dumb xfrmer question

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rutledj
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Joined: Sun Sep 17, 2006 2:08 am

dumb xfrmer question

Post by rutledj »

Is there supposed to be a benefit to lay-down types vs standup xfmrs?

Rut
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Phil_S
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Re: dumb xfrmer question

Post by Phil_S »

The lay down ones tend to reject hum better and that's due to the orientation when in the amp. The draw back it the amount of chassis real estate they consume. You "need" 20" for a 16" amp if you use laydown, through the chassis mount trannies.
rutledj
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Re: dumb xfrmer question

Post by rutledj »

So does that mean that the lay down type need to be turned a specific way in relation to the windings and chassis to acheive the maximum hum reduction?
Stanz
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Re: dumb xfrmer question

Post by Stanz »

As I understand it, the bell of the xfrmr is where the most noise comes from. Where the laminates are is where the least noise comes from.

With a lay-down xfrmr, anything on the same plane as the chassis, like tubes, will be sitting in the area of least noise no matter what. With a stand up xfrmr, you have to orient it for maximum rejection. Anything the bells are pointing at will have more noise, anything the laminates are pointing at will have less noise. That is why standup OT & PT will alternate orientation 90 degrees to reject more hum. PT laminates facing the OT and choke, and OT laminates facing the tubes.

The key is that with laydown xfrmr, most of the noise is going straight up and down, thus missing the tubes all together. So oriantation of laydown is not a factor.
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