c4ad9d77   
   From: tony.miklos@gmail.com   
      
   NJ Mike wrote:   
   > This might be a stupid question, but aside from physical damage or   
   > defects, when should this be done?   
   >   
   > The reason I'm asking is that on my RO1454, I've had the amp rebuilt,   
   > new tubes (two different matched pairs), new cartridge installed (P51   
   > with a .7mil stylus), and I'm still not 100% happy with the sound   
   > quality.   
   >   
   > What I hear is a harshness in the midrange.   
   >   
   > So, is this is good as its going to get, or is the next step to recone   
   > the speaker and horn?   
   > (physically, they look good).   
   >   
   > Thanks,   
   > Mike   
      
   Other things to check.  Tap quickly but gently on the speaker cone, if   
   you can hear a little rattle, the "spider" between the coil and the cone   
   is broken.  Recone.   
      
   Also use two or four fingers to push the cone inward and relese it out   
   as if it was hitting some low bass notes.  Push it straight, don't lean   
   it to one side.  If you hear a scratching sound, first make sure you   
   aren't causing it by pushing to one side.  If it is the speaker, the   
   voice coil is halfway fried, expanded, and rubbing.  Recone.   
      
   If it checks out OK, well I've fixed supposedly *rebuilt* amps from many   
   sources.  Some of them from a few of the biggest dealers in the states,   
   some of them just don't test them properly.  Many test the amp by   
   listening to it.  Everyones hearing is different so there is no standard   
   to go by.  The proper way is to use a square wave input and look at the   
   output on a scope.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)