Beginning the RCA LC-1A adventure.

[Limberpine]

Run roh, I came across quite the deal on one of these. I've yet to see it in person, so I wanted to ask:

What things do I need to pay attention to with regards to wear/degradation?

The seller has had this for like 15 years and never played sound through it.

I assume the cap needs to be replaced on the tweeter. Reccomendations on those?

Does anyone have an schematics on the orginal Art Deco boxes? I'd like to look into the cost to build one of those. If that goes well, I might consider buying another LC-1 at market price to have a stero set.

This will certinaly be a long term project, but I'm excited to go on the journey and maybe even see if I can sneak a stereo set of these in our living room to replace the La Scalas. We have a deco theme, so it might just work! 🤣

 

[Audionut]

Great find!!! I’ve never owned one but the biggest thing to look for next to the ohm reading for an open VC is to play sound through it to make sure it doesn’t have voicecoil rub. It looks to be in great shape from the pics.
@RCA NUT may chime in with greater detail on what to look for.

 

[Limberpine]

Great find!!! I’ve never owned one but the biggest thing to look for next to the ohm reading for an open VC is to play sound through it to make sure it doesn’t have voicecoil rub. It looks to be in great shape from the pics.
@RCA NUT may chime in with greater detail on what to look for.

Thanks! It's was just completely random that I found one! But, I've listened to a couple videos on youtube and there is something to the way they sound. Something very alluring.

 

[MrEd]

Very nice find.... a bit on the jelous side here 😉

 

[Topper]

Leave the cap alone. If you're uncomfortable not knowing for sure you can test it but I'd be shocked if it were bad.
Overall it looks good to me so I'm pretty sure you're good to go. Hook it up, keep the volume down and give it a very gentle listen to start.

 

[gilmorneau]

What things do I need to pay attention to with regards to wear/degradation?

Check the tweeter (independently from the woofer) to see if its voice coil is open. The tweeters on these speakers are fragile and (AFAIK) irreplaceable. They were commonly blown in the early solid-state days by buffoons with poor volume knob habits.

Check the paper roll surround on the woofer for fatigue/cracking. Common with LC-1A's. Less common with the early ones like yours, but then on those, sometimes the surround "goop" goes stiff, limiting the free movement of the woofer, so you'll want to check for that.

Otherwise just general old speaker stuff--does the woofer voice coil rub? This is not always fatal on these speakers as they are built to be serviced/adjusted to some degree. I've got the service data sheets around here somewhere.

I assume the cap needs to be replaced on the tweeter.

Probably the last thing I'd worry about. These capacitors are paper/foil in oil and hermetically sealed. Should survive anything. Leave it.

Does anyone have an schematics on the original Art Deco boxes?

You mean these?


You'll find them a challenging build without a sample to take measurements from. Even then, you'll need excellent woodworking skills, particularly to reproduce the louvers. I've restored a couple pairs of these (including the ones in the photo above), but I'll need to dig around to see if I still have documentation photos of the process. It was a while ago.

Excellent sounding speakers, BTW. Consider building a mono system around the one you have. They were designed in the mono days and sound fantastic used that way. I had one that was the centerpiece of my mono set up for years and loved it.

 

[Limberpine]

Check the tweeter (independently from the woofer) to see if its voice coil is open. The tweeters on these speakers are fragile and (AFAIK) irreplaceable. They were commonly blown in the early solid-state days by buffoons with poor volume knob habits.

Check the paper roll surround on the woofer for fatigue/cracking. Common with LC-1A's. Less common with the early ones like yours, but then on those, sometimes the surround "goop" goes stiff, limiting the free movement of the woofer, so you'll want to check for that.

Otherwise just general old speaker stuff--does the woofer voice coil rub? This is not always fatal on these speakers as they are built to be serviced/adjusted to some degree. I've got the service data sheets around here somewhere.



Probably the last thing I'd worry about. These capacitors are paper/foil in oil and hermetically sealed. Should survive anything. Leave it.



You mean these?
View attachment 64940

You'll find them a challenging build without a sample to take measurements from. Even then, you'll need excellent woodworking skills, particularly to reproduce the louvers. I've restored a couple pairs of these (including the ones in the photo above), but I'll need to dig around to see if I still have documentation photos of the process. It was a while ago.

Excellent sounding speakers, BTW. Consider building a mono system around the one you have. They were designed in the mono days and sound fantastic used that way. I had one that was the centerpiece of my mono set up for years and loved it.

Thanks for the help with service manuals and photos/process of the restore. Since those might be challenging to reproduce, what is the next best box that is reccomedned to put these in?

 

[Limberpine]

Leave the cap alone. If you're uncomfortable not knowing for sure you can test it but I'd be shocked if it were bad.
Overall it looks good to me so I'm pretty sure you're good to go. Hook it up, keep the volume down and give it a very gentle listen to start.

okay, I was thinking it should be fine if I hadn't seen and leaking or seeping of oil.

 

[gilmorneau]

In addition to the "furnace" style cabinets shown above, RCA put them into these:


these:


And these:


The cabinet in the top photo is called the LS-11 (I think), and is probably the best option and also easiest to build. Pretty sure the plans are online somewhere.
The cabinet in the middle photo was a "home furniture" cabinet marketed by RCA. They can also sound quite good and sometimes show up for sale.
The bottom photo shows the "wall wedge" style, which are virtually useless for home hi-fi IMO. Too small of an enclosure. They were usually used at the ceiling/wall junction in recording studios. BTW, they weren't originally blue like in the photos--the owner of those has taken artistic license when repainting them.

 

[Limberpine]

In addition to the "furnace" style cabinets shown above, RCA put them into these:
View attachment 64941

these:
View attachment 64942

And these:
View attachment 64943

The cabinet in the top photo is called the LS-11 (I think), and is probably the best option and also easiest to build. Pretty sure the plans are online somewhere.
The cabinet in the middle photo was a "home furniture" cabinet marketed by RCA. They can also sound quite good and sometimes show up for sale.
The bottom photo shows the "wall wedge" style, which are virtually useless for home hi-fi IMO. Too small of an enclosure. They were usually used at the ceiling/wall junction in recording studios. BTW, they weren't originally blue like in the photos--the owner of those has taken artistic license when repainting them.

Awesome. If anyone has the plans for the first and second one that would be helpful. I'll do some searching around online as well. Those 2 cabinets will be WAY less expense to build than the furnace style, although the furnace style looks so cool and deco.

I don't think I can get away with putting anything except the furnace style in the living room though.....haha!

 

[gable]

The LS-11 is reported to be a very good cabinet for them. I have a single driver, and am building a single LS-11 cabinet for it this fall. I think I have a scan of the plans I'm working from.

I'll see if I can dig them up.

 

[gable]

Found it. I don't remember where I found it originally, but here is my scan:

 

[Topper]

Found it. I don't remember where I found it originally, but here is my scan:

That's from "Radio and Television News" May 1951. "Cabinets for HIgh-Quality Direct Radiator Loudspeakers".
It also shows up in the November 1950 issue in another article.
I don't understand why but that article seems magically to just disappear after it's link is posted, something I must do at least once a year.
There's a hard copy of May 1951 on the bay right now, btw.
I have a pair built from those plans that are very good. I do have a pair of furnace cabs here as well but I've never bothered to listen to them side by side. My impression is that the RTN cabs may actually be the better sounding.

There's a picture here:

I listened to a pair of RCA LC-1A coaxes this week

The more I hear them, the more I crave a pair of RCA LC-1As. I spent some quality time listening to a pair driven by SE 45 and also by PP 2A3 amplifiers yesterday, and it just reinforced my earlier impressions. Dr. Olson & RCA knew what they were doing; these are great, great reproducers of...

hifihaven.org

 

[Topper]

There's also an Olson article from "Radio News" in 1954 "A New Line of HI-Fi Speakers" that has a bit more info about the LC including a quick explanation of why the bumps are really there... Tease!

 

[Limberpine]

Thanks all!

 

[Dan Quick]

Yes, it sounds great in a mono setup. At times I prefer to stereo. There is something so pure and immediate. Elvis is in the room.

 

[je2a3]

Run roh, I came across quite the deal on one of these. I've yet to see it in person, so I wanted to ask:

What things do I need to pay attention to with regards to wear/degradation?

The seller has had this for like 15 years and never played sound through it.

I assume the cap needs to be replaced on the tweeter. Reccomendations on those?

Does anyone have an schematics on the orginal Art Deco boxes? I'd like to look into the cost to build one of those. If that goes well, I might consider buying another LC-1 at market price to have a stero set.

This will certinaly be a long term project, but I'm excited to go on the journey and maybe even see if I can sneak a stereo set of these in our living room to replace the La Scalas. We have a deco theme, so it might just work! 🤣

Congrats!

This is the RCA LC model I'm most familiar with since a friend owns a pair in deco cabs sporting original hermetically sealed PIO XO cap.

The -1A goes a bit lower in the bass but the smooth cone LC1 has nicer mids to my ears.

Enjoy it in mono or stereo!

 

[forkliftman15]

There's a picture here:

I listened to a pair of RCA LC-1A coaxes this week

The more I hear them, the more I crave a pair of RCA LC-1As. I spent some quality time listening to a pair driven by SE 45 and also by PP 2A3 amplifiers yesterday, and it just reinforced my earlier impressions. Dr. Olson & RCA knew what they were doing; these are great, great reproducers of...

hifihaven.org

But who is that sagacious and handsome fellow photobombing via reflection?

 

[Redboy]

But who is that sagacious and handsome fellow photobombing via reflection?

Hey, I hadn’t noticed that!😆

 

[nelsress]

Nice MI-11411/LC-1 original. Both the original and all of the LC-1A drivers without the "-1" utilized the same cone/surround assembly. They were all one piece. The second iteration of the LC-1A which sported the serial number on the reverse WITH the "-1", supposedly had a stronger/beefier cone material. The LC-1B version utilized a cone that looks like the original and the LC-1A but has a fabric surround instead of the contiguous paper surround like the original and the LC-1A. The serial number on the back of the LC-1B drivers have a "-2" on them. Both the LC-1A and the LC-1B have the ovoid bumps on the cone and have the metal deflectors mounted on the tweeters.

I've had 11 LC-1 drivers over the years and still have 8 in my possession, two LC-1B's in LS-11 cabinets, two LC-1Bs I'm thinking of putting in the LS-11 cabinets and see how two per side sounds! I also have two originals that had torn paper surrounds so I cut off the paper surrounds and replaced them with fabric surrounds that I found on eBay a while back that were a very close match or exactly like the surrounds on my LC-1B's. This past year I purchased several sets of the ovoid bumps from an eBay seller which I plan to glue onto the cones of these two originals and I have an extra set in case I stumble onto an LC-1A or LC-1B with badly damaged bumps, which I've seen in the past.

The last thing I'm going to try to have done is have some tweeter deflectors made from one of the ones on my remaining speakers. Give this a really good listen, I'm not saying I'm the final word but these are very special speakers. I'll be 69 in a couple months and bought my first decent stereo in 1972 and have been into audio for most of those 50+ years. I've owned, auditioned and listened to countless speakers and there were always something I ended up chasing, until I found my first pair of LC-1 originals, listened to them for several months and then sold them to pay for a sewer line repair at our home. It didn't take me two weeks and listening to some pretty highly regarded Infinity speakers that I thought would be just fine. From that point on I decided to chase LC-1s until I felt I was set and haven't even looked at speakers with the intention to buy them for my use. Not everyone appreciates them like I do but I'm hardly alone. :-) Enjoy the music