Orban 624B transformer question

[phantombox]

Hi.
I just installed input transformers into my Orban 524B. They are Quad Eight 3436 input bridging transformers.
After the installation I had a huge hum on both channels. Then I turned the power transformer by 90 degrees and the hum disappeared.
My question is: If I put the Orban in a rack with other equipment, would any power trafo from these other units induce this hum again?

Merry Xmass.

 

[abechap024]

Very Subjective question. Depends on the equipment your going to surround it with.

Very iffy I would say, if there was hum and just rotating the transformer made it disappear...Do you have equipment to measure exactly how much hum you are getting? Probably isn't all the way gone, try RMAA free software. I bet the hum is still there, just lower, probably won't bug you till you try to boost some low end on the EQ

How did you hook up the transformer? And why did you change the input stage? Just experimenting or just don't like the balancing circuit thats in there?

Cheers,
Abe

 

[phantombox]

Hi Abe.

The Orban isn't mine. A customer asked me to add input and output transformers in order to have more range with line levels. I only have these Quad Eight trafos so I offered him the Q8 3436 input bridging trafos and a pair of Q8 3041 (150/600 ohm in, 600 ohm out) output trafos.
I don't know if you are familiar with these units, but there are basically 4 wires for 20k and/or 5K input (I used a switch for selecting both options), and 2 wires for 600 ohm at the output. Ground is the transformers chassis. I connected the input trafos between the power supply board and the A and B channels. No hum appears with the out put trafos.