my latest traffo build

[Tony]

thanks, just ask here if you have other concerns and we'll see what we can do....

[tranqspogi]

yeah, i like that... sir tony can you give me the right computation of toroidal 70 volts and 12 volts? in the EI Core transformer here is my computation.


Here is the Computation of EI core Transformer Philippines Base

[Tony]

^you need to give me the dimensions of your torroid core, inside diameter, outside diameter, height......

torroid cores operate with higher T's.....more than EI's....

[Tony]

8k a-a primaries to 4/8/16ohm secondaries:

with power traffo:

4k a-a primaries to 4/8/16ohm secondaries:

with power traffo:

two sets of irons for two amplifiers:

[Grega]

lovely - very well done - those end bells look fantastic. was wondering today how hard it would be to press them from sheet steel if you had a mandrel made ect and used a 12T press. definately going to have a go at this - i found the winding tool on fleabay also so I will order one from hong kong and give it a try. we can (locally here in AU) get the E I and bobbins / copper wire no problems.

[TechGuy]

Grega,

50/60 hz Laminated Transformers use Silicon steel instead of ordinary steel to reduce core losses.

Electrical steel - Wikipedia, the free encyclopedia

[AndrewT]

Do you think that the sellers/manufacturers of the cheaper offerings bother to read Wikipedia

[Tony]

traffo for a 12AX7 tube preamp.....

2 traffos, one for plate B+, 280volts at 50mA, the other one for filament supply, 12-0-12volts at 0.8A













installed inside the preamp chassis:

[Tony]

to break the boredom i decided to make a current transformer, ratio is 1:1000 so that an ampere on the primary causes 1mA to flow thr the seconday.....

secondary coil uses 1000turns #33 wire on a 5/8 bobbin:


secondary leads ready for termination...



primary coil is a single turn of an insulated flat copper foil(from an atx psu traffo), pigtails soldered at both ends...





cores are installed next:




brackets installed:



i am going to use this ct to make a 0-10A analog meter using a dc 0-10mA panel meter.

[Tony]

finished 2 power traffo's last night:

i used bamboo pegs on 4 holes of the traffo, slightly tight fit, so they don't fall off......


dipping in a pool of varnish, traffo is completely submerged, wait until bubbles disappear, do this several times:


draining off excess varnish, again bamboo barbecue sticks are useful here:



when dripping stops, traffos are hung out to dry, this takes 2 to 3 days: