Kill Switch For Excessive Volume?

[tropicallutefisk]

OK, I know this is a weird and probably dumb question, so please be kind.  I do not have the luxury of being able to have two separate systems for Home Theater and 2 Channel. Instead, I have routed my left and right output channels from my HT Processor as inputs to my stereo preamp. So when I am listening to 2 channel, I just select the input for my streamer. However, when listening to HT I select the input coming from my processor, set my preamp to passive mode and turn the preamp volume to Max. This allows the HT signal to pass straight through the preamp and HT volume is adjusted from the processor as I would if there were not a preamp in the path. This works very well except its not idiot proof. 

Now on to the idiot part of this story. I, playing the part of the idiot, sat down last night to listen to some music. The wife had been watching TV, so I needed to switch over to the preamp. Its really as simple as I stated. Select the input for my streamer, select passive, JFET gain or tube gain AND turn down the preamp volume to a suitable level. This is obviously not a difficult routine. However, in the process of doing so my wife interrupted me to ask about dinner, and when I returned to my ritual I forgot to turn down the volume. FYI I am not blaming her. This was just me being a bonehead. So when I pressed "play" I hit my speakers with a full 650+ watts of power. The result was of course an ear piercing blast of REM and the smell of burnt mylar. I had just fried the ribbon tweeters on my Maggies. Luckily I know they are easy to repair. However, I would rather this not happen again. Yes, hopefully, this has been a wake up call to be more careful, but I also know that anything that can happen has a good chance of happening. So my question is... Is there a better way to integrate my preamp and processor or is there a device I can insert in the path that will kill the signal before it reaches my speakers? FYI - My DR1s did not go into protection mode and the fuses in my Maggies did not blow. 

[pedrocols]

Bummer 😕

[jackfish]

So how does one repair blown ribbon tweeters in Magnepans?

13.3" MacBook Air, 4GB RAM, 256GB SSD, iTunes/BitPerfect
MacBook Air SuperDrive
Western Digital My Book Essential 2TB USB HD
Schiit Bifrost USB DAC and Audioengine D3 DAC
Emotiva USP-1, ERC-1 and two UPA-1s
Pro-Ject Xpression III and AT440MLa
AKAI AT-2600 and Harman Kardon TD4400
Grado SR80i
Wharfedale Diamond 225
Rythmik Audio F12

[davidl81]

I don't want to sound like an idiot, but is the pre-amp really any better than just running everything through the AV8802a that the OP has and using it is stereo mode when listing to music?

[tropicallutefisk]

Aug 8, 2019 8:49:56 GMT -5 jackfish said:

So how does one repair blown ribbon tweeters in Magnepans?

13.3" MacBook Air, 4GB RAM, 256GB SSD, iTunes/BitPerfect
MacBook Air SuperDrive
Western Digital My Book Essential 2TB USB HD
Schiit Bifrost USB DAC and Audioengine D3 DAC
Emotiva USP-1, ERC-1 and two UPA-1s
Pro-Ject Xpression III and AT440MLa
AKAI AT-2600 and Harman Kardon TD4400
Grado SR80i
Wharfedale Diamond 225
Rythmik Audio F12

They are essentially plug and play. Magnepan sends a new ribbon assembly and I send the blown assembly back. Its one plug in connection but many, many screws. 

[tropicallutefisk]

Aug 8, 2019 9:00:21 GMT -5 davidl81 said:

I don't want to sound like an idiot, but is the pre-amp really any better than just running everything through the AV8802a that the OP has and using it is stereo mode when listing to music?

You're not asking a dumb question. For years I was not sure it was worth investing in a separate stereo preamp. I finally gave it a try and the difference is astounding, a real game changer. My stereo preamp provides a bigger soundstage, better imaging, a ton more detail and even more bass. The difference was so stark that even my wife, who never notices a change in my system, remarked at the improvement. 

[jackfish]

Aug 8, 2019 9:16:58 GMT -5 tropicallutefisk said:

Aug 8, 2019 8:49:56 GMT -5 jackfish said:

So how does one repair blown ribbon tweeters in Magnepans?

13.3" MacBook Air, 4GB RAM, 256GB SSD, iTunes/BitPerfect
MacBook Air SuperDrive
Western Digital My Book Essential 2TB USB HD
Schiit Bifrost USB DAC and Audioengine D3 DAC
Emotiva USP-1, ERC-1 and two UPA-1s
Pro-Ject Xpression III and AT440MLa
AKAI AT-2600 and Harman Kardon TD4400
Grado SR80i
Wharfedale Diamond 225
Rythmik Audio F12

They are essentially plug and play. Magnepan sends a new ribbon assembly and I send the blown assembly back. Its one plug in connection but many, many screws. 

So I can get replacement QR tweeters for the MMG?

[davidl81]

Aug 8, 2019 9:25:27 GMT -5 tropicallutefisk said:

Aug 8, 2019 9:00:21 GMT -5 davidl81 said:

I don't want to sound like an idiot, but is the pre-amp really any better than just running everything through the AV8802a that the OP has and using it is stereo mode when listing to music?

You're not asking a dumb question. For years I was not sure it was worth investing in a separate stereo preamp. I finally gave it a try and the difference is astounding, a real game changer. My stereo preamp provides a bigger soundstage, better imaging, a ton more detail and even more bass. The difference was so stark that even my wife, who never notices a change in my system, remarked at the improvement. 

That's really awesome and good to know.  I also have the AV8802a that I upgraded to from the SR7009.  I was very impressed with the AV8802 but as many on here can attest to I am always looking for something better/different.

[tropicallutefisk]

Aug 8, 2019 9:31:48 GMT -5 jackfish said:

Aug 8, 2019 9:16:58 GMT -5 tropicallutefisk said:

They are essentially plug and play. Magnepan sends a new ribbon assembly and I send the blown assembly back. Its one plug in connection but many, many screws. 

So I can get replacement QR tweeters for the MMG?

I don't believe the QR tweeters are plug and play. Its only the ribbon tweeters that are a separate assembly that can pulled out and swapped. I believe the QR ribbon is a part of the panel  and would need to be sent to Magnepan for repair.  

[tropicallutefisk]

Aug 8, 2019 9:38:10 GMT -5 davidl81 said:

Aug 8, 2019 9:25:27 GMT -5 tropicallutefisk said:

You're not asking a dumb question. For years I was not sure it was worth investing in a separate stereo preamp. I finally gave it a try and the difference is astounding, a real game changer. My stereo preamp provides a bigger soundstage, better imaging, a ton more detail and even more bass. The difference was so stark that even my wife, who never notices a change in my system, remarked at the improvement. 

That's really awesome and good to know.  I also have the AV8802a that I upgraded to from the SR7009.  I was very impressed with the AV8802 but as many on here can attest to I am always looking for something better/different.

I love my 8802a and its the best sounding processor I've owned. Previously I owned a Yamaha receiver with preouts, then a Rotel processor and before the 8802a was Marantz's version from 2009. However, I had felt I was missing something when listening in stereo. Even in Pure Direct mode it just seemed flat, not bad, just flat compared to other systems I had heard. Then I decided to make a modest purchase just to try a separate stereo preamp. I figured for $900 why not try a Schiit Freya? It gave me the option of trying tubes without any risk because it also did passive and solid state gain. I'm sure there are plenty of other great options if you decide to try a separate preamp. This just happens to be the only I have had in my system, so I can't comment on other brands or models.  

[KeithL]

There is such a thing as "a kill switch for excessive volume"...

And it's not exactly something new...

(It's also very reliable, easy to use, and it doesn't even cost much...)

It's called a fuse...

(You can buy a fuse holder that mount son a surface, like the back of your speaker, or one that goes in-line into your speaker cable.)

In fact, most speakers used to have fuses (and I thought Magneplanars did).

However, there are two things you need to know about fuses (+1 if you like tube gear).....

1)

Fuses do have resistance, and fuses rated for lower amperage tend to have higher resistance.

This means that adding a fuse will slightly reduce your damping factor.

It also means that a fuse might cause a very slight change in frequency response if it interacts with the impedance of the speaker.

(Neither of these matters nearly as much with Magenplanars as with most other speakers - because Maggies have a relatively resistive impedance - and their motor coupling isn't especially tight.)

2)

Forget all of the calculations you would use when selecting a fuse to protect a power supply.

You want a 2A or 3A fuse - and you want a FAST BLOW fuse.

Slow Blow fuses are much too slow to protect a speaker - a 3A slow blow fuse will pass plenty of power long enough to blow a speaker.

Back when most speakers had fuses most smaller speakers came with a 2A fast and most bigger speakers came with a 3A.

(Fuses DO blow occasionally; buy spares; they're cheap and easy to change.)

3)

THIS IS THE ONE FOR TUBE FANS.

In general, solid state amps won't mind if a fuse flows while they're delivering a lot of power... and it won't hurt them in the least.

However, TUBE AMPS REALLY REACT BADLY TO GOING OPEN-LOAD WHILE RUNNING AT HIGH POWER.

IN FACT, RUNNING A TUBE AMP INTO CLIPPING, INTO AN OPEN CIRCUIT, CAN RESULT IN A BLOWN OUTPUT TRANSFORMER.

(That's probably the single most expensive part in your tube amp - so well worth avoiding.)

So.....

Will adding an in-line fuse make your speaker sound a tiny bit different?

Possibly - but probably not much - and not nearly as much as being blown out.

Should you buy fancy "audiophile fuses"?

Absolutely, positively, not...

Plain old, fifty cent, glass "cartridge fuses" work just fine.

(Just remember to use FAST BLOW or STANDARD ones and NOT slow blow.)

I might also suggest a minor change in your ritual.

Rather than "turn down the Volume to a suitable level when you need to"...

Try getting in the habit of "making sure the preamp is set to a safe level whenever you do ANYTHING to it"...

(So, turn it down when you switch it in, then turn it down again before you switch it out....)

By including the "safety instruction" at multiple points in your ritual you reduce the chance of missing it entirely.

(Sort of like making sure your car is in Park when you shut it off, and when you start it, and before taking your foot off the brakes.)

(Think of having the Volume on your preamp set to anything other than full off as "being in the armed position"....)

As I mentioned above, I though at least some Maggies did include fuses.

If yours do, and they simply didn't blow, consider substituting smaller fuses.

(see considerations above.)

Aug 8, 2019 7:08:34 GMT -5 tropicallutefisk said:

OK, I know this is a weird and probably dumb question, so please be kind.  I do not have the luxury of being able to have two separate systems for Home Theater and 2 Channel. Instead, I have routed my left and right output channels from my HT Processor as inputs to my stereo preamp. So when I am listening to 2 channel, I just select the input for my streamer. However, when listening to HT I select the input coming from my processor, set my preamp to passive mode and turn the preamp volume to Max. This allows the HT signal to pass straight through the preamp and HT volume is adjusted from the processor as I would if there were not a preamp in the path. This works very well except its not idiot proof. 

Now on to the idiot part of this story. I, playing the part of the idiot, sat down last night to listen to some music. The wife had been watching TV, so I needed to switch over to the preamp. Its really as simple as I stated. Select the input for my streamer, select passive, JFET gain or tube gain AND turn down the preamp volume to a suitable level. This is obviously not a difficult routine. However, in the process of doing so my wife interrupted me to ask about dinner, and when I returned to my ritual I forgot to turn down the volume. FYI I am not blaming her. This was just me being a bonehead. So when I pressed "play" I hit my speakers with a full 650+ watts of power. The result was of course an ear piercing blast of REM and the smell of burnt mylar. I had just fried the ribbon tweeters on my Maggies. Luckily I know they are easy to repair. However, I would rather this not happen again. Yes, hopefully, this has been a wake up call to be more careful, but I also know that anything that can happen has a good chance of happening. So my question is... Is there a better way to integrate my preamp and processor or is there a device I can insert in the path that will kill the signal before it reaches my speakers? FYI - My DR1s did not go into protection mode and the fuses in my Maggies did not blow. 

[tropicallutefisk]

Aug 8, 2019 10:05:51 GMT -5 KeithL said:

There is such a thing as "a kill switch for excessive volume"...

And it's not exactly something new...

(It's also very reliable, easy to use, and it doesn't even cost much...)

It's called a fuse...

(You can buy a fuse holder that mount son a surface, like the back of your speaker, or one that goes in-line into your speaker cable.)

In fact, most speakers used to have fuses (and I thought Magneplanars did).

However, there are two things you need to know about fuses (+1 if you like tube gear).....

1)

Fuses do have resistance, and fuses rated for lower amperage tend to have higher resistance.

This means that adding a fuse will slightly reduce your damping factor.

It also means that a fuse might cause a very slight change in frequency response if it interacts with the impedance of the speaker.

(Neither of these matters nearly as much with Magenplanars as with most other speakers - because Maggies have a relatively resistive impedance - and their motor coupling isn't especially tight.)

2)

Forget all of the calculations you would use when selecting a fuse to protect a power supply.

You want a 2A or 3A fuse - and you want a FAST BLOW fuse.

Slow Blow fuses are much too slow to protect a speaker - a 3A slow blow fuse will pass plenty of power long enough to blow a speaker.

Back when most speakers had fuses most smaller speakers came with a 2A fast and most bigger speakers came with a 3A.

(Fuses DO blow occasionally; buy spares; they're cheap and easy to change.)

3)

THIS IS THE ONE FOR TUBE FANS.

In general, solid state amps won't mind if a fuse flows while they're delivering a lot of power... and it won't hurt them in the least.

However, TUBE AMPS REALLY REACT BADLY TO GOING OPEN-LOAD WHILE RUNNING AT HIGH POWER.

IN FACT, RUNNING A TUBE AMP INTO CLIPPING, INTO AN OPEN CIRCUIT, CAN RESULT IN A BLOWN OUTPUT TRANSFORMER.

(That's probably the single most expensive part in your tube amp - so well worth avoiding.)

So.....

Will adding an in-line fuse make your speaker sound a tiny bit different?

Possibly - but probably not much - and not nearly as much as being blown out.

Should you buy fancy "audiophile fuses"?

Absolutely, positively, not...

Plain old, fifty cent, glass "cartridge fuses" work just fine.

(Just remember to use FAST BLOW or STANDARD ones and NOT slow blow.)

I might also suggest a minor change in your ritual.

Rather than "turn down the Volume to a suitable level when you need to"...

Try getting in the habit of "making sure the preamp is set to a safe level whenever you do ANYTHING to it"...

(So, turn it down when you switch it in, then turn it down again before you switch it out....)

By including the "safety instruction" at multiple points in your ritual you reduce the chance of missing it entirely.

(Sort of like making sure your car is in Park when you shut it off, and when you start it, and before taking your foot off the brakes.)

(Think of having the Volume on your preamp set to anything other than full off as "being in the armed position"....)

As I mentioned above, I though at least some Maggies did include fuses.

If yours do, and they simply didn't blow, consider substituting smaller fuses.

(see considerations above.)

Aug 8, 2019 7:08:34 GMT -5 tropicallutefisk said:

OK, I know this is a weird and probably dumb question, so please be kind.  I do not have the luxury of being able to have two separate systems for Home Theater and 2 Channel. Instead, I have routed my left and right output channels from my HT Processor as inputs to my stereo preamp. So when I am listening to 2 channel, I just select the input for my streamer. However, when listening to HT I select the input coming from my processor, set my preamp to passive mode and turn the preamp volume to Max. This allows the HT signal to pass straight through the preamp and HT volume is adjusted from the processor as I would if there were not a preamp in the path. This works very well except its not idiot proof. 

Now on to the idiot part of this story. I, playing the part of the idiot, sat down last night to listen to some music. The wife had been watching TV, so I needed to switch over to the preamp. Its really as simple as I stated. Select the input for my streamer, select passive, JFET gain or tube gain AND turn down the preamp volume to a suitable level. This is obviously not a difficult routine. However, in the process of doing so my wife interrupted me to ask about dinner, and when I returned to my ritual I forgot to turn down the volume. FYI I am not blaming her. This was just me being a bonehead. So when I pressed "play" I hit my speakers with a full 650+ watts of power. The result was of course an ear piercing blast of REM and the smell of burnt mylar. I had just fried the ribbon tweeters on my Maggies. Luckily I know they are easy to repair. However, I would rather this not happen again. Yes, hopefully, this has been a wake up call to be more careful, but I also know that anything that can happen has a good chance of happening. So my question is... Is there a better way to integrate my preamp and processor or is there a device I can insert in the path that will kill the signal before it reaches my speakers? FYI - My DR1s did not go into protection mode and the fuses in my Maggies did not blow. 

Yes, the Maggies have a 2.5 amp fuse that I assume is fast blow. For whatever reason neither fuse blew and all that current went straight to the right and left tweeters. 

I'm definitely making a ritual that includes adjusting the volume first. However I wanted to investigate a possible idiot proof solution.  

[klinemj]

You need a home theater bypass.

Mark

[donh50]

There are a number of answers but not many are simple... A pro compressor/limiter is the usual solution. I have in the primordial past built custom circuits that would limit the volume but have not anytime recently. You can switch to a lower-value fuse but fuses take a little bit to react (it's a thermal process; they heat up until they separate, good for not blowing on brief peaks but that also means a really large brief peak can do damage) and a very high-power surge can blow the ribbon. My Flame Linear took out tweeters without blowing fuses.

As stated above replacing the true ribbon tweeter is an easy and fairly cheap process. Back when I worked in the biz I got very good at swapping them out. The QR tweeters are part of the panels and not user-replaceable.

I would not max the preamp's gain but rather adjust the gain chain so the volume is essentially the same in HT and music modes. That way no worry about vastly different levels when you switch and it's a free solution.

FWIWFM - Don

[tropicallutefisk]

Aug 8, 2019 21:53:19 GMT -5 donh50 said:

There are a number of answers but not many are simple... A pro compressor/limiter is the usual solution. I have in the primordial past built custom circuits that would limit the volume but have not anytime recently. You can switch to a lower-value fuse but fuses take a little bit to react (it's a thermal process; they heat up until they separate, good for not blowing on brief peaks but that also means a really large brief peak can do damage) and a very high-power surge can blow the ribbon. My Flame Linear took out tweeters without blowing fuses.

As stated above replacing the true ribbon tweeter is an easy and fairly cheap process. Back when I worked in the biz I got very good at swapping them out. The QR tweeters are part of the panels and not user-replaceable.

I would not max the preamp's gain but rather adjust the gain chain so the volume is essentially the same in HT and music modes. That way no worry about vastly different levels when you switch and it's a free solution.

FWIWFM - Don

"I would not max the preamp's gain but rather adjust the gain chain so the volume is essentially the same in HT and music modes. That way no worry about vastly different levels when you switch and it's a free solution.
"

Excellent idea and its a simple fix. Thanks for your help! 

[pedrocols]

Aug 8, 2019 9:31:48 GMT -5 jackfish said:

Aug 8, 2019 9:16:58 GMT -5 tropicallutefisk said:

They are essentially plug and play. Magnepan sends a new ribbon assembly and I send the blown assembly back. Its one plug in connection but many, many screws. 

So I can get replacement QR tweeters for the MMG?

Send it back to the Gunn guy he will gladly fix it for you for a not so small fee.