Quote from: J M Fahey on September 05, 2009, 01:03:03 PM
Hi Phil. Those old transformers *did* have a built-in gap, even if apparently it was not there.
To begin with, the EI lamination was *not* interlaced, as in "regular" transformers, but had all "E"s facing the same side, and all "I"s together closing the magnetic circuit. This already provides a usable gap, simply because of die cutting defects and irregularities. To this some added a single sheet of paper (regular printer paper will do) which becomes invisible after varnish impregnation.
For *mechanical* mounting reasons, the first and last E/I laminations were interlaced, simply to act as clamps enclosing the others.
Thus, on visual inspection the transformer looks exactly as an ungapped one, it can be only seen by dismounting it.
Hi JMF,
Looks like I owe you a chip point or two
Yes I pulled some OTr's apart today and just as you say the *Lams* are arranged to make the gap.
Though no paper shim in the two OT's I've pulled apart?
Never the less there must be some low power point where this *Gap* is not an issue?
I'm sure you can understand my reason for persuing such an idea.
*If* almost any small Mains Tr can be used as an OT (Cheap and easy to source) and powered from the likes of a computer style SMPS (a lot deliver ~about~ 20VDC).
Then the cost is dramaticaly reduced to the point where anyone could build a small 1/2 watt Amp for very little outlay.
Hey this is a SS forum and a lot of *Chipamps* so I'm just trying to add something a little different.
At the moment it's only a novilty but with the right minds working on it I feel it may have merit.
Thanks for the help :tu:
Joe mentioned Dalington but I've had little success with those.
The circuit I've tried seems to have the highest output due (I think?) to the bootstraping effect but the distortion is huge. sounds Kinda nice going through the transformer but I'd like to have some clean headroom before I post a working unit. Phil