SP 9 Chassis Layout

I've started mocking up a custom SP9 chassis layout in which the toroid transformer would be located for the most part under the power supply section of the PCB. The overall preamp width and depth would be close to the PCB dimensions, perhaps 6"X8", and the preamp would be about 5" high. I'm wondering if the transformer location beneath the PCB would create problems. I intend to fabricate the chassis using 1/4" Aluminum plate and can isolate the transformer putting the plate between the transformer, PCB and front panel, which can also be isolated with Aluminum plate. There would be about 1/2-3/4" between the top of the transformer(horizontal orientation) and the bottom of the PCB.

The front panel would lie along one 8" edge of the PCB, the input and output jacks would be behind the PCB along what would be the back of the PCB and within the length of the PCB that includes the 12AX7 tubes, in other words, as far as possible from the transformer and power supply section of the PCB.

TN Allen wrote:I've started mocking up a custom SP9 chassis layout in which the toroid transformer would be located for the most part under the power supply section of the PCB. The overall preamp width and depth would be close to the PCB dimensions, perhaps 6"X8", and the preamp would be about 5" high. I'm wondering if the transformer location beneath the PCB would create problems. I intend to fabricate the chassis using 1/4" Aluminum plate and can isolate the transformer putting the plate between the transformer, PCB and front panel, which can also be isolated with Aluminum plate. There would be about 1/2-3/4" between the top of the transformer(horizontal orientation) and the bottom of the PCB.

The front panel would lie along one 8" edge of the PCB, the input and output jacks would be behind the PCB along what would be the back of the PCB and within the length of the PCB that includes the 12AX7 tubes, in other words, as far as possible from the transformer and power supply section of the PCB.  

Aluminium plates won't isolate the magnetic fields. You will need steel ( or my-metal) for that. Even better, locate the transformer further away.

If I use steel, what thickness do you recommend?

TN Allen wrote:If I use steel, what thickness do you recommend?

Normal "soft steel" , i guess 1mm will screen most magnetics, but i'll leave the exact answer to more knowledgeable person.

Stainless won't do however ! IT's non-magnetic.