425a particle board back

[VMGravy]

I picked up a used mint 425a from my local music store last weekend, got it home and pulled off the back and the back was birch.
I've had another 425a since 2007 and the back is particle board . Does that seem a little weird to anyone ? Funny thing is the particle board back cab sounds better, or maybe the speakers aren't broken in on the "new" cab yet but there is definatley a big sound difference.

[Torshalla]

Interesting... I think Marshall went to mdf in the 80s / 90s and somehow went back to plywood around 2012... Which was a good move. But so litle comm about it... Not sure why... As it would help their sales to markeg this...
Maybe they don't want to impact used value for their customers...

[Torshalla]

And I really think the difference comes from the speakers not being broken in... Although you can swap the back to experiment... :)

[dukealexan]

Sometime the spray glue makes the backs look like PB but there not.

[surfnorthwest]

I have four 425 cabinets. As far as I know they are all plywood but I have only ever opened one of them. They are a great sounding cabinet for sure, but also are a cabinet that takes time to break in for sure. Some of my cabs are 8 years old now and continue to get better with age.

[VMGravy]

Yup pulled the jack plate and its particle board. Maybe it was made on a Friday and the cab shop just used what they had on hand. Still a difference in sound when the two back panels were switched either way a killer cab that's why I bought a second. Now I just have to get two 425b cabs lol

[surfnorthwest]

I don't think its particle board, it should be MDF. MDF is more dense than plywood, so perhaps it makes a better back panel.

Particle Board

Advantages
Low Cost
Light-Weight
Perfect for Ready-Made Furniture

Disadvantages
Low Strength - Cannot Support Heavy Loads
Not as Eco-Friendly as Wood Furniture
Expands or Discolors Due to Moisture




MDF

Advantages
Low Cost
Very Smooth, No Splinters
Easy to Paint
Easy Cutting
Denser and Stronger than Particle Board
Composed of Small Wood Fibers So There is No Wood Grain

Disadvantages
MDF is Dense Making is Heavy
Cannot Be Stained
Can Dull Blades Quickly



Plywood

Advantages
Comes in Different Thicknesses
Different Wood Species Available
Very Strong Material
Less Susceptible to Water Damage
Stainable and Paintable
Holds Screws Well
Possible to Purchase with Low or No VOCs.

Disadvantages
More Expensive
Have to Finish Edges Because Layers Show
Plywood Often Splinters
Difficult to Cut

[VMGravy]

One ply and one particle board.

[dukealexan]

I could not tell from that bottom pix that's it's PB too much black to see thru