April 2017

Jolida FOZ XT-R   –  The Fozgometer
Solving crosstalk inherent in turntable cartridges.
Review By Ron Nagle

  The debut of the FOZ XT-R, strange name. Could it be a secret Black Ops project ? With a name like that anything seems possible. I think we should take a much closer look at this little black box. It turns out that the box is actually a new precision tool from the fertile mind of Mr. Jim Fosgate. The man is certainly not new to Hi-End audio. His reputation for innovation is well known. He has contributed extensive developmental advances related to surround sound audio processing. The review XT-R is manufactured by the Jolida company based on his designs. A few years ago I purchased another Jim Fosgate invention called the 'Fozgometer'. That predecessor device has something in common to the XT-R. Both measure and balance internal cartridge generated voltages. Both can be very useful for vinylholics. There are always slight differences in the sound scape due to cartridge alignment or internal coil interactions. Another way to describe this cartridge positioning is, Axial Tilt or Vertical Azimuth. I believe both of these Jim Fosgate tools can and should be used together for critical cartridge set up and testing.

First, Let's Look At TheFozgometer
For me this device is a necessary first step to measure and then adjust a cartridges channel balance. The device is designed to measure the millivolt outputs generated independently from the left and the right channels of a stereo cartridge. Consequently theFozgometer's only power source is the output voltages generated by the phono cartridge itself. Both of these Jim Fosgate precision measuring devices, the XT-R and the Fozgometer require a record that has a separate left and right channel test signal. I use and recommend the 'Ultimate Analog Test LP" from Analog Productions. To begin alignment with the Fozgometer, start by playing the Left channel reference level 1 kHz test tone from Track #2.

Then repeat and play Track #3 the 1 kHz frequency for the right channel. You will read the left and right channels output with the Fozgometers sensitive volt meter. When setting I twist the tone arms head shell slightly to position the cartridge into a vertical position relative to the record surface. There is usually enough play in that connection so that I can get the voltage readings from each cartridge coil nearly the same. If you are using a tone arm similar to the Rega or SME arms then there is no way to adjust the Axial position. You will probably need to use the XT-R. Because simply looking at the position of the cartridge body can only be an approximation.

Foz XT-R
Size-wise the XT-R measures: 7.5 Inches wide by 4.5 deep by 2.5 high. The MSRP is listed as $350. It is painted with a mottled finish black paint. The control functions are silk screened over that with gold colored paint. The half gambrel enclosure has three small toggle switches. They are designated as, Power On/Off, Calibrate Left/Right and an Adjust Function switch with two positions, active and off. Next two large black knobs, Left and Right channel adjustments. Both knobs denoted Negative at the 7 O'clock position and Positive at the 5 O'clock position.

A large section of the XT-R front panels real estate contains a large D'Arsonval meter.

At this point the narrative can get a bit strange. You will see that the dial scale is marked in db (Decibels) and starts at left with, 20, 10, 5, 3, up to a Zero. After the zero a red scale at right ends with the number 3.

The odd thing is that all of these dial scale number markings "Don't mean anything" !I spoke with Mister Fosgate at his home and he informed me that the XT-R meter he selected was simply an available unit picked off the shelf.

To quote Jim Fosgate, "The exact meter reading means nothing, we are setting the control for the lowest crosstalk in the off channel (opposite channel). The control is adjusted for the lowest reading we can get. It will be at the same precise level in an anti-phase (out of phase) orientation to cancel crosstalk, l call it the "Null Point". Just below the meter you will see a small hole labeled Meter Adjust. Under that opening there is a small trimpot. If ever the meter pointer goes past the zero point and pegs the right side of the dial scale. You will need to reset the meter needle position with the trimpot, an unlikely event. But still theoretically possible if the amplitude of the signal strength is very large. I can't imagine this happening especially if you previously measured the cartridge signal with the Fozgometer.

Unlike the Fozgometer the XT-R is externally powered by 120 Volts.

The XT-R may be used in a receiver or preamp with a record or process loop. But my evaluation was conducted in my system using my Tavish Design Adagio Vacuum Tube Phono Stage. The XT-R was slotted in between the output of the Adagio phono amplifier and a line input to my preamplifier. The audio connections going to the XT-R are all unbalanced RCA jacks.

The XT-R is designed to measure and correct something different than the Fozgometer. However if precision is your goal then you should use both devices. Even after you have measured and equalized the cartridge coils output with the Fozgometer there still can exist the problem of coil interactions or, "Crosstalk". That is the reason Mr. Fozgate designed the XT-R. The cartridge azimuth position and crosstalk are interdependent. Some crosstalk can occur just by virtue of the proximity of the phono cartridge coils. Precision matching will equalize channel output and provide a reference setting for stereo imaging. Both of these factors effect the stereo image that is so very important to me. What you hear in the stereo center stage can tell how a vinyl recording was mic'ed, mixed, and even something about the venue.

The Foz XT-R was designed to correct or at the very least null/minimize crosstalk in the cartridge coils and that includes all the connective wiring routed through the phono amplifier and into a preamplifiers line level input. To cancel cartridge crosstalk you need to have a reverse polarity signal somewhere and often the terms polarity and phase are used interchangeably. So what is this device trying to correct? In this case my Phono Cartridge is a Denon 103 moving coil. The tiny voltages, 3 mV generated by the Denon's two stereo channels coils do overlap.

How You Use The XT-R
Foz XT-R measures and then corrects something other than voltage levels but you should consider both devices as interdependent. Even after you have measured and set the cartridge vertical azimuth with the Fozgometer you can still squeeze even more performance out of your groove tracker. With the output of your phono amplifier connected to the XT-R cue up the The Analog Test LP. (Note at this point you do not have to be connected to a preamplifier) First start by playing track 2. This is the 1 kHz left channel only, test tone. Move the Calibrate switch to the LEFT position. Then move the Adjust switch to Active. Rotate the left side adjustment knob to move the meter's pointer as far left as it will go. You will notice as you rotate the knob the dial pointer will dip down to the left, You have found a null point. With additional turning in the same direction it starts to go back up the other way, not good! OK, you just found the low null point on the dial for the left stereo channel. Next playing the test tone track #3 for the right channel move the Calibrate switch to measure the right channel and repeat the same procedure rotating the right knob to find the meters null/low point for the right channel. You're done!

Now the book tells us the XT-R can correct for a maximum phase shift up to 8 degrees. That is far more deviation than you are likely to find in a typical phono cartridge but remember there is also some interconnect wiring induced distortion.

The Results
After you have minimized stereo channel crosstalk and a big part of the vinyl systems phase related influences, the results will probably be not exactly what you would expect. Understand that you can A/B the XT-R in and out of your system while you are listening to your records. A very big part of the difference you will hear is the fact that the vast majority of us audio types have never heard a vinyl record system without any crosstalk. Lets get down to cases. Specifically my Denon 103 moving coil cartridge has channel separation specified at 25dB at 1kHz. Remove the effects of crosstalk and the channel separation is greatly enhanced. I have been told that channel separation may then be expanded from 25dB to beyond 40dB.

If you have achieved that separation you may have to trash your old time standard stereo stage. My evaluation takes place in a relatively small room, my Aurum Cantus V30M two-way speakers sit in front of a twelve foot wide wall. The speakers are six feet apart and are toed inward to create a solid center image. You start by playing a stereo recording with great dimensionality, width and depth and a clearly defined center image. In my case that is usually a female voice. Visualize a parabolic curve forming a shallow bowl shaped stage between two speakers. When you switch in the XT-R the bowl shape in the center seems to deepen. At the same time as a result of this everything behind the speakers and especially near to the center seems to come into much sharper focus. At first this different image seems odd, but after a time you realize those players on the stage are now separated and each player is revealed in their own better defined space. But now there is a trade off. 

Image width, that is the lateral dimension seems less defined. We are accustomed to hearing a more definite right and left channel stereo mix. It is exactly that which generates a wide pseudo stereo sound stage. What the XT-R has done is removed some of the overlapping (crosstalk) information from the image formed between the left and right speakers. And now its mostly the center stage that comes under the magnifying glass. Understand that your perception of the sound stage changes, however there is no information lost in the process. The timber, the pace, the transient attack all remain unaffected. The paper pages of high-end audio publications would probably call this "Dimensionality" but it is really much more to it.

Remember you can flip the switch and take the XT-R in and out of the system. Switch out the XT-R and everything goes back to what you are accustomed to listening too. Purists would tell you that they would never insert another component into the vinyl path. But in my test the effect of the XT-R, the insertion loss when switched in or out of the system is negligible. As a matter of fact the XT-R was carefully designed to have unity gain.

The Jury Is Still Out
I would like to tell you what a wonderful and ingenious device It is but I can only tell you what it does in my system. Phono channel separation is due to a combination of factors. The Axial tilt may not be exact, a slight misalignment in the cartridge coils or cantilever, or signal leakage between the coils or tone arm wiring. Not only that but two cartridges of the same type and production run will usually require different corrections due to varying production tolerances. However I am confident that it will most definitely alter what you are accustomed to hearing.

My significant other tells me she prefers the sound with the XT-R in the system. "The performers sound clearer." Understand it's effect will vary greatly depending on everything in you vinyl system. Even the quality and type of vinyl music you listen to. I surmise that in a much larger listening space the effects I describe will be even more pronounced. I could tell you in great detail about the recordings I listened to but that could never duplicate your experience. It has been said before, you really should audition it for yourself.

Remember to Enjoy the Music and from me, Semper Hi-Fi.

News Flash
News Flash, The Company, Jolida is changing its name to, Black Ice and they will redesign the appearance of their entire product lineup. The company contact information remains the same.

Foot Note: Modern stereophonic technology was invented in the 1930s by British engineer Alan Blumlein at EMI. His patent was accepted on 14 June 1933 as UK patent number 394,325. Unfortunately Alan Blumlein was killed in a plane crash in World War II while testing radar equipment.

Specifications
Type: Analog LP turntable cartridge optimizer
Gain: Unity
Input Z: 71kOhms
Output Z: 400 Ohms
SNR: > then 90dB "A weighted"
Distortion THD: Less than 0.25% (1kHz)
Perfect Square wave response, no ringing or overshoot. 
Frequency response DC to 200 kHz (+/-3dB) 
Phase Inverting 
Distortion THD: Less than 0.25% (1kHz) 
Power Requirements: 110V-120 Vac, Power Power 240watts, maximum VAC 50Hz option)
Dimensions: 8" x 7" x 3" (WxDxH)
Weight: 2 lbs.
Fuse: 110 - 120 VAC, 0.1 Amp Slow Blow, 200 - 240 VAC, 0.05 Amp Slow Blow
Warranty: Six month limited parts and labor.
Price: $349

Company Information
Jolida, Inc. 
21310 Ridgecroft Drive 
Brookeville, MD 20833

Voice: (301) 953-2014)
E-mail: info@jolida.com 
Website: www.Jolida.com