and yet the audio precision actually reports .0008 % thd at 1khz. so much for that being worth anything.
sure looks like about 10 volts per microsecond slew rate. pretty grim at higher voltage levels.
winding transformers correctly really is not that hard. too bad the lundhal transformers won't fit inside the box.
hmm, there is that size thing again. (usa_love)
what really gets me is the really poor soldering job, probably there is a significant failure rate of topping products in the field.
And yet led lit sails that makes you think there are tubes inside.
my guess is that the koss box sounds better than this, for roughly the same price.
quoting from someone who knows how to actually make transformers like this..
quote
In a transformer winding, inter-turn capacitance is generally negligible compared to inter-layer capacitance.
We can approximate the winding self-capacitance within a small factor by considering only the capacitance between winding layers, approximating the layer to a conductor sheet.
The highest capacitance arrangement is when each layer is wound in opposite directions, so left to right on the first, right to left on the next. That's because the first turn of the first layer is opposite the last turn of the next layer, so there's twice the voltage per layer between those turns. As the energy stored in the self-capacitance goes as the square of the voltage, this more than offsets the lower voltage difference at the other side of the windings.
A lower capacitance can be obtained by winding each layer in the same direction, returning between layers, so left to right, then left to right again. The voltage between layers is now uniform at the per layer voltage.
end quote
transformers made this way have to be partially done by hand. no winding machine currently available does this. its why esl63 replacement transformers are $500 each.