Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
In Reply to: RE: Classic Mac Sound posted by 6bq5 on February 19, 2017 at 18:29:10
The McIntosh circuit topology was not Ultra-linear. They had a patent on so-called "unity coupled" amplifier circuitry, which was the basis for all their tube designs from the MC 30 on. They made use of a special transformer winding technique along with a cathode winding to provide large amounts of local feedback around the output stage.
Mea Culpa- Unity coupled vs Ultralinear-
I saw this video on the making of the Mac 275 power amp. When they got to the transformers they were pouring this tar goopy like liquid into the housing or bells to seal them up.
I know the Dyna transformers didn't do that and would that process make a more silent transformer?
Why I started this thread was not only the Willie Nelson cigarette I smoked but the fact of believing all this time from reading stereo mags that the best preamp is the one that least colors the signal. Barring tubes vs. transistors debates the 6000 dollar C-22 came into view.
So when the reviewer said the pre amp had that classic Mac sound it threw me for a ground loop.
Every time you guys write I get a great audio lesson...keep em coming....thanks Mark K.
Transformers are an interesting element of the audio chain-
The can generate noise
they - in the form of output x-formers- define the frequency response of the amp
however if well made- can make a unit be sublime-
putting that 'tar goopy' stuff in does a few things -
1: if done well, the material can get into the air spaces to keep the transformer quiet (from mechanical noise)
2: protect the windings from the lams - consider it added insulation
3: enable the transformer to be more uniform with respect to heat - and to then transfer the head to the external surfaces-
This is usually called 'potting' or potted transformers
not many people do it any more, as it adds expense...
but some of the best amps made have potted transformers-
Post a Followup:
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: