Pop noise from speakers when turn off power amp

[Deleted member 160668]

Hi all,

This doesn't massively bother me but just want to check not doing any damage to speakers...

When I turn off power amp (Linn LK140) at button on front, my speakers (PMC's) make a sort of "pop" noise.

They've done this since I got power amp about 9 months (ish) ago. It's just occurred to me this could cause them (speakers) damage?!

Please reassure me I'm being a doughnut, or to get my power amp immediately looked at!

thanks!

 

[SemiChronic]

I had annoying pop noise about a year ago , turned out rick astley had found his way onto my nas.

 

[Al ears]

Hi all,

This doesn't massively bother me but just want to check not doing any damage to speakers...

When I turn off power amp (Linn LK140) at button on front, my speakers (PMC's) make a sort of "pop" noise.

They've done this since I got power amp about 9 months (ish) ago. It's just occurred to me this could cause them (speakers) damage?!

Please reassure me I'm being a doughnut, or to get my power amp immediately looked at!

thanks!

To my knowledge this is quite normal, mine does the same although its not particularly loud.

Do you turn volume right down on preamp before switching off?

 

[DocG]

To my knowledge this is quite normal, mine does the same although its not particularly loud.

Do you turn volume right down on preamp before switching off?

Indeed. Either turn the volume down, or turn your preamp/source off first, and then the power amp. Any pops when turning on the power amp after the pre/source too?

 

[Deleted member 160668]

Usually turn pre-amp off first...

 

[DocG]

I had annoying pop noise about a year ago , turned out rick astley had found his way onto my nas.

Yes, but with the OP, it even happens when he turns his amp off. Imagine... The horror! *shok*

 

[CnoEvil]

My LK100 didn't pop, but I've had amps that did.

 

[Deleted member 160668]

Thanks folks. No worries then!

Cheers,

 

[DocG]

Usually turn pre-amp off first...

See what happens if you first turn off the pre, wait 5 minutes and then turn off the power amp. No pops? Then it's the pre's capacitors that need a little time to unload. Voltage on the power amp's input when turning it off = pops in your speakers.

As Al said, turn the volume right down (i.e. get the input voltage to zero) before switching the power amp off. Any pops?

 

[davedotco]

Turning the pre-amp off first is precisely what you must not do...!

Any wierd noises, audible or otherwise, will be amplified by the power amp and can cause real damage to the speakers.

Switch power amp on last, switch it off first.

Christ, this is basic stuff...!

 

[hybridauth_Facebook_100004211376004]

Just buy a Naim amp.then you never need to switch it off.lol.If I'm ever powering down.I always mute the speakers or turn the volume down to zero.

 

[Al ears]

Turning the pre-amp off first is precisely what you must not do...!

Any wierd noises, audible or otherwise, will be amplified by the power amp and can cause real damage to the speakers.

Switch power amp on last, switch it off first.

Christ, this is basic stuff...!

Quite agree, in that order......

Volume down, power amp off, pre amp off.

 

[lindsayt]

amormusic, follow the wise advice from the first post here to set your mind at rest:

http://audiokarma.org/forums/index.php?threads/amplifier-distortion-dc-offset-and-you.5634/

Specifically

As a semi-poll, I'd like to see those on this board whip out their multimeters and take a look at the DC that is being presented to the speakers. This means..

1. Speakers disconnected (or connect the meter to the 'B' speakers and set the front panel speaker control accordingly)
2. Input set to an unusued position (not Phono)
3. Volume control at minimum.
4. Balance in center
5. Tone controls either defeated or set to mid position
6. Set your meter to read DC, and set to a low scale (300mV scale is common) Connect directly to the Pos and Neg of the speaker terminals
7. Give the amp 10 minutes to settle. Report back...I'd like to see how healthy all these old amps are.

If you read:

0 - 15mV: good!! If you read '0V', you may have a capacitor output, or your meter is set wrong

16mV - 50mV: An acceptable value, especially at the lower end of this range. 2nd harmonic distortion is probably twice to four times what manufacturer's spec calls for at higher frequencies. Probably not audible, as the distortion is mostly in the upper octaves. At the upper end of this range I begin to raise an eyebrow. :saywhat:

50 - 85mV: Something is certainly amiss, and while this is not enough to put your speakers or equipment in jeopardy, the amp is running nowhere near where it should. I'd venture to guess that most of the DC-coupled amps that are in use by forum members here fall into this range.

100mV to ?: A high enough voltage will cause the DC protection to kick in. This happens at a level determined by the designer, but is usually equivalent to about a diode drop (600mV)or so. Needless to say, if you are listening to an amp with 100mV or more of DC offset, you have no idea what the amp really is supposed to sound like. Indeed, some amps without a differential input are actually designed to have a bit of DC at the outputs, but this is triple-rare, and I don't think anyone here owns one. (in my book it's poor design, but if you can sell it WTH..)

Soooooo...go grab a meter and tell me what you find...

(I've edited out a couple of words from this quote that are unsuitable for the What Hi-fi forum)

If you don't have a mutlimeter, buy one. They're not expensive and they're useful for various jobs around your house and car. But please remember to be doubly safe around electricity at all times.

 

[DocG]

Turning the pre-amp off first is precisely what you must not do...!

Any wierd noises, audible or otherwise, will be amplified by the power amp and can cause real damage to the speakers.

Switch power amp on last, switch it off first.

Christ, this is basic stuff...!

http://www.whathifi.com/forum/hi-fi/does-alcohol-affect-your-hearing

But does it affect the brain? Definitely! From now on, I'll try to post first, and have the wine afterwards... Would be less embarrassing*blush*

 

[andyjm]

I had annoying pop noise about a year ago , turned out rick astley had found his way onto my nas.

I was going to post some boring stuff about the asymetric collapse of supply rails as the amp shuts down and how this is handled by the output cirtcuitry of the power amp, but the Rick Astley comment gets my vote.

On that subject, was it ever revealed why he was waving his arms around in the 'Never gonna give you up' video? Was it really supposed to be dancing?