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Monster Replier
'97 Strat Plus, '22 LP Studio
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Discussion Starter · #1 ·
So I was wondering, is there anything to stop someone from building an amp chassis put of wood? I can't really see why there should be.

Build a box, make the top a plate of aluminum for all the grounding and that should be about that wouldn't it?

Maybe load a plate behind the pot/jack area and solder a ground wire to the top?

I suck at metal work and wood and I get along. I am wondering where I might go wrong with a plan like this?
 

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Premium Member
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well for one thing, to get the strength and rigidity you need, wood would have to be much thicker than metal. Most pots and tube sockets and thing aren't made for going into/through a 3/4" (19mm) piece of wood. And then there's the fire hazard thing too. What would your insurance company say when fire inspectors tell them the new tube amp you just built shorted out and burnt your house down?
 

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Monster Replier
'97 Strat Plus, '22 LP Studio
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Discussion Starter · #4 ·
And then there's the fire hazard thing too.
Pffft, hazard. I am a fire hazard, don't worry about that ;)

Let us stay concerned with grounding and feasibility. Let me worry about burning my house down :)

Pots and jacks would just need to be reamed out so that eliminates that problem. If Gibson tops can work, so can this.

So here is the forming plan in my brain....

Build a base and 4 sides with wood, probably some walnut because it is sexy as hell. Top plate of 0.08 aluminum. All the grounding would fall onto the top plate, or failing that, grounding lugs onto a bus with the PT ground.

I'm just wondering what grounding issues one might have to overcome. As for the function beyond that, well there isn't anything I'm concerned about as they are basically wall art in my house. Wall art that sounds amazing.
 

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1965 Fender Mustang, Ampegs, anything to test an amp.
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Wood is a poor heat conductor, tube amps require proper heat-sinking...the chassis is the main heat sink of a tube amp and as you know the greater the thickness the greater the heat transfer...16 gauge is ideal.
It also serves as a Faraday shield, when properly designed.
Possibly a fire hazard.
 

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Monster Replier
'97 Strat Plus, '22 LP Studio
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Discussion Starter · #8 ·
Wood is a poor heat conductor, tube amps require proper heat-sinking...the chassis is the main heat sink of a tube amp and as you know the greater the thickness the greater the heat transfer...16 gauge is ideal.
It also serves as a Faraday shield, when properly designed.
Tubes go outside.
I'm hearing a lot of "probably shouldn't" but not a lot of why not :)
 

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Monster Replier
'97 Strat Plus, '22 LP Studio
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Discussion Starter · #11 ·
When I operate my V5 or V7 hard for an hour, the chassis gets quite warm...the heat is mainly from the transformers.
Those are top mounted too.

I'm not paying 130 dollars for iron to hide it in a box :)

So I'm just gonna do it as apparently the worst thing that will happen is I will need to isolate for interference. I'll report back!
 

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1965 Fender Mustang, Ampegs, anything to test an amp.
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Those are top mounted too.
The idea is to use the chassis as a heat sink...to transfer heat away from the devices. Top mounted on a wooden chassis means that heat can only be transfered to the air...the chassis is a better heat conductor than the air.
This way heat is transferred and dispersed more efficiently.
 

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Monster Replier
'97 Strat Plus, '22 LP Studio
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Discussion Starter · #13 ·
The idea is to use the chassis as a heat sink...to transfer heat away from the devices. Top mounted on a wooden chassis means that heat can only be transfered to the air...the chassis is a better heat conductor than the air.
This way heat is transferred and dispersed more efficiently.
All of that is true, however look at 99% of amplifier chassis that are cab mounted. Steel/aluminum plate, mounted inside a box with the trannies and tubes orientated to the bottom with heat radiating and the subsequent air rising. So if it were that much of a problem I cannot help but think there would be much more robust engineering to design a solution. What seems to be done is quite literally the worst possibly option from the perspective of heat dissipation.

I'm not trying to argue with you Paul because you are correct and smarter than I am, but I cannot imagine how an open air system could possibly be worse than the classic design. It is probable I am missing something that may be obvious to you as I tend to do with concepts over my head :)
 

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Those are top mounted too.

I'm not paying 130 dollars for iron to hide it in a box :)

So I'm just gonna do it as apparently the worst thing that will happen is I will need to isolate for interference. I'll report back!
What about shielding? What about immunity from RF interference? How about the safety benefits of having an electrically grounded chassis? There are actually reasons why modern amplifiers are built the way they are. I know it's presently fashionable to dismiss everything that has come before us, but..., intelligent human beings have been here for quite some time and adopting some of their tried and true practices, makes plenty of sense.

I'm presently in the process of acquiring a box and pan brake for the very purpose of fabricating a proper metal chassis for my amps. 130$ is nothing, spend it.
 

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What seems to be done is quite literally the worst possibly option from the perspective of heat dissipation.
It could be improved by increasing the surface area ie. finned heat-sinking and forced-air which some manufacturers apply to their products.
The tubes alone require heat to operate efficiently however, for most components, heat is detrimental.
I believe that if there was no heat generated or absorbed by these components, there would be many less component failures...heat is a killer for most physical objects.
If manufacturers designed products with ideal heat transfer characteristic, there would be a lot less failures which means that consumers would not need to seek replacements. How would that affect their business?
Products are designed with some failure to maintain business.
 

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Tom Anderson Raven
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It works great and can look so too if done well. It's a tried and true way to build DIY Audio Amps. Components should be on the chassis plate for easiest implementation and there needs to be enough air flow to keep tubes from over-heating - feet to raise the frame at least a 1/4" above surface and vent holes around power tube sockets should do it. Google it - tons of examples.
If you get EMI or RFI noise you might have to shield the inner frame walls with copper tape and put a metal bottom plate on (make sure ground connection is good and no gaps - bottom plate needs vent holes too.
If also made one with cut outs for a small metal panel with input, output, and power connections in the frame and grounded the panel to top-plate - for a power amp I've never needed to shield but for preamps and especially high-gain guitar preamps shielding is recommended.
 

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Monster Replier
'97 Strat Plus, '22 LP Studio
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5,265 Posts
Discussion Starter · #20 ·
It works great and can look so too if done well. It's a tried and true way to build DIY Audio Amps. Components should be on the chassis plate for easiest implementation and there needs to be enough air flow to keep tubes from over-heating - feet to raise the frame at least a 1/4" above surface and vent holes around power tube sockets should do it. Google it - tons of examples.
If you get EMI or RFI noise you might have to shield the inner frame walls with copper tape and put a metal bottom plate on (make sure ground connection is good and no gaps - bottom plate needs vent holes too.
If also made one with cut outs for a small metal panel with input, output, and power connections in the frame and grounded the panel to top-plate - for a power amp I've never needed to shield but for preamps and especially high-gain guitar preamps shielding is recommended.
I knew I wasn't fucking crazy :)

Back that up... I am crazy, but I knew this should work lol

That image there @Paul Running lifted from the internets was more or less what my brain was thinking. Wood box, metal top plate back ended input/output controls, pots on top.

This is why I was asking more about grounding than "feasibility". Seeing as the champ I built has an open bottom and 2 ends and sits 8 inches from a 25" monitor and 24" from a wireless antenna I am not extremely concerned with interference. Old dumpy amp circuits aren't really all that sensitive and even if one encounters it, it is easy to overcome.
 
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