Single-Ended LARGE Vacuum Tube OUTPUT TRANSFORMERS WE-300B LOWER SHIPPING COST

Description

This is a pair of output transformers for a stereo pair of single-
ended vacuum tube audio power amplifiers.
They were made in China, designed for the popular WE-300B
directly heated power triode, although they can be successfully
paired with many other output tubes including the old 2A3, as
well as triode-connected sweep tubes, and also power
pentodes and beam-power tubes such as the 6CA7 / EL34,
6550, 6550A, 6L6GB, and so on.
The primary impedance is 3500 ohms, (3.5Kohms), when
matched to secondary speaker loads of 4 or 8 ohms.
Both carry the same serial number indicating they are a
matched pair.
I have shown close-up photos of the markings
and part number indications.
Both also carry the same small badge that says “1048B INDR
WE 1KY80”
There is slight damage to one corner of one of the coil forms on
one unit, but will have no effect on function.
They include a pair of metal covers to make them more
aesthetically pleasing on the amplifier chassis.
The covers are
painted black with a fine wrinkle / crinkle finish.
I have match-
drilled the cover bases to match the transformers, and the
necessary mounting hardware is included.
There is a slight
dent to one, visible in the photo.
The photo showing the bases of the decorative covers were take
before I carefully drilled them to match the transformers.
I purchased them from an audio enthusiast of Chinese heritage,
who had traveled to China on pleasure or business, and selected
these for a DIY audio project, which he didn’t complete.
That’s a common enough story.
I started working with vacuum tube audio amplifiers back in
1977.
I was a textbook kind of guy, and built push-pull power
amplifiers.
There was a resurgence of interest in single-ended
power amps that seemed to gain traction in Japan, and spread
from there to the USA and Europe, and to other Asian countries
as well.
China seemed to have become a center of great admiration for
single-ended power amplifiers, and so I gambled on this pair
when I decided that I owed it to myself to give the idea a fair
shake.
But I never got around to it.
I chose these because of their generous size and weight.
In
output transformers, there is no substitute for iron and copper if
you want good bass response.
I have shown an old Tung-Sol 6550 tube in the ST bottle to give
you a sense of scale, but the tube is for illustration only and not included.
The air-gapped iron cores on these measures about 4-1/8 x 3-
1/2 x 2 inches, or about 105mm x 87mm x 50mm, and the
individual laminations are very thin, which provides excellent
magnetic permeability and results in excellent low-frequency
response with minimal distortion.
Each one weighs just shy of 8 pounds.
The mounting-hole
pattern measures about 2-1/8 x 3 inches.
I have included photos of some of my DIY tube projects
including a pair of re-designed Dynaco MKIII, a pair of home-
brew amps using triode-connected 6FW5 sweep tubes, and a
preamp.
All are for shown for fun only, and not included in this
auction.