In article , "west"
wrote:

Why do Dynaco Amps and even Uncle Ned's schematic of a Hi Power Williamson
Amp use the 16ohm OPT tap instead of the 8ohm for feedback? What would
happen if you took a stock ST-70 or MKIII and moved the feedback over to the
8ohm? Thanks.

Taking the feedback signal from the 16 Ohm tap provides improved high
frequency stability when either the 8 or 4 Ohm tap is in use. This is a
result of the "unused" end of the secondary winding providing some of the
stability benefits of a tertiary feedback winding, although obviously
since this tertiary winding is in series with the "active" portion of the
secondary, the advantage of the tertiary for feedback is diluted.


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/