There is no aspects of minimization
of the inductor size. You can go to 30K, or 50K, or 100K input LPAD. The LPAD (which
is not inductive switched attenuators with good resistors) anyhow sites behind
the filter, so the input impedance of the attenuators will be “visible” by
other channels only at HF, so the value of the attenuators is semi-irrelevant.
The reasons why I went with 20K is because I would like to keep the value of
the resistors that formed the attenuators lower. If I use S102 resistors that
have no inductance of any kind then the value of the resistors would be absolutely
irrelevant. I use very good resistors for attenuator (RN/CMF55/60), they are
metal film and non-indicative but they still have “some” residual inductance
and my presumption was that higher value the more inductance. I warn you that
this is such an irrelevant minor thins that we can talk about it but I very
confident that it has no practical impact to the sound you will get out of it.
So, in term of the input attenuators for HF you can do anything you want. |
|