transformer build thread

[jkeny]

Let's list the requirements and see how many we can fulfill with one trafo, it can have a few taps (depending on the bobbin's complement of pins).

So do we want only unbalanced output and 2VRMS? Or how about allowing 1VRMS output for better compatibility with direct feeds into poweramps (where the DAC's the volume control) ?

Then the primary needs to be at least 2VRMS but perhaps 4VRMS if you're using balanced DACs in anti-phase.

would a power amp not need more than 1vrms, would have assumed that would be approx where moderate vol levels would be

surely would be safer going with 2vrms output transformers?

That seems reasonable

i doubt we will be using balanced dacs in anti-phase any time soon

Oh, I don't know about that :)

[nige2000]

Can't a trafo perform balanced & single ended duties by connecting the two side of the secondary balanced windings in series?
What are the design restrains to doing this?

is it not just center tapped on both input and output?

[jkeny]

Can't a trafo perform balanced & single ended duties by connecting the two side of the secondary balanced windings in series?
What are the design restrains to doing this?

is it not just center tapped on both input and output?

Yea, but I was thinking (getting difficult with a stonking cold) what impedance & inductance choices can we have which would work for our desired uses?

[nige2000]

Let's list the requirements and see how many we can fulfill with one trafo, it can have a few taps (depending on the bobbin's complement of pins).

So do we want only unbalanced output and 2VRMS? Or how about allowing 1VRMS output for better compatibility with direct feeds into poweramps (where the DAC's the volume control) ?

Then the primary needs to be at least 2VRMS but perhaps 4VRMS if you're using balanced DACs in anti-phase.

would a power amp not need more than 1vrms, would have assumed that would be approx where moderate vol levels would be

surely would be safer going with 2vrms output transformers?

That seems reasonable

i doubt we will be using balanced dacs in anti-phase any time soon

Oh, I don't know about that :)

using 4 chips in stereo 2 pos and two neg, i2s into inverter, shift register then dc blocking caps to chips ?

[jkeny]

i doubt we will be using balanced dacs in anti-phase any time soon

Oh, I don't know about that :)

using 4 chips in stereo 2 pos and two neg, i2s into inverter, shift register then dc blocking caps to chips ?

Yea or programming :)

[nige2000]

Can't a trafo perform balanced & single ended duties by connecting the two side of the secondary balanced windings in series?
What are the design restrains to doing this?

is it not just center tapped on both input and output?

Yea, but I was thinking (getting difficult with a stonking cold) what impedance & inductance choices can we have which would work for our desired uses?

suppose we need to know what impedance and inductance values were looking for, to even start
how are we to know whats optimal?

[nige2000]

using 4 chips in stereo 2 pos and two neg, i2s into inverter, shift register then dc blocking caps to chips ?

Yea or programming :)

well you definitely weren't up all night studying arm or xmos programming and have it all figured out ;)

amanero?

[jkeny]

suppose we need to know what impedance and inductance values were looking for, to even start
how are we to know whats optimal?

I wouldn't be sure that I was taking all factors into account but things like the voltage compliance of dac's outputs, output current, voltage required, etc.
Richard has much more knowledge & experience of trafos & I'm hoping he can help?

[jkeny]

using 4 chips in stereo 2 pos and two neg, i2s into inverter, shift register then dc blocking caps to chips ?

Yea or programming :)

well you definitely weren't up all night studying arm or xmos programming and have it all figured out ;)

amanero?

Yep, Amanero but anyway a split secondary gives us more options than just balanced or single ended - we can use one side or both side in series or both sides used in parallel.

[nige2000]

Yep, Amanero but anyway a split secondary gives us more options than just balanced or single ended - we can use one side or both side in series or both sides used in parallel.

split secondary not the same as center tapped?

is inversion an option in current firmware?
dont remember seeing that