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Ground Loop Issue


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On 6/18/2021 at 3:56 PM, bluesboy said:

With both the Grounded Grid/phono pre combo and the phono section of the Slider I'm hearing what seems to be a ground loop hum. I swapped power amps ( 2A3 amp) and the hum goes away. Same result when I tried an old Yamaha ss receiver. You can't hear the hum with music playing just slightly between tracks. The hum increases with volume. These amps are otherwise dead quiet through the other line inputs even with the volume turned all the way up. I've tried cheater plugs on all components and installed an isolation transformer that cost me 200 bucks in between the amp and preamps with no results.

 

The hum level varying with the volume control indicates the hum is being induced into the circuit before the volume control.

 

I’m wondering if your hum is due to a radiated magnetic field from the problem amplifier as it relates to the physical location of the amplifier versus the Grounded Grid/phono pre combo and the phono section of the Slider and not a chassis ground voltage differential issue between the equipment induced Hum. Note: The High Gain of the phono section of the equipment would be the most likely to expose this interference effect.

 

Have you tried physically rearranging the Amplifier’s location and wiring relative to the Grounded Grid/phono pre combo and the phono section of the Slider to see if the Hum Level changes…? Changing Distance and/or Orientation relative to each other could solve or reduce the issue.

 

miketn

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Last night I hooked up the 2A3 amp to the Slider. The phono section is dead quiet even with the volume turned way up. Tonight I'm going to swap positions of the Slider and the TT to get even more separation between the Slider and the Mini Beast. That might eliminate that slight hum altogether.

Stereo 9.jpg

Stereo 7.jpg

Stereo 8.jpg

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On 6/23/2021 at 8:01 PM, mikebse2a3 said:

 

The hum level varying with the volume control indicates the hum is being induced into the circuit before the volume control.

 

I’m wondering if your hum is due to a radiated magnetic field from the problem amplifier as it relates to the physical location of the amplifier versus the Grounded Grid/phono pre combo and the phono section of the Slider and not a chassis ground voltage differential issue between the equipment induced Hum. Note: The High Gain of the phono section of the equipment would be the most likely to expose this interference effect.

 

Have you tried physically rearranging the Amplifier’s location and wiring relative to the Grounded Grid/phono pre combo and the phono section of the Slider to see if the Hum Level changes…? Changing Distance and/or Orientation relative to each other could solve or reduce the issue.

 

miketn

Well Mike was right. I got 4 feet of separation between the slider and the mini beast and the hum is gone. With the volume turned all the way up a very slight hum can be heard but that's probably normal.

 

Anybody need a Jenson Iso Max?

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26 minutes ago, bluesboy said:

Anybody need a Jenson Iso Max?

I’m glad to hear your problem has been resolved bluesboy. 🙂


I might suggest (since you already have the  Jensen ISO MAX) before you sell it off that you might want to reinstall it between your amplifier and pre-amplifier or some other positions in your system and give a closer evaluation of if you hear any improvement in clarity/detail especially on female vocals and cymbals for example that might make it worthwhile for you to want to keep it in your system. 
 

I use Jensen Isolation Transformers (being of a very high quality design) in my system on balanced and unbalanced equipment for several reasons and not just because I have any obvious issues but more as a guarantee that I have the highest quality signal preservation when the equipment is interconnected. 
 

miketn

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2 hours ago, Tarheel said:

Interesting speakers in the corners bluesboy!  Looks like an Altec horn?

That horn and the tweeter do look familiar! Come to think of it, so does his avatar!

Hmmmm

Good looking system bluesboy!

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On 6/26/2021 at 5:57 PM, bluesboy said:

Well Mike was right. I got 4 feet of separation between the slider and the mini beast and the hum is gone. With the volume turned all the way up a very slight hum can be heard but that's probably normal.

 

Anybody need a Jenson Iso Max?

More reasons to stay away from unbalanced tube equipment:) Glad you got it figured out and fixed.

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