Connecting an SK1 to a Leslie 3300 and an amp

[Dan56]

Hello,
I am asking this as the sound guy for the key board player in my band.
We are trying to go direct with his SK1 to the mixer and the Leslie 3300 thus eliminating the amp. I have connected the SK1 to the Leslie via the 8 pin connector. I then connect the Sk1 via the stereo outs for the other register sounds. Unfortunately this resulted in a ground like hum. If we disconnect the Leslie the hum goes. It does not matter is we connect the SK1 via one line out (mono out), there is still the hum.

Until this, I had not noticed but the hum is present when we connect the SK1 to his Roland amp and the Leslie it's just not as noticeable but then the Roland is noisy.

Any suggestions? Has anyone tried connecting the SK1 line outs to the Leslie line in along with the 8 pin?

 

[happyrat1]

My advice is to use an isolation transformer to eliminate the ground loop in the signal.

Here's an article regarding hum in Video systems but it can be adapted to audio with the proper transformer.

http://www.audioholics.com/home-theater-connection/ground-loops-eliminating-system-hum-and-buzz

http://en.wikipedia.org/wiki/Mains_hum

http://www.audioholics.com/home-theater-connection/ground-loops-eliminating-system-hum-and-buzz

 

[Dan56]

Thanks for responding Happyrat. I figure it's a ground issue but, everything was plugged into the same outlet at least with the Roland in the loop. I tried using a couple direct boxes to the mixer and it seemed louder which is not usually the case when using DI boxes.

 

[happyrat1]

Am I correct in assuming this is a mix of vacuum tube and transistor circuitry? If so then an isolation transformer inline in your feed would probably fix it.

 

[Dan56]

The only tube is in the Leslie for the pre-amp to allow an overdrive. The SK1 outs go to the mixer or Roland all is transister.

The noise is only present when the 8 pin from the SK1 is connected to the Leslie and the noise comes out the line outs to the mixer. Disconnect the 8 pin to the Leslie and the noise is completely gone. There is no noise in to the Leslie.

 

[happyrat1]

I'm still guessing ground loop.

 

[Dan56]

Happy,

Thanks for the video. I familiar with ground loops. I'm going to have to give it another try with the DI's I have though I'm looking at getting one by Radial Engineering. I'm waiting to hear from them on their opinion.

It is odd, in that the Yamaha plugged in has no noise. It is only the Hammond when connected by both the 8 pin and the line outs. The noise can be heard even when connected to his key board amp by only one line out. Using both line for stereo just makes it louder.