Power transformer: Inside or outside chassis?

[armstrom]

I'm starting to work on a stereo guitar amp using a pair of LM3886 chips. My 2 x 25V 200VA toroid arrived the other day and it JUST fits inside the hammond chassis I plan to use. So, are there any disadvantages/issues with mounting the transformer inside the chassis? Or should I stick to mounting it to the top of the chassis like you usually see.

Thanks!
-Matt

[joecool85]

I'm starting to work on a stereo guitar amp using a pair of LM3886 chips. My 2 x 25V 200VA toroid arrived the other day and it JUST fits inside the hammond chassis I plan to use. So, are there any disadvantages/issues with mounting the transformer inside the chassis? Or should I stick to mounting it to the top of the chassis like you usually see.

Thanks!
-Matt

I always mount mine inside the chassis.  That said, in theory there could be less "noise" with the transformer on the outside of the chassis.  The key words in that last sentence were "in theory", I wouldn't bother and I would put it right inside the chassis with no worries.

[armstrom]

That's what I'm leaning toward as well. There's tons of free space inside the chassis. That 200VA toroid is a heavy beast though Not exactly tube amp PT territory, but big by SS standards. I wanted some extra capacity since I'll be running a pair of LM3886 chips at 50W into 8ohms (well, as close to 50W as I can get, the 25V AC secondaries should get me close to the +/-35V DC I need for 50W into 8 ohms. The speakers are a pair of Weber Ceramic Sig 12B. All wrapped up in a (hopefully!) lightweight 2x12 combo with a fiberglass composite cabinet. My goal is to keep this thing as light as possible for gigging musicians. 40lbs is the target weight, but we'll see.

-Matt