Lay down transformers. Are they any more prone to noise?

scottosan

Well-known member
FOr my next project I am having trouble finding a chassis that is undrilled on the front panel and can only find one suited for a lay down PT. Because it doesn't have a bell on the underside, is it more prone to noise or should it be avoided for a higher gain application?
 
Marshall DSL/TSL and others have laydowns and that is after years of having standups as the standard. Maybe it was a money-saving move but I'd like to think if it was noticeably noisier they wouldn't have done it.

Mesa Mark series are tightly packed chassis and have laydown PTs.

Just based on those two I'd think you're fine but I'm just extrapolating.
 
Transformer orientation matters only such that the core of the output transformer and the core of the power transformer are not lying in the same plane oriented in the same direction in 3D space. Transformers exhibit fringing fields around the coils and at the voltages/currents we're seeing, the fields can be as big as a 3ft diameter. Because of this, transformers which are oriented in the same direction within the same plane in 3D space exhibit magnetic coupling of flux called flux linkage. This coupling effect is undesired and as such will play hell on your signal to noise ratio.

TLDR; Does it matter which direction the PT lies? No. Does it matter which direction it lies with respect to the OT? Yes.
 
scottosan":3ix8jmv2 said:
FOr my next project I am having trouble finding a chassis that is undrilled on the front panel and can only find one suited for a lay down PT. Because it doesn't have a bell on the underside, is it more prone to noise or should it be avoided for a higher gain application?


No. As long as the sensitive side of the pre-amp v1 grids and input are on the far opposite side of the chassis. Should be doing it this way anyhow as a good building technique.
 
CrazyNutz":3apbwykj said:
scottosan":3apbwykj said:
FOr my next project I am having trouble finding a chassis that is undrilled on the front panel and can only find one suited for a lay down PT. Because it doesn't have a bell on the underside, is it more prone to noise or should it be avoided for a higher gain application?


No. As long as the sensitive side of the pre-amp v1 grids and input are on the far opposite side of the chassis. Should be doing it this way anyhow as a good building technique.

Not necessarily. Transformer placement has nothing to do with small signal grounding techniques like using shielded cables where necessary. What you don't want is an AC line coupling to a small signal line by running the two parallel to one another. If they must cross unshielded, cross them at 90 degrees.
 
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