Metropoulos Forum

I am looking into picking up a used cab. I have found a few Marshall JCM 800 and 900 cab's. I was wondering what the build quality is on these (is it birch). I had a 1990 (I got it new in '90, may have been an '89) 800 series cab that sounded fantastic.

What is the word on the 800 and 900 series cab's ?

Try to find older mono -1 input cab with g12T75 speakers
don't know if it's birch ply...I've seen eighties jcm800 bass cabs 2x15 made of MDF

All 1960A/B and 1982A/B cabs JCM800 thru JCM900 up till today feature the same construction methods as the mid to late 70's cabs 13 ply marine grade birch using a particle board back as the late 70's cabs did.

The JCM 900 cabs did use a nastier black tolex adhesive not clear like the JCM800 or older cabs.

Still a great value though, I picked up a JCM900 for $300 ans sold the speakers for $200.

Cab sounds as good as my 70's cabs.

Yes I had a JCM900 2x12 MDF cab it really sucked IMHO!

Thanks guy's, I guess I'll have to decide on one then.

harddriver wrote:All 1960A/B and 1982A/B cabs JCM800 thru JCM900 up till today feature the same construction methods as the mid to late 70's cabs 13 ply marine grade birch using a particle board back as the late 70's cabs did.

The JCM 900 cabs did use a nastier black tolex adhesive not clear like the JCM800 or older cabs.

Still a great value though, I picked up a JCM900 for $300 ans sold the speakers for $200.

Cab sounds as good as my 70's cabs.

Yes I had a JCM900 2x12 MDF cab it really sucked IMHO!

Um, not quite.

They use 11 ply 5/8 baltic birch plywood. Nothing I've ever seen has led me to believe it's marine grade. It's most likely standard or cabinet grade (BB1 or BB2).

The 800's had less particle board in them as used for raising the grill cloth off the baffle (baltic birch baffle, also 5/8 11 ply). The 72 cabs through the early 81 time frame had particle board back panels. The JCM 800's had particle board back panels plus logo mounting wood was particle board. The JCM 900 cabs had particle board cloth risers, logo mounting blocks and back panels.

They all had 5/8 11 ply sides.

The 800's had a clear glue used for tolex, the 900's had a VERY NASTY black glue that is totally a PITA to get off.

The 70's cabs had more/better slant baffle bracing than the 800's and 900's, with the sound post getting cut down to 2" in 73/74. Before that it was the big sound post size (2x4 or just larger) like my 69 spec or George's True Replica cabs.

Get an 800 cab if at all possible, the 900 would be a distant second choice. If you want a slant, I have one in storage that I put basketweave cloth on, but shipping from LA to you won't be cheap, probably around $190 with packing.

I was only two plys off Jim!

There you have it Tone Slinger the synopsis of Marshall Cabs!

Jim knows his Marshall Cabs and Speakers!

I made a similar mistake on the plys counted...once! LOL

I thought it was 10 plys. Then I realized I was looking at a cab that needed restoration and someone had worn one ply off on the bottom of the cab where I looked. When I stripped the rest of the cab, sure enough, 11 plys. D'oh!

We've all made mistakes, harddriver, I'm sure I'll make more.

Whats marine grade anyways?

The cabs passed Basic Training at Parris Island.

- WOT

vanhalen5150 wrote:Whats marine grade anyways?

I've never used it, but I think it's supposed to be waterproof, or water resistant. That surely hasn't worked with any Marshall cab I know of with all the staining, rotting, delaminated plys, etc I've seen.

http://www.helium.com/items/1124584-the ... ed-plywood" onclick="window.open(this.href);return false;

This sums it up guys

Bunnest wrote:http://www.helium.com/items/1124584-the ... ed-plywood

This sums it up guys

That tells us about marine grade now tell us about cabinet grade.

What I've seen sold as "cabinet grade" plywood is typically void-free plywood with a stain-grade veneer finish on one or both surfaces, like maple, oak, cherry, etc. Not sure if the plywood is a softwood (spruce/pine/fir) or hardwood (birch). Probably not what you would use for a speaker cab unless you want a lovely hand-polished oil finish instead of tolex...

Marine plywood is made of mahogany from Africa or the Phillipines, more info here:

http://www.westwindhardwood.com/price_marine_ply.php" onclick="window.open(this.href);return false;

There are three grades of Baltic Birch (Finnish/Russian grown) plywood according to my cab guy. Here's how his source describes and grades it. All I know is whatever he's using, I never see any footballs or repairs, and he says that's BB3...but that name changes depending on what GOST chart you use (below). Good luck guys!

BB1 - standard grade. Has more repairs (footballs), gaps, etc.

BB2 - cabinet grade. Less repairs, higher quality birch.

BB3 - furniture grade, no repairs, highest quality birch.

Of course, that also depends on which grading chart you're using. Talk about a nightmare. I found three and their descriptions overlap, converge or change according to which one you use! LOL

Table 1. GOST 3916.1-96

Grade of Face Veneer
Maximum amount of permitted defects for wood and manufacturing (per piece)
E No visible defects
I 3
II 6
III 9
IV Many wood defects and manufacturing defects are allowed.

The following comparative chart shows the relations of plywood face veneer grades in GOST 3916.1-96, GOST 10.55-71 and GOST 3916.1-89 .
GOST 3916.1-96 GOST 10.55-71 GOST 3916.1-89
E - A
I B AB
II BB B
III CP BB
IV C C

Welcome back Jim! You didn't say whether or not you got a sunburn!

Wicked woods specs there, thanks for providing them.
My brother left me a few chunks of birch ply for some future cab build, but it's all BB1 or worse I'm afraid.

Here's a pic of a scrap of BB1 (they should call it BBQ) and BB2 cab grade? 5 plys vs 11 ply, and then the skins.