Wooden chassis

[E. Pardaans]

First of all i like to thank mr Nelson Pass for sharing his knowledge with the diy community, and give us the possibility to build really good amplifiers.

I am in the middle of collecting the parts for two Aleph-2 monoblocks and a Bosoz preamp.

I am planning to use a wooden chassis for my amps.

Question: Is there a downside of using wood for the chassis.

Edwin.

[eLarson]

The only real drawback that I know of from using wood (and wood alone) as an enclosure material:

- Not one iota of shielding from radiated interference.

Also beware of the way wood moves with changes in temperature and humidity.

[analog_sa]

Is there a downside of using wood for the chassis.

None i can think of. All my tube amps are built on wood and sound a little better than on alu or steel. It may be a combined effect of pleasant microphonics and absence of eddy currents. Shielding at power amp levels is pretty much a non-issue as far as i am concerned.

[ingvar ahlberg]

Question: Is there a downside of using wood for the chassis.

Answer: Yes the part of wood facing the shelf it´s placed upon, upside of wood is other end

[E. Pardaans]

eLarson

Interference as you mentioned is my greatest concern, but just like Analog_sa says most tube amplifiers are build with a wooden chassis.

Maybe other members have a oppinion on this subject.

Edwin

[E. Pardaans]

Its true that later at the evening the people get funnier

[ingvar ahlberg]

Hi Edwin
On a more serious note: Wood is a good material for chassis, shielding is as good, or better, by covering inside with aluminium foil conected to system ground, as any bolted together metal box.
Conductivity of screen and transfer to ground is all that matters, size of holes has a part in this but related to frequency, regarding audiofrequency hole would be large enogh to let the cat in before interference becomes a matter. ( although cat in amp makes as much havoc as electrical interference)

[Panelhead]

I have used wooden chassis for my last couple of diy amplifiers. Just for ease of fabrication. But Peter Daniels said that wood may sound better.
The last one was lined with the mu metal foil from www.lessemf.com. This is the 18.95 per linear foot foil. It is 16 inches wide. Works great to sheild the top and bottom of a chassis.
A good friend has insulated some of the small ga mu-metal wire and used it to make up chassis wire. It seems to be as good as copper or silver for this application. Another good use for mu-metal.

George

[joensd]

What a coincidence.... just have been thinking about wooden chassis and their drawbacks though I was worried more about safety issues and yes shielding.

Being in the Passlabs section : I´ve read at least about one case where the wood cracked due to the heat so you probably want to avoid a lot of direct contact to hot heatsinks and include clever ways to lead the air through your chassis.

[E. Pardaans]

Shielding the chassis is a possibility i will considder.
I will have plenty of copper left over from my heatsinks.
So lining the inside of the amp sounds like a good idea.

Cracking off the wood due to heat and humidity has crossed my mind lately.
My chassis will be made off Birch plywood, and maybe covered with some nice oak finish.

I use temperature controlled fans to cool my heatsinks so the interior of the amp will also be cooled by air.