Beginning the RCA LC-1A adventure.

Question: is it an audio sin to recone an LC-1A with a non-hump cone?

SpeakerExchange tells me that they can work on the speakers, but the cone will be an aftermarket replacement.

If I'm not able to get original parts, I think the better option is to have a functioning pair of speakers than not...
 

gable

Senior Member
I would probably wait awhile, see if other options turn up. It's possible there are not any other options, but I tend to think that it's worth being patient to try and search them out.

You might reach out to Dave from Planet10, he used to do a lot of vintage refurbishing and may have some resources.

planet_10 hifi
 
@Salectric, heard back from Millersound - they do not have parts and thus do not feel confident they could maintain their high standards while working on these speakers. That denial is a true sign of quality work in my book. They did, however, recommend I reach out to Jonathan Weiss of OMA, which I did.

Jonathan has been of great service to me in the past year as I've tracked down old RCA gear. He had helped me work through the different parts of an old Photophone theater system I picked up last August.

I placed a call to the number listed on OMA's website and was surprised when Jonathan picked up. He was kind enough to talk about RCA and not his own business - in his words, with a broken LC-1A it's best to just walk away. Repair parts for a blown tweeter don't exist; he asked for an update if I did find anything out about possible repairs, otherwise he said it's best left as a parts unit.

I've got these boxed up for the time being while I continue the search for repairs. Art Dudley's writeup on the speaker made it seem like parts could exist somewhere - I wonder if it's possible to reach out to him.
 

Salectric

Senior Member
@Salectric, heard back from Millersound - they do not have parts and thus do not feel confident they could maintain their high standards while working on these speakers. That denial is a true sign of quality work in my book. They did, however, recommend I reach out to Jonathan Weiss of OMA, which I did.

Jonathan has been of great service to me in the past year as I've tracked down old RCA gear. He had helped me work through the different parts of an old Photophone theater system I picked up last August.

I placed a call to the number listed on OMA's website and was surprised when Jonathan picked up. He was kind enough to talk about RCA and not his own business - in his words, with a broken LC-1A it's best to just walk away. Repair parts for a blown tweeter don't exist; he asked for an update if I did find anything out about possible repairs, otherwise he said it's best left as a parts unit.

I've got these boxed up for the time being while I continue the search for repairs. Art Dudley's writeup on the speaker made it seem like parts could exist somewhere - I wonder if it's possible to reach out to him.
Bummer. I imagine that will be a problem with a lot of very old collectible gear, and the situation can only get worse as time goes by.
 
Ok, well that was painful. Had to register to comment of course. Had to switch machines to retrieve the confirmation. Then search to find this thread again. Search doesn't like RCA or LC-1A, to short a phrase to search. Eventually I used MI-114111.

I usually find these threads when they're long dead.

There are a few people that know a surprisingly large amount about these speakers. I'm still collecting information.

I inherited my 3 speakers from my brother, who acquired them back in the 70's. We were amazed at quality of voice reproduction. Problem was they didn't sound anything like the JBL studio monitors of the time, so mixing on them was a disaster. That's how I got them.

From what I've found out so far, they have become notorious for aging poorly. The tweeters were super fragile. Matching from drive to drive was very poor. All that said I still love mine, and I've converted my wife into a believer.

The front or outer surround was reportedly doped at factory, and this doping changed over time causing the surround to stiffen. The three I have were all "treated" for this affliction. Unfortunately the individual used Kodak Photoflow to soften the surround. Over time this will leave the appearance of water damage. The solution continues to migrate through the paper drawing in moisture from the air. With my speakers the surrounds eventually turned to mush. I used various hacks to strength the surround. After I spent days gently flushing the treated areas with water to remove the Photoflow, once I understood what was happening to my speakers and why.

The bumps as you've all noticed are a "push here" target for inquiring fingers and cat paws. My solution/fix is to use some water to soften the bump to be repaired and a low power vacuum clearer with wand attachment to pull the bump out. Mostly works. Cosmetic results will vary.

The tweeters on the original LC-1 (no bumps) and LC-1A, were reported as being rated at some ridiculous power of 5 watts. The replacement tweeter and the version in LC-1B and LC-1C were said to be rated at 40 watts.

One of my three had a blown tweeter. The enamel was completely burnt. I'm told that there is 17 feet of aluminum wire on the voice coil. Don't know about this. Parts were scarce even back in the 70's. There was supposedly someone in Camden that had bought all the spairs. Not knowing how to contact that person, I got brave and wound my own voice coil using the finest wire I had at the time, #44. My first attempt was a fail. Voice coil was to tight. Second attempt actually worked. For those interested, just really thin paper and metal lacquer holding it all together. That speaker is in my basement for music while working on other projects. The other two are currently stored in vacuum pages with silica-gel packs. I recently did a sweep test on that speaker, its has output to 15k Hz. Then its gone, which is ok as I can't hear that high anymore. With all the peaks and dips from room reflections you really can't tell if there is a level mismatch. I can't hear one anyway. The other speaker that sits with it is a JBL 4312 with titanium tweeter, just no comparison to the RCA.

Hope this story will inspire you all. Even in their near dead condition these are still great speakers worth the effort.

Oh and if you hear of a source of parts let everyone know.
 
Ok, well that was painful. Had to register to comment of course. Had to switch machines to retrieve the confirmation. Then search to find this thread again. Search doesn't like RCA or LC-1A, to short a phrase to search. Eventually I used MI-114111.

I usually find these threads when they're long dead.

There are a few people that know a surprisingly large amount about these speakers. I'm still collecting information.

I inherited my 3 speakers from my brother, who acquired them back in the 70's. We were amazed at quality of voice reproduction. Problem was they didn't sound anything like the JBL studio monitors of the time, so mixing on them was a disaster. That's how I got them.

From what I've found out so far, they have become notorious for aging poorly. The tweeters were super fragile. Matching from drive to drive was very poor. All that said I still love mine, and I've converted my wife into a believer.

The front or outer surround was reportedly doped at factory, and this doping changed over time causing the surround to stiffen. The three I have were all "treated" for this affliction. Unfortunately the individual used Kodak Photoflow to soften the surround. Over time this will leave the appearance of water damage. The solution continues to migrate through the paper drawing in moisture from the air. With my speakers the surrounds eventually turned to mush. I used various hacks to strength the surround. After I spent days gently flushing the treated areas with water to remove the Photoflow, once I understood what was happening to my speakers and why.

The bumps as you've all noticed are a "push here" target for inquiring fingers and cat paws. My solution/fix is to use some water to soften the bump to be repaired and a low power vacuum clearer with wand attachment to pull the bump out. Mostly works. Cosmetic results will vary.

The tweeters on the original LC-1 (no bumps) and LC-1A, were reported as being rated at some ridiculous power of 5 watts. The replacement tweeter and the version in LC-1B and LC-1C were said to be rated at 40 watts.

One of my three had a blown tweeter. The enamel was completely burnt. I'm told that there is 17 feet of aluminum wire on the voice coil. Don't know about this. Parts were scarce even back in the 70's. There was supposedly someone in Camden that had bought all the spairs. Not knowing how to contact that person, I got brave and wound my own voice coil using the finest wire I had at the time, #44. My first attempt was a fail. Voice coil was to tight. Second attempt actually worked. For those interested, just really thin paper and metal lacquer holding it all together. That speaker is in my basement for music while working on other projects. The other two are currently stored in vacuum pages with silica-gel packs. I recently did a sweep test on that speaker, its has output to 15k Hz. Then its gone, which is ok as I can't hear that high anymore. With all the peaks and dips from room reflections you really can't tell if there is a level mismatch. I can't hear one anyway. The other speaker that sits with it is a JBL 4312 with titanium tweeter, just no comparison to the RCA.

Hope this story will inspire you all. Even in their near dead condition these are still great speakers worth the effort.

Oh and if you hear of a source of parts let everyone know.
Glad this alive is well enough to get some fresh blood. And thanks for going through the effort to sign up - welcome, this is really a fantastic bunch.

I've gotten word that there is someone who has experience repairing these. Don't know how yet - I haven't asked yet as I'm afraid to spend too much money repairing these at the moment, knowing full well that that's exactly what I want to do. I'll provide an update when there's real information to be shared.

These speakers are going to stay with me for a while. Working or not, they're too cool to purge. I'm very much looking forward to hearing perfect pair, but even a partially revived pair will do me well given the inklings I've heard out of my one working speaker.
 
Glad to read that you're still active on this project. You asked way back when about reconing. Yes it would be an audio-sin to recone with an after market cone. Not for the collect-ability value, but more from an engineering point of view. The cone is very specific on the LC-1 series speakers. Shallow, very stiff, and very heavy compared to the typical high efficiency speaker. You'd have a very different creature in the end.

I did see an ad about a year ago for a recone kit for an actual LC-1A, RCA replacement part. Beinging sold out of Japan. The parts do surface once in awhile. I've never seen the bumps show up. When I look long enough at them they look a lot like the cones of those tiny oval speakers that where around years ago.

I've considered redoing the surrounds on mine. Using a fabric version as was used on the LC-1C. They're still working properly, no rubbing, so I'm leaving well enough alone.

I'm curious about the LC-1's tweeter arrangement. Can you post a close-up of the tweeter. Later models had a "butterfly" deflector mouned in the centre of the tweater. I'm curious of what they did on the first model.
 
Question: is it an audio sin to recone an LC-1A with a non-hump cone?
If by that you mean an original RCA "non-hump" cone as found in the early MI-11411 speaker, no, not a sin. The "bumps" don't make that much of an audible difference. I might not use one in a stereo pair with another cone having the bumps, but if it's all that's available.....

But if by the above you mean using some sort of generic or other brand replacement cone in an LC-1A, yes, that's a sin. You won't end up with anything like the original LC-1A sound unless you use original RCA cones. Sorry. True dat.

Over the years, I've had dozens of these speakers of all versions. The RCA cones are very unique. Never seen a replacement that was even close.

Oh and if you hear of a source of parts let everyone know.
Hate to be the one to say this, but you won't. What few NOS RCA parts there may ever have been are long since used up or in hoards by now. If you're lucky, you might get a shot at a hoarder's estate, or some obsessive LC-1A owner with money and ambition may try and reproduce them, but even that's a long shot, given the extreme expense in so doing and the limited opportunity for any kind of return on investment.

They're still working properly, no rubbing, so I'm leaving well enough alone.
Very wise.

Later models had a "butterfly" deflector mouned in the centre of the tweater. I'm curious of what they did on the first model.
Early tweeter (in the MI-11411--no "humps" or butterly) is the same as the LC-1A tweeter. It just has the center screw, but no butterfly. I don't have a photo, but maybe someone can post one.
 
Went back to the OP's starting post. Now that I have an Account the pictures are visible.

Do you think they're related?
IMG_5488.JPG

Regarding the bumps, I can't hear a difference when I'm in front of it. My understanding was they're greatest effect was off-axis. Now there I can tell the difference. I walk all around the room with little change. With my single JBL, get five or six feet off-axis and you're listening to a completely different speaker. Someone once said that the RCAs were flatter off-axis. Some day I may measure them to see if that's true.
 
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