Zener Tweeter protection

[svberger]

25 minutes ago, Curious_George said:

Ironically, Crites uses them in a lot of stuff. Crazy money for distortion generators!

Exactly why I went with the Type A for my '77 La Scala's. $200 less and no diodes to disconnect. Even with the dreaded(by some) Sonicaps they sound just fine to me and no distortion. Almost as smooth as the original 44 year old AA's but with just a pinch more top end sparkle.

[Deang]

24 minutes ago, svberger said:

Almost as smooth as

Welp. 

[svberger]

1 minute ago, Crankysoldermeister said:

Welp. 

All good.

[Limberpine]

1 hour ago, babadono said:

And hopefully you are doing this with no input to the speaker. Those tweeters are fragile. Usually back in the day they got blown out  on an impulse, like someone dropping the needle onto a record. With the volume up too high.

Correct. No load going to the speakers when disconnecting then. 

[Limberpine]

2 hours ago, captainbeefheart said:

 

It's crazy. The 1N3996 is going for $38 each ouch

 

https://www.mouser.com/ProductDetail/Microchip-Technology/1N3996?qs=%2BRKXB2WKlSeuDut61y4Atw%3D%3D

 

You could probably list all 4 for $60 and get it, that's $15 a pop. I suppose people leave them in case they sell the speakers and someone wants them stock with the protection circuit.

Well geesh, I wish I would have known that last weekend. I went to an estate sale an they were selling like 100 of them for $10.  They're probably in the trash now......😕

[captainbeefheart]

1 hour ago, Limberpine said:

Well geesh, I wish I would have known that last weekend. I went to an estate sale an they were selling like 100 of them for $10.  They're probably in the trash now......😕

 

I can't walk away from things like that, $10 I would have thrown my money at them. Of course I would use them for other applications and not in crossovers. There are some seriously great deals on electronics if you just keep an eye out for them. I know people hate them but I got a disgusting amount of vintage Ohmite "little devil" carbon composition resistors. I like them, they were stored very well and within tolerance and for $20 it took me the better part of a year to organize them there were so many. I see people selling them for $3.00 each it's sick. I only use them as basically extremely cheap parts to breadboard with and make stuff. They have proven to be very reliable for what they are. I obviously don't use them in critical circuits but as I said to have gross supply of resistors cheap to play with is wonderful. I believe they were sold by weight which was weird, it was something like 20 lbs of resistors for $20.

[Limberpine]

13 minutes ago, captainbeefheart said:

 

I can't walk away from things like that, $10 I would have thrown my money at them. Of course I would use them for other applications and not in crossovers. There are some seriously great deals on electronics if you just keep an eye out for them. I know people hate them but I got a disgusting amount of vintage Ohmite "little devil" carbon composition resistors. I like them, they were stored very well and within tolerance and for $20 it took me the better part of a year to organize them there were so many. I see people selling them for $3.00 each it's sick. I only use them as basically extremely cheap parts to breadboard with and make stuff. They have proven to be very reliable for what they are. I obviously don't use them in critical circuits but as I said to have gross supply of resistors cheap to play with is wonderful. I believe they were sold by weight which was weird, it was something like 20 lbs of resistors for $20.

 

I did have the thought to buy them along with a bunch of resistors, but then I was thinking that I didn't want a bunch more clutter on my  each, so I didn't buy them. There was a bunch of electronics stuff like that at this sale. Next time.

[Deang]

Bumped. 
 

Someone is telling people that 1) Klipsch dropped these because of cost, and 2) was the only PWK approved form of tweeter protection. Neither is true. 
 

They introduce distortion, and according to Roy, can also short out an amplifier. 

[JohnA]

On 1/29/2022 at 8:33 PM, Curious_George said:

I assume the tweeter in the below diagram is a K77?

 

 

Yes, it was.  The bulb and resistor form an L-pad (~1 dB, maybe 1.5] until the bulb heats and its resistance rises. 

[JohnA]

On 1/29/2022 at 7:35 PM, Curious_George said:

It was a compromise between blown tweeters and sound quality. It’s a known fact the tweeters were (are) delicate. Perhaps the threshold could have been a bit higher so the distortion would not begin until a higher wattage. 
 

Newer technology performs better such as poly switches, but they are not the final answer. 
 

I personally prefer the right light bulb. 

 

 

The K-77-M is substantially more durable with a 10w cont. rating.  In a home setting they are not at much risk so you can defeat the KLiP diodes.  I would not recommend that for Pro Audio.