Buzzing sound from Rotel 1095 amplifier

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Tomasito
Tomasito Posts: 142
edited April 2008 in Electronics
I just bought a Rotel 1095 power amp from ebay. It gives a buzzing sound even if the CD player is not playing. Listed below is the trouble shooting I have done so far.

1. Turn off the entire stereo system, only the 1095 is on - I can still hear buzzing sound coming from the speakers.
2. Changed the RCA interconnects from the pre amp to the 1095 - I can still hear buzzing sound coming from the speakers.
3. Disconnected the RCA interconnect. I still hear a Buzzing sound.
4. Connected a dedicated speaker cable from the 1095 to the speaker to ensure no ground loops. I can still hear a buzzing sound.
5. Connected to a different outlet - I can still hear a buzzing sound.
6. Use a monster cable power filter (HTS1600) - I can still hear a buzzing sound.
7. If I disconnect the speaker cable . The buzzing sound goes away
8. Used another power amplifier. There is no buzzing sound.

I have a feeling, it is the 1095 that is the problem.

I'll appreciate comments.

Thanks in advance....
Post edited by Tomasito on
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  • tonyb
    tonyb Posts: 33,077
    edited April 2008
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    If the amp is on with nothing connected,and there is no buzzing,then chances are it is not the amp.ground loop buzz can come from various places within your system.Try a cheapo 2 buck cheater plug on the amp.Some gear is just more sensitive to ground loops.
    HT SYSTEM-
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  • Tomasito
    Tomasito Posts: 142
    edited April 2008
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    Yes, there is buzzing even if there is nothing connected. I have a 1080 which is driving my fronts. If I really press my ear to the speakers I can hear a little buzzing sound. But the 1095 the buzzing sound is a bit loader.

    Tony, you mentionedf a cheapo 2 buck cheater plug. What is this plug, can you tell what it is and I will buy one. I run to walmart if I can get it there?

    Thanks in advance
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  • tonyb
    tonyb Posts: 33,077
    edited April 2008
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    Any Home Depot,hardware store,it's a plug that connects to the plug on the power cord to your amp and makes the 3 prongs into 2 prongs,essentially doing away with the ground.Not to worry though,the amp will still be grounded by way of the I/C's.For the 2 bucks,it's worth a shot.
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • tonyb
    tonyb Posts: 33,077
    edited April 2008
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    I thought you said when you removed the speaker cables,the buzzing stopped?
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • Tomasito
    Tomasito Posts: 142
    edited April 2008
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    Ok I understand. Maybe I can also try a Rodioshack noise suppressor?
    Thanks
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  • tonyb
    tonyb Posts: 33,077
    edited April 2008
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    My man,this is important,with the amp on,and nothing connected to it,can you hear buzzing from the amp itself? If so,then you have a problem with the amp and would not recommend lifting the ground at that stage of the game.If no buzzing is comming from the amp itself,then your good to go,try a cheater plug.Got it?
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • tcrossma
    tcrossma Posts: 1,301
    edited April 2008
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    How loud is the buzzing? And i'm thinking that if you remove the speaker cables it's obviously not going to buzz, since the amp is no longer connected to the speakers. If there's nothing else connected to the amp except the speakers and you're getting a loud buzz, i'm thinking there's something wrong with the amp.
    Speakers: Polk LSi15
    Pre: Adcom GFP-750 with HT Bypass
    Amp: Pass Labs X-150
    CD/DVD Player: Classe CDP-10
    Interconnects: MIT Shortgun S3 Pro XLR
    Speaker cables: MIT MH-750 bi-wire
    TT:Micro Seiki DD-35
    Cartridge:Denon DL-160
    Phono Pre:PS Audio GCPH
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  • Tomasito
    Tomasito Posts: 142
    edited April 2008
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    Yes, the buzzing stops if I remove the speaker cables.

    I had an extra power cord. I removed the ground terminal with a pair of pliers. To my surprise the buzzing was minimized , even though there is still a buzzing but it is now very low!

    Thanks a million for the advise.
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  • rainman31
    rainman31 Posts: 76
    edited April 2008
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    Tomasito wrote: »
    Yes, the buzzing stops if I remove the speaker cables.

    I had an extra power cord. I removed the ground terminal with a pair of pliers. To my surprise the buzzing was minimized , even though there is still a buzzing but it is now very low!

    Thanks a million for the advise.

    Did you finally find the 1095 in silver? How much did you pay?

    7.2 Set Up
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    Gefen HD video 1080p scaler
    Mitsubishi TV 73927 1080p

    Future purchase Rotel RMB 1095 200x5 THX
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  • Tomasito
    Tomasito Posts: 142
    edited April 2008
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    I was able to win the ebay auction for $1,050 + shipping of $85. It still carries the factory warranty.
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  • dorokusai
    dorokusai Posts: 25,637
    edited April 2008
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    Where do you live that they charged $85 shipping? Talk about being raped.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • danger boy
    danger boy Posts: 15,722
    edited April 2008
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    did you contact the seller about the buzzing problem? if so, what did he say? try one of them $1.50 three prong cheater wall plugs.. that some times may help with a buzz or humm problem.

    do you have a ceiling fan in that room by chance or florescent lighting? both of those can introduce sound problems. lastly.... there may be something going bad on the inside of the amp.
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  • danger boy
    danger boy Posts: 15,722
    edited April 2008
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    dorokusai wrote: »
    Where do you live that they charged $85 shipping? Talk about being raped.

    and this is helping him to solve his problem how ?? ;)
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • rainman31
    rainman31 Posts: 76
    edited April 2008
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    Tomasito wrote: »
    I was able to win the ebay auction for $1,050 + shipping of $85. It still carries the factory warranty.

    Great find, congrats on the new buy, hope you solve the buzz.

    7.2 Set Up
    Onkyo 805
    X-Box
    3DO
    PS3
    Velodyne DPS10 sub
    Polk Audio 2- RTI 12's
    Polk Audio CSI 5
    Polk Audio 4- FXI 5's
    Pronto 7500 LCD remote
    Gefen HD video 1080p scaler
    Mitsubishi TV 73927 1080p

    Future purchase Rotel RMB 1095 200x5 THX
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  • dorokusai
    dorokusai Posts: 25,637
    edited April 2008
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    danger boy wrote: »
    and this is helping him to solve his problem how ?? ;)

    I misread and thought he bought another amplifier while still having a problem.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • VXR8
    VXR8 Posts: 291
    edited April 2008
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    Tomasito wrote: »
    Yes, there is buzzing even if there is nothing connected. I have a 1080 which is driving my fronts. If I really press my ear to the speakers I can hear a little buzzing sound. But the 1095 the buzzing sound is a bit loader.

    Tony, you mentionedf a cheapo 2 buck cheater plug. What is this plug, can you tell what it is and I will buy one. I run to walmart if I can get it there?

    Thanks in advance

    Hi Tomasito,

    I also purchased a RB-991 second hand on eBay Oz and had exact same issues. Tried everything you did but to no avail. I ended up taking it to an authorised Rotel repairer here in Oz and the amp did have an internal issue (my amp was out of warranty). It cost me $220 AUD to repair, but is whisper quiet since the repairs.

    I note you said it is still under warranty,that being the case, I would return it to Rotel / an authorised repairer to have it fixed while still under warranty - you have nothing to lose.
    Regards - Gaz from the land of Oz

    Main System
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  • Tomasito
    Tomasito Posts: 142
    edited April 2008
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    Hello Gaz,
    I was able to minimize the buzzing sound by using the 3 prong to 2 prong socket adapter. There is still a buzzing sound, but I have to press my ear to the speaker to hear it.

    Gaz,
    Did Rotel tell you what was the cause of the buzzing sound?

    I do plan to get the amp check by Rotel.
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  • VXR8
    VXR8 Posts: 291
    edited April 2008
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    Tomasito wrote: »
    Hello Gaz,
    I was able to minimize the buzzing sound by using the 3 prong to 2 prong socket adapter. There is still a buzzing sound, but I have to press my ear to the speaker to hear it.

    Gaz,
    Did Rotel tell you what was the cause of the buzzing sound?

    I do plan to get the amp check by Rotel.

    Yes - there was a few issues:

    1. I had 2 output transistors replaced.
    2. Some repairs to the pre amplifier?
    3. 2 resistors replaced
    4. Plus some dry solder joints fixed.

    My buzzing would drown out the music unless at a substantial volume level. When connected to the pre-outs of a Yamaha RX-V2700, it was a lot worse than when it was hooked to either a Marantz SR-5300 or a SR-8001 - Marantz obviously filter their pre out connections better for interference.

    Anyway, hope all goes well with the 1095, as I will be upgrading to a new one of these in the short term. Let me / us know how you progress with your humming.
    Regards - Gaz from the land of Oz

    Main System
    Denon - AVC-4700H
    Emotiva - XPA-9
    Cambridge Audio - Azur 851C - CXUHD
    Polk Audio - Legend L800 - Legend L400 - Legend L900 - LSiM fx - OWM3
    SVS - PB1000 x 2
    Foxtel - iQ4
    Belkin - Pure AV PF40
    Sony K77A9G

    Front Room System
    PS Audio - Sprout 100
    Cambridge Audio - CXC S2 - CA752BD
    Sony - UBX800 4K BluRay
    Polk Audio - Legend L200
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  • Tomasito
    Tomasito Posts: 142
    edited April 2008
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    Hello Gaz,

    The humming is now un-noticeable.
    Unlike the buzzing sound you had, I can only hear the buzzing sound with the sound off, and I have to press my ear to the speaker to hear it.
    I want to send the amp in to Rotel for checking, but it just weights too much. I can hardly carry or pick it up. My problem is bringing it to UPS for shipping.

    At present. I am very happy with it. Good ebay buy.

    I don't know why the buzzing sound was minimize. Maybe somebody can explain.

    If anybody is interested....
    I'll be posting another thread on my experiment in using a high end microphone in the MCACC calibration.
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