Russco Studio Pro Plinth Build

adnick

Addicted Member
Decided to document the building of a custom plinth for a Russco Studio Pro, Broadcast table, this is against my better judgement ;) but the mistake(s) made and yet to be made, might be useful to someone in the future….

This will have layers of plywood internally, but the outside cabinet will come from a slab of very old naturally dried Black Walnut.

This particular build has to fit in an existing space so it can’t be more than 17.5 inches wide, but doesn’t have a height restriction.

Broadcast motors run hot, the temperature rating for the motor on these is given as, above ambient, so it requires an open air source and there are tonearm and electrical considerations.

There’s also that pesky gearshift mechanism that has to work unencumbered inside the plinth.

My first order of business was construction of a “to scale model” from scrap wood.

The plywood used in the model can be reused as part of the inner layers when the time comes.

Most of my woodwork is done the old fashioned way, with handtools, however it’s very convenient to use a biscuit joiner for splines to hold the model together.

No glue is used so it can be taken apart while figuring out and/or fitting the inner layers. One can also throw it across the room when the situation calls for it and probably be able to recover most of the parts :rolleyes:

Here’s some photos of the Russco sitting atop the working model:
C96D3379-240B-4A3F-A9EF-72A242A9A30F.jpeg B80938EF-4D6A-4734-930E-0E78AA74F403.jpeg 67910709-1FC7-4B67-9F4D-FF938AC23676.jpeg

Next up is figuring out the inner layers :idea:

VR
Andy
 
Be aware that a box with equal dimensions will become a resonant chamber. You mentioned the width restriction if you can make the depth and height an odd order so there are minimal standing waves setup inside the plinth.

IME rigidity and damping of vibrations makes a massive improvement in SQ.

Keep the photos coming.
 
Be aware that a box with equal dimensions will become a resonant chamber. You mentioned the width restriction if you can make the depth and height an odd order so there are minimal standing waves setup inside the plinth.

IME rigidity and damping of vibrations makes a massive improvement in SQ.

Keep the photos coming.

None of that (resonance from equal dimensioned sides) is valid if internal bracing is added that staggers the outer dimensions. IE, using inner bracing that are of unequal dimensions and thickness, left to right, upper side and lower side, and layering top-to-bottom. It will break up any resonant nodes.
 
It will be an inspiration for me. My Russco is sitting in a very temporary setup and deserves something better.

View attachment 2289636 View attachment 2289640

What you have is certainly functional, but that table deserves something more to bring out its best, as you are well aware….

Do you have the ability to construct your own?

The most important and difficult part of the build functionally speaking, as has been discussed, is the internal layers.

VR
Andy
 
Andy, Werner has been detailing his rebuild over at the Lenco Heaven forum. Quite a lot has been done to bring it up to spec and beyond. Its a good read.

BillWojo
 
Yeah, didn’t know that, but one can tell lots of work has already gone into it….

I’ll have to take a look,

Andy
 
If the ply wood box you have constructed works well and you have answered all the stable sound issues mentioned above instead of using your walnut at this point why not buy walnut veneer and glue it on to the plywood using good wood glue and clamps . You could then stain it to the colour you want . Most speakers are made this way. Any mistakes you may have made could then be changed later after using your nice prototype for inspiration . Ledbailey
 
If the ply wood box you have constructed works well and you have answered all the stable sound issues mentioned above instead of using your walnut at this point why not buy walnut veneer and glue it on to the plywood using good wood glue and clamps . You could then stain it to the colour you want . Most speakers are made this way. Any mistakes you may have made could then be changed later after using your nice prototype for inspiration . Ledbailey


Probably wasn’t clear, written language isn’t my forte, actually not much of anything is my forte;)

The plywood box is a prototype, a functional model, and yes if someone was in need of a simple plinth it would suffice.

The wood becomes part of the anti-resonance components, not to mention the aesthetic effects of beautiful wood coupled with the knowledge that it’s real; even if it serves no other purpose the owner has the inner peace of knowing it’s real wood :rolleyes:

The plywood would have to be veneered, as you stated, plus it would require edging at the top to look finished, but none of that is required, it could still fulfill the task with just stain/paint or as is….

Nothing gets wasted,

VR
Andy
 
Rothwell, read the entire post, that is a mock up, not a finished plinth.
As far as the layers go, it mass loads and dampens the vibration from the turntable. It's a proven design used by almost everyone building a high end idler drive turntable.

BillWojo
 
When you say it will have layers of plywood internally, do you mean it will be stacked horizontal plywood for mass, with cutouts for clearance and air circulation, or a simple plywood box surrounded by a hardwood box?
 
Andy, I’m looking forward to this, it’s going to be quite a striking plinth due to its dimension. Your workspace and tools look very artisan and reference to biscuit joints, no glue, makes me think you are something of a craftsman. A slab of walnut makes me think of cake for some reason…..
 
Andy, I’m looking forward to this, it’s going to be quite a striking plinth due to its dimension. Your workspace and tools look very artisan and reference to biscuit joints, no glue, makes me think you are something of a craftsman. A slab of walnut makes me think of cake for some reason…..

@Kno you made me actually LOL with that cake comment, not something that happens a lot :rflmao:

Thanks for the kind comments, however don’t over estimate my skills, the final product will have glue. Even if it was joined with dovetails it would have glue.

For instance the attached photo is my amp stand made with hand cut dovetails, probably would never come apart but the glue gives it reinforcement.8B820487-6377-4434-B6A9-D2D68A40EB98.jpeg

There are times that one doesn’t want or need glue, it’s by design, the workbench the plinth box is sitting on does not have glue in certain joints so it can be disassembled and moved, the top is in 2 pieces, and weighs around 400 lbs, the joints are so tight it has to be jacked apart with hydraulic jacks, but it does come apart.:thumbsup: Here’s a photo of it in an uncommonly clean shop:
CE4EC77F-7551-4E2B-87BA-263B0E8F9358.jpeg

VR
Andy
 
When you say it will have layers of plywood internally, do you mean it will be stacked horizontal plywood for mass, with cutouts for clearance and air circulation, or a simple plywood box surrounded by a hardwood box?

@Lapslah, yes to your first statement, the internal portion is layered with clearance for mechanical parts, vents for cooling and access to tonearm and such….. Can be done several ways and as Bill pointed out, it’s to stop the resonance or “echo effects” of the box.

VR
Andy
 
Uncommonly clean or not, that photo could be a poster to hang in most folks shop it's so nice. Did you paint the floor as well?
As far as the slabs of real wood on this plinth, I see it as more like icing on the cake! Yummy!

BillWojo
 
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