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Would adding more ohm impedance hurt my amp

Last response: in Home Audio
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June 9, 2011 1:15:02 AM

Hello,
i have resently purchased an AV reseiver, (techniques) it is rated at 160 W and 8 ohm impedance. will it damage my amp if i were to connect multiple speakers in series (adding more ohm impedance)
June 9, 2011 4:30:31 AM

a general answer is no.
but for any amplifier, if the impedance is too high.. then there wont be a lot of output, and that leads to people turning the amplifier up higher.

i'm not saying a bunch of 15 watt or 30 watt speakers wont get loud, because it can happen.
but
it probably wont be as loud as what you would get with some speakers able to take 100 watts (single connections)
but
most people dont listen to their speakers that loud anyways, unless they are in a different room.

amp circuits are kinda like an engine and transmission.. if you ask the vehicle to pull a trailer, there is always going to be a weight limit eventually.
where the impedance gets too high for the amp, i wouldnt know.

see.. there is a big difference between functioning and the amp dieing early.
more impedance could mean that the amp will function without clipping at higher volume levels.
but, the extra electricity could shorten the lifespan of the amp by drying up the pieces.
it is a design choice, whether the amp is supposed to live longer for low impedance or high impedance.

maybe there is a general rule about high or low impedances and the lifespan of the product.
and
maybe there isnt a rule.

how much impedance and how many watts the speakers are rated for is the biggest question.
if the impedance is jumping up high, then the speakers need to be rated for much less wattage.
this will give you output without constantly asking the amp to scream at the top of its lungs.
sometimes amps are designed to do that, and they dont sound very good when they dont do it.
in that case, you might have a 'monster' and would be proud that the amp just goes and goes and goes with all of the load you put on it.

that is usually when we feel bad for the sensitive hardware that broke way too quickly because it was used wrong.
sometimes the only way to know is to try.
a repair person might be able to tell you the specifications of each piece, but that doesnt mean there is a 'name-brand' on the piece to help know how long it will last.

it is a question of failing from being used.
heat and the high voltage going through the pieces will or will not cause them to dry up, or 'age' , faster.
again, this is how some stories are made.
if the amp proves to be worthy, then you will have a story about the amp that kept on going at high volume levels.
while you might compare your story with somebody else's story.. and the other person's amp died from the high volume levels.

if the amp is designed right, the extra impedance is only going to weaken the output from the speakers until it is really low.
and any damage would be the same based on the volume level used, and how often the volume level was used.
the higher impedance might prevent clipping, and it might not.. depends on the design.
but
i think if you listen to the amp with 75% volume all of the time.. it isnt going to matter if the speaker load is 8 ohms or 24 ohms.
since the electricity going to the pieces is the same at 75% volume level.
however, if the impedance is higher.. the electricity might not leave the electrical pieces as easily compared to a lower impedance.
and this is the trick that can prevent the amplifier from clipping.. since the electricity stays on the piece for longer, it can stabilize things.
but if the pieces are sensitive, the failure to release immediately could also be what causes the stability to grow worse.
and the extra voltage sticking around for a moment is probably going to cause more heat.
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June 13, 2011 2:27:56 PM

in series, no it won't hurt anything.
in parallel, you can load it with 4 ohms, that's the max.
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June 13, 2011 2:53:17 PM

well know this..
a 4 ohm speaker will drop lower than 4 ohms.
the average is 4 ohms because the impedance goes up and down depending on frequency.

so if you say 4 ohms is the max.. you dont want the 4 ohm speaker going lower and stressing/damaging the amp.

have a look at 'impedance curve' and you will see the line changes from whatever ohm is in the specifications.
a 4 ohm speaker might drop well down to 2 ohms.
and some people would either destroy their amp faster, or cause their protect mode to turn on, or cause their protect mode to grow more and more sensitive until the receiver doesnt want to work with 8 ohm speakers ever again.
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!