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What's under the black paint on the motherboard?


rpampt

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I looked everywhere and can't find the info. I have some Birch Cornwalls and I'm getting closer to refinishing them. What is under the black paint on the motherboard. More of the birch ply? Something different. I was thinking of sanding it smooth and refinishing it to match the rest of the cabinet if so.

Am I just going to have to strip it and find out for myself?

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What year were they manufactured?

What kind are they? CBR, CDBR, CBB, CDBB, CBL, CDBL? This info is on the label and the serial number tells time of manufacture, but a good pic(or pics) would answer most of the questions.

I assume thay have a black-painted inset, stapled-in MOTORboard (motherboards are in computers)? If that is the case they are MOST LIKELY to be either the same kind of plywood the rest of the cabinet is, OR they may be baltic birch plywood, so see if you can tell how many plys the plywood has, including its outer veneer layers. If it is a Decorator model, without the drop in front (ie., flush fronted) which uses a different cabinet build than the inset fronts cabinets use, then the front panel is the SAME plywood as the rest of the box. Some of the Cornwall II (more recent version) had lumber-core panels or MDF panels veneered with birch, and a plywood motorboard...it all depends on what the info on the labels says and/or what can be seen in pics.

Give us more info and we can give a definite answer, thanks!

Andy

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They are the birch as I mentioned above. I believe 1979 and marked CBR. Cabs are 7 ply and looking at the edge of the "motorboard" it is 5 ply and it is indeed stapled in. I'm used to calling it the front baffle, and just wasn't paying attention when typing. Multi-tasking LOL. They are not decorator and have the inset board that is indeed painted black.

Anyway, the rest of the cabinet is the 7 ply baltic birch.

Thanks for the quick responses!

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They are the birch as I mentioned above. I believe 1979 and marked CBR. Cabs are 7 ply and looking at the edge of the "motorboard" it is 5 ply and it is indeed stapled in. I'm used to calling it the front baffle, and just wasn't paying attention when typing. Multi-tasking LOL. They are not decorator and have the inset board that is indeed painted black.

Anyway, the rest of the cabinet is the 7 ply baltic birch.

Thanks for the quick responses!

I probably built them, if from 1979, and the cabinet is NOT baltic birch, because 3/4" (more or less) baltic birch has , if I remember correctly, 11 plys. Your speakers are custom laid GEORGIA-PACIFIC Birch-veneered fir (or birch) plywood, 5-plys of equal thickness fir, or even birch, with one thinner veneer birch ply on each side. Your drop-in fronts will most likely be the same material, unless they were built for the VERY short time that we used the baltic birch for the drop in fronts. We went back to the Georgia-Pacific stuff for the fronts because the 1-1/8'X1/4" staples were folding too often instead of penetrating the baltic birch and it was taking too much time to pull them and put in another staple that was likely to fold, too!

Anyway, the fronts will be about the same as the sides, but won't be pretty...with staple holes and maybe puttied places around the routed holes. Remember, those fronts should have been pulled to the bottom of the opening in the cabinet when first stapled, and because of that the gaps around the fronts will be about equal along the sides but may be more than you want at the top...not exactly a nice aesthetic situation, ya'know?

Leave that area black, IMHO, to include the inside edges of the sides and top, and bottom where they are black. You likely won't like the fruits of all the labor it will take to refinish the fronts anyway.

Look at the back otf the speakers, on side panel to your left (facing the rear of the speaker), up near the top joint, and in the plys there you SHOULD see a letter "A" stamped into the plys there, along with another letter beside it...I AM THE LETTER A! The sander of the cabinets will be a single letter(not part of a pair), which should appear crisper and maybe even deeper, either just above or below the two letters for the cabinet builder team.

If you don't see the letter "A", then either I was on vacation or off sick the day they were built.

Andy

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OK, the letter R was on the edge where you mentioned with USA just below. That would have been cool talking directly to the builder! When looking closer, the front is actually 7 ply if you count what looks like the thin outer veneer. With the edges painted, it's hard to tell for sure. But it is different than the rest of the cab. There definitely is a difference between the cab and the front motorboard. And the cab would actually be 9 ply if you count the layer of outer veneer.

1979 is just what I remember, that could be wrong. serial # is 168017 and 168018.

The spacing around the endges of the motorboard is actually pretty consistent. It doesn't look pulled to the bottom. Appears to be about 1/8" all the way around, give or take.

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Andy,

I had no idea you built speakers at Klipsch. I've only been on the forum for about 2 years.

My name isn't a dead giveaway? HA, HA!

I did a little bit of speaker box assembly while at Klipsch.

I worked there from July 1976 to Septrember 1983...over 90% of birch Heresys from 1977 til I left were built by me either solo or as leadman of a team.

I figure at least around 20% of mitered Heresys were built by me in about 3 years of that time, too.

Almost all the Cormwalls (any cabinet style or veneer) during that period (77-83) were also built by me, sometimes solo, but more likely as lead man on a team.

I built a few LaScalas, and teamed up to build quite a few of the MWM, MSM, MSSM, and MTM cabinets for the MCM 1900 system. I also either fabricated parts and/or prefabricated parts assemblies for everything made during that period, to include routing parts, sawing, you name it...but I was just one of many who did that as the need arose.

Even though I never got much experienmce in K-horn bass bin or Belle assembly, I know how to do it, and can still do it.

Whenever we got too far ahead of the sanding room in production and ran out of room for more cabinets waiting on sanding, we sometimes worked in final assembly or shipping...wherever they needed some help!

Working at Klipsch back in the day was learning to be a jack of all trades, to put it bluntly!

Ya learn something new everyday on this forum, dontcha??[;)]

-Andy

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OK, the letter R was on the edge where you mentioned with USA just below. That would have been cool talking directly to the builder! When looking closer, the front is actually 7 ply if you count what looks like the thin outer veneer. With the edges painted, it's hard to tell for sure. But it is different than the rest of the cab. There definitely is a difference between the cab and the front motorboard. And the cab would actually be 9 ply if you count the layer of outer veneer.

1979 is just what I remember, that could be wrong. serial # is 168017 and 168018.

The spacing around the endges of the motorboard is actually pretty consistent. It doesn't look pulled to the bottom. Appears to be about 1/8" all the way around, give or take.

Ronnie Barham was the lead on the team that built your Cornwalls, I wasn't there that day...probably home studying for final exams or mid-terms, since I started back to college at nite summer of '79.

Ronnie and Charles Horn shared duty of cabinet shop foreman for a few years before Lynn Stevenson took over that position. Lynn was the builder of many of the Belles and other things here and there.

1979 was a weird year, we couldn't get Georgia Pacific to up the quality of the plywood they custom laid-up for us, too many voids, and many of those voids right under the veneer, which made the panels useless for speaker cabinets...we got other sources, then went to another source, then another, finally GP and the company came to an agreement where Klipsch agreed to pay more for panels that were void-free under the outer veneer and had smaller voids in the inner plys...and we went back to GP stuff,

Yours may have fronts made by a completely different supplier than the side/top/bottom panels, but it is not 3/4" baltic birch, and neitherare the other panels, based upon your description of the plys. For a time we even made a few of the fronts out of veneered lumber core plywood, that did not meet the standards for being used for outside panels. Once again +/-3/4"BALTIC Birch has around 11-12 plys, if I remember correctly, maybe more! Baltic birch plywood it wears out table saw blades and router bits like crazy...too much hard glue dulls the blades or heats them up and the teeth separate, just like the edges of the router bits will dull rapidly or explode into pieces rom too much heat...that is why we tried to avoid using it...plus it is much heavier!

Baltic birch was an experiment for motorboards that just didn't work out well. We only got any 3/4" baltic birch because it came to us in irregular sized sheets, which the company got for an extremely good price since the supplier was not able to move them.

On the other hand, the thinner baltic birch plywood (+/- 1/2" thick) worked out VERY WELL for many of the K-horn bass bins parts, and was adopted for that purpose.

-Andy

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OK. I may still strip them off and I can always repaint them again. I misread the serial numbers. It was 16(S)017, not 168017. I think that sets the date as 1978.

Shows inspected by: Paul Ward and tested by: N W Bradford. Maybe some more folks you remember from the old days.

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Rick,

Jay (can't remember his last name, sorry) built your cabs, Ola Mae Davis sanded them (I chose her to do the sanding on my Heresys, she was a REAL character!), Ron did final assembly and Harold inspected. They all were there when I was there, Jay left a few years before I did, though. I think Ron did too! I don't have the year of MFG date code cheat sheet, but you can do a search for that on the website, and probably find it.

-Andy

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Really cool to hear you talk about the actuall people that built our cabs Andy, and your relationship with them. Hope you dont mind if I ask about mine.

They are CD-BR. One is #12R320 and I can see 2 initials stamped. An M and an S. inspected by Bob Hamilton and tested by what looks Iike N.W. Bradford ?

2nd is # 12r296 and I can only find 1 initial ® stamped. Cant read inpected by but also tested by N.W. Bradford.

Really enjoy reading about your experiences working at Klipsch.

Thanks

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Really cool to hear you talk about the actuall people that built our cabs Andy, and your relationship with them. Hope you dont mind if I ask about mine.

They are CD-BR. One is #12R320 and I can see 2 initials stamped. An M and an S. inspected by Bob Hamilton and tested by what looks Iike N.W. Bradford ?

2nd is # 12r296 and I can only find 1 initial ® stamped. Cant read inpected by but also tested by N.W. Bradford.

Really enjoy reading about your experiences working at Klipsch.

Thanks

I think "R" is 1977, and I was building Cornwalls that year, but I didn't really become lead man on them until early/mid '78. Now, yours are CD BR models which means butt joints with flush front. That particular cabinet design was very strong, with the additional bonus (for building cost, anyway) of only needing ONE builder instread of a team to get a good production day accomplished. So, just because one was built by one builder, in no way means that the second of the "pair" was built b y the same builder.

Here is why: as the speakers were sanded (more than one person was sanding them) they may have cabinets from numerous days of production leaving the sanding room for pain/stain...or raw...to final assembly at the same time. Now the speakers were not BUILT as pairs, but in final assembly (where the guts were installed), the people there made a semblence of an effort to match two speakers as a pair, based upon color/grain/etc. Ok, though few were IDENTICAL (that being the "luck of the draw"), they were normally sequentially given serial numbers according to the approximate match as a pair. Serial numbers were designated in final assembly, but the labels were not installed until after the speaker passed testing...just left sitting on the rolling table the speakers were on. Once the PAIR passed testing the labels were put on, they were boxed up and ready for shipping.

So, this "pair" of Decorators makes it to a dealer, and fhey are put into warehouse stock. Now, there is a VERY good chance they will be separated and not even sold as the "pair" they were identified to be at the factory...understand?

So a purchaser could easily end up taking home two speakers that had not been planned to be sold as a pair TOGETHER, and this is shown by how often old decorator pairs are picked up nowadays that DON'T have consecutive serial numbers.

So, all this being said, you can probably see why your decorator cornwall builders are not even the same person to begin with.

Ronnie Barham built the one with the "R". I don't remember who had the other initials on your second CDBR, but one of those initials was the builder and the other the sander.

We had lots of turnover back then in personnel...some years more than others. Some personnel just didn't keep up the quality standards, and got sent home, but were more likely to be sent to other departments to see how they worked out there first.

Also, new engineers had to learn how to build the product, so some of you folks on the forum may have speakers built by them when they were newbies to the company.

Either way, I didn't build either of your cabinets, and was probably pretty busy building HDBR heresys the day(s) yours were being built.

Hope this helps you some!

-Andy

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