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Noise coming from loudspeakers when Sony CMT-CP100 is connected to a preamp.

I have a phono preamp connected to my sony cmt cp100 in order to use my turntable, but i recently noticed a random deep growling noise coming from the speakers when the preamp is on. It happens super randomly, once every few minutes. I can't wrap my head around what it could be. Is there some sort of "incompatibilty" between the cmtcp 100 and the preamp? I switched cables, loudspeakers, and even replaced the preamp but the darn noise is still there! any clues? thanx in advance!

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  • Sony Master
  • 667 Answers

Hi Humberto, comment the brand and model of the phono preamplifier, also if it has a separate power supply or inside the preamplifier cabinet
I ask you this, because if you were armed in a plastic cabinet, you could pick up interference caused by cell phones or other type of component that can emit electrical noise and these interferences are those that could generate the noises that you hear in your speakers at the moment that you listen to the discs
I await your comment
Greetings Franco Dosil

Hola Humberto, comenta la marca y modelo del pre amplificador de fono, tambi?n si tiene fuente de alimentaci?n separada o dentro del gabinete del pre amplificador
Te pregunto esto, porque si estuviera armado en un gabinete pl?stico, se podr?an captar interferencia que producen los tel?fonos celulares u otro tipo de componente que pueda emitir ruidos el?ctricos y estas interferencias son las que podr?an generar los ruidos que escuchas en tus parlantes en el momento que escuchas los discos
Espero tu comentario
Saludos Franco Dosil

Posted on May 10, 2019

Testimonial: "Hey Franco thanks for your message! I was using this LD PPA2 preamp when I noticed that weird noise. The preamp has an external charger. Then I replaced it with this TCC-750, which is in fact better and more expensive, but it keeps making the same noise! This preamp also has an external charger. The turntable is a Yamaha P-350. The noise is not a hum but more of a short, low, kind of growl (for lack of better words). It happens intermittently, only once every few minutes. Very randomly. Super weird but very annoying too! I appreciate the help. Thanks!!"

  • 7 more comments 
  • Franco Dosil
    Franco Dosil May 10, 2019

    Hello again Humberto, I understand your expression regarding the annoying noise that occurs
    The pre amplifier, I do not know it, but it has finishing details that show a good quality product
    Making an analysis of the possible generators of this noise, try to check the capsule holder of the tray, that the contacts are clean and firm, that the interconnection cables from the capsule to the capsule holder, do not have samples of humidity or rust
    I understand that the mass cable of the tray, you have connected to the Pre amplifier terminal
    Revised all this, I would suggest, that if you have nearby electronic elements, notebook, router, WI-FI or other possible noise generators, or disconnect or bring the equipment, along with the tray to another area less contaminated by electronic interference and there , arm the audio system again and control, if the noise goes
    On the other hand, if you live near a mobile phone antenna or other type of communication antenna, you would be exposed to this possibility of interference and the only thing that occurs to me is that you should have the equipment inside a Faraday cage, it is a protection system for electrical interference
    Another point of failure could be if the equipment is connected to a multiple socket, there may be a false contact and it is reflected in the sound of the pre amplifier
    Another test, connect tray and pre amplifier in other equipment
    I can not think of more possibilities of proof
    I hope that with the options that you comment, you can solve the problem, luck in the tests
    Greetings Franco Dosil

    Hola nuevamente Humberto, entiendo tu expresi?n referente al ruido molesto que se produce
    El pre amplificador, no lo conozco, pero tiene detalles de terminaci?n que muestran un producto de buena calidad
    Haciendo un an?lisis de los posibles generadores de dicho ruido, prueba revisar el porta-capsula de la bandeja, que se encuentren los contactos limpios y firmes, que los cables de interconexion desde la capsula al porta capsula, no tengan muestras de humedad u oxido
    Doy por entendido que el cable de masa de la bandeja, lo tienes conectado al terminal del Pre amplificador
    Revisado todo esto, te sugerir?a, que si tienes elementos electr?nicos pr?ximos, notebook, router, WI-FI u otros posibles generadores de ruido, o los desconectes o lleves el equipo, junto con la bandeja a otra ?rea menos contaminada de interferencias electr?nicas y ah?, arma nuevamente el sistema de audio y controla, si se va el ruido
    por otro lado, si vives cerca de una antena de telefon?a m?vil u otro tipo de antena de comunicaciones, estar?as expuesto a esta posibilidad de interferencias y lo ?nico que se me ocurre es que tendr?as que tener el equipo dentro de una Jaula de Faraday, es un sistema de protecci?n de interferencias el?ctricas
    Otro punto de falla podr?a ser si los equipos est?n conectados a un toma de corriente m?ltiple, que pueda haber un falso contacto y se refleja en el sonido del pre amplificador
    Otra prueba, conecta bandeja y pre amplificador en otro equipo
    No se me ocurren mas posibilidades de prueba
    Espero que con las opciones que te comente, logres resolver el problema, suerte en las pruebas
    Saludos Franco Dosil

  • Humberto Duque
    Humberto Duque May 10, 2019

    Thanks for your message!

    Pardon my ignorance but what do you mean by capsule and tray capsule holder?

    The TT is connected to the preamp, then to an rca splitter, and finally to the sony sound system.
    In any case, I made a test connecting the cables directly form the sony SS to the preamp without going thru the splitter and the noise persisted.

    Looks like all the connections are clean and tight.

    Everything is plugged into a multiple socket but I made a test with a different one and the noise continued.

    I also removed a bluetooth receiver that was close by. Nothing….

    But yeah, the room is small and there’s notebooks, wifi, cellphones, you name it.
    So I guess it’s gonna be hard to pin down whatever is causing this weird noise...

  • Humberto Duque
    Humberto Duque May 10, 2019

    BTW I think I voted your comment pretty low by mistake. Sorry 'bout that! Dn't really know how this voting thing works.

  • Franco Dosil
    Franco Dosil May 11, 2019

    Hello Humberto, I call it a capsule, to the phonocaptor, in English pickup and capsule holder to the device that holds the phonocaptor, which in English is head shell asembly
    I do not understand, because you use an RCA splitter, which is the objective
    Another test that occurred to me, is to put two RCA connectors shorted, that is, when the live is connected to ground at the entrance of the preamplifier, in this way, if there was noise, the problem would be in the preamp of the turntable
    I must tell you that I do not master English, and what I write, I do in the Google Translator, that's why there are terms that Google Translator, does not recognize therefore the difficulty of expressing ideas
    OK, do the test with the RCA and tell me
    Greetings Franco Dosil

    Hola Humberto, le llamo capsula, al fonocaptor, en ingles pickup y portacapsula al dispositivo que sostiene al fonocaptor, que en ingles es head shell asembly
    no termino de entender, porque usas un divisor RCA, cual es el objetivo
    Otra prueba que se me ocurri?, es poner dos conectores RCA en cortocircuito, es decir que el vivo este conectado a masa en la entrada del preamplificador, de esta manera, si hubiera ruido, el problema estaria en el preamplificador de de la bandeja giradiscos
    Debo decirte que no domino el ingles, y lo que escribo, lo hago en el Google Traductor, por eso es que hay terminos que Google Traductor, no reconoce por eso la dificultad de expresar las ideas
    bien, haz la prueba con los RCA y comentame
    Saludos Franco Dosil

  • Humberto Duque
    Humberto Duque May 11, 2019

    Hola Franco, si quieres podemos hablar en castellano, no hay problema!

    El divisor rca lo uso para poder conectar la computadora a trav?s de un receptor bluetooth. El mini componente sony s?lo tiene una entrada rca, por eso tengo ese splitter para poder cambiar de canal.

    Hice ya una prueba conectando el preamplificador directamente al minicomponente, sin pasar por el rca splitter, y el ruido contin?a. Cuando el preamplificador est? apagado, no hay ning?n ruido, por lo que lo m?s seguro es que sea el preamp. La duda es qu? es lo que est? causando este ruido tan raro…

    Otra cosa, el ruido viene s?lo de la bocina derecha, que es la que est? m?s cerca al tornamesa y preamp, no s? si esto tenga que ver.

    El cable rca que conecta el preamp al minicomponente es de 5 metros, no s? si afecte esto.

    En fin, sigue siendo un misterio, en especial porque cambi? bocinas, cables, preamp. B?sicamente cambi? todo, menos el minicomponente sony, y el ruido persiste.
    Gracias por el inter?s!


  • Franco Dosil
    Franco Dosil May 11, 2019

    Hola Humberto, a mi parecer, a la entrada del Sony, en vez del Splitter, deber?as tener una llave selectora que conectar?a o el pre amplificador de la bandeja gira discos o el receptor Bluetooth, lo mejor seria un peque?o mixer de tres entradas est?reo o mas, seria muy bueno que tuviera una de las entradas de fono
    Vuelvo a sugerirte la prueba de colocar en la entrada del pre amplificador, dos RCA en corto,
    en cada uno de los RCA de entrada, que significa en corto, que esta unido la conexi?n de la masa y la del vivo, para que te sugiero esto, para ver si el ruido lo esta generando el pre amplificador, si haces esto y continua el ruido, este lo estar?a generando el pre amplificador, si el ruido no esta, entonces el conflicto lo tienes en la bandeja gira discos
    si fuera la bandeja, vuelvo a enumerar los puntos que deber?as revisar
    Las conexiones entre el pickup(que yo lo llamo Capsula) y el head shell assembly(que yo lo llamo porta capsula), ver que est?n limpias y conectados correctamente, te describo los colores de los cables de interconexion y su posici?n, positivo canal L, Blanco, negativo canal L, Azul. positivo canal R, Rojo, negativo canal R, Verde
    Puedes Probar con un multimetro, la continuidad entre los contactos en el brazo y los cables RCA, para esto retiras el porta capsula y vas a ver 4 contactos, tienes que comprobar continuidad entre cada contacto y las fichas RCA, si detectas alguna falta de continuidad, ah?, estar?a el problema
    Revisa que el cable, no tenga lastimaduras
    No se donde vives, yo en Argentina, no creo que pueda ir a revisarte los equipos
    Si llegas a comprender lo que te he sugerido, prueba y comenta
    A mi tambi?n me gustar?a saber por donde esta el origen del molesto ruido
    Espero que encuentres la falla y comentala, para saber un poco mas
    Si puedes lleva todos los aparatos a otro lugar, distante de donde est?n ubicados ahora y haz la misma prueba, como para descartar interferencias
    Si se me ocurre algo mas, te lo comento
    Saludos Franco Dosil +54 9 11 4479 5276
    Lo pongo en ingles por si le sirve a otra persona

    Hello Humberto, in my opinion, at the entrance of the Sony, instead of the Splitter, you should have a selector key that would connect or the pre amplifier of the tray rotates discs or the Bluetooth receiver, the best would be a small mixer with three stereo inputs or more, it would be great if I had one of the phone entries
    Again I suggest the test of placing two short RCAs in the entrance of the pre amplifier,
    in each of the input RCA, which means short, that is connected the connection of the mass and the live, so I suggest this, to see if the noise is generating the pre amplifier, if you do this and continue the noise, this would be generated by the pre amplifier, if the noise is not there, then the conflict you have in the platter rotates discs
    If it were the tray, I'll list the points you should check
    The connections between the pickup (which I call Capsule) and the head shell assembly (which I call the capsule holder), see that they are clean and connected correctly, I describe the colors of the interconnection cables and their position, positive channel L , White, negative channel L, Blue. positive channel R, Red, negative channel R, Green
    You can test with a multimeter, the continuity between the contacts on the arm and the RCA cables, for this you remove the capsule holder and you will see 4 contacts, you have to check continuity between each contact and the RCA cards, if you detect any lack of continuity , there would be the problem
    Check that the cable does not have any injuries
    I do not know where you live, I in Argentina, I do not think I can go to review the equipment
    If you come to understand what I have suggested, try and comment
    I would also like to know where the source of the annoying noise is
    I hope you find the flaw and comment it, to know a little more
    If you can, take all the devices to another place, far from where they are located now and do the same test, as to rule out interference
    If something else happens to me, I'll tell you
    Greetings Franco Dosil

  • Humberto Duque
    Humberto Duque May 13, 2019

    Mil gracias Franco.
    En efecto, tengo un peque?o mixer con llave selectora, no un splitter como dije anteriormente.
    Dime una cosa, no entiendo muy bien la prueba que me sugieres. No s? bien que es la masa y el vivo.

    En la ?ltima prueba que hice conect? el tornamesa al preamplificador, pero sin enchufar el tornamesa a la corriente. A su vez conect? los cables rca directamente del preampplificador al sony. El ruido persist?a.
    Hasta donde yo sepa los cables est?n limpios y bien conectados. Me intriga saber qu? es lo que pasa.
    No puedo cambiar los equipos de lugar porque la casa es peque?a.
    Vivo en Finlandia por lo que ser? dif?cil revisar el equipo pero te lo agradezco mucho. Si tienes alguna otra sugerencia m?ndamela por favor.
    Saludo grande hasta la Argentina!

  • Franco Dosil
    Franco Dosil May 13, 2019

    Hola Humberto, lo de masa y vivo, me refiero al cable y a la ficha RCA, los cables de audio, que usas para interconectar los equipos, tienen internamente dos conductores el?ctricos de la se?al de audio, el que esta en el centro del cable de audio, lo llamo vivo, en ingles muchas veces aparece como "Hot" y el cable que recubre al cable central(vivo), lo llamo masa, en ingles aparece con varios nombres, Ground, Screen, Shield
    Vuelvo a sugerir que te consigas dos conectores RCA sueltos, que le unas la conexi?n del centro (Vivo) y la conexi?n exterior (Masa), o sea poner en cortocircuito las fichas y las pongas en la entrada del preamplificador, en lugar de las fichas RCA de la bandeja giradiscos, y luego prender el Sony y el Preamplificador, y escuchar si aparece el ruido, si el ruido no esta, el preamplificador, no es el que lo genera
    En este caso hay que comprobar las conexiones de la bandeja, desde el pickup(Capsula), hasta las fichas RCA
    Porque te sugiero esto, es para encontrar que elementos pueden producir el ruido,
    Espero que me hayas entendido y puedas realizar las pruebas que te comento y que puedas determinar que produce el ruido
    Saludos Franco Dosil

    Hello Humberto, what mass and live, I mean the cable and the RCA card, the audio cables, which you use to interconnect the equipment, have internally two electrical conductors of the audio signal, which is in the center of the cable. audio, I call it live, in English many times it appears as "Hot" and the cable that covers the central cable (live), I call it mass, in English it appears with several names, Ground, Screen, Shield
    I suggest again that you get two loose RCA connectors, that you connect the center connection (Live) and the outer connection (Mass), that is, short circuit the chips and put them in the preamplifier input, instead of the chips RCA of the turntable, and then turn on the Sony and Preamplifier, and listen if the noise appears, if the noise is not, the preamplifier, is not the one that generates it
    In this case you have to check the connections of the tray, from the pickup (Capsule), to the RCA tabs
    Because I suggest this, it is to find what elements can produce the noise,
    I hope you have understood me and can perform the tests that I have told you and that you can determine what produces the noise
    Greetings Franco Dosil

  • Humberto Duque
    Humberto Duque May 13, 2019

    Gracias Franco,
    Como te comentaba anteriormente ya prob? con dos preamplificadores distintos, de distintas marcas, y el ruido persist?a, por lo que tengo duda que sea el preamplificador.
    No s? si sea posible que exista un problema entre el sony el preamp, o si sea un elemento externo en el ambiente que est? causando una interferencia.
    De todas maneras intentar? hacer la prueba que me dices.
    Muchas gracias!


    Thanks Franco!
    As I was telling you, I already tried with two different preamps, from 2 different brands, and the noise continued. It could be a problem between the sony amplifier and the phono preamp, or maybe some magnetic static caused by something in the room, like wifi or cellphone.
    I’ll anyway try to do the test you suggest.
    Thank you!



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