UTC HA-100X and UTC A24


Aug 9, 2012
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Hi  :)

A few questions :

I have a drip opto 4 pcb and a case without a cutout for I/O and O/P transformers.  Do I need to mount the A24 on the outside too or is mounting the UTC HA-100X on the outside of the case sufficient?  (I have seen a coulple of people mounting the A24 on the inside. ) How far from the Torodial do i need to be with the HA-100X? I have pre drilled holes for the XLR and there is not much room beside mounting the HA-100X in  the middle of the backside. Is that ok?

I  need to cut holes for for both the connections and the 4  4 40 screw for each transformer. Anyone have a template for cutting the holes for these two? I found them using the search function but the links where dead.

Last question.. bear with me guys... I have bought used UTC HA-100X and UTC A24. Is there a way of testing them with a multimeter to see if they are working?

Thanks :)


Well-known member
Jun 3, 2004
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HA-100X is triple shielded plus the outside can, so you should be able to mount it wherever you want,

HA-100X is an A-10 with a few extra lams and more shielding,

you can ohm out the pri and sec on the transformers,

some folks might say "watch out, you will magnetize the core!" if you put a meter on it,

but if you use a hand held meter there is only a slight chance of this happening,

you can degauss the input by playing a Cannibal Corpse track at top volume,  :D

used to think the UTC stuff was 80% permalloy, but they use a lower perm, closer to 50/50, which has less chance of becoming magnetized, and if it does, it will usually lose this naturally over a few days,

a template is Very useful for the UTC stuff as there is minimum clearance between the terminals and the big hole,  :-[

you can get on a drawing program and print your own on a piece of paper and then transfer to metal or thick plastic of some sort,


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