Conference napalm::commusic_v1

RE < Note 2209.1 by WEFXEM::COTE "Call *who* Ishmael???" >

>                              -< Dirty Slider?? >-

	But would it do that if the slider is not moving?

	Dan    

    It's been my experience that it would, or at least *can* cause the
    output signal to break up.
    
    I've seen it on my Mirage, and on one of the input trimmers on my
    board...
    
    Edd

	What kind of cleaner?

	Dan

    
    Rat Shack ozone depleter followed by compressed air
    
    CdH
    

    I've used Color TV tuner cleaner with totally acceptable results,
    however, I've heard that this maybe too 'abrasive' for pot use. (?)
    Again, I keep a can handy and use it freely.
    
    Rat Shack undoubtedly sells a switch cleaning fluid.
    
    If it clears it up, you may want to consider treating your pots and
    sliders with a 5% Cramolin solution...
    
    Edd

	I'll pick up a can of cleaner tonight and see what happens.  Thanks all.

	No improvement.  Any other suggestions?  

	Dan

    Have you done the requisite experiments to confirm that the distortion
    is originating in the unit itself and not downstream?   If it is
    in fact within the unit, can you adjust some programmable gain
    parameter?  It's relatively easy to drive just about any synth into
    distortion with a suitable combination of parameters and the VCA
    gain topped out.  If the distortion seems to be patch specific,
    that could be an indication of this kind of problem.
    
    len.
    

RE < Note 2209.9 by DRUMS::FEHSKENS >

	Well, the RD200 is an entirely pre-set instrument.  The only controls
over patches I have is master volume, chorus (on/off) and tremelo (on/off/rate/
depth).  As I said earlier, the problem may be mostly in the chorus circuitry, 
as the distortion is magnified when it is turned on.  Or it could be that the 
chorus circuitry adds the kind of modulation that amplifies the distortion in 
the output stage.

	Oh, there is a three postion switch in the back (as in most Roland 
products) to control output level.  It appears that the distortion is happening 
before it reaches this attentuator, since it distorts at any setting.

	And yes, I have traced the distortion to the RD200 and not in other 
components (mixers/amps/etc.).

	Dan

    Well, that uses up my supply of standard answers.  Sounds like
    something's broke.  I suspect the chorus is just making it worse
    rather than being the source.
    
    len.
     

RE < Note 2209.11 by DRUMS::FEHSKENS >

	Well, I don't know how anxiously I will pursue sending it out.  As I 
said, it works o.k. if I leave the volume fader at "half mast".  I was just
hoping to find some "useful tips" here (which I did, but to no avail).

	Dan

    I had a similar problem with a Yamaha sound module (EMT-10). The piano
    sounds had distortion when I hammered the keys during playing. I traced
    this to a bad power supply (it uses what you guys call a wall bug)
    which was not providing enough guts to drive the output stages cleanly
    when high volume was being output. This resulted in clip distortion.
    
     I know that the RD200 doesn't use wall bugs but you could check the
    PSU part of it if you were feeling brave. Perhaps there is a suspect
    smoothing capacitor, &c.
    
     Try putting a 'scope across the audio out and see if you can see any
    clipping of the output signal (probably require many hands to do
    this!).
    
    					Andy

RE < Note 2209.13 by AYOV16::ABELSEY "Tha mi sg�th de Luchd na Beurla." >

	Thanks for the suggestions, but I'm really not a hardware type of guy,
though I dabble a bit here and there just enough to be dangerous.  I don't know 
how to find the "smoothing" capasitor in the PSU, nor would I know what to do if
I did find it.  Same goes for the suggestion of using a scope - I don't have 
one, have access to one, nor do I know how to use one...

	(So what did you start this note for, Dan?)

	I guess I was just hoping for some obvious leads, such as the checking 
of the volume slider (which I did check, and it didn't help).

	Anyway, thanks for the suggestion.  If you can give me more exact 
instructions on how to find this particular capacitor and what to do once I
find it, I follow instructions well.

	Dan

    
      I have a less-expensive keyboard that I use a wall bug with. I can run 
    on batteries which causes the keyboard sound to distort as the volume 
    increases.
    
      It does sound like a power supply.
    
       - Bob

    Just to put a closing note to this topic...
    
    	Shortly before I moved down to misery - er - Missouri, I brought the
    piano into Union Music to have them look at it.  It was there for quite
    a while and it seems that the tech there tried a lot of different
    angles.  It seems that this is not a common bug as he went through a
    number of ROM changes and such to uncover the difficulty.  He finally
    gave it back to me at no charge saying he did the best he could.
    
    	What is intersting about it all is that whatever he did actually
    *did* seem to help out.  There's still some distortion there if you
    turn it up really high, but it seems to be less than what was there
    before he worked on it.  I am please, and it cost me nothing.
    
    	Dan