As we know in for making good OPT, the criteria is to minimize inter
winding capacitance and leakage inductance.

-Are these two things critical for interstate transformers also?
-Is there any need to provide air gap in IST just like SE OPT?
- many web sites give maths for calculating OPT but I did not find a
single web site for IST.
Thanks

jeff kapp wrote:

As we know in for making good OPT, the criteria is to minimize inter
winding capacitance and leakage inductance.

-Are these two things critical for interstate transformers also?

Yes.



-Is there any need to provide air gap in IST just like SE OPT?

If the IST is powered by an SE triode, it needs an air gapped core.



- many web sites give maths for calculating OPT but I did not find a
single web site for IST.

Well not many ISTs are used.

But many of the general principles for OPTs are the same
for IST.

But IST usually have RL a lot higher, so LL can be larger,
but C must be smaller than OPT.

You still need to interleave a bit for best performance.

And best performance comes from winding one, measuring it,
then winding another so the improvements make this next one better,
ie, higher bandwidth, less thd, and then when you wind no3,
its pretty darn good but this is only possible only if you have some idea
why No1 was so bad to begin with.

You must understand the basics.

Patrick Turner.


Thanks

jeff kapp wrote:
As we know in for making good OPT, the criteria is to minimize inter
winding capacitance and leakage inductance.

-Are these two things critical for interstate transformers also?
-Is there any need to provide air gap in IST just like SE OPT?
- many web sites give maths for calculating OPT but I did not find a
single web site for IST.
Thanks

Hello Jeff.

IMHO, the criteria of inter-winding capacitance and leakage inductance
are important in interstage transformers (but, I think, easier to solve
with less power and higher impedance) like in OPT.
The air gap is a different problem : it is inescapable in an SE OPT, not
for an IST.
If you need more detail on IST, look at this site :
www.susan-parker.co.uk/
I think Ms. PARKER knows a lot about IST.
If you didn't find much information about IST, it's because most people
think about them as things of the past. Wait and see..

Please, don't hesitate to contact me for further information.

Regards,

Eric BRANDIZI )
www.thylenea.com
THYLENEA, your partner in High-End Audio.

Eric BRANDIZI wrote:

jeff kapp wrote:
As we know in for making good OPT, the criteria is to minimize inter
winding capacitance and leakage inductance.

-Are these two things critical for interstate transformers also?
-Is there any need to provide air gap in IST just like SE OPT?
- many web sites give maths for calculating OPT but I did not find a
single web site for IST.
Thanks

Hello Jeff.

IMHO, the criteria of inter-winding capacitance and leakage inductance
are important in interstage transformers (but, I think, easier to solve
with less power and higher impedance) like in OPT.
The air gap is a different problem : it is inescapable in an SE OPT, not
for an IST.
If you need more detail on IST, look at this site :
www.susan-parker.co.uk/
I think Ms. PARKER knows a lot about IST.
If you didn't find much information about IST, it's because most people
think about them as things of the past. Wait and see..

Please, don't hesitate to contact me for further information.

Regards,

Eric BRANDIZI )
www.thylenea.com
THYLENEA, your partner in High-End Audio.

That Susan Parker really knows her stuff.

She has an excellent website and even if anyone is tube dominated
I recommend a visit there.

Patrick Turner.