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#1
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
Paul G asks:
"[W]hat is the best way to protect a speaker from destruction if the amp is sufficiently powerful, and you have no control over volume? It happens.... the kids have fun with your stereo, the grounds come loose on the inputs (huge buzz), the system oscillates, etc." I don't know if you want to design and build your own stuff from scratch, Paul, or merely want to buy a plug-in protector. If you can solder, here's a halfway house in a couple items to protect your loudspeakers from switch-on pops and from DC. Velleman K4700 Loudspeaker protection kit, stereo with switch-on delay Velleman K4701 Loudspeaker DC-protection, mono The reason I've identified them is that I have a QUAD 405 MkII which occasionally eats an ESL-63, which soon gets expensive, and it is tricky rebuilding them because here is no way to solder except over the fragile panels... So an audiophile's fancy turns to ripping out the 405's inadequate clamp circuit and replacing it with industrial strength protection. The reason I choose Velleman is I've built some of their kits, including the multimeter I've used for years and a 100W PP tube amp, and found their stuff first class, head and shoulders above the competition (well, in most cases there is no competition, because the other guys make crap); in the end Velleman is worth the premium price. Andre Jute I just listen to one channel at a time. You do have to listen twice. Adequate stereo separation. -- Al Marcy |
#2
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
In article , Andre Jute wrote:
Paul G asks: "[W]hat is the best way to protect a speaker from destruction if the amp is sufficiently powerful, and you have no control over volume? It happens.... the kids have fun with your stereo, the grounds come loose on the inputs (huge buzz), the system oscillates, etc." I don't know if you want to design and build your own stuff from scratch, Paul, or merely want to buy a plug-in protector. If you can solder, here's a halfway house in a couple items to protect your loudspeakers from switch-on pops and from DC. Velleman K4700 Loudspeaker protection kit, stereo with switch-on delay Velleman K4701 Loudspeaker DC-protection, mono The reason I've identified them is that I have a QUAD 405 MkII which occasionally eats an ESL-63, which soon gets expensive, and it is tricky rebuilding them because here is no way to solder except over the fragile panels... So an audiophile's fancy turns to ripping out the 405's inadequate clamp circuit and replacing it with industrial strength protection. The reason I choose Velleman is I've built some of their kits, including the multimeter I've used for years and a 100W PP tube amp, and found their stuff first class, head and shoulders above the competition (well, in most cases there is no competition, because the other guys make crap); in the end Velleman is worth the premium price. Andre Jute I just listen to one channel at a time. You do have to listen twice. Adequate stereo separation. -- Al Marcy For a solid state amp, I usually put in a fuse on the speaker lines, only if I feel its necessary. The fuse is not a sure thing, and you have to use the right value. It can save speakers some of the time. The Velleman devices have nothing to do with over volume, unless the overvolume cause a shift in average DC offset. greg |
#3
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
On 10/09/2010 08:47, Andre Jute wrote:
Paul G asks: "[W]hat is the best way to protect a speaker from destruction if the amp is sufficiently powerful, and you have no control over volume? It happens.... the kids have fun with your stereo, the grounds come loose on the inputs (huge buzz), the system oscillates, etc." I don't know if you want to design and build your own stuff from scratch, Paul, or merely want to buy a plug-in protector. If you can solder, here's a halfway house in a couple items to protect your loudspeakers from switch-on pops and from DC. Velleman K4700 Loudspeaker protection kit, stereo with switch-on delay Velleman K4701 Loudspeaker DC-protection, mono The reason I've identified them is that I have a QUAD 405 MkII which occasionally eats an ESL-63, which soon gets expensive, and it is tricky rebuilding them because here is no way to solder except over the fragile panels... So an audiophile's fancy turns to ripping out the 405's inadequate clamp circuit and replacing it with industrial strength protection. I would fit a sensor that detects the onset of ionization and instantly shorts the input to ground with a triac. And maybe a soft-clipping circuit that works a few dB below the shutdown level. I can't think why Peter Walker didn't think of doing it.... -- Eiron. |
#4
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
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#5
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
Paul G. wrote in
: snip I've heard a story where some guy takes a crappy little amp, runs it flat out (square waves or worse) and destroys speakers that have a reasonable power rating. I'm not sure if its an audio myth, but it was supposed to have ocurred when a knowledgable customer challenged a salesman at a hifi store, claiming the expensive powerful speaker could be damaged by the little amplifier. I have heard similar, from technicians I used to work with. It is the distorted nature of the sound waves that destroys the speakers, not the volume (of course, volume CAN kill speakers as well). It is not coincidental that cheap crappy amps claim 5,000 PMPO (about 15W/side) and deliver clipped non-sound, and THAT is what will destroy a speaker. 20 W per side of QUALITY is all anyone really needs, unless, as MANY people do, you own equipment to appreciate IT, not the music it lets you hear. A GREAT musician I used to go to music school with had a crap little amp (with two volume controls and one tone control, built circa 1970, Radio Shack branded...). But he was a MUSICIAN and he cared about the MUSIC - he was not a ****** who only cares about the fact that only 30 other people in the world can afford a system like his - on which he (once or twice a year) plays his ***3*** CD's (which came free with one of his magazine subs). -- Any mental activity is easy if it need not be subjected to reality. |
#6
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
On Sep 10, 9:28*pm, Paul G. wrote:
On Fri, 10 Sep 2010 14:00:49 GMT, (GregS) wrote: In article , Andre Jute wrote: Paul G asks: "[W]hat is the best way to protect a speaker from destruction if the amp is sufficiently powerful, and you have no control over volume? It happens.... the kids have fun with your stereo, the grounds come loose on the inputs (huge buzz), the system oscillates, etc." I don't know if you want to design and build your own stuff from scratch, Paul, or merely want to buy a plug-in protector. If you can solder, here's a halfway house in a couple items to protect your loudspeakers from switch-on pops and from DC. Velleman K4700 Loudspeaker protection kit, stereo with switch-on delay Velleman K4701 Loudspeaker DC-protection, mono The reason I've identified them is that I have a QUAD 405 MkII which occasionally eats an ESL-63, which soon gets expensive, and it is tricky rebuilding them because here is no way to solder except over the fragile panels... So an audiophile's fancy turns to ripping out the 405's inadequate clamp circuit and replacing it with industrial strength protection. The reason I choose Velleman is I've built some of their kits, including the multimeter I've used for years and a 100W PP tube amp, and found their stuff first class, head and shoulders above the competition (well, in most cases there is no competition, because the other guys make crap); in the end Velleman is worth the premium price. Andre Jute I just listen to one channel at a time. You do have to listen twice. Adequate stereo separation. -- Al Marcy For a solid state amp, I usually put in a fuse on the speaker lines, only if I feel its necessary. The fuse is not a sure thing, and you have to use the right value. It can save speakers some of the time. The Velleman devices have nothing to do with over volume, unless the overvolume cause a shift in average DC offset. greg (snip) I've heard a story where some guy takes a crappy little amp, runs it flat out (square waves or worse) and destroys speakers that have a reasonable power rating. I'm not sure if its an audio myth, but it was supposed to have ocurred when a knowledgable customer challenged a salesman at a hifi store, claiming the expensive powerful speaker could be damaged by the little amplifier. (snip) Paul G. I think it's only the tweeters that are wrecked by cheap, clipping amplifiers Cheers, Roger |
#7
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
"Engineer" wrote
I think it's only the tweeters that are wrecked by cheap, clipping amplifiers It is. When an amplifier is driven into clipping the high-order harmonics increase significantly and can damage the tweeter. This is no myth, it has happened many times. Bullet-proof speaker protection is difficult because a high amplitude short duration overload can damage the speaker mechanically, whilst a sustained high-level signal, well within the speaker's mechanical limits, can cause thermal overload. The answer is to always keep the volume setting below that at which audible distortion is present! David. |
#8
Posted to rec.audio.tubes,uk.rec.audio
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Protecting speakers against switch-on pops and DC
"David Looser" wrote in
message "Engineer" wrote I think it's only the tweeters that are wrecked by cheap, clipping amplifiers It is. When an amplifier is driven into clipping the high-order harmonics increase significantly and can damage the tweeter. This is no myth, it has happened many times. This is at least partially a myth. The fact of the matter is that very few people know exactly what happens when a tweeter fails because to know this, you'd have to instrument the situation and sacrifice at least one tweeter. The fact of the matter that there is a lot of music that actually has its high frequency content *decreased* when it is clipped. The one thing that is sure is that speakers fail when too much power is applied to them for too long. One way to facilitate this is to use a larger power amplifier. Bullet-proof speaker protection is difficult because a high amplitude short duration overload can damage the speaker mechanically, whilst a sustained high-level signal, well within the speaker's mechanical limits, can cause thermal overload. Agreed. The answer is to always keep the volume setting below that at which audible distortion is present! Also agreed. |
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