# Isolation transformer before a P3...overkill?

**URL:** <https://forum.psaudio.com/t/isolation-transformer-before-a-p3-overkill/4492>\
**Category:** Power Components\
**Created:** [November 20, 2017, 8:58am UTC](https://forum.psaudio.com/t/isolation-transformer-before-a-p3-overkill/4492 "2017-11-20T08:58:06Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![tboooe](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@tboooe](https://forum.psaudio.com/u/tboooe)\
**Post date:** [November 20, 2017, 8:58am UTC](https://forum.psaudio.com/t/isolation-transformer-before-a-p3-overkill/4492/1 "2017-11-20T08:58:06Z")

</div>

Hi folks. Just curious what your thoughts are on adding an isolation transformer before a P3? Would it be overkill? There has been a lot of discussion on this thread ([https://www.computeraudiophile.com/forums/topic/29662-discussion-of-ac-mains-isolation-transformers-started-wposts-moved-from-quotlps-1-troubleshootingquot-thread/](https://www.computeraudiophile.com/forums/topic/29662-discussion-of-ac-mains-isolation-transformers-started-wposts-moved-from-quotlps-1-troubleshootingquot-thread/)). Sounds like the key is select a transformer with very low inter-winding capacitance.

Any input would be greatly appreciated.

---

<div class="post-metadata">

**Author:** ![speed-racer](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/speed-racer/32/115653_2.png) [@speed-racer](https://forum.psaudio.com/u/speed-racer)\
**Post date:** [December 19, 2017, 10:07am UTC](https://forum.psaudio.com/t/isolation-transformer-before-a-p3-overkill/4492/2 "2017-12-19T10:07:18Z")

</div>

To add on to the question above:

I have a 2.5kVa Topaz isolation transformer wired for balanced power. This is a unit with .0005pF interwinding capacitance. This thing reduces common-mode noise by 146dB and normal-mode noise by 65dB. It also acts as surge suppressor reduce a 6,000 volt spike down to .003 volts.

What would the PS Audio power unit buy me over that?

---

<div class="post-metadata">

**Author:** ![stevem2](https://avatars.discourse-cdn.com/v4/letter/s/cab0a1/32.png) [@stevem2](https://forum.psaudio.com/u/stevem2)\
**Post date:** [December 19, 2017, 1:01pm UTC](https://forum.psaudio.com/t/isolation-transformer-before-a-p3-overkill/4492/3 "2017-12-19T13:01:35Z")

</div>

Lower output impedance for one thing.

---

<div class="post-metadata">

**Author:** ![Elk](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/elk/32/1240_2.png) [@Elk](https://forum.psaudio.com/u/Elk)\
**Post date:** [December 19, 2017, 1:45pm UTC](https://forum.psaudio.com/t/isolation-transformer-before-a-p3-overkill/4492/4 "2017-12-19T13:45:08Z")

</div>

Which makes an astounding difference.

---

<div class="post-metadata">

**Author:** ![Paul](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/paul/32/6_2.png) [@Paul](https://forum.psaudio.com/u/Paul)\
**Post date:** [December 20, 2017, 5:56am UTC](https://forum.psaudio.com/t/isolation-transformer-before-a-p3-overkill/4492/5 "2017-12-20T05:56:51Z")

</div>

And, regulation even under dynamic conditions (music is dynamic).