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April 23, 2021, 06:37:33 AM

Author Topic: Eros 2 - Right channel suddenly very quiet after a year of great sound  (Read 141 times)

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Offline charleskeough

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Hi, I completed the setup of the amp last January and it has been working perfectly. But a few days ago I went to power it on and the right channel is barely audible. First thing I did was confirm that the problem was within the Eros and not my turntable or Stereomour. Second thing was to swap tubes but the right channel stayed quiet. Then I broke out the meter and did the resistance and voltage checks. They all checked out and nothing seemed out of whack there so I'm not sure what the problem could be. Any tips on to how to move forward would be greatly appreciated.

Thanks,
Charlie Weber

Online Paul Birkeland

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Re: Eros 2 - Right channel suddenly very quiet after a year of great sound
« Reply #1 on: February 23, 2021, 10:11:15 AM »
I would triple check your cables and measure the DC resistance of each channel of your phono cartridge (just measure at the cable ends that plug into your Eros).  If your phone has a headphone jack, you can turn the volume all the way down, then up just one click and feed some music into your Eros with an 1/8" TRS to RCA cable to eliminate the TT entirely from the debugging process.

I recently had a similar issue and it turned out that one side of my phono cartridge was dead.

If all the voltages are OK in the Eros, that leaves solder joints on the inputs/outputs, cables, and the phono cartridge as the primary possibilities. 
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline charleskeough

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Re: Eros 2 - Right channel suddenly very quiet after a year of great sound
« Reply #2 on: February 24, 2021, 05:34:57 AM »
I just fed some music into the Eros with my phone via the 1/8" TRS to RCA cable and the problem still persists. Just to be sure I broke out a cheap little phono preamp I have and hooked my turntable and Stereomour up to that and the problem is gone, so I definitely think the problem is in the Eros somewhere.

I was wondering if there's a longer list for the resistance and voltage checks because I purchased a Reduction a while back and looking at that manual theres a reading for every terminal. Where as my Eros manual has resistance and voltage checks for just a few of them. I'm guessing that its not necessary but I wonder if with a longer list that maybe a problem could be diagnosed in there?

Online Paul Birkeland

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Re: Eros 2 - Right channel suddenly very quiet after a year of great sound
« Reply #3 on: February 24, 2021, 05:57:02 AM »
A Reduction will have more consistent resistances in the stock form because it does not have active loads and it doesn't have the big bypass caps that an Eros does.  These parts in the Eros make a lot of resistance readings pretty meaningless, and the resistance readings are really only intended to give the go ahead for voltage checks. 

You very likely have a loose connection or a solder bridge somewhere that is causing the issue.  What resistance to ground do you get on the center pin of each RCA jack?
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline charleskeough

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Re: Eros 2 - Right channel suddenly very quiet after a year of great sound
« Reply #4 on: February 25, 2021, 11:24:41 AM »
Ok yes that makes sense to me in regard to the resistance checks.

Here's the resistance to ground readings I'm getting from the center pin of each RCA jack.

Right output center pin 469K
Right input center pin 47.1K
Left input center pin 47.1K
Left output center pin 470K

Thanks for all your help so far with this.

Online Paul Birkeland

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Re: Eros 2 - Right channel suddenly very quiet after a year of great sound
« Reply #5 on: February 25, 2021, 12:15:50 PM »
Nothing wrong there. 

Still, look for loose connections and debris in the amp. 
Paul "PB" Birkeland

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Offline charleskeough

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Re: Eros 2 - Right channel suddenly very quiet after a year of great sound
« Reply #6 on: February 27, 2021, 06:49:38 AM »
Sounds good, I'll check look for loose connections and debris this weekend and let you know what happens.