On 9/15/12 4:26 PM, Scott Yost wrote:
> Is Isobar still considered a decent product for RFI reduction or has it been
> eclipsed by some other manufacturer? The Isobar website seems thin on specs
> for noise suppresion data. Interested in specs especially at LF.
>
> I have an old unit that performs well. Not sure if their past performance
> has carried over to current products.
>
> Any opinions or experience?
>
> tnx,
>
> Scott
> NM8R
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They are differential mode only, standard cap and powdered iron inductor.
The interesting bit is that they are multi-stage, not just filtering
from line, but between stages.
They have stopped printing the figure on the cases sometime in the last
7 - 10 years, but comparing the internals of my most recent (< 5 years)
with 10 - 15 year old internals I see no differences.
Published figures were based on 50ohm line and load impedance LISN
specs, so in real world performance varies wildly with actual.
IIRC they were rated at ~ 25db per stage with a stage between line and
first outlet pair and between each pair of outlets after that. The
Ultra8 listed 25db, 50db, 75db, 100db for the outlet pairs as the "from
line" spec.
NOTE: Only talking about ultra line, the non-ultra are different units
that seem to have changed multiple times.
I still use them as my standard outlet box, but have not picked one up
new in at least a decade. Have picked up ultra6 and 8 5 - 10 at a time
surplus. Open case, replace MOVs (always assume MOV is failed) and re-use.
I use em because they are metal bricks that last forever. The do make a
noticable dent in noise from a number of different devices, but all of
mine also have a stacked toroid common mode choke or 2 on the cord.
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