Shhho much shhhhibilance

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  • 03-01-2010, 05:35 PM
    atomicAdam
    Shhho much shhhhibilance
    Needs some help in pin pointing a problem, or before I approach Simaudio again.

    I'm getting a lot more sibilance out of the TT than I remember before I moved down to SoCal.

    I just got it aligned, and the phono amp sort of checked, last Saturday. When I came home, plugged it in, sounded fine. Today on certain LPs it sounds bad again.

    I switched out cables, amps, pre-amps, and still have the shhhh/hissss sound at vocal peaks.

    It seems to me there can only be two possibilities.
    1) The alignment isn't right
    2) There is something wrong with the phono amp

    What do you all think?

    Thanks
    -adam

    Brooks said to come back if I wasn't happy, and seeing as it is raining again this Saturday I suppose I will. But, with the Phono amp having fried a power adapter before, I wonder if something is wrong with the unit.
  • 03-01-2010, 06:22 PM
    JohnMichael
    Do you have another phono preamp you can use? I can not imagine if the alignment sounded good when you brought it home it could have changed. I wonder if the preamp has a part out of spec that causes the distortion.

    Do you have the preamp set up for MM/high output MC? Setting it for low output MC could cause problems. I also wonder if the cartridge could be defective since you have had it adjusted at two different shops.

    I wish I could be there to help diagnose the problem.
  • 03-01-2010, 06:34 PM
    atomicAdam
    Hey JM,

    I don't have a second phono amp.

    Well, maybe should good when I got it home isn't right. I didn't play the records I played today. So, it sounded good on what I played that day.

    The phone amp is set for MC because the Blue Point Special is MC, with a 47k Ohms load impedance. So I've got the phono amp set to 47. Funny thing, on the circuit board there are 3 pins for the jumper. Left is 47k and right is 100k. Under the pins is marked MM and MC. The way it looks, if I set it to 47k load impedance like the cart says, then I am on the MM side of the 3 pins. Maybe I should set the other way.

    So, I switched back to the BJC cables at the moment for the phono amp to pre-amp, and being low impedance cables, I suppose I should set the output loading to 100 Ohms instead of the 0 I have it at.

    Anyways,....

    At Brooks, he set up and test the TT on his system, and then used my phono amp. It all sounded good, and I brought in an LP that caused sibilance at home, but then realized that it is cut 2 that has it more than cut 1 and we didn't play cut 2 at the store.

    So, if I play CDs. I get no sibilance at all, with any configuration of pre-amp or amp or cable set up.

    I'll try setting up the pins differently and giving it a spin.
  • 03-01-2010, 06:45 PM
    JohnMichael
    Set it for moving magnet because of the output of the cartridge places it at the mm level. Yes it is generated by a moving coil cartridge but at a level of MM. Set the preamp to the MM and you will be happy. You are overdriving the preamp using the moving coil input.
  • 03-01-2010, 07:03 PM
    atomicAdam
    well as if to test my resolve, the phono amp isn't putting out sound now.

    light lights up, but no sound.

    it did do sound for a second, then I plugged the CD player, the sound wavered, and then stopped. giving the unit a minute to gather its thoughts before I take it out back and shoot it.
  • 03-01-2010, 07:08 PM
    atomicAdam
    ok, i set up as you suggest. no sound still. turned everything off and will give it some time to settle.
  • 03-01-2010, 07:19 PM
    JohnMichael
    Quote:
    Originally Posted by atomicAdam
    well as if to test my resolve, the phono amp isn't putting out sound now.

    light lights up, but no sound.

    it did do sound for a second, then I plugged the CD player, the sound wavered, and then stopped. giving the unit a minute to gather its thoughts before I take it out back and shoot it.

    Even with using it in moving coil mode with a high output moving coil should not have damaged the unit. I am sure Simaudio would want to make it right. Sounds like a deffective unit. Do you need a loaner phono preamp?
  • 03-01-2010, 07:25 PM
    atomicAdam
    i've really got to solder the power light connection back together in the AVA pre-amp. Guess I had unplugged that and not the CD player earlier. Things working now.

    I'll give it some listen now. The phono amp is set to MM 47 Ohms.

    Thanks JM for the help/suggestions.

    So far the sibilance seems back to normal.
  • 03-01-2010, 07:27 PM
    atomicAdam
    don't i make for a good 'point and laugh at the retard'?

    at least I didn't caulk the phono amp, right PC?