OLAs again

[JKent]

The owner of the local electronics shop took these in. When I told him they were desirable he asked if I wanted to restore them for him. The obvious problem areas are;

1. Foam rot of course
2. ripped grilles
3. scratch on top of one a few chips

This will be my 3rd pair of OLAs to restore so I know the basics but have a couple of questions for you Advent experts:

1. Original grille cloth is apparently unobtainium. I googled some discussions here and on AK and there were a couple of suggestions but none perfect. I previously did some utility large Advents in linen and they looked pretty good. Any other suggestions?
2. On the last pair I replaced the foam blocks with fiberglass. Any thoughts on this? I'm inclined to leave the foam.
3. I added bracing on the last pair. Should I brace these?

Haven't opened them up yet to see which version of the crossovers they have but I'll replace the caps at least.

Kent

 

Edited April 5, 2023 by JKent
removed 1 pic

[Norman Nicolai]

Nice project, JKent.

I’ve worked on 2 sets of Advents over the last year, a set of OLA’s and a set of NLA’s. The OLA’s were in far worse shape than the NLA’s, so the restoration was far more extensive. Your OLA’s look to be close in appearance to my OLA’s.

1. I used the same linen cloth on both sets of speakers. You should be able to get sonically transparent linen in a matching color to the original. I used a linen cloth that was just slightly more coarse looking than the original fabric, and it looks and sounds fine.

2. I’ve never seen foam in Advents. I’ve read that they started to use foam in later models to replace the fiberglass, but your Advents look like earlier models so they should have fiberglass. I’d be inclined to switch to fiberglass on the off chance that they have foam. Here’s a thread addressing that issue. It also talks a bit about cabinet bracing:

https://community.classicspeakerpages.net/topic/2802-proper-placement-of-foam-damping-material-in-large-advent/

3. The NLA’s I worked on were braced by a previous owner. I always felt that the bass response was a little better on the NLA compared to the OLA when I would listen to them back-to-back. Whether that was due to bracing or other design differences, I’m not sure. Here’s a thread from another site on bracing Large Advents:

https://audiokarma.org/forums/index.php?threads/bracing-the-new-large-advent-nla-cabinet-and-econowave-pete-basel.538810/
 

Good luck on your project. Please post photos of the finished project when you are done!

[JKent]

Thanks for all the useful info Norman. The OLAs I worked on before had foam blocks but these, as you said, have fiberglass. One is stuffed with pink, the other with yellow. Tweeters and woofers are all date stamped 1973. It looks like I have the Rev. 1 crossovers with two 16uF caps each. I know Pete (maybe others) recommend building a Rev. 2 xo and that's what I did with the pair I had planned to keep but these will be sold and I think new caps will suffice. Very tight in ther so I "may" try to knock the xo boards loose. We'll see...

The pair of foams I have on hand was marked (by me) "OLA flange". I'm guessing I meant metal frame so it looks like I'll be ordering foams. Also, the surrounds were totally gone and I had forgotten these get mounted inverted. Glad I looked at some old photos 😌

Besides pulling the woofers and testing the tweeters I steamed the big dents and filled the small chips with brown epoxy. When I get some good weather I'll sand the cabinets and figure out what to use for a finish. One cab is darker than the other so I'll want to address that too.

I "may" take a piece of the grille cloth to JoAnn's Fabric but probably not--avoiding indoor places as much as possible. I have some nice CharlesCraft "Irish" linen that may work. It's 28 count, so finer than the original. Also undecided about the black skrim. I don't like the double layer but maybe a potential buyer will look for that.

[Norman Nicolai]

I have refinished many pieces of furniture over the years, not counting the the speaker cabinets I have worked on the last 2 years, and had never heard of “steaming” the dents out of wood. Your mentioning that in your post caused me to google it and I came across a few videos illustrating the process on YouTube. I always considered myself pretty well versed on wood working techniques, but did not know about that one. Boy, do I feel dumb!

Thanks for pointing out a new trick, unrelated to electronics!

[Doug G.]

See this thread for the fabric to get:

https://audiokarma.org/forums/index.php?threads/large-advent-cloth-pics-of-new-cloth-and-original-cloth.878255/

It's what I bought and it's so close to the original, you can't really tell the difference.

As far as fiberglass or foam blocks, I would restore them to whatever was originally in them. The foam blocks didn't start until about 1975. I have pairs with both in them and soundwise, there really isn't any difference.

There really isn't much difference between the 16,16 and 16,8 capacitor combinations, either.

Doug

[JKent]

Thanks Doug

I'm going to think about that. I've used that same fabric in "lanbswool" for AR speakers but the Advent cloth does not look like linen. Linen has an irregular weave and slubs. The color looks good though. Also not sure I want to spend the money on these speakers, since they are for resale. I have some nice CharlesCraft linen on hand and may use that. Still undecided about the black skrim so I painted the Masonite grille boards black.

Bought some 15uF Carli caps from Madisound. I was going to get 16uF from Erse but they have a $20 minimum order. 15uF will be fine or if I feel OCD I do have some 1uF caps on hand.

Interesting note on finishing: The serial numbers are about 4,000 apart (82946 & 86444). One is a little darker so I want to make them match better. I started to clean up the earlier one with lacquer thinner and the finish came off. Lacquer. But the later one is impervious to lacquer thinner. Varnish? I dunno. So I'll sand the finish off and make sure I'm down to bare wood, stain as needed and then either spray them both with lacquer (if I get a day warm here in NJ in winter) or maybe use wipe-on poly. Thoughts on this welcome.

Kent

[Doug G.]

Somebody must have added the lacquer or varnish as they would originally just have been oil rubbed. I have a feeling lots of Advents ended up being redone over the years. I have one pair like that but they did a good job and they still look like they are oil rubbed so I left them.

Doug

[Pete B]

I thought that someone found a source for very similar 16 count grille cloth.

I don't remember where it was mentioned.

There's 12 and 13 TPI here and they look close buy maybe not in real life:

https://dorrmillstore.com/index.php/site/products/category/foundation_cloth/17

[Pete B]

Here's 18 TPI Irish Linen:

https://www.123stitch.com/m/18-Count-Linen-style-Cross-Stitch-Fabric

Discussed many years ago in this thread:

https://community.classicspeakerpages.net/topic/2884-advent-large-grillcloth-restorationreplacement/?tab=comments#comment-67500

 

[JKent]

Pete, that first link shows a 12 TPI "primitive linen" that looks close in the picture. The 18-count Weichelt linen from 123 Stitch is perfect for AR speakers but not so much for Advent, but it would look nice.

Finished the recap today. I used 15uF Carlis to replace the 16uF caps. I figure close enough--certainly within spec. The Carlis measure just a tad over 15.

Woofers are re-foamed. I got the surrounds for the Masonite woofers from SpeakerWorks but have since learned I could have used the ones for metal frames (which I happened to have on hand).

They're playing now and sound good. I'll probably insert one of your Baffle Step Compensators Pete. I have one that I cobbled together a few years back.

Cabinets could use a little more refinisheing and then there's the grilles. Hope to have them complete this year 😉

 

[Doug G.]

Yes, these days, the same surrounds are usually sold for both versions of the first Advents (original and New). Some vendors still sell separate ones, as you found, Kent. The only difference is the original surrounds for the original Advents have a wider outside flange where it fits behind the Masonite ring but the ones for the New Advents, with the narrower flange, work fine for the original Masonite woofers, too.

The main things are that the compliance (floppiness) and roll size are correct.

Doug

[JKent]

Making progress. I decided to go with some material I had on hand. It's "M.C.G. Textiles Heritage Rug Hooking 100% Linen Burlap". The color and texture seem good and I like to work with linen or another natural fiber because I never get the material tight on the frames. With linen I can spritz it with water, dry with a hair dryer and it's tight as a drum. Think I bought this at Michaels when I was looking for grille cloth for the KLH Model Eight radio speaker. Just googled it and apparently it's no ;onger available.

Cabinets are coming along but not quite finished.

 

 

Edited November 23, 2022 by JKent
Removed pictures

[Jim Pearce]

Superb work as usual, J.

As always, your posts are of great interest.

[Norman Nicolai]

They look like they’re coming along fine, JKent. Nice work!

I imagine that you will be listening to them a bit before you return them to their owner. I’m curious how they fit into your “pantheon” of classic speakers now that you have had the opportunity to reacquaint yourself with them. I know from your posts that you admire and are familiar with the KLH Model Five and the AR-3a, as well as many other vintage speakers. How does the original Advent Loudspeaker, in a restored version, sound to you these days?

[JKent]

Thanks Jim & Norman.

Norman, I'm fixing these up for Wayne Electronics so if you want to buy them, they'll be for sale. So not staying here. Kind of hard to do a fair comparison because my reference speakers are AR-91s, much bigger and pricier, but I'll give a listen and report my impressions. A much fairer comparison would be the AR-2ax and I can tell you that when I did own OLAs I had high hopes. I replaced all of the crossover components with PeteB's help and added oak bracing. I'm sure that pair were as good as it gets for the OLA but I thought the 2ax was a superior speaker. Sadly, I sold those too so can't compare. Speakers I can use for comparison now would be the AR-91 & AR-3a, both bigger than the OLA and the AR-4x & Cizek KA-1, both smaller. Regarding the KLH Model Five, I no longer have those but when I did I was struck by how much alike the Fives and OLAs looked. I could imagine a surround setup with Fives in front and OLAs in the rear.

Kent

PS: I hijacked this post back in 2011: 

The August 17 shows the Five and OLA side by side. Aug 19 post shows new xo and bracing. On Aug 24 I discovered one tweeter was bad. Our late friend Carl to the rescue! Starting with the Aug 30th post I write about my listening impressions. I just didn't love them. Let's remember these were developed to prop up Henry's projection TV business. They were built to a price point ($114 to $141) so compromises were made. I'm guessing these were designed as Rock n Roll speakers--big bass, exaggerated highs--but I could be wrong. I think they were outstanding speakers at the time and for the price. Just not what I prefer.

 

[Doug G.]

That material actually looks good. I can see very minor differences in thread thickness but that's really only apparent to someone who knows exactly what the original cloth looks like and is OCD about it. 

How did you attach the grille cloth? I still haven't installed the cloth I got a while ago and I'd rather do it as it was originally done but I have only found one source for 1/8" leg staples and I don't know if they are heavy duty enough to be driven into Masonite. So, I may just use contact cement but I have been hedging.

Doug

[JKent]

Hi Doug

I didn't use any black scrim, just the linen. I sanded the faces of the Masonite to get rid of the bumps from the staples then spray painted them black.

Then I use Aleene's Tacky glue. Cut the cloth about 1" oversize all around, then do one edge. I smear the glue with my fingers and press the cloth into it. It takes time, working the glue into the material and continuing until the glue starts to set up. Then I do the opposite end, pulling the cloth as tight as I can get it and following the same procedure. Then each side. It's time consuming but I've has good success. Then it dries overnight, then I spray the linen with water and dry with a hair dryer. The result is nice and tight. This is the method I've used with little KLH Model Eight grilles but it works for full-size ones too.

Kent

[Doug G.]

Thanks!

Doug

[RTally]

23 hours ago, JKent said:

I didn't use any black scrim, just the linen. I sanded the faces of the Masonite to get rid of the bumps from the staples then spray painted them black.

Then I use Aleene's Tacky glue. Cut the cloth about 1" oversize all around, then do one edge. I smear the glue with my fingers and press the cloth into it. It takes time, working the glue into the material and continuing until the glue starts to set up. Then I do the opposite end, pulling the cloth as tight as I can get it and following the same procedure. Then each side. It's time consuming but I've has good success. Then it dries overnight, then I spray the linen with water and dry with a hair dryer. The result is nice and tight. This is the method I've used with little KLH Model Eight grilles but it works for full-size ones too.

 

I use a similar technique except I glue one side and then clamp it while I work on the opposite side. I clamp the opposite side when I get it glued.

I have some aluminum bars (about 1/8" x 1/2" x 20") that I place against the glued section. I use paper spring clips as clamps. It is compact and works well for me. I can usually get the cloth tight enough using this method without resorting to spritzing. The Aileene's glue has enough working time to let me stretch the fabric to align the fibers with the edge. 

[Norman Nicolai]

Every time I tried glueing grill cloth I wound up with a sticky mess and got glue on my fingers which wound up on the front of the grill cloth. I’ve even watched videos on YouTube and still can’t get the knack of it. 

I get the shallowest staple I can find, then cut off a little length on each side of a group of as 10 staples still attached to each other with an old scissor. After you do that to a few sections of staples, you load up a staple gun. Normally when you staple something, you press down on the stapler so the staple penetrates. But using that technique will shoot the staple all the way through the Masonite so it protrudes to the other side. If you lessen the pressure on the stapler, it will penetrate enough to secure the speaker cloth, but not enough to go through to the other side.

The other thing I find is that Masonite seems to vary in thickness, so using a stapler can be tricky.

Here are a couple of photos of different cloths I have used. Products that are actually sold as “speaker cloth” are almost always unattractive to me, so using fabric stores is my only option. The lighter fabric is just a standard linen I installed on a set of EPI 100W’s. The other is like a burlap linen that I used on all my Advents. I only have one set of OLA’s now.

[JKent]

Nice job Norman I could never get the cloth that tight without spritzing/shrinking. And thanks for the tip on trimming staples. Who woulda thunk?

I've finished the OLAs. Top dings came out OK and the cabinets aren't bad. If it weren't January in the Appalachians I'd probably have taken these outside for chemical stripping.

Anyhoo, after trying to get a better color match, which wasn't entirely successful, I used a couple of coats of wipe-on poly. I don't normally use poly but still don't know what the hard finish is on some of Henry's speakers. After the gloss poly dried I buffed it out by hand with steel wool followed by white Scotch Brite.

 

 

 

 

Edited April 5, 2023 by JKent
removed 3 photos

[Norman Nicolai]

Nice!

They look like vintage speakers that are in mint condition. It looks like you have managed to preserve the character of the old wood during the restoration, yet they look almost new. One of the best restorations I have ever seen.

Good work. 

[Norman Nicolai]

I just purchased another set of OLA’s on eBay today. They need new foam, caps and refinishing. I don’t have anything on the bench right now so I’m looking for something to keep me busy while sheltering at home during the pandemic. Not going to pick up the OLA’s for about 2 weeks.

JKent, a couple of questions about your process, please.

I don’t normally use wipe on polyurethane either, but I love the way your speakers look, so I think I’m going to try it. Satin finish poly, I presume? Any specific brand?

Did you start with 0000 steel wool or use different coarser grades leading up to the scotch brite buffing?

Did you use any paste wax after the scotch brute?

Thanks!

 

[JKent]

Norman, I think these speakers look better in the photos than they do in person. The be honest, I'm not 100% thrilled with the finish. I don't think I got everything down to totally bare wood, which is kind of tricky with these Advents (and KLH Five, Twelve, others). I don't know what was on there originally but it's tough to remove.

I used Minwax Gloss wipe-on poly. It's more clear than semi. The steel wool/ScotchBrite knocks down the gloss. 

Yes, the steel wool was a bit coarser. Maybe 00? Then green, then white ScotchBrite. I did not use wax.

FWIW, my preferred finish when a hard coat is needed is Minwax lacquer in a rattle can. Several coats (5-8) applied outdoors about 15 minutes apart. Again, Gloss, softened with ScotchBrite if desired.

[Norman Nicolai]

JKent, it’s funny because they really do look good in the photos. Part of it may be the grill cloth.

I may try wipe on poly for my next refinishing job anyway, just for a change. I haven’t used it for years, but if the coats are thin enough and the excess wiped off between coats, you can get a nice finish. I have a leaf table with that finish that gets a great deal of use and it has held up well over the years.