What causes amp. to overload?
Wesley
What causes amp. to overload?
I have old Infinity RSIIIA speakers (Emit tweeter, Polydome midrange and 2 x
10" woofers) those speakers are about 15 years old, and are rated 6ohms, my
new AV receiver Yamaha RX-V995 is rated 100W/ch x 5 channel 2-8ohms. And is
set for 6ohms speakers.
The problem is that when I increase volume to about 11 o'clock and the movie
contains loud explosions my amplifier's
protection circuit is switching the amplifier off. It only happens during
very low frequencies such as explosions etc. I have quality optical cables
linking my DVD, CD and amplifier and OFC cabling for the speakers, all
connections are clean and secure. Both speakers sound the same, there is no
sound distortion nor coloration. The protection circuit switches off the
amp. on volumes between 10 and 11 o' clock and as I said only while plying
what I would say very low frequencies.
Is this the amplifier or speakers fault?, as I said those speakers are old
and someone told me that electrolytic capacitors in the crossover could be
faulty. I know there is one large 1,200uF NPE electrolytic capacitor and
40mH coil in the crossover to boost bass.
Any ideas what is causing amp to overload?
Wesley
donald
guru
Regards,
Vlad
<donald @pearce.uk.com (Don Pearce)> wrote in message
news:3a022c7c...@news.cis.dfn.de...
Stig Erik Tangen
The impedance in the low freq area of those speakers is very low, so
your amp might be shutting down because it hits the output current
protection. I've measured some Infinity (Kappa) systems using the same
low frequency boost circuit as these, and they reached down well below 2
ohms. If its possible to run the speakers without the LF boost, this
should help. (or get a Krell amp..)
Stig Erik Tangen
Ergo Esken
the minimum impedance on some frequency could be as low as 3 ohms for
example and if that is the case it is very likely that the overcurrent
protection in your amplifier turns on (turning amplifier off). The setting
on your volume control doesn't mean much as the output voltage of the signal
source could be quite high and 11 o'clock setting already gives you a very
high power output....
Solution. Not to turn the volume up so high or find a amp with more generous
output current capability.
Rgds
Ergo
"Wesley" <wes...@one.net.au> wrote in message
news:39fc...@pink.one.net.au...
Trevor Wilson
**These speakers have an impedance curve which reaches below 3
Ohms. You should be running an appropriately rated amplifier. ie:
Your amp should be able to cope with 2 Ohm loads, under CONTINUOUS
conditions. The fact that you Yamaha has an impedance switch,
suggests a compromise product. There are much better amps
available.
>
> Is this the amplifier or speakers fault?,
**Both. The speaker's impedance curve is too severe for most mass
market products. The speaker manufacturer should have more
accurately specified the impedance of it's products. The Yamaha
should have been designed to cope with 'real world' loudpseakers,
not just dummy loads.
as I said those speakers are old
> and someone told me that electrolytic capacitors in the
crossover could be
> faulty. I know there is one large 1,200uF NPE electrolytic
capacitor and
> 40mH coil in the crossover to boost bass.
**Correct.
>
> Any ideas what is causing amp to overload?
**Tough speaker loads, combined with a wimpy amplifier. Look for
an ME amp
www.me-au.com
, for the best performance. Failing that, a Rotel (2 channel) amp,
will be a big step foreward.
--
Trevor Wilson
http://www.rageaudio.com.au
---
Or the NAD. Or Adcom, or Parasound. Can't go wrong with any of these.
:-)
Watts rating are pretty much meaningless. All wattages are *not*
created equal.
Alex
Mike Suhm
you see if the woofer surrounds are still intact? If they have foam-type
surrounds, the material may have disintegrated (or at least be extremely
soft and not support the cone movement anymore). At low volumes, this
problem might not be noticable, but at higher volumes the drivers could
over-extend , the voice coils could short, and the amp would cut out.
Mike / Audio Pros
"Wesley" <wes...@one.net.au> wrote in message
news:39fc...@pink.one.net.au...
Wesley
As to Mike Suhm reply, I have replaced all four woofers with Infinity
replacement drivers
(original drivers are no longer available).
Has any one got actual specs or test data of Infinity RSIIIA speakers?, I
believe Infinity Kappa are very similar.
If such data is available please send it to my e-mail address.
Thanks all of you
Wesley
Boris Mohar
In the not so old days we would put on the first cut from the Pink
Floyd - Dark Side of the Moon. It has a throbbing heart beat part
that could make elephants defecate and speakers cones pop out of the
gaps if one was not careful. Good overload test track.
Regards,
Boris Mohar
Viatrack Printed Circuit Designs
Wesley
> Floyd - Dark Side of the Moon. It has a throbbing heart beat part
> that could make elephants defecate and speakers cones pop out of the
> gaps if one was not careful. Good overload test track.
>
>
>
>
> Regards,
>
> Boris Mohar
>
> Viatrack Printed Circuit Designs
Would you believe that was the reason why I have bought those speakers 15
years ago.
Wesley
Trevor Wilson
Well, Wes, I've searched my files. I don't have any literature on
the RSIIA's. My suggestion, for you, is still for you to listen to
an ME amp, sometime. I guarantee it will blow you away. If you are
near Sydney, drop me a line. I will be happy to arrange a loan,
for a couple of days. You will then hear what your Infinity's are
really capable of.
BTW: Don't forget: I can modify your RSIIIA's for significantly
improved sound quality. I offer a full, money back, satisfaction
guarantee.