transformer build thread

[abraxalito]

That one's got a fixed spindle (I have a similar one, has LED counter). So only larger bobbins will fit over that. No worries if you're wanting to use thicker wire as only larger ones will accommodate that. I think you'll be fine with PQ20 type bobbins and above, which is where I started out in the trafo game. Only more recently have I gained enough confidence to build them with hair-thin wire...

The cordless drill option is possible though you'll most likely want to fit a rev(olutions) counter. Some kind of wheel and optical sensor would be a goer, not sure how you can fit that to a drill though.

[nige2000]

ordered the winder
supposed to deliver 7-14 days dhl
too good to be true...... probably

i can mod it to put a chuck on it and add drill to power it all

[jkeny]

I missed all these posts - didn't get notifications - it's intermittent at the best of times

Jeez, Nige, not only are you the best electronics store north of the Liffey but are fast becoming the best fab plant too
Are you thinking of moving into pcb manufacturing any time soon? I'm also in need of equipment panel manufacturing.
Any interest in these? :)

[nige2000]

I missed all these posts - didn't get notifications - it's intermittent at the best of times

yea its buggy i havnt got notification for any thing well over a year

Jeez, Nige, not only are you the best electronics store north of the Liffey but are fast becoming the best fab plant too
Are you thinking of moving into pcb manufacturing any time soon? I'm also in need of equipment panel manufacturing.
Any interest in these? :)

the outlay "might" be substantially more for such
did come close to buying an reflow oven a few times
anyway not as if the winder will go up in "blue smoke" within 15 mins of first use :)

[nige2000]

https://www.amazon.co.uk/gp/product/B00 ... UTF8&psc=1
found it for less

[nige2000]

https://www.aliexpress.com/store/produc ... 35286.html

this what were lookin for?

[abraxalito]

That would be my guess for the smallest core that's probably usable with 0.15mm wire in this application. But I've not done the sums on it yet to confirm so hold off a little while...

[abraxalito]

Done some calcs, turns out we want two sizes up due to using the 0.15mm wire - PQ32/25 which are here : https://www.aliexpress.com/item/Tangda- ... 820546ab65

The primary then is 1000 turns of 0.15mm wire which can comfortably cope with 2VRMS. Secondary depends on what output voltage you're looking for.

[nige2000]

would a step up have any neg effect?

output is sufficient as is but its nice to have head room

[abraxalito]

Step up means the load impedance driven by the secondary (output) of the transformer gets reduced. So if your amp had say a 50k pot setting the input impedance and you went 1:2 step up, that 50k would look to the DAC like 12.5k. Of course you still get the benefit of the isolation/common-mode noise rejection.

Because the inner turns of the transformer are shorter in length than the outside ones you would get a modest step up if you wound the secondary to full capacity with 0.15mm wire. To get 1:1 you should use slightly thicker wire for the secondary to compensate for the extra length required.

A quick calculation tells me if you fill the remaining space (this is after you've done the 1k turns for the primary) with 0.15mm wire for your secondary you'll get about 1600 turns. Hence you'll have 1: 1.6 or a gain of 4dB.