Are transformers rotated in steel amps?

Liz Williams · From: California, USA

I picked up my Dynalap kit (with Wallace TruTone single coil pickup) yesterday after having Steven White, an extraordinary guitar tech, wire it up. When he turned on his guitar amp there was a noticeable hum until he picked up the lap steel and held it like you would a regular electric guitar. Steven said "Ah, the transformer in a guitar amp is rotated so the hum disappears when you're holding the guitar normally. You'll probably want to get an amp made especially for steel with the transformer aligned accordingly."

Is there such an amp?

Lane Gray · From: Topeka, KS

I've never heard of such a thing. And my steel is dead quiet through Fenders
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2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Rick Barnhart · From: Arizona, USA

Don't let him change the fluid in your headlights:)
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Clinesmith consoles D-8/6 5 pedal, D-8 3 pedal & A25 Frypan, Pettingill Teardrop, & P8 Deluxe.

Lane Gray · From: Topeka, KS

Have him rotate his fluorescent lights.
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2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Liz Williams · From: California, USA

I appreciate your protectiveness and your experience with your quiet guitar. However, the point of my post is to learn about electronics generally rather than solve a problem.

I'm especially interested to hear what amp builders have to say about the orientation of the transformer in amplifiers generally. It would be especially cool is someone were willing to experiment and report back. I do notice that when I pick up my humming steels (I have others), the hum goes away. Maybe it's bunk, and maybe not. Anyone out there willing to wonder with me?

Lane Gray · From: Topeka, KS

Not meaning to be flippant, more like "it doesn't make sense."
And I've not noticed a change in transformer orientation.
Not saying that the amp ISN'T the cause, but my money is on something else in the room is the culprit.
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2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Liz Williams · From: California, USA

I appreciate that, Lane. Why doesn't it make sense?

Not trying to be a jerk here, I really don't understand.

Lane Gray · From: Topeka, KS

It doesn't make sense to me because it's usually NOT the amp that causes the hum. And steel players have been using guitar amps since the 30s. And til Jim Evans started making Sho-Bud amps, we pretty much had to.
When a Tele starts humming, a 90Â° rotation on nearly any plane will usually kill it. I suspect he has something ELSE in his room that hums up a guitar turned right side up (the rest of the pickers turn them wrong. After all, Martin makes flattop guitars, not flat sided...)
He might have a point, but experience and history make me raise an eyebrow
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2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Scott Duckworth · From: Etowah, TN Western Foothills of the Smokies

Transformers transform AC current, which alternates 180 degrees every half cycle. The only way a transformer might be rotated is to put the primary on the secondary side, and vice-versa. Then it would cease to function as intended. I'm like Lane, look for something in the room causing the problem.

There is such a thing that some electricians refer to as "phase rotation" but it only applies to 3 phase circuits. An standard amp is a single phase circuit.
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Lane Gray · From: Topeka, KS

Scott, two transformers' fields can interfere with each other, so in tube amps they mount output and power transformers at right angles (and the reverb one at a 45).
I wonder if that's where he developed his theory.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Liz Williams · From: California, USA

Thanks for the discussion so far. I love the collective intelligence at work. I'm going to ask Steve to elaborate a bit, then post what he says.

Eric Dahlhoff · From: Point Arena, California

My steel king has a massive transformer & does put out a big 60hz field. If I set the bridge end of my ZB within a foot of it, the hum is very noticeable.
Also, I found that if I set my blues jr. on top of the SK, the reverb pan in the jr picks up the 60hz.
However, aside from being really near the transformer, I have found that all other noise comes from CFLs, light dimmers, computers, etc...
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Craig Baker · From: Eatonton, Georgia, USA - R.I.P.

Liz, et al.,
A magnetic guitar pickup is an inductive device and may be considered one winding of a transformer. It will most certainly receive signal (60 Hz hum) from nearby transformers. By varying the axis of the pickup, this hum may be fully transferred into the pickup, OR fully cancelled as the pickup goes through a null in the near-field of the power transformer. This principle is well established.

Respectfully,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024
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Peter Harris · From: South Australia, Australia

...and all this time I've been lying my Bassman on its side for no reason at all??
..Damn!!!!

Embarassed

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If my wife is reading this, I don't have much stuff....really!

Craig Baker · From: Eatonton, Georgia, USA - R.I.P.

Peter,
You may be on to something. Things might change when you cross the Equator

Craig
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"Make America Great Again". . . The Only Country With Dream After Its Name.

Lane Gray · From: Topeka, KS

Peter, does changing the orientation reduce or kill the hum?
Craig, it does make the sound waves rotate the other way.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Scott Duckworth · From: Etowah, TN Western Foothills of the Smokies

Maybe to get a steel to sound like an organ, we need to explore this rotating transformer concept. Ring contacts and a stepper motor should do it. Of course when the rings contacts get dirty, it will sound like a spark gap transmitter....

And Liz, we ARE NOT picking on you... the hum could be cause any number of things.
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Amateur Radio Operator NA4IT (Extra)
http://www.qsl.net/na4it

I may, in fact, be nuts. However, I am screwed onto the right bolt... Jesus!

Peter den Hartogh · From: Cape Town, South Africa

Steven White knows what he is talking about
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1977 Sho~Bud D10 ProIII Custom; Sho~Bud SD10 The Professional ; ETS S10 5x5;
Fender 1000; 1993 Remington U12; 1978 Emmons S10 P/P; GeorgeB Weissenborn;
Fluger Cat-Can; Asher Electro Hawaiian; Gibson BR4; Fender FS52; Guyatone 8str;
Fender Resonator ; Epiphone Coronet 1937; Rickenbacher Ace; Rickenbacher NS;
Dynalap 8string; Harbor Lights 8string; Aiersi Tri-Cone; Fender Stringmaster

John Billings · From: Ohio, USA

"The only way a transformer might be rotated is to put the primary on the secondary side, and vice-versa. Then it would cease to function as intended. "

Scott,
One would rotate the transformer, but not change the wiring. Line still hooked to primary. Just turn the transformer, not re-wire it.

My tech and I modified my Delta Blues 15. It had tiny transformers. It couldn't handle the low-end of my Baritone. So we put in a BIG Hammond PT, and a BIG Dr Z OT. We got hum, which was cured by rotating the OT 45 degrees.

Scott Duckworth · From: Etowah, TN Western Foothills of the Smokies

OK, maybe there is something to it...
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Amateur Radio Operator NA4IT (Extra)
http://www.qsl.net/na4it

I may, in fact, be nuts. However, I am screwed onto the right bolt... Jesus!

Lane Gray · From: Topeka, KS

I just had an interesting talk with C.M. Baker about this, in which he related his experience taking the hum out of a [Session 400? I forget: he called me up whilst I was doing yard work on a 95 degree day].
He decided to move the power transformer to the bottom of the cab, and the reverb tank to the top, just under the chassis.
He found that by rotating the transformer (Scott, that means the entire thing Winking

BTW) back and forth, he could hear the hum wax and wane (not his words; that pair would have included a pun, I've no doubt), with some angles being nearly unlistenable and some being hum-free. He chose to lock down the transformer at the position that it cause the least buzz.
So Liz, I've no doubt that the phenomenon happens. But it appears to play a secondary role, and you can move the amp a bit to knock it back.
I've still never seen an amp with the transformers reoriented to accomodate a steel guitar, however.
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2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Paul Arntson · From: Washington, USA

I have definitely gotten hum from a flourescent light fixture mounted on the ceiling directly below where I was playing. My old practice room did this.
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Excel D10 8&4, Supro 8, Regal resonator, Peavey Powerslide, homemade lap 12(a work in progress)

Peter Harris · From: South Australia, Australia

Jack Stoner · From: Kansas City, MO

Transformers, in all amps I've seen are not "rotated". Being a former amp tech I've worked on a lot of amps and there was never indication the transformer was oriented for any particular reason.

In theory that could be the case, but that is in theory, not real world. I suppose there is some custom built/boutique or modified amp that has a transformer set a certain way, but in typical production units it is not.

Georg Sørtun · From: Mandal, Agder, Norway

Over the 40 years I have worked on electronic equipment, from stage-amps to FM-transmitters, I have learned to test if transformers and other coils are positioned and orientated for optimal co-existence and minimal noise-induction. Have fixed more "hum noise" problems than I care to remember, by making changes in position and orientation of such components, mainly to mains transformers as they usually radiate the strongest fields.

Moving instruments and equipment a little around in a room, depending on what units in the room that radiate the most electric noise, also often works wonders to lower amplified hum levels.

So, coil orientation's effect on hum levels, is a real issue.

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