50Hz buzz

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nebelfuerst
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50Hz buzz

Post by nebelfuerst » Fri Aug 24, 2018 12:55 pm

Some time ago, I had the ( stupid ?) idea to use cables which convert asymetrical outputs to symetrical.
This way I attached my old synths to an A16 ultra.
Unfortunately, 50Hz buzz was present more intense than before.
Today I switched back to "mono-cables" and the buzz is gone.

Is there a reason, why I should try to use symetrical inputs for my old synths ?

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valis
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Re: 50Hz buzz

Post by valis » Fri Aug 24, 2018 4:49 pm

They are not balanced outputs most likely. There are various ways to break the inverted side of the connection documented online, or you can use a DI box (this can also add some nice color), or you can use this: https://www.musiciansfriend.com/amplifi ... eliminator

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garyb
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Re: 50Hz buzz

Post by garyb » Fri Aug 24, 2018 4:56 pm

no.

whatever way works best is best. it's all about eliminating ground loops.

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valis
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Re: 50Hz buzz

Post by valis » Fri Aug 24, 2018 8:40 pm

This is what the Hum Eliminator is doing internally
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valis
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Re: 50Hz buzz

Post by valis » Fri Aug 24, 2018 8:41 pm

Here's a good article that covers this in more depth than I can muster right now. I'll attach the relevant image here and reference that it's probably #14 that interests you, but I do suggest reading the article too if you have time.
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garyb
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Re: 50Hz buzz

Post by garyb » Fri Aug 24, 2018 8:49 pm

don't usually need a transformer in the first pic...

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garyb
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Re: 50Hz buzz

Post by garyb » Fri Aug 24, 2018 8:52 pm

anyway, when connecting balanced devices to unbalanced devices, there are often significant level differences as balanced lines are usually +4 and unbalanced lines are usually -10 or -20. there can be impedance mismatches as well. surprisingly, there is no such thing as a standard, although there are conventions...

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valis
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Re: 50Hz buzz

Post by valis » Sat Aug 25, 2018 12:31 am

Agreed on those points as well

nebelfuerst
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Re: 50Hz buzz

Post by nebelfuerst » Sat Aug 25, 2018 12:37 am

I used setup 14, but the cable was 1-conductor shielded. ( so black and green in pic 14 was identical)
When using 15, all is quiet again.

I also tried a DI-Box, but it didn't help. Probably due to my cabling ?

As gary said, I'm happy to find at least one solution, that works.
But being a curious person, I'd can't stop experimenting :-)

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garyb
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Re: 50Hz buzz

Post by garyb » Sat Aug 25, 2018 9:54 am

here is the "bible" for audio engineers. if you REALLY want to be pedantic, you can buy the latest edition on Amazon or similar...

https://soundsfxedit.files.wordpress.co ... ndbook.pdf

this is all the basic information an audio engineer needs. remember, the guy that runs the train is the engineer. if you own a studio, you are supposed to be one. otherwise, you're just a monkey with his hand on the throttle of the train... :lol:

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