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Jensen Transformers PI-2XX

ISO-MAX Stereo Audio Input Isolator

Made in the USA
Jensen Transformers PI-2XX ISO-MAX Stereo Audio Input Isolator

Jensen Transformers PI-2XX ISO-MAX Stereo Audio Input Isolator

The Jensen Transformers PI-2XX Stereo Audio Input Isolator provides powerful 90 dB common mode isolation at 60 Hz while also helping to eliminate RF interference from sources like radio and television stations.

The PI-2XX is recommended for most all applications where a high-impedance line input, such as the line input of a power amp or crossover needs to be isolated.  It can eliminate noise inference, such as 60 cycle hum as well as higher frequency noises, such as buzzes, clicks and pops from motors, light dimmers, and RF.

Both the sources and loads may be either balanced or unbalanced for maximum interconnection flexibility.  The PI-2XX is housed is a sturdy metal enclosure, measuring 7.0" W x 3.5" D x 1.6" H., including the flanges.  The flanges have mounting holes, which are handy for permanent installations.

FYI: The capacitance of the cables on the output side of the PI-2XX need to present a load of less than 200 pF, so that generally means that the cable can be no longer than 1 meter.  The input of the equipment connected on that side must have a minimum impedance of 10k Ohms.  There is no cable length restriction on the input side of the PI-2XX.

The standard connector configuration is XLR to XLR, but is also available in an XLR to RCA configurations PI-2XR, RCA to XLR as PI-2RX - you may also specify any combination of  XLR, RCA, 1/4" Phone Jack or BNC connectors.  You may also choose the "None" option if you prefer to use the barrier strip alone.

If you're not sure which model to choose, please check out our Jensen Transformers Application Guide.

Please do not confuse the PI-2XX with similar (but inferior) products.  Jensen Transformers' ISO-MAX Audiophile-Quality stereo audio isolators provide the ultimate signal interface solutions.  They solve the fundamental problems associated with ground loops, without degrading signal quality.

With inferior products coming from all over the world, we think it is a genuine treasure to find a company like Jensen Transformers, actually designing and manufacturing some of the finest products in the world, right here in the USA, and we are proud to be able to offer their products. The PI-2XX is made in the USA, is backed by the manufacturer's comprehensive one-year warranty, and has a remarkable 20-year warranty on the transformer device itself.

Ground Loops?

(or why the best planned systems sometimes sound bad)

It is a subject that is seldom discussed in manufacturers publications, or even in magazines of the trade, but ground loops can happen even in the most carefully planned audio system.

When devices in the same system are powered by separate power sources, that can cause a difference in ground potential between the two pieces of equipment. It can be because one of the circuits is loaded more heavily than the other, or because one run is longer than the other, or any number of other reasons that are beyond the scope of this article, but the result of this difference in ground potential is commonly referred to as a ground loop.

The Solution

The Jensen Transformers PI-2XX is elegant in its simplicity. Simply insert the PI-2XX anywhere in the signal path and immediately, the effects of the ground loop become a non-issue. Problem solved. There are not too many things that one can install in an audio system that can provide so much improvement with so little effort.

Don't Forget the Cables!

Good cables are very important in the fight against hum and noise. You will need at least one short patch cable in order to insert the PI-2XX into your signal path, and you may want to consider upgrading your existing cable(s) as well. The PI-2XX does not include any cables, but if you need them, we have some very high-performance XLR cables available. Please click here to see them!

Jensen Transformers' Description

Jensen Transformers PI-2XX

Stereo Audio Input Isolator

The Model PI-2XX is designed to provide over 90dB of common mode isolation at 60Hz and to help eliminate R.F. interference from radio and television stations. Transformer isolation allows maximum interconnection flexibility, since both sources and loads may be either balanced or unbalanced.


  • Ruler flat frequency response preserves "Audiophile Quality" signals
  • High-Grade Nickel-Iron-Molybdenum alloy cores for extremely low distortion
  • Faraday shielded windings for maximum R.F. interference rejection
  • High quality gold plated connectors for long term reliability
  • Available with a choice of XLR, RCA, 1/4" Phone Jack or BNC connectors
    [Some configurations are special order, as shown in the drop-down selection boxes]
  • Unpluggable screw terminal strip for easy "Home" to "Road" changeovers
  • Convenient 7.0" W x 3.5" D x 1.6" H. dimensions allow rack tray or rail mounting
  • Gold Contact DIP Switches allow for flexibility in grounding configuration


Jensen Transformers PI-2XX Stereo Audio Input Isolator - Open

The Jensen Transformers PI-2XX is shown here with the cover removed.

Jensen Transformers PI-2XX Datasheet - click to download PDF

Here is the datasheet, in PDF format.

Jensen Transformers PI-2XX Manual - click to download PDF

This is the User Guide, in PDF format.

In-Stock Configurations and Pricing
Product Description SKU MSRP Your Price Quantity
Jensen Transformers ISO-MAX Stereo Audio Input Isolator
RCA inputs / XLR outputs
PI-2RX $439.99 $399.99
Jensen Transformers ISO-MAX Stereo Audio Input Isolator
XLR inputs / RCA outputs
PI-2XR $439.99 $399.99
Jensen Transformers ISO-MAX Stereo Audio Input Isolator
XLR inputs / XLR outputs (as shown on this page)
PI-2XX $439.99 $399.99
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Special-Order Configuration and Pricing
Product Description Base SKU MSRP Your Price
Jensen Transformers ISO-MAX Stereo Audio Input Isolator PI-2 $380.99 $319.99
Option Description Select Options
Select Input Connectors
Select Output Connectors
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Jensen Transformers Authorized Reseller Seal

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