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Thread: RF (radio frequency) tests performed on my system.

  1. #1
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 4,782
    I'm Alan.

    Default RF (radio frequency) tests performed on my system.

    This testing is with Grounding boxes in mind, just to see what the background RF levels and emissions are from stereo kit.

    Radio Frequencies cover a very wide frequency range, the test equipment I have goes right up to 1GHz.
    That is 1000 MHz or to put another way 50000 times the audio bandwidth.

    RF energy is very pervasive, it is all around us and is induced into anything metallic. Even a screened lead will pick up RF on its outer braid.

    The test kit is known as a spectrum analyser and shows the frequency along its X axis with the logarithmic amplitude on the Y axis.
    The X axis is linear so shows frequencies from Zero to 1GHz, so each graticule line is 100MHz.

    The Y axis shows signals above the noise floor mush at the bottom of the screen, at about 20uV. This is ten times lower than a low output moving coil cartridge to give a context.

    Test 1.
    A 1 metre whip antenna connected to show the background RF level.



    Test 2.
    A probable ground box lead connected, made from some RG58 coaxial cable.




    A test lead was made to connect to only the outer shell of an RCA socket and used for subsequent tests.
    Test 3.
    Test lead connected a CD transport output. Transport mains OFF.



    Test 4.
    As test 3 but CD transport mains ON.



    See the slightly raised mush up to about 430MHz.

    Test 5.
    Test lead connected to a SPDIF input of Bel Canto DAC3, mains OFF.



    Test 6.
    As test 5 but DAC3 mains ON.



    Look at all those clock harmonics

    Test 7.
    Test lead connected to XLR output of DAC3, mains ON.




    Test 8.
    Test lead connected to spare input of KIN preamp, mains ON.

    Firebottle - for the no bottleneck approach.

    I love Hendrix for so many reasons. He was so much more than just a blues guitarist - he played damn well any kind of guitar he wanted. In fact I'm not sure if he even played the guitar - he played music. - Stevie Ray Vaughan

  2. #2
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 8,408
    I'm Oliver.

    Default

    What does all that mean?!!!! Lol
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK6 tonearm > Ortofon Kontrapunkt b > Bigbottle Jfet MC Valve Phonostage (Telefunken Valves)
    Digital: Raspberry Pi 3+ With Allo Boss 1.2 + Isolator.
    Amplification: Nelson Pass DCB1 with Khozmo 48 Step Series Attenuator & Krell KSA100 MK2 Amplifier
    Cables: SPOTFIRE Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A
    Price List For Cables:https://bit.ly/2Uxiv3j

  3. #3
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 4,782
    I'm Alan.

    Default

    It is the amount of RF that is picked up with various connections to bits of kit.

    You are never free of it. All the spikes coming from the Bel Canto surprised me.

  4. #4
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 8,408
    I'm Oliver.

    Default

    Quote Originally Posted by Firebottle View Post
    It is the amount of RF that is picked up with various connections to bits of kit.

    You are never free of it. All the spikes coming from the Bel Canto surprised me.
    Ah I see.

    Yes, RF everywhere!
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK6 tonearm > Ortofon Kontrapunkt b > Bigbottle Jfet MC Valve Phonostage (Telefunken Valves)
    Digital: Raspberry Pi 3+ With Allo Boss 1.2 + Isolator.
    Amplification: Nelson Pass DCB1 with Khozmo 48 Step Series Attenuator & Krell KSA100 MK2 Amplifier
    Cables: SPOTFIRE Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A
    Price List For Cables:https://bit.ly/2Uxiv3j

  5. #5
    Join Date: Feb 2008

    Location: Down South

    Posts: 2,335
    I'm Neal.

    Default

    ....and thatís only up to 1Ghz, mobile phones at 1.9Ghz, 2.4Ghz and 5Ghz WiFi etc etc.
    Listening in a Foo free Zone...

    Only a Sith deals in absolutes.

  6. #6
    Join Date: Mar 2017

    Location: London N2

    Posts: 1,340
    I'm Edward.

    Default

    Very interesting Alan. Would your test equipment and methodology be useful in proving (or not) the improvement in SQ we both heard (separately) when trying out Tony's RTZ boxes at his place? I'd imagine that you would be able to show the RF reduction. But perhaps I'm being too simplistic?
    Source: Tidal/Roon
    DAC: Metrum HEX, Chevron Paradox

    Amp: Sugden Masterclass 2018 spec, Radford Revival STA25 V,
    Speakers: Tannoy Eaton, Kudos Cardea


  7. #7
    Join Date: Sep 2010

    Location: West Midlands, UK

    Posts: 639
    I'm Lee.

    Default

    I popped into Alans house last night whilst he was doing these experiments with the spectrum analyser and it was quite interesting to see how much RFI is actually present within the room, I guess that all rooms would be similar? What effect this RFI has upon the sound is way above my electrical knowledge of putting a 3 pin plug on but Im interested all the same.

    If by reducing the amount of RFI present within the room does have a desired effect on the sound then this will be something that I will definitely be looking at myself
    Vinyl rig 1 - NAS Spacedeck / Jelco 750D / EAR 834P modified / Denon DL 103. Vinyl rig 2 - Lenco GL75 c/w original arm and Shure M75ED MM cart / trichord Diablo with NCPSU. Amplifiers - Audio Note Empress Silver / Hattor Passive Pre. Digital - Mac Mini / Lampizator Atlantic Plus tube rectified Dac / Linear PSU / Hummingboard Network audio adaptor. Speakers - Horns.pl Mummy's. Cables are Audio Note / Albedo / Duelund WE16GA Speaker wire. Power conditioner is a Gigawatt PC2 EVO

  8. #8
    Join Date: Jan 2008

    Location: Forest of Dean, Glos

    Posts: 10,965
    I'm Jerry.

    Default

    Now if only you had a Grounding Box to plug in - RF up, down or the same?
    Jerry

    Internet streaming > various electronics and cables > MBL 116F speakers

  9. #9
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 8,408
    I'm Oliver.

    Default

    Quote Originally Posted by jandl100 View Post
    Now if only you had a Grounding Box to plug in - RF up, down or the same?
    indeed!
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK6 tonearm > Ortofon Kontrapunkt b > Bigbottle Jfet MC Valve Phonostage (Telefunken Valves)
    Digital: Raspberry Pi 3+ With Allo Boss 1.2 + Isolator.
    Amplification: Nelson Pass DCB1 with Khozmo 48 Step Series Attenuator & Krell KSA100 MK2 Amplifier
    Cables: SPOTFIRE Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A
    Price List For Cables:https://bit.ly/2Uxiv3j

  10. #10
    Join Date: Nov 2011

    Location: Seaton, Devon, UK

    Posts: 1,469
    I'm Adrian.

    Default

    Quote Originally Posted by Bigman80 View Post
    indeed!
    Perhaps Mr C.would lend you one so you could repeat the test with a grounding box connected. Very interesting
    [FONT="Arial"]
    Listening is the act of aural discrimination and dissemination of sound


    Michel GyroDec (slightly modified), SME IV arm(special build virtually a V), Michel Cusis MC cartridge, Furutech AG-12-R4 High Performance Phono Cable, LFD MMC special phono stage, RaspberryPi/HifiBerry Digi to Beresford Caiman SEG DAC, Meridian 508 CD to Caiman SEG, ALLNIC T1500 MKII SET 300B amp, Vienna Acoustics Mozart SE speakers, Chord Epic speaker leads, & signature links, the Eccose Conductor CA1 cd to pre

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