Integrated Amp Construction

[Paul Dimaline]

For reasons of space, WAF and mostly just for the hell of it I am building a "super integrated" amp based around a Naim pre/power with a DIY power supply.
As i'm an electronic novice I shall be seeking profesional advice and help with the electrical side of things but the casework is down to me.
As i'm a toolmaker by trade this is no problem, what I need is advise on constrution and materials.
As the case is to act as the heatsink aluminium would be the obvious choice, but what about shielding the transformers and the rest of the power supply, suround it in copper? If I do this do I just do the transformers or the rectifier and caps also? The plan is to put the regs as close to the pre amp boards as possible.
Any other hints and tips would also be appreciated!

Paul.

[Paul Dimaline]

OK, we now have a large box of bits courtesy of AVONDALE AUDIO . I've got all the gear to build the power supplies for both the pre and power amp section. There are 2 toroids, (one for pre and one for power amp), 2 rectifiers, 2 TPR regulator boards and some 15,000uf caps.
I'm now sorting out a layout so as I can start to build the case work. As I want to keep the whole amp as compact as possible what "Golden Rules" do I follow for the wireing and placement of components?

Paul.

[maylar]

Keep magnetics as far away from input circuits as possible. Use shielded wire to connect input jacks to your circuit. Keep power supply wiring close to the chassis and as short as practical. Wire from the transformers to rectifiers directly, and from there to the filter caps. Power is taken from the capacitor terminals, not the rectifier.

Magnetic fields can only be shielded with magnetic materials - iron and steel. Copper and aluminum are effective at high frequencies (RFI) but not at powerline frequencies (EMI). The best magnetic shielding material is a nickel steel called MuMetal, if you get into trouble.

[Paul Dimaline]

Thanks for the advice Dave, much appreciated.

I've got a layout that seems to me as if it will work. The amp has an internal size of aprox 12"W x 14"D x 4"H and is divided into roughly 3 sections. At the front will be the toroids and rectifiers. Mains will come in from underneath to avoid the line stage.

The smoothing caps will be in the center of the amp, mounted upright.

At the back will be the power amp modules, pre-amp boards and rectifiers. The pre-amp boards will be mounted on the back panel in front of the input sockets and the volume pot will be just in front of them. I will try and build this as a single unit to minimise the amount of cable used.

Dave, you mentioned running power supply wiring close to the chassis, but I intend to mount the caps upright, will this cause problems? Also should I lightly twist the power supply wires? Also, am I correct in thinking that the power supply wires should be routed in one run as much as possible to avoid earth loops?

Thanks for any help,

Paul.

[mikesnowdon]

Hi Paul,

Did you ever get this amp finished?

[mikesnowdon]

Paul,

If you looking in please drop me a email. Very interested in this project.

Rgds,
mike