[HAM] 21H Leslie

[Dave Bishop]

5881s are similar to, or in the case of Tung-Sol identical to, 6L6WGB tubes: 
max plate 360 volts at 23 watts and screen at 270volts, 3 watts.  Here are 
sites that compare the 5881 with the various 6L6 versions:

http://www.vacuumtubes.com/6l6.html
http://thetubestore.com/6l6review.html

The cathode bypass resistor makes the amp self-biasing to a degree:  mixing 
within the 6L6 family isn't much of a problem.  The power tubes aren't being 
stressed hard in a 32H, so they can last a long time.  If the Leslie sounds 
dull a new tube set might wake it up a bit.

If the 32H has all stock parts except the tubes, its a clear candidate for 
replacement of passive components.  I ordered them from Newark last week and 
the bill came to around $80.  Some people say that 5881s sound warmer than 
6L6GCs, with less harmonic distortion and more output before clipping.  The 
122 has roughly 10 watts more output than the 32H, so one would expect the 
32H to clip at a lower volume.  Drifting in the cathode bypass can increase 
distortion at higher volumes.

You might have a torn woofer or dirt in the horn driver throat that is 
causing the breaking up you describe.

You can find techs on the list who sell motor controllers by Googling 
"Caribbean Controls" "Hamptone" or "EIS".  Installation is a couple hours 
the first time, and you need to be able to solder under the amp chassis in a 
couple places.

Regards,

Dave Bishop