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Carver ALS III problem

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Posted on May 4, 2016 at 18:33:57
deafbykhorns
Audiophile

Posts: 1067
Location: Florida
Joined: October 17, 2003
 Just auditioned them. Very minty but one of the ribbons sounds like it has a bad connection at times on just the lower 10% of ribbon. When you turn up the volume it's more noticeable and changes volume like a dirty potentiometer. The mid to upper part of ribbon is nice and clear. The amp shutdown once or twice but that might of been the lack of power from a 125wpc Denon.
Is this an easy fix?

 

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RE: Carver ALS III problem, posted on May 4, 2016 at 18:46:43
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 The Denon is a poor choice of amp for THAT speaker. I suspect the Electrons didn't have enough Energy to get to the END of the Ribbon.
Too much is never enough

 

RE: The other speaker performed well and, posted on May 4, 2016 at 19:02:11
deafbykhorns
Audiophile

Posts: 1067
Location: Florida
Joined: October 17, 2003
 The volume was not that loud, maybe 100-103 DB
The other speaker did not seem to run out of steam

 

RE: The other speaker performed well and, posted on May 4, 2016 at 22:21:43
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 What Denon? Not to forget these are LOW sensitivity speakers. Maybe 86db. AND they are 4ohm nominal which tells me to 'bring on the current'.

that being said, you DO probably have dead ribbons. You'll need to search out a rebuild kit or or a rebuilder.

These speaker suck up power like you owned stock in the Electric Company.

I don't know what you mean by 100 to 103 db. Continuous or Peak? If continuous with 115 db PEAKS than you wouldn't believe how much power you need.
Too much is never enough

 

RE: The other speaker performed well and, posted on May 4, 2016 at 23:27:29
Roger Gustavsson
Audiophile

Posts: 2058
Location: Huskvarna
Joined: February 12, 2010
 As the other channel is not running out of steam, it is not the lack of power showing up. First thing, swap the speakers to see if the problem follow the speaker and not the Denon driving them.

 

+1 on amp channel swap , posted on May 5, 2016 at 03:18:21
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 The amp is insufficient to drive the speakers to the levels you are getting. It would run out of power and clip. If it is an older amp over 15 years some of the power supply caps might be out of spec and one channel can run out of power before the other. So first swap channels to see if the problem remains on the same amp channel.Alternately try another more powerful amp.

The mid/tweeter driver can not produce the kind of problem you are describing on its own. That said, if it is the problem BG RD drivers might be available again for the DIY community as their Neo drivers have been made available recently but Parts Epress' stock is already out. An alternative is a line of Neo8 PDR drivers. Costly but very good.

The woofers are likely to have problems first since the speakers are old and they may need new surrounds (refoaming) not a costly project and can be done DIY. The problem you describe sounds more like a woofer problem. Another problem can be a crossover cap being out of spec. IIRC they used an electrolytic cap in the bass low pass filter.

 

RE: Carver ALS III problem, posted on May 5, 2016 at 05:16:42
deafbykhorns
Audiophile

Posts: 1067
Location: Florida
Joined: October 17, 2003
 Yes, I agree about the amp but I was only hitting maybe 100-103db peaks and it only did it on one speaker. And yes, it followed the speaker, this is troubleshooting 101.....The other speaker performed nicely, even with 125w chip amp (Denon receiver).
I didn't have an extra amp with me when I auditioned them in the sellers home. I have a couple high current amps at home but confident this would not resolve anything.

Woofers have been repaired with new surrounds.
If it were a cap, the entire ribbon should perform poorly, not just the last 8-12".

The foam in front of the ribbon has been replaced, any chance this material got behind the ribbon and caused some damage? Foam shouldn't conduct so I wouldn't believe this would cause an issue.
What about the ribbon, is this a heat/humidity sensitive material that could be shrunk with heat (similar to an acoustat)? Does the over excursion cause a short in ribbons?

 

RE: Went thru the troubleshooting process, posted on May 5, 2016 at 06:06:38
deafbykhorns
Audiophile

Posts: 1067
Location: Florida
Joined: October 17, 2003
 Yes, I agree about the amp but I was only hitting maybe 100-103db peaks and it only did it on one speaker. And yes, it followed the speaker, this is troubleshooting 101.....The other speaker performed nicely, even with 125w chip amp (Denon receiver).
I didn't have an extra amp with me when I auditioned them in the sellers home. I have a couple high current amps at home but confident this would not resolve anything.

Woofers have been repaired with new surrounds.
If it were a cap, the entire ribbon should perform poorly, not just the last 8-12".

The foam in front of the ribbon has been replaced, any chance this material got behind the ribbon and caused some damage? Foam shouldn't conduct so I wouldn't believe this would cause an issue.
What about the ribbon, is this a heat/humidity sensitive material that could be shrunk with heat (similar to an acoustat)?

 

RE: Carver ALS III problem, posted on May 5, 2016 at 06:13:08
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 If there is a portion of the mid/tweet driver that is not performing correctly across the entire length would indicate localized damage to the driver. It may be foam pieces lodged in it it can be loosened adhesives due to moisture exposure. If it is obviously a specific area on the driver then it will probably need to be replaced. Either an RD48 off of Ebay or if it ever comes back to the DIY sellers, Or replace both sides with 6 X Neo8 PDR or an AMTpro4 line (requires a higher crossover). An expensive proposition at $1200 for the Neos and $2000 for the AMTs

The best thing would be to try and repair the driver, or replace it from an ebay source.

 

I would say run away while you can. No Parts, no repairs.. Bad mojo., posted on May 5, 2016 at 13:38:02
Smelly_Socks
 So you want to buy a pair of speakers with an unusual problem. IF repeat IF they had an actual dealer network and parts and a factory.. Well maybe.
WIth NO company left, no parts, no one who even knows how to fix them.. You ARE asking for endless bad shit to be your new life (at least when it comes to listening to music.)

Run Run while you can far far away from those speakers.
Unless they are for sale for $50 'as is'. Do NOT buy them.
Buying broken 'unrepairable' crap is for fools or folks with plenty of experience and money to throw away.

 

RE: Went thru the troubleshooting process, posted on May 5, 2016 at 17:46:45
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 I was being 'smart' in my 1st post, but in my 2nd, I DID say 'dead ribbon'.

I don't know how the ribbons are supposed to be assembled, but I'm sure a problem DOES exist.
Too much is never enough

 

RE: Repaired!, posted on May 5, 2016 at 18:13:25
deafbykhorns
Audiophile

Posts: 1067
Location: Florida
Joined: October 17, 2003
 A rebuilder in Tennessee seemed to think its tensioning, he was right! They usually go dead or buzz according to the rebuilder.
He gave me instructions on how to tension and was confident I wouldnt need to send them to him.
I felt it was worth the risk after speaking to the rebuilder. Besides, the speakers were mint with original boxes, manual and used for a home theater system so they saw very little use.

 

RE: Repaired!, posted on May 9, 2016 at 04:58:24
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 So you bought the speakers and fixed the RD48 driver yourself?

What was involved in the repair?

 

RE: Repaired!, posted on May 14, 2016 at 19:52:19
deafbykhorns
Audiophile

Posts: 1067
Location: Florida
Joined: October 17, 2003
 I retensioned the ribbons, at the same time I resoldered ribbon end connections.
Not sure which fixed it but I assume it was the tensioning

 

RE: Repaired!, posted on May 15, 2016 at 09:30:40
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 Did you take pics? I am curious to see the insides of the driver.

 

RE: Repaired!, posted on May 31, 2016 at 23:37:55
3car
Audiophile

Posts: 2
Joined: May 31, 2016
 I'd be really interested to hear how one "retensions" the AL III ribbons.

 

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