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Jensen Transformers PI-XX

ISO-MAX Single Channel Mono Audio Input Isolator

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

Jensen Transformers PI-XX ISO-MAX Mono Audio Input Isolator

The Jensen Transformers PI-XX Single Channel Mono 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-XX 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 and well as higher frequency noises, such as buzzes, clicks and pops from motors, light dimmers, and RF.

Both the source and load may be either balanced or unbalanced for maximum interconnection flexibility.  The PI-XX is housed in a sturdy 1/8" thick metal enclosure for superior strength, 3" wide x 3" deep x 2" high.

FYI: The capacitance of the cable on the output side of the PI-XX needs 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-XX.

The standard connector configuration is XLR to XLR, but you may also specify any combination of  XLR, RCA, 1/4" Phone Jack or BNC connectors.  Corresponding model numbers are:


NOTE: Please be aware that with all variations, output cables from the device must be no more than 2 feet long.

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

Please do not confuse the PI-XX with similar (but inferior) products.  Jensen Transformers' ISO-MAX Audiophile-Quality mono 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-XX 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-XX is elegant in its simplicity. Simply insert the PI-XX 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-XX into your signal path, and you may want to consider upgrading your existing cable(s) as well. The PI-XX 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-XX

Single Channel Isolators for Pro and Home Theater/Hi-Fi

Single channel units similar to our Pro Series Available in a wide variety of connector options and transformer choices Ideal for stage/road use as well as in front of Monoblock amps

These units are ideal for use in stage or road show environments where durability is most important. They are packaged in an aluminum extrusion that is 1/8" thick for maximum strength. They are also the perfect solution in Home Theater systems where you need to isolate a Monoblock amp or powered subwoofer.


  • 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 or RCA connectors
  • [Sturdy and attractive 1/8" thick die-cast aluminum case, 3.0 W x 3.05 D x 2.05 H inches (76.2 x 77.5 x 52.1 mm  Add .09" (2.2 mm) to height with feet]
  • [Weight: 14.5 oz. (410 g)]
  • Gold Contact DIP Switches allow for flexibility in grounding configuration

FULL PDF DATASHEET (for the very similar stereo version)

Jensen Transformers PI-XX, back

Here is the back of the PI-XX.

Jensen Transformers PI-XX, included items

The PI-XX is shown here with product box and User Manual,  Notice that the manual shown is for the functionally identical 2-channel version.

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

Here is the datasheet for the two-channel version, in PDF format.  Specs are identical for the PI-XX.

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

This is the User Guide for the very similar two-channel version, in PDF format.

In-Stock Configurations and Pricing
Product Description SKU MSRP Your Price Quantity
Jensen Transformers ISO-MAX Single Channel Audio Input Isolator
RCA inputs / XLR outputs
PI-RX $241.99 $219.99
Jensen Transformers ISO-MAX Single Channel Audio Input Isolator
XLR inputs / RCA outputs
PI-XR $241.99 $219.99
Jensen Transformers ISO-MAX Single Channel Audio Input Isolator
XLR inputs / XLR outputs (as shown on this page)
PI-XX $241.99 $219.99
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