Adcom GFA 5500 produces static

bored184
bored184 Posts: 324
edited June 2014 in Electronics
I just recently bought and Adcom GFA-5500. At start up it sounds greats but after about 10-15minutes both channels start to distort. No distortion light comes on and no thermal protection light comes on. Also I notice the left side of the amp is a little warmer then the right. Any ideas?
Speakers: TL Monitor 10s, RTA 11TLs, Fortes, Thiel CS 1.2
Amplifiers: ]Ashly FTX 2001 III, Dynaco ST-70, DIY F6
Pre: Adcom GFP 750, Aikido Tube Pre
Post edited by bored184 on
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  • bored184
    bored184 Posts: 324
    edited June 2014
    ZLTFUL wrote: »
    Physical grounds...loose nuts. Also, potentially some weak solder joints.

    I am a little confused though, why would a loose ground developed static in both channels 10-15 minutes into playing? I thought a loose ground would cause static from the beginning.
    Speakers: TL Monitor 10s, RTA 11TLs, Fortes, Thiel CS 1.2
    Amplifiers: ]Ashly FTX 2001 III, Dynaco ST-70, DIY F6
    Pre: Adcom GFP 750, Aikido Tube Pre
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  • bored184
    bored184 Posts: 324
    edited June 2014
    ZLTFUL wrote: »
    Amp warms up, tolerances change...

    I have a GFA-5503 that had hum on 2 of the 3 channels. Would only show up after 15 or more minutes.
    Took it to my tech who found like 4 loose grounds and 3 solder joints that were suspect. After he fixed those and tightened up the grounds, the only noise is normal noise floor from the amp.
    Just throwing out a suggestion that worked for me. Take it for what it is.

    I appreciate it believe me I just never never knew a ground issue could do that. When I opened this amp up there was quite a bit of rust on some of the connections. I will open it up again and and look to see if I missed anything or accidentally loosened anything while I was in there cleaning.
    Speakers: TL Monitor 10s, RTA 11TLs, Fortes, Thiel CS 1.2
    Amplifiers: ]Ashly FTX 2001 III, Dynaco ST-70, DIY F6
    Pre: Adcom GFP 750, Aikido Tube Pre
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  • Polkie2009
    Polkie2009 Posts: 3,834
    edited June 2014
    bored184 wrote: »
    I appreciate it believe me I just never never knew a ground issue could do that. When I opened this amp up there was quite a bit of rust on some of the connections. I will open it up again and and look to see if I missed anything or accidentally loosened anything while I was in there cleaning.
    Rust huh? Was the amp stored out in a garage or attic for awhile?
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  • bored184
    bored184 Posts: 324
    edited June 2014
    Polkie2009 wrote: »
    Rust huh? Was the amp stored out in a garage or attic for awhile?
    It was stored in a garage for over a year. He said he had dehumidifiers running.
    Speakers: TL Monitor 10s, RTA 11TLs, Fortes, Thiel CS 1.2
    Amplifiers: ]Ashly FTX 2001 III, Dynaco ST-70, DIY F6
    Pre: Adcom GFP 750, Aikido Tube Pre
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  • [Deleted User]
    [Deleted User] Posts: 10,716
    edited June 2014
    Well, my Crown amps have never had that particular problem...
    I wish I could help.
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  • bored184
    bored184 Posts: 324
    edited June 2014
    I took the amp downstairs and placed it in a new setup, no hum developed down there. I am beginning to think though something has happened in this old duplex my wife and I are renting. I am picking up hums in my audio gear that I have never heard before.
    Speakers: TL Monitor 10s, RTA 11TLs, Fortes, Thiel CS 1.2
    Amplifiers: ]Ashly FTX 2001 III, Dynaco ST-70, DIY F6
    Pre: Adcom GFP 750, Aikido Tube Pre
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  • EndersShadow
    EndersShadow Posts: 17,687
    edited June 2014
    bored184 wrote: »
    I took the amp downstairs and placed it in a new setup, no hum developed down there. I am beginning to think though something has happened in this old duplex my wife and I are renting. I am picking up hums in my audio gear that I have never heard before.

    John... I know your like me and cheap. Pickup one of these babies for your gear and you should be fine.

    http://www.rakuten.com/prod/furman-sound-ac-215a-line-conditioner-ac-noise-ac-surge-over-voltage/215887528.html

    You can run a audioquest multi plug or signal cable multi outlet off it and have enough plugs for your gear.

    And you can be 100% sure you wont be current limited with this thing.
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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  • bored184
    bored184 Posts: 324
    edited June 2014
    EndersShadow wrote: »
    John... I know your like me and cheap. Pickup one of these babies for your gear and you should be fine.

    http://www.rakuten.com/prod/furman-sound-ac-215a-line-conditioner-ac-noise-ac-surge-over-voltage/215887528.html

    You can run a audioquest multi plug or signal cable multi outlet off it and have enough plugs for your gear.

    And you can be 100% sure you wont be current limited with this thing.

    The wiring in this old place is 2 prong. I can only imagine what it would look like if I actually delved into the wiring of his place.
    Speakers: TL Monitor 10s, RTA 11TLs, Fortes, Thiel CS 1.2
    Amplifiers: ]Ashly FTX 2001 III, Dynaco ST-70, DIY F6
    Pre: Adcom GFP 750, Aikido Tube Pre
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  • EndersShadow
    EndersShadow Posts: 17,687
    edited June 2014
    bored184 wrote: »
    The wiring in this old place is 2 prong. I can only imagine what it would look like if I actually delved into the wiring of his place.

    LOL... then I would be VERY CAREFUL about plugging stuff in lol...
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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