Cornwall Issue

[wishkahdaddy]

I recently purchased a Manley Chinook and introduced it to my audio chain. My chain now consists of a totally restored Sansui 1000, Manley phono pre, Empire Turntable, 1982 Klipsch Cornwalls. I've recently turned it up louder than normal, but not fully cranked, and not more than a few minutes. Perhaps the volume on the Sansui was shy of half way up, around 11:00.
The next day I noticed my Sansui's treble was all messed up. I had to turn the treble almost off to make it sound right. If I put it at the normal 12:00 position (flat), it sounds really thin with way too much treble. Now when I crank the bass knob I get a loose bass and it starts this low frequency hum when the bass and volume of the receiver get turned up past 9:00. Any idea on what could have happened? I have B3 crossover's, k77 Tweeters, K57 drivers/horns, k33E woofer. Everything is stock and sounded great to this point. It's not the receiver, preamp, or turntable as I've cross checked all of them with different speakers and they sound and respond just fine. A back up Marantz receiver does not sound great through the Cornwall's now. It's the Cornwalls...

 

[biscuithead]

I recently purchased a Manley Chinook and introduced it to my audio chain. My chain now consists of a totally restored Sansui 1000, Manley phono pre, Empire Turntable, 1982 Klipsch Cornwalls. I've recently turned it up louder than normal, but not fully cranked, and not more than a few minutes. Perhaps the volume on the Sansui was shy of half way up, around 11:00.
The next day I noticed my Sansui's treble was all messed up. I had to turn the treble almost off to make it sound right. If I put it at the normal 12:00 position (flat), it sounds really thin with way too much treble. Now when I crank the bass knob I get a loose bass and it starts this low frequency hum when the bass and volume of the receiver get turned up past 9:00. Any idea on what could have happened? I have B3 crossover's, k77 Tweeters, K57 drivers/horns, k33E woofer. Everything is stock and sounded great to this point. It's not the receiver, preamp, or turntable as I've cross checked all of them with different speakers and they sound and respond just fine. A back up Marantz receiver does not sound great through the Cornwall's now. It's the Cornwalls...

Seems unlikely that a cap was damaged...
is this issue in both R&L speakers ?

 

[wishkahdaddy]

Sounds like it might be a tweeter on my right speaker. That speaker sounds very high/piercing. The tweeter on the left side sounds more smooth. It's tough to tell as three speakers are all going at once inside the Cornwall cab, but that's what it sounds like to me.

 

[biscuithead]

Sounds like it might be a tweeter on my right speaker. That speaker sounds very high/piercing. The tweeter on the left side sounds more smooth. It's tough to tell as three speakers are all going at once inside the Cornwall cab, but that's what it sounds like to me.

Could be, the 1982 diaphragm could have given up the ghost. New ones are easy to come by.

 

[wishkahdaddy]

I checked the tweeter diaphragm and it looks to be fine. Talked with Crites today and he said it's probably not the tweeter. "It either works or it does not," and both tweeters are working. He's not convinced it's the crossover either, but I did order two new B3 crossovers and will install them tomorrow and report back. If it's not the tweeter or crossover then perhaps it's the driver? Process of elimination I guess, I'm fairly inexperienced with this so we shall see. I appreciate the input and welcome more as I try and solve this. Thank you

 

[avguytx]

Are the speakers still using those old 37 year old can caps in them? Is so, that would be something I would change out soon. And your Sansui is fully recapped? Which would be good being it's almost 50 years old. Replacing the capacitors is easy in those B-2 crossovers and you can either get them from Crites (he uses Sonicaps) or places like Parts Express (Dayten, Solen, Audyn, etc). Not a lot of money to get those ol' turd caps outta there. I believe it's a 20uf cap on woofer, 3uf on mid, and 2uf on tweeter. Can't get much simpler.

Edit: Just re-read where you ordered new B-3 crossovers. Nevermind.

 

[avguytx]

Also, do you have another pair of speakers you could hook up to the receiver that would let you see if it leans more towards the electronics side and not speakers? Is the noise is still there on different speakers, it's not the Cornwalls. If it stays with the electronics, it's somewhere upstream. Does it do this on all sources or just vinyl? Any other source like CD, streaming from phone, etc., that you can use?

Also, were those original transistors replaced in the Sansui when it was restored? Maybe they were just finally taxed out.

 

[BilboBaggins]

My first thought, after the OP description, is a bad output transistor. Have you swapped the speaker output cables around to see if the problem stays with the speaker, or the channel?