Thanks for that pointer, drlowmu.
In Post #31 I had mentioned that R Core is not uncommon (as a Mains Transformer) Just that I had never come across its use as an output transformer in Tube amps
The McIntoch MA6000 seems to use it as a Power transformer, .... and unfortunately, going by reviews... it is not too good high drive levels ....
I suspect they have cut corners in the design to meet a relatively low (For McIntoch ) price point
You are welcome. What if McIntosh uses R-Cores in most, if not all of their new designs? We don't know that, but I could call the company and ask, if I wanted to do so. Can we attribute a poor review to their use of an R-Core power transformer, as you seem to deduce ? Not really, IMHO.
Softone has had Kitamura-Kiden, the 1978 R-Core originator, build a line of S.E. and Push-Pull Softone R-Core
output transformers -
for at least twenty years now. There are
typically many theorist-types, will look at one or two narrow specifications or measurements, and dismiss a design. Here, as an example, is a " Audio Asylum " Forum discussion in 2001, 20 years ago, of the RW-20, which does this "
narrow theoretical dismissal " perfectly :
Audio Asylum - Audio Asylum Thread Printer - Get a view of an entire thread on one page
www.audioasylum.com
The common denominator, among
all these 2001 theorists ( who are all very smart ) is that
not a single one of them has any direct experience using and listening to the device !!! You are included in that bunch, as being
very smart, but having absolutely
no specific direct experience.
" Mikey", who owned Magnequest Transformers, posted in the above-referenced thread a whole series of impressive calculations. Guess what my friends, I personally now own and also have heard Mikey's highly-rated MQ-DS-025, versus a $120.00 USD RW-20 in 2019. There was no comparison between the two at all. The Softone's
music playback far-excelled Mikey's E-I output transformer,
by a very large margin ... audibly lower in distortion, more
introspection into the music. ( with $19,000 USD 2A3 SE amps ) .
Unlike
all the smart people posting above,
I do have direct experience. ( 2019 and 2021 ). In my listening experiences, and for my needs with efficient ( over 100 dB horn loaded speakers ) the RW-20 is by far, the best output transformer, of a Single Ended variety, I have
ever heard.
All I need is about one Watt or so, with my ALTEC VOTT A7-8s. I seriously doubt that any other S.E. transformer type, available today, at any cost, will match the RW-20's
overall sonic performance. Especially once the RW-20 is fully broken in ( 400 hours ).
The many unique advantages of a R-Core transformer, ( lower distortion, cooler running, less fields, etc, etc ) also applies directly to it's use - as a power transformer. I am presently working on a design specification for my new 6005 amp, to convert from it's Hammond E-I power transformer, to a custom-designed Shilchar Technologies R-Core.
All of these observations, and my own opinion, comes about as a result of experiencing a Kitamura-Kiden R-Core product, as an output transformer,
directly.
Interesting, huh ? We live and we learn.