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

  1. #41
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 904
    I'm Russell.

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    Quote Originally Posted by Audio Al View Post
    YES
    So I ran some cable from the grounding connection on the pre amp (still with the TT also grounded but not on) to the case of the power amp (undid a screw & removed the paint) and.......


    It’s worse!!!

    I give up - then I’ll stick to integrated’s!

  2. #42
    Join Date: May 2016

    Location: Milton Keynes

    Posts: 3,577
    I'm Andrew.

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    You’re welcome to try it here mate if that might help


    Sent from my iPhone using Tapatalk

  3. #43
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 904
    I'm Russell.

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    Quote Originally Posted by andyrlb View Post
    You’re welcome to try it here mate if that might help


    Sent from my iPhone using Tapatalk
    Thanks Andy - appreciate it.

    As it stands I’ve got the hum to a very bare minimum by using various power sockets & cables etc.

    I’m also picking up a new TT tomorrow so will how it all behaves then & go from there.

  4. #44
    Join Date: Mar 2013

    Location: nottingham

    Posts: 328
    I'm nigel.

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    Is your WiFi modem positioned anywhere near your amps perchance?
    Tubes are remarkably sensitive to WiFi emmisions.....a tube preamp I ran recently was placed near my modem and picked up all sorts of nasties.

  5. #45
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 904
    I'm Russell.

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    Quote Originally Posted by sumday View Post
    Is your WiFi modem positioned anywhere near your amps perchance?
    Tubes are remarkably sensitive to WiFi emmisions.....a tube preamp I ran recently was placed near my modem and picked up all sorts of nasties.
    I did think that so turned the router off - no discernible difference.

    It’s about 10ft away from the amps & around 2ft from one of the speakers.

    Had a play around yesterday with everything again & still the hum - worse on the Phono stage which tends to go up & down when I increase / decrease volume.

    Today I’m going to clean all the valve seats etc with contact cleaner & reposition them - see if that helps.

    Also will try different lengths / types of speaker cable & interconnects however I fear it won’t have much impact.

    Thinking down the route of going back to my Integrated as this was more or less silent through my speakers.

  6. #46
    Join Date: Apr 2009

    Location: Near Saffron Walden, Essex

    Posts: 7,087
    I'm Dave.

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    The pre is faulty.

  7. #47
    montesquieu Guest

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    I already suggested the other day that Russ get it checked over and I'll cover any repair. The original manufacturer is back in business and not that far from him. https://www.vintagevalveandvinyl.co.uk/about-us/

    It has been behaving fine for me this past year or so right up till I stopped using it a few weeks ago when the Croft went to Jake, but it does seem that there's some kind of issue appeared on the phono stage. I doubt it can be anything too serious.

  8. #48
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 904
    I'm Russell.

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    OK, after lots of fettling & cleaning etc. I think I can safely say it is the pre at fault.

    I've taken both pre & power apart & cleaned all valves, pots etc. with contact cleaner.

    Put it back together & powered up - hum still there, louder on the Phono input, increases with volume (& speakers flap).

    Used my Croft integrated paired to WML speakers - a lot quieter, hardly any background noise at all. This doesn't have a phono input however I used my Schiit Mani to hook up the TT. This is sligthtly noisier than a regular input but I would expect that with the extra gain. Still not as loud as the Gate pre.

    I then used a SS Power Amp I have (Cymbol CPA3) & used the Gate as the Pre - background hum is there again, louder on phono stage.

    Used the Cymbol as the Power with my X40 streamer as the pre - virtually silent with no source playing, even whacking the volume up.

    Last permutation is using the Gate as a Phono Stage only, coming out of the tape outs into the input on the X40 & using that as the pre. Noise is back which increases with volume, using the Croft Valve & Cymbol SS Power Amps.

    This makes me think it is the Pre which is loud, particularly on the phono stage, however what I still can't understand is why my Croft Integrated (active pre & power sections) is still quieter than the Croft 5C Power Amp - I guess it's different gain 7 the way it's set up?

  9. #49
    Join Date: Apr 2009

    Location: Near Saffron Walden, Essex

    Posts: 7,087
    I'm Dave.

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    Hallelujah, see post 15.

    The Croft 5C is all valve and now old. The Croft Integrated is hybrid and very quiet.

  10. #50
    Join Date: Jan 2019

    Location: Cambridgeshire, United Kingdom

    Posts: 904
    I'm Russell.

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    Quote Originally Posted by hifi_dave View Post
    Hallelujah, see post 15.

    The Croft 5C is all valve and now old. The Croft Integrated is hybrid and very quiet.
    Appreciate that the Croft 5C is relatively old - maybe new valves required & that might quieten it down a bit.

    The Croft integrated is newer but still valves on pre & power stages - was adapted by Glenn himself & upgraded power supply at the same time

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