18Watt.com

I'm about to embark on my next project (My first 18 Watt clone!) using the EL34's that I found. Although I was thinking of using a homemade chassis. The only problem with this is the fact that this chassis is one of steel.

I've heard of many problems with steel (magnetic field hum...etc), but never actually used one and i'd like to find out the pro's and cons of a steel chassis' (sp?).

Thanks,
Law.

I use steel with a ground bus system. No humming ground problems at all.

Nico

Cheers. I'll start drilling then!

Law.

Good luck
Nico

Law wrote:I'm about to embark on my next project (My first 18 Watt clone!) using the EL34's that I found. ...The only problem with this is the fact that this chassis is one of steel. I've heard of many problems with steel (magnetic field hum...etc), but never actually used one and i'd like to find out the pro's and cons of a steel chassis''.

Well, with two EL34s it won't strictly be an 18 watter! Or did you mean EL84s? If you really mean EL34s, what B+ voltage are you planning to use? And also then don't forget to reduce the tail resistor on your PI to around 15k, so you get enough drive on the EL34 grids.

And there's nothing wrong with steel chasses. A lot of commercially built amps use steel - particularly Marshall. I don't know where you heard these stories, but in fact steel will actually provide small amount of magnetic shielding from the transformer flux and thus somewaht help reduce unwanted hum and instablity.