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I am planning a Plexi size cabinet and to keep the weight down I am thinking of going for a lighter-weight wood.

So instead of using the usual Birch ply I am thinking either Poplar or Spruce plywood? Any downsides of using these woods?

So far I am struggling to find good grade Spruce in the UK and therefore thinking of Poplar.

I would think that anything structurally sound will be ok if it's going to be tolexed. I build all my Tweed cabs out of pine boards that are really light. A head with no speaker or tone concerns, whatever you can find that will get the job done will be fine.

For strength, use whatever has the most laminations and least filler. My 3/8" birch ply has 5-6 layers, no visible filler. Cheap stuff will only have a few solid layers and lots of glue & sawdust filler.

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Many thanks Jason!

I like very much light woods but if the transformers weight much, the overall structure will have to support high stresses, should the head ever fall - or at least support high accelerations -

Poplar is a great choice. I also use pine ply for it's light weight. Your joints have to be well executed as that is the "weak link". Your not going to break 3/4" plywood under normal conditions.

telentubes wrote: ↑Fri Nov 02, 2018 5:02 pm Poplar is a great choice. I also use pine ply for it's light weight. Your joints have to be well executed as that is the "weak link". Your not going to break 3/4" plywood under normal conditions.

Thanks everyone for the help! I will go fo the 18mm (3/4") poplar

One more approval for poplar ply. Working for the headliner at a big South California rock concert in the early 90's, we had as an opener Craig Chaquico's Jefferson Starship. Excellent band. Clearing their gear off stage after their show, I found the Hughes & Kettner guitar cabs they used weighed almost nothing. "Are there speakers in these?" I asked their crew. "Sure are! Celestions (don't remember which model) in Italian poplar ply cabs" Apparently have an excellent strength to weight ratio.

I've never seen poplar ply offered in the USA. Maybe I'm not looking hard enough, or in the right places. But - I was impressed enough to remember.

telentubes wrote: ↑Fri Nov 02, 2018 5:02 pm Poplar is a great choice. I also use pine ply for it's light weight. Your joints have to be well executed as that is the "weak link". Your not going to break 3/4" plywood under normal conditions.

Well executed ?

The angles sure are candidates for high stresses, but afterwards I thought that the screwed parts, be it the chassis or pieces of wood, also contribute to the overall resistance.

I am very glad to having read all this here. Poplar plywood has a terrible reputation on some french forum(s). I won't refrain from using it much longer, I believe - as it also is really easy to find, in France though.

Great inputs everyone! Many thanks again! As I am in Europe is Italian Poplar the way to go?

I know nothing about Italian poplar, but if it's the same species that grows here in north America then I would use solid rather than ply. The advantage of plywood is that it's stable, but poplar is already tremendously stable - more so than pine, and lots of excellent cabs have been made from solid pine. The advantage of solid wood is that it's both stiffer and lighter. Depending on your joinery, it will result in a stronger cabinet.

Tony Bones wrote: ↑Sun Nov 04, 2018 2:40 pm I know nothing about Italian poplar, but if it's the same species that grows here in north America then I would use solid rather than ply. The advantage of plywood is that it's stable, but poplar is already tremendously stable - more so than pine, and lots of excellent cabs have been made from solid pine. The advantage of solid wood is that it's both stiffer and lighter. Depending on your joinery, it will result in a stronger cabinet.

That is a great advice Tony! Many thanks.

I will try to source some solid poplar! If anyone in Europe has a good supplier for those please let me know

Solid wood, especially pine, resonates much more than plywood, and thus becomes part of the sound of the cabinet.

xtian wrote: ↑Wed Nov 07, 2018 4:20 pm Solid wood, especially pine, resonates much more than plywood, and thus becomes part of the sound of the cabinet.

True that. Consider poplar is used for organ pipes. And the variety tulip poplar was used for supports in mines. When bent by pressure, the posts and boards "sang" audibly with grunts groans & squeaks, alerting miners to get out of the danger zone. Would make a great speaker cab for the Marshall combo I just worked on, with microphonic growling output tubes. Shades of Marley's ghost - rattling & groaning noises galore.

I'd use solid poplar - I've built several speaker cabs with it. If you use modern glues like Titebond II or III the joint will be stronger than the wood. If you plan to cover it use screws.

Russ

Hi Russ, you Cabinet looks stunning. Bear in mind this project will be for a head cabinet and hence no tonal effect.
Anything I should bear in mind while selecting the solid poplat wood?