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Thread: New set up annoying buzz / hum I can't get to the bottom of......

  1. #31
    Join Date: Feb 2010

    Location: Berkshire, UK

    Posts: 3,796
    I'm Tom.

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    Just to say that Russ bought both of these from me (at different times - the power amp had been on loan to Jake).

    They worked together really well here with no hum beyond the minimum ear up to the speaker noise that's normal with valve amps. I had them running together in the study for a while with a Garrard 401, latterly with a Technics SL10 (into the phono input), an Arcam iBlink and a Sony ES CDP, into Tannoy DC6's - this was actually a stunning combo. I ran them both separately into the main rig as well driving the big Tannoys with no problems and the pre driving my Radford STA100 at the time. All no issues.

    The pre-was driven north by Petrat and collected, so wasn't shipped - it would definitely have arrived undamaged. The Croft was shipped to Jake's (where it was fine for several weeks) and on to Russ. Prior to me getting it it was fettled by Alan (Firebottle) and sounded stunning here. Behaved fine for Jake too.

    Unless something has damaged the power amp in transit (which I guess is possible) then this is most likely to be a local mains hum issue. @Russ can you show the layout? It's still most likely to be a ground loop in my view, though it's also possible that it or the attached interconnect is picking up transformer noise from something too close. The speaker flap is a bit odd though and looks a bit like DC.
    Main: Speakers 'RFC' Tannoy Canterburys / custom crossovers with Tannoy ST50 supertweeters; Amp - Silvercore 833C monoblocks; Pre EAR 912; Vinyl: Thorens TD124 MkII + Ikeda IT345-CR1 9 inch and Ikeda IT-407 12 inch tonearms; Cartridges Stereo - Miyajima Madake, Miyajima Takumi, Ikeda 9TT, vintage Ortofon SPU GE; Mono - Miyajimas - Zero 0.7, Premium 1.0, Miyajima/Edison '78' 4.0 conical, and Shure M44 strapped for mono with several Expert Stylus conicals for different eras of 78s; Phono stage and SUT from EAR 912 + Miyajima ETR-Mono SUT; Esoteric Sound Re-Equalizer for equalisation of early mono and 78, switchable in from tape loop; Digital: Audio Note CDT2/II transport, heavily modded AN Kit DAC + Mutec MC3+USB.

    Study: Speakers - Tannoy DC6; Amp: Sony TA-F3000ES; Digital: CDP Sony CDP-X3000ES & Arcam rBlink; Vinyl: Technics SL10 with Pickering TL-3.

  2. #32
    Join Date: May 2017

    Location: West Sussex, UK

    Posts: 691
    I'm Steve.

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    Hi
    Had the very same issue with my power amps
    Turned out to be a loose connection in the amp.

    Get it checked

    Steve
    Project 2experience sb dc, Cart: At33ptg
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    Steve...

  3. #33
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 186
    I'm Russell.

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    Thanks All for the comments - have just spent the best part of an hour trying all various combo's & have massively reduced the hum...

    I now have the power plugged into to a different mains socket to the rest of the kit. Also using some Van Damme studio interconnects with locking connectors & have tightened the input connections on the back of the power amp as noticed these were easily spun round by hand.

    There is no only a very slight hum when ear is next to the speakers which is usual with Valve amps when using a normal line, however when using the Phono (MM) input on the Gate pre amp, the hum gets louder as I increase volume (no source playing of course) & also noticed the speakers flapping again???

    Beyond bemused!!!

  4. #34
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,323
    I'm Chris.

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    Quote Originally Posted by Weeman1973 View Post
    Thanks All for the comments - have just spent the best part of an hour trying all various combo's & have massively reduced the hum...

    I now have the power plugged into to a different mains socket to the rest of the kit. Also using some Van Damme studio interconnects with locking connectors & have tightened the input connections on the back of the power amp as noticed these were easily spun round by hand.

    There is no only a very slight hum when ear is next to the speakers which is usual with Valve amps when using a normal line, however when using the Phono (MM) input on the Gate pre amp, the hum gets louder as I increase volume (no source playing of course) & also noticed the speakers flapping again???

    Beyond bemused!!!
    If available attach the separate ground lead of your phono RCA cable to dedicated ground post on the preamp. But it looks like You may also have some acoustic feedback creeping in, which is where the turntable
    is not isolated well enough on its stand, and is converting feet movement vibration, or indeed just the speakers nearby to become very low frequency energy.

    Jimi Hendrix used to make direct use of feedback with guitar , amp and speakers but in your case its an annoying artifice.

    Look carefully at how the turntable attaches to its stand, and seek to cure any vibration as picking up and being re-amplified.Hendrix Albert hall.jpg

  5. #35
    Join Date: Mar 2008

    Location: Dunfermline, Scotland, UK

    Posts: 12,656
    I'm inthescottishmafia.

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    Quote Originally Posted by walpurgis View Post
    Is the signal neg common with the amp chassis/case? It could be worth running a wire between the metal casework of the power amp to the case of the pre-amp to see what happens. It may go quiet, get worse or do nothing.
    Yeah that would have been my next suggestion. Looks like he has it sorted though.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  6. #36
    Join Date: May 2012

    Location: Dagenham Essex

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    I'm I'mteachingmarcotheartofpishanto.

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    I assume you have a earth connected from the TT onto the pre and then onto the power amp ?
    Music , fills the gaps between silence !

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  7. #37
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 186
    I'm Russell.

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    Quote Originally Posted by walpurgis View Post
    Is the signal neg common with the amp chassis/case? It could be worth running a wire between the metal casework of the power amp to the case of the pre-amp to see what happens. It may go quiet, get worse or do nothing.
    Thanks but this was the 1st thing I tried - did nothing. Even stripped the paint away from the case of the Power Amp & attached a piece of speaker wire to the grounding connection of the pre amp - nada!

  8. #38
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 186
    I'm Russell.

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    Quote Originally Posted by Audio Al View Post
    I assume you have a earth connected from the TT onto the pre and then onto the power amp ?
    I have the TT grounded to the pre amp but then nothing onto the Power amp.

    Do you think I should run another cable from the pre amp to the case of the power amp then?

  9. #39
    Join Date: Apr 2012

    Location: Southall, West London

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    I'm Geoff.

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    Quote Originally Posted by Weeman1973 View Post
    Do you think I should run another cable from the pre amp to the case of the power amp then?
    I suggested that. You have nothing to lose by trying it. If there are eath terminals use those, if not just loosen a case screw on each unit and slip the bare wire end under it. Don't do this with anything switched on and make sure the pre-amp volume is right down.
    "when common sense, logic and plausibility are excluded. All that remain are foolishness and lies"

  10. #40
    Join Date: May 2012

    Location: Dagenham Essex

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    Quote Originally Posted by Weeman1973 View Post
    I have the TT grounded to the pre amp but then nothing onto the Power amp.

    Do you think I should run another cable from the pre amp to the case of the power amp then?
    YES
    Music , fills the gaps between silence !

    TAT Sale post Leader " Marcos Mentor "

    Also a pishanto specialist confirmed by Head Daftee

    Real name " Allen " or "Zoomer Nut”, “Numpty Napper”.

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