Lets's talk phono preamps!

2»

Comments

  • schwarcw
    schwarcw Posts: 7,337
    edited May 2008
    Look Here

    It's too late for me to give this serious thought. Analog97 will respond unless someone wakes up and beats him to it.
    Carl

    · Share on FacebookShare on Twitter
  • analog97
    analog97 Posts: 328
    edited May 2008
    I am not familiar with the Belles 28A. Can you pull the manual and see what the process is for adjusting loading? Maybe there are dip switches inside? Maybe there is an open resistor pair near the MC input? Does the Belles use a step-up transormer internally? If so, the cart loading has already been reduced via the transformer windings to about 500 ohms. Maybe that's why your rig already sounds so good! Maybe you're already done!
    · Share on FacebookShare on Twitter
  • Ricardo
    Ricardo Posts: 10,636
    edited May 2008
    The Belles has an extra pair of RCA jacks for resistor loading, and it comes with several RCA plugs with resistors of different values. Manual says that input impedance is "Adjustable at extra RCA input 0 to 1,000 ohm". It does not say anything about internal transformer.....

    I think that the default is 1,000 ohm, but I might be wrong. I guess that I'll start plugging them in and see what happens.
    _________________________________________________
    ***\\\\\........................... My Audio Journey ............................./////***

    2008 & 2010 Football Pool WINNER
    SOPA
    Thank God for different opinions. Imagine the world if we all wanted the same woman
    · Share on FacebookShare on Twitter
  • analog97
    analog97 Posts: 328
    edited May 2008
    OK, so Belles gave you plugs that go into the RCA jacks. Each of these plugs contains a resistor of different values, so I am guessing (again) that your plan is a good one. The Belles "system" is asking you to place a resistor in parallel with the MC input to lower the loading. That's fine. Are the resistor "plugs" marked with the ohm rating? If so, they probably marked the value of "final" loading taking into account whether there is a step-up transformer in the MC circuit. So, I am guessing that you probably have resistor plugs for about 30-50 ohms, 100 ohms, and maybe 500 ohms or so. These are common MC cart loading ranges. For high output carts, usually loading is 47K ohms. That's why you can just plug most of them into a MM phono input. The low output MC's are generally most finicky about loading, with the largest sonic difference heard below 500 ohms. Your Benz is a "tweener", so if the inherent loading at the Belles MC input is 500-1000 ohms, I think you are probably getting very close to a sweet spot. If you want to hear a sonic difference, try plugging in the lowest RCA resistive plug they gave you. Enjoy. The Belles is one fine piece of gear.:D
    · Share on FacebookShare on Twitter
  • Ricardo
    Ricardo Posts: 10,636
    edited May 2008
    What you say makes sense (the ohm values being the final loading). That would be the logical thing to do, instead of having people calculating resistor values....

    I checked the values I have and there are 10, 20, 50 and 150 ohm pairs. It seems that my Benz with a >200 spec would be better without any of them...but I will anyway play with them to see the differences.

    Thanks!!!
    _________________________________________________
    ***\\\\\........................... My Audio Journey ............................./////***

    2008 & 2010 Football Pool WINNER
    SOPA
    Thank God for different opinions. Imagine the world if we all wanted the same woman
    · Share on FacebookShare on Twitter