What’s causing this hum?

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Ice10

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What’s causing this hum?
« on: 20 Sep 2020, 01:33 am »
So I purchased a used Odyssey Cyclops and when I installed in my power cord, my streamer inputs, and speaker cables and powered it up I had a 60Hz hum coming from one speaker. I unplugged everything and plugged it all back in. Same hum.  So through a bunch of plugging and unplugging I’ve determined that the hum appears in my left speaker when I plug my speaker cables into the left binding posts. I’ve switched speaker cables, I’ve switched cable direction, and still it still hums. Opening up the case doesn’t reveal anything out of place or poorly connected.

Does anyone have any thoughts why this is happening. All cords, cables, etc were unplugged from my old cyclops into this newer, more highly upgraded one.

Thank you.

klaus@odyssey

Re: What’s causing this hum?
« Reply #1 on: 20 Sep 2020, 01:58 am »
Probably doesn't come from the amp output,  but rather from the inputs...try to change RCA's left to right and vice versa...hum should then come from the right channel......if it stays in the left,  then there's something funky in the amp,  yes......if it changes to the right,  then something is bleeding into the amp and the amp just shows you that there's something going on..............most likely then from the source eithher because of an internal problem or picking it up from the AC........

Ice10

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Re: What’s causing this hum?
« Reply #2 on: 20 Sep 2020, 02:11 am »
Thanks Klaus!  Even if I can figure this out would I be able to get in the queue to have it looked at by you?  The volume control is gritty and grabby as well so it may need to get replaced. 

Ice10

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Re: What’s causing this hum?
« Reply #3 on: 20 Sep 2020, 02:33 am »
Okay, I unplugged everything but the power cord-Quiet.  I plugged speaker cables into right binding posts-quiet. I plugged speaker cables into left binding posts -hum.  It was the same no matter which way I plugged in the rca’s and no matter if rca’s were plugged in before speaker cables or not.

I have also tried two other power cables and still everything hums when I plug into the left binding posts.

klaus@odyssey

Re: What’s causing this hum?
« Reply #4 on: 20 Sep 2020, 03:23 am »
Yes,  of course I'll look at it...and yes,  easy to replace the Alps...with used units,  one never knows,  but the Alps shouldn't be affected...

Anyway,  nonono....leave the speaker cables alone,  have both hooked up to the speakers....take  the RCA's only and swap them left to right,  right to left and see if the hum stays in one channel or if it moves to the other side......

Ice10

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Re: What’s causing this hum?
« Reply #5 on: 20 Sep 2020, 03:37 am »
Thank you for your help Klaus! 
So power cord in, speaker cables in- turn on power and there’s a hum in left speaker only
Plug in rca’s (red to red, white to white) and there’s a hum in the left speaker (louder than before with no rca’s plugged in)
Switch rca’s (red to white, white to red) and hum stays in left speaker.

Something funky in the amp?


klaus@odyssey

Re: What’s causing this hum?
« Reply #6 on: 20 Sep 2020, 09:08 am »
Yes,  call me......

Ice10

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Re: What’s causing this hum?
« Reply #7 on: 20 Sep 2020, 01:26 pm »
I’ll give you a call on Monday evening Klaus. Thanks again.

JLM

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Re: What’s causing this hum?
« Reply #8 on: 20 Sep 2020, 02:41 pm »
Did you try swapping interconnects, then speaker cables (left with right, or different sets of interconnects/cables)? 

Ice10

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Re: What’s causing this hum?
« Reply #9 on: 20 Sep 2020, 04:02 pm »
Unfortunately I have only one set of speaker cables but I’ve moved the right pair to left and there’s no change.  I’ve reversed them (they have one side spade, one side banana plug) with the same result.  I tried different RCA cables and reversing them and still the hum.  I’ve also made sure that no cable touches the floor or touches another cable which no change.

With the streamer hooked up and a speaker cable hooked up the right binding posts it sounds great, albeit in mono.  Try and hook up the speaker cable to the left binding posts and the hum starts.  I’ve popped the hood of the amp and all connections to the binding post look solid.

I appreciate your help, this is frustrating...