noise when powering down

leftwinger57
leftwinger57 Posts: 2,917
edited October 2012 in Electronics
After owning my Adcom 555 for about 2yrs and change I've noticed what I would call the spooling down of the amp through the Bose 601s.The amp turns on very fast and takes about 3 minutes to totally power down the overheat
leds never come on and it always is very cool to the touch.During the power down I noticed a faint kind of
whistle noise but it's there and just to be safe is this normal and I just never noticed it before.I also believe all
sources are off as well as the pre/amp.
2chl- Adcom GFA- 555-Onkyo P-3150v pre/amp- JVC-QL-A200 tt- Denon 1940 ci cdp- Adcom GFS-6 -Modded '87 SDA 2Bs - Dynamat Ext.- BH-5- X-Overs VR-3, RDO-194 tweeters, Larry's Rings, Speakon/Neutrik I/C- Cherry stain tops Advent Maestros,Ohm model E

H/T- Toshiba au40" flat- Yamaha RX- V665 avr- YSD-11 Dock- I-Pod- Klipsch #400HD Speaker set-

Bdrm- Nikko 6065 receiver- JBL -G-200s--Pioneer 305 headphones--Sony CE375-5 disc
Post edited by leftwinger57 on
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  • deronb1
    deronb1 Posts: 5,021
    edited October 2012
    leftwinger57 wrote: »
    After owning my Adcom 555 for about 2yrs and change I've noticed what I would call the spooling down of the amp through the Bose 601s.The amp turns on very fast and takes about 3 minutes to totally power down the overheat
    leds never come on and it always is very cool to the touch.During the power down I noticed a faint kind of
    whistle noise but it's there and just to be safe is this normal and I just never noticed it before.I also believe all
    sources are off as well as the pre/amp.

    mine made a strange noise (like a ****) after shutdown too. After I added a tube buffer, it doesn't do it anymore! No idea why lol.
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  • jim 249
    jim 249 Posts: 347
    edited October 2012
    I also have a 555 and mine is totally silent at shutdown. The amp is turned off first and I wait for the red led to go completely out, then the cd player and pre. Total time for amp shut down is approx 30 seconds.
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  • polkfarmboy
    polkfarmboy Posts: 5,703
    edited October 2012
    Sometimes but not all the time I get a little whistle as it powers down from the back channel. It sounds a little like a tiny water balloon deflating, it only happens with my new Anthem mca
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  • jim 249
    jim 249 Posts: 347
    edited October 2012
    You might want to check the DC output voltage at the speaker connections on the amp. With the amp on but no signal the speaker outs should be no more than 50 mvs. If they are higher you should get the amp checked out. These amps have no dc speaker protection built in, so if an output transistor fails you will see a rush of dc to your speaker, and a towering inferno will result. I check mine a few times each year. Today it checked at 22mvs on each channel.
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  • polkfarmboy
    polkfarmboy Posts: 5,703
    edited October 2012
    So I should just put the amp on and stick the black and red things from my multimeter into the terminals of the............................................. ..... :eek: binding posts :eek:
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  • Glowrdr
    Glowrdr Posts: 1,103
    edited October 2012
    deronb1 wrote: »
    mine made a strange noise (like a ****) after shutdown too.

    I do this from time to time. Wife thinks there's something wrong. I tell her not to worry about it. lol
    65" Sony X900 (XBR-65X900E)
    Pioneer Elite SC-37
    Polk Monitor 70's (2)
    Polk Monitor 40's (4)
    Polk Monitor CS2
    Polk DSW Pro 660wi
    Oppo BDP-93
    Squeezebox Duet
    Belkin PureAV PF60
    Dish Network "The Hoppa"
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  • FTGV
    FTGV Posts: 3,649
    edited October 2012
    Turn on turn off noises are typical with amplifiers sans muting circuits.
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  • leftwinger57
    leftwinger57 Posts: 2,917
    edited October 2012
    That pretty much describes it. I did open the thing up a few weeks ago and by my uneducated eye this is the cleanest amp inards
    I've ever seen.No dust,rust or leaking caps or bad solder joints. I'm going w/ that every time I turned it off I left the room and the noise however slight was always there.
    2chl- Adcom GFA- 555-Onkyo P-3150v pre/amp- JVC-QL-A200 tt- Denon 1940 ci cdp- Adcom GFS-6 -Modded '87 SDA 2Bs - Dynamat Ext.- BH-5- X-Overs VR-3, RDO-194 tweeters, Larry's Rings, Speakon/Neutrik I/C- Cherry stain tops Advent Maestros,Ohm model E

    H/T- Toshiba au40" flat- Yamaha RX- V665 avr- YSD-11 Dock- I-Pod- Klipsch #400HD Speaker set-

    Bdrm- Nikko 6065 receiver- JBL -G-200s--Pioneer 305 headphones--Sony CE375-5 disc
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  • leftwinger57
    leftwinger57 Posts: 2,917
    edited October 2012
    That pretty much describes it. I did open the thing up a few weeks ago and by my uneducated eye this is the
    cleanest amp inards I've ever seen.No rust,no dust,nor leaking or bulging caps which tower in the chassi.
    2chl- Adcom GFA- 555-Onkyo P-3150v pre/amp- JVC-QL-A200 tt- Denon 1940 ci cdp- Adcom GFS-6 -Modded '87 SDA 2Bs - Dynamat Ext.- BH-5- X-Overs VR-3, RDO-194 tweeters, Larry's Rings, Speakon/Neutrik I/C- Cherry stain tops Advent Maestros,Ohm model E

    H/T- Toshiba au40" flat- Yamaha RX- V665 avr- YSD-11 Dock- I-Pod- Klipsch #400HD Speaker set-

    Bdrm- Nikko 6065 receiver- JBL -G-200s--Pioneer 305 headphones--Sony CE375-5 disc
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