jaudere

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Hello friends,

I am using Yamaha RX V 361 AVR as my amplifier. it says it will accept a speaker of minimum 6 ohms. it does not state what maximum is allowed . i talked with a dealer and he said upto 16 ohm is allowed. is that true?

why i am asking this is because i am in process of designing a 3 way open baffle speaker. my full range is 8 ohms and tweeter is 4 ohms, if i don't get a good sub (12") for 4 ohms, i will have to use 8 ohm subwoofer. with this combo in parallel, the impedance will rise to 13 ohms. :sad:

now i don't know what this 13 ohm can do to the amp. is it good/bad/indifferent? if good, why commonly used speakers are 8ohm? if bad, then in what way? will it do anything more than reducing sound output.

i have heard that more the impedance , easier it is for the amp. but what's the upper limit?
 

spirovious

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My Onk receiver can be paired upto 8 ohms.
read manual & check whats with Yam.
 

venkatcr

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The Yamaha 863 manual says

'If you use two sets (A and B), the impedance of each speaker must be 16 ? or
higher.'

I am assuming that using speakers with impedance of UPTO 16 ? will be safe with Yamaha amplifies. Unless you have specific information do not load the amp with speakers with impedance beyond that.

Cheers
 

arunlouie

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Apology for asking this question here.

What is the difference in using different impedance speakers (apart from the power it needed. Lower the impedance need more power to drive)?

In performance what will be the difference?
 

anm

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my GUESS - inefficient (not necessarily bad) designs keep impedance low as a design strategy to pull more power out from the same amps. But this stresses the amp more than what they would face with a higher impedance speaker. If an amp is designed/ tested for lower impedance loads, then it should be fine to suck out as much power as you can from it. Otherwise if components inside amps are such that they assume higher impedance, the amp may melt in long run with lower impedance speakers.

This is just a guess - don't take my word on it. More engineers on this forum can confirm/ deny/ correct.
 

odyssey

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P=(V^2)/R

An amp will deliver half the power at twice the impedance, as the maximum voltage swing of an amp is usually fixed at a certain value depending on its internal supply voltage.

Most speakers are 8/6/4 ohms nowadays, though the number is not as straightforward as it sounds. There are dips and peaks, but for the purpose of this thread, it is exceedingly difficult to get speakers above 8 ohms in any case.

Most receivers and amps struggle with low impedance loads, so that is the number to worry about. Cheap equipment has severe problems with low impedance loads as they require more current, and cheaper amps have problems with such loads. My receiver cannot drive my Dynaudio monitors, shutting down at any decent volume level due to the current protection kicking in.

You are using a receiver :D
whats the world coming to? ;)
 

Asit

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Hi cranky and sridhar,

The Leben integrateds have 4/6/8 Ohm taps for use with speakers of different impedances. Now I have read a forum discussion where somebody is wondering what to do because his speakers have 16 Ohm impedance and somebody ultimately suggested that on request Leben would make the map also with 16 Ohm tap. I guess the thread initiator is asking a similar question.

Now if the larger impedance would not matter at all ( and I would tend to agree completely with the sentiment that with speaker impedance increasing it should be easier for the amp to drive because the power needed is less according to the formula above), then what these guys are talking about? Are they talking about something they should not be worried about?

Unfortunately, that link is (hopefully) stored on my laptop which I have not brought to office today.

Cranky, are you referring to one of your chipamps (perhaps in combination with a tuner) as a reciever? Well in old days (before the advent of AV receiver or AVR) receivers meant a 2-channel object (=amp+tuner).
 

odyssey

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Hi Asit
For output transformer based tube amplifiers (which the Leben is), if there is a speaker that has a 16 ohm impedance (compared to an 8ohm in turn compared to a 4 ohm) the low freq bandwidth should be better from the higher tap of the output transformer than from the lower tap (assuming the tap and the Z of the speaker matches). Your overall distortion should also be better. one has to make sure that the tap matches the speaker impedance as much as possible. speakers with 16 ohms are really uncommon nowadays. If you use a lower tap it should give more current but I dont believe the transformer (or the tubes) will see the appropriate load and may even result in some distortion.
High Z speakers work very well for "voltage amplifier" based amps (read tubes) vs current amplifiers (read solid states)...

cheers
 

spirovious

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The Yamaha 863 manual says

'If you use two sets (A and B), the impedance of each speaker must be 16 ? or
higher.'

I am assuming that using speakers with impedance of UPTO 16 ? will be safe with Yamaha amplifies. Unless you have specific information do not load the amp with speakers with impedance beyond that.

Cheers

As per the words,if you use A & B at a time then imp can be 16each?
or the language wld have been like- imp upto 16ohm or higher(as you said)

My Onk330 says use spk with 8 to 16ohm only unlike other ONK AVR.
 

udaji

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A higher impedance than 16 ohm will never damage the amp. At worst it may degrade distortion specification slightly. The OP mentioned he is planning to have speakers in parallel. A parallel combination will LOWER the impedance, not increase. Impedance lower than the specified 6 ohms can lead to amp damage (although most amps will have current-limit protection) due to heating of output stages, so be careful about having several drivers in parallel.
 

jaudere

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thanks you very much guys,

what i am planning is 8-4-4 in parallel to get 8ohm resistance

or 8-8-2 to get 7ohm. in the original post it was 8-8-4 giving 13 ohms.

in any case, i have come to conclusion that 13 ohm is acceptable and won't damage ampl.

i am not going to use any cross over.
will allow the woofer to naturally roll off beyond given frequencies, midrange is philips full range so no need of cross over and the third driver will be a 2 or 3 way car speaker. planning to use car speaker for 2 reasons,
1) it has built in cross over so i don't have to scratch my head for cross over.
2) high frequency response is likely to be better than that of a full range
driver due to presence of a tweeter.
 

jaudere

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A higher impedance than 16 ohm will never damage the amp. At worst it may degrade distortion specification slightly. The OP mentioned he is planning to have speakers in parallel. A parallel combination will LOWER the impedance, not increase. Impedance lower than the specified 6 ohms can lead to amp damage (although most amps will have current-limit protection) due to heating of output stages, so be careful about having several drivers in parallel.


wow! thanks a lot for that post. due to this post i went back to calculate the resistance and found that i was goofing up big time.:eek::eek:

but i think this is a pardonable mistake for a doctor who has not touched maths beyond addition and subtraction for 14 years. :D after all tha's why i depend so much on the forum
 

jaudere

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hello,

my yamaha amp(AVR) is easily taking 16 ohm load. that solves my problem.
 
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