Adcom GFP-715 Vibration sound with TT at higher volumes

Toolfan66
Toolfan66 Posts: 17,243
edited July 2009 in 2 Channel Audio
I am having vibration like sounds coming from the speakers when I am playing vinyl with my Adcom 715 PRE and my TT at higher volumes.

As a song is getting over it is very loud, the best way to discribe it is a vibration sound.

Is it possible that my Denon DL160 is not compatible with this Pre Amp?

I am very concerned here, I just hope I have not damaged the crossovers in my speakers or anything else.
Post edited by Toolfan66 on
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited July 2009
    Larry I'm not sure what you mean by "vibration sounds." Have you tried isolating your turntable? This is a myriad of isolation devices out there. I use Black Diamond Racing Cones and Isol-Pads from Quest for Sound on my turntable to isolate it from vibration.
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    It's coming from the speakers, and I had no problem with the Yamaha RXV-863 or the Pioneer SC-07.

    It vibrates the speakers big time.
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited July 2009
    Is it like a rumbling sound?
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  • strider
    strider Posts: 2,568
    edited July 2009
    Does it sound like an electrical oscillation, like something abnormal is happening to the signal, or are the drivers moving in and out visibly?


    Does it occur when you're on the lead in or lead out groove, or just during a track?

    Can you put your hand on the plinth and stop or minimize the sound?
    Wristwatch--->Crisco
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  • zarrdoss
    zarrdoss Posts: 2,562
    edited July 2009
    sub sonic filter? I have read about this problem on here before and they said it was because the warp-age of the record and said a sub sonic filter would clear it up, or I need more coffee.
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    hearingimpared wrote: »
    Is it like a rumbling sound?


    Yep!! you hit the nail on the head.
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited July 2009
    TOOLFORLIFEFAN wrote: »
    Yep!! you hit the nail on the head.
    strider wrote: »

    Can you put your hand on the plinth and stop or minimize the sound?

    I think you need to isolate your turntable that is decouple it from the stand especially if what Ben asked above occurs. You also might want to consider checking the platter bearings to make sure the platter isn't wobbling.
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    strider wrote: »
    Does it sound like an electrical oscillation, like something abnormal is happening to the signal, or are the drivers moving in and out visibly?


    Does it occur when you're on the lead in or lead out groove, or just during a track?

    Can you put your hand on the plinth and stop or minimize the sound?



    It seems to occur on the lead out groove.

    I was listening to Nazerath's Hair of the Dog ( First Track ) as the song was ending the vibration/rumbling sound scared the **** out of me.

    When I get home I will put my hand on the plinth to see if it stop's or minimize's the sound.
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  • heiney9
    heiney9 Posts: 25,165
    edited July 2009
    Subsonic filter or better isolation for the table.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • dkg999
    dkg999 Posts: 5,647
    edited July 2009
    Subsonic filter should be on if it's available on the pre. I am guessing it's feedback caused by vibration and positioning. Try better isolation of the TT, and also try moving the TT so it's not in the direct path of the sound waves from the speakers.
    DKG999
    HT System: LSi9, LSiCx2, LSiFX, LSi7, SVS 20-39 PC+, B&K 507.s2 AVR, B&K Ref 125.2, Tripplite LCR-2400, Cambridge 650BD, Signal Cable PC/SC, BJC IC, Samsung 55" LED

    Music System: Magnepan 1.6QR, SVS SB12+, ARC pre, Parasound HCA1500 vertically bi-amped, Jolida CDP, Pro-Ject RM5.1SE TT, Pro-Ject TubeBox SE phono pre, SBT, PS Audio DLIII DAC
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  • strider
    strider Posts: 2,568
    edited July 2009
    TOOLFORLIFEFAN wrote: »
    It seems to occur on the lead out groove.

    I was listening to Nazerath's Hair of the Dog ( First Track ) as the song was ending the vibration/rumbling sound scared the **** out of me.

    When I get home I will put my hand on the plinth to see if it stop's or minimize's the sound.

    I'd have to guess that it is subsonic rumble (that's just what it's called, I too know that you can damn sure hear it!), like the others have said your best bet is to start optimizing the table's placement. The biggest thing I found to cause it in my set up was having the platter not be completely level. After that, making certain the system was isolated from airborn and mechanical vibrations was the next step.
    Wristwatch--->Crisco
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    strider wrote: »
    I'd have to guess that it is subsonic rumble (that's just what it's called, I too know that you can damn sure hear it!), like the others have said your best bet is to start optimizing the table's placement. The biggest thing I found to cause it in my set up was having the platter not be completely level. After that, making certain the system was isolated from airborn and mechanical vibrations was the next step.

    Thanks Strider,

    I will look into this when I get home. I will have to order some isolation pads, wether i need them or not I will get them.


    Larry.
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  • dkg999
    dkg999 Posts: 5,647
    edited July 2009
    A Herbies TT mat and some Herbies dots under the TT feet might do the trick. A Herbies TT mat eliminated a very slight 45 rpm rumble on my TT.
    DKG999
    HT System: LSi9, LSiCx2, LSiFX, LSi7, SVS 20-39 PC+, B&K 507.s2 AVR, B&K Ref 125.2, Tripplite LCR-2400, Cambridge 650BD, Signal Cable PC/SC, BJC IC, Samsung 55" LED

    Music System: Magnepan 1.6QR, SVS SB12+, ARC pre, Parasound HCA1500 vertically bi-amped, Jolida CDP, Pro-Ject RM5.1SE TT, Pro-Ject TubeBox SE phono pre, SBT, PS Audio DLIII DAC
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    Keiko wrote: »
    Is this just at loud volumes Larry? Never had this problem with my Technics 1210. :confused:

    Well I havent spent a lot of time with the vinyl since I moved everything upstairs, so I am not sure I just shut it all down ASAP once I heard that noise.

    I knew I would get some direction here on what it might be.

    I am still wondering if the DL160 is not compatible with the phono input on the PreAmp. With it being a moving coil and all, but I can not find anything about that with the Adcom.








    EDIT: I just found this, so that is not it.

    GFP-715 also has a high quality phono stage that accepts signals from Moving Magnet and High Output Moving Coil phono cartridges allowing the listener to enjoy their favorite analog recordings.

    So I will continue with the suggestions above when I get home.
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  • MillerLiteScott
    MillerLiteScott Posts: 2,561
    edited July 2009
    Do you have the dust cover attached to the TT? I have found that to be a big issue with my TT. I have disconnected it and just sit it on top when not in use. No Rumble.
    I like speakers that are bigger than a small refrigerator but smaller than a big refrigerator:D
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    MillerLiteScott wrote: »
    Do you have the dust cover attached to the TT? I have found that to be a big issue with my TT. I have disconnected it and just sit it on top when not in use. No Rumble.


    I do, but why did I not have a problem with the Pioneer SC-07 or the Yamaha RXV-863? This is what has been having me scratch my head.
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  • heiney9
    heiney9 Posts: 25,165
    edited July 2009
    TOOLFORLIFEFAN wrote: »
    I do, but why did I not have a problem with the Pioneer SC-07 or the Yamaha RXV-863? This is what has been having me scratch my head.

    The 715 has a better phono stage......probably a lot more sensitive.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • MillerLiteScott
    MillerLiteScott Posts: 2,561
    edited July 2009
    May be they have some built in subsonic filtering.

    Try just holding the dust cover to dampen it in the suspect parts of your listening to see if that is your issue.

    Scott
    I like speakers that are bigger than a small refrigerator but smaller than a big refrigerator:D
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited July 2009
    heiney9 wrote: »
    The 715 has a better phono stage......probably a lot more sensitive.

    I agree wholeheartedly.
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    heiney9 wrote: »
    The 715 has a better phono stage......probably a lot more sensitive.

    I was thinking that as well but was not 100% sure.

    I have some work to do for some of the guys here;) Then I will play with it if I get some time tonight.
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  • Toolfan66
    Toolfan66 Posts: 17,243
    edited July 2009
    Thanks for the help here guys.

    I got some Iso Pads, and leveled everything out. All systems go!! Took care of my problem.


    Larry.
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  • hearingimpared
    hearingimpared Posts: 21,137
    edited July 2009
    Good to hear.
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