Vinyl Asylum

Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ.

Return to Vinyl Asylum

Message Sort: Post Order or Asylum Reverse Threaded

Fozgometer different results UATLP vs HFNATLP

98.227.108.108
Posted on July 25, 2015 at 12:46:51
craigr
Distributor or Rep

Posts: 12
Location: Chicago USA & Berlin Germany
Joined: July 25, 2015
 So I just got a Fozgometer and am really happy with the tool. I am however vexed because I am getting substantially different results on the Fozgometer when using The Ultimate Analogue Test LP versus the Hi-Fi News Analogue Test LP.

The Fozgometer manual recommends The Ultimate Analogue Test LP above all others. The manual says to use bands 2 & 3 to balance left and right for azimuth adjustment and then to use band 1 to check channel balance.

The Fozgometer manual also says that the Hi-Fi News tracks 4 & 5 may be used for azimuth and track 3 may be used for channel balance.

The Ultimate Analogue Test LP uses 1kHz test tones, while the Hi-Fi News test LP uses Pink Noise. The Ultimate Analogue Test LP also specifies that the tracks are 7 cm/s which is what the Fozgometer manual suggests should be the most accurate.

The thing that is also bothering me is when looking at the azimuth with the naked eye after setting with each test LP, the HFN test LP results in an almost perfectly level cart, while the Ultimate Analogue test results in a couple degrees (or maybe a bit more) of counter clockwise rotation to the cart when viewed from the front (inside of cart is lower and closer to the record).

I am wondering what others think and if anyone else has seen an issue like this before. Does anyone have a recommendation on another good quality test LP that would provide left and right tracks that can be used by the Fozgometer? Another issue with the HFN record is that there is more cross-talk that can be heard from the opposite speaker and that can also be seen on the Fozgometer.

I have a hearing deficit in my right ear due to an autoimmune disease that makes it difficult for me to judge imagery properly. So it is difficult (impossible) for me to tell if a test tone sounds like it is coming from the center. Hence I need to depend more on my tools then other hobbits. My primary goal is to make sure my stylus is properly aligned so that my records don't prematurely wear.

For reference I am using a VPI Scout 1.1 and a ClearAudio Concept MC cart.

Best regards,
craigr

 

Hide full thread outline!
    ...
RE: Fozgometer different results UATLP vs HFNATLP, posted on July 25, 2015 at 13:09:47
Poinzy
 I had to Google "Fozgometer."

If you have to check the results of the meter against your eye, do you think you should keep using the meter? It sounds like the meter's making things more complicated rather than easier for you.

I can't recommend another test record. Sorry about that.

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 25, 2015 at 13:56:41
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 Hi Craig,

I tested a Fozgometer four years ago and I got different results with different test records. The Fozgometer works as advertized and I think it is an excellent tool, but if every test record is different, it makes you wonder how necessary it is to set azimuth with a meter. I have always set azimuth by adjusting the cartridge to be level with the record playing surface. I shine a flashlight at the front of the cartridge while playing a record and observe the reflection on the vinyl surface. That's the way I like to set azimuth.

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 25, 2015 at 14:35:54
craigr
Distributor or Rep

Posts: 12
Location: Chicago USA & Berlin Germany
Joined: July 25, 2015
 Thanks for the input so far guys.

I just hooked up to one of my digital storage oscilloscopes and have confirmed what the Fozgometer is showing. One or both of the test records has some error in it. I wonder how I can determine which test record is correct (if either).

While I was at it, I used the scope to tweak my azimuth based on the UATLP. The scope and Fozgometer were very close, but I was able to get things even slightly closer with the oscilloscope.

I wish I could at least get some feedback somewhere regarding the accuracy of these two very well regarded test records.

I'm going to look at your link now John.

Best,
craigr

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 25, 2015 at 14:40:03
craigr
Distributor or Rep

Posts: 12
Location: Chicago USA & Berlin Germany
Joined: July 25, 2015
 Hey John, I just banged around on your link for a few minutes and couldn't find any info regarding the Fozgometer testing you mentioned. Could you please provide a direct link?

Thank you,
craigr

 

Sorry!, posted on July 25, 2015 at 15:36:34
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 I put the wrong link in my message. I just changed it so it works now.

 

RE: Sorry!, posted on July 25, 2015 at 16:42:59
craigr
Distributor or Rep

Posts: 12
Location: Chicago USA & Berlin Germany
Joined: July 25, 2015
 Ah, I found this...

http://www.audioasylum.com/cgi/t.mpl?f=vinyl&m=974083

Do you think the AUDIO TECHNICA disc would be worth hunting down?

craigr

 

RE: Sorry!, posted on July 25, 2015 at 21:57:04
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 > Do you think the AUDIO TECHNICA disc would be worth hunting down?

Well, it's an accurate test record. I just got lucky and found it at a reasonable price in a used record store. You will have to decide what you need and what you would be willing to spend. The older professional test records are few and far between these days so if you find one in good condition at a reasonable price, I would recommend buying it. You can always sell it if you don't need it.

Good luck,
John Elison

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 26, 2015 at 02:32:23
PAR
 This may be a little tangential to your immediate concern but may be worth your attention given that you say you have oonly recently got the Fozgometer.

 

RE: "I wish I could at least get some feedback somewhere regarding the accuracy of these two ...", posted on July 26, 2015 at 05:39:03
kitch29
 Have you considered actually listening to some music?

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 26, 2015 at 07:00:29
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 Every test record I measured with a Fozgometer produced slightly different azimuth results. You can extrapolate this to conclude that all records with music will probably have slightly different azimuth, too. Therefore, I always adjust my cartridge such that it is level with the playing surface and be done with it. I never heard a difference anyway when I adjusted azimuth with either an oscilloscope or a Fozgometer.

Best regards,
John Elison

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 26, 2015 at 08:08:17
Mel
Audiophile

Posts: 2993
Location: New York City Area
Joined: February 21, 2001
 I agree. It sounds like the Fozgometer, like so many other things in audio, is exploiting audiophile insecurities.

Certain devices, like the Soundsmith Counterintuitive for VPI arms make it easy, and repeatable, to adjust the azimuth in small increments. Some other arms have convenient controls for this as well. If you can hear the difference, fine. If not, it's better not to obsess.

In any event, I do as you do John. I match my cartridge to its reflection off the vinyl at least as a starting point. In my case it is aided by Soundsmith's virtually perfect setting of the stylus and cantilever.

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 27, 2015 at 13:11:25
BCR
Audiophile

Posts: 2444
Location: connecticut
Joined: April 7, 2009
 This is the way I check azimuth. No Fozometer needed. Just a mirror.

Viewing the cartridge from dead-on in front, check to see that it is absolutely parallel to the mirror. If there is any azimuth tilt error, the mirror will show this as being doubled, giving you twice as much adjustment accuracy as you can get otherwise (fig.3). Some arms have a locking collar for the headshell, which can be loosened to adjust the tilt angle. With others, it will be necessary to add thin metal shims or washers between the high side of the cartridge and its headshell. (The arm base itself should not be shimmed, as this will upset the arm's lateral balance and impair its dissipation of tracking-induced disc vibrations.)
image: http://cdn.stereophile.com/images/archivesart/ttsetfig3.jpg



Fig.3 A mirror under the cartridge doubles the visibility of any cartridge tilting.

Shimming will separate the cartridge body from the arm, reducing the latter's ability to transmit vibrations from body resonances. The intervening space should be filled with some dense plastic material like automobile undercoating, "Plasticine" modeling clay, or the stuff sold in hardware stores as "rope caulk" weather stripping.




 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 27, 2015 at 13:20:00
BCR
Audiophile

Posts: 2444
Location: connecticut
Joined: April 7, 2009



Here is the image.

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 27, 2015 at 19:32:41
flood2
Audiophile

Posts: 2558
Joined: January 11, 2011
 The Fozgometer won't work accurately with a broadband tone such as the vertical modulated pink noise on the HFNRR test record. You really need a single frequency. Channel separation is also typically maximum at 1kHz which is why manufacturers choose to specify at this frequency and why the Fozgometer instructions suggest you use this test tone to maximise the sensitivity. The frequency response of typical cartridges are not uniform between channels. When you use the pink noise test tones, you are basically averaging out the errors in output and channel separation. If you use a 1kHz frequency then you can minimise crosstalk at that frequency, but it doesn't necessarily apply to other frequencies due to the output variance with frequency. Hence the difference in your results.

Setting the azimuth electrically is predicated on the assumption that the coils are entirely equal in value (for inductance) as well as the stylus chip being perfectly aligned with respect to the coil axes. This is almost never the case so you are unlikely to do much better than setting the cartridge up "visually". John's preference is for the cartridge body to be perpendicular to the record surface. IME, this is often as good as it gets for advanced line contact designs. However, for me, I prefer to ensure that the stylus tip is perpendicular to the groove surface as I have found this approach minimises problems with sibilance. If you have a bi-radial tip, you are changing the contact area and shape on each wall and so the maximum resolution/bandwidth is different for each wall. A Shibata tip with its curving contact line will give rather terrible results by effectively changing the rake angle on each wall and increasing the phase error between channels.

Either way, there is always a channel imbalance so you can never null the antiphase signal perfectly. Also, lateral output imbalance is never quite the same as vertical output imbalance due to the tolerancing of the coils.

Regards Anthony

"Beauty is Truth, Truth Beauty.." Keats

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 28, 2015 at 12:31:29
craigr
Distributor or Rep

Posts: 12
Location: Chicago USA & Berlin Germany
Joined: July 25, 2015
 Thanks for the useful information especially regarding the reason for using 1 KHz test tones. This is what I was suspecting; that pink noise can't possibly be as good as a single tone for azimuth measurement.

I will however point out that the Fozgometer is designed to adjust azimuth based on cross talk as opposed to channel balance. In other words, the Fozgometer essentially disregards the volume, but considers the cross talk. When I looked at the output on my digital storage oscilloscope it agreed strongly with the Fozgometer. After setting with the Fozgometer my scope measured 760 mV output in the left and 40 mV on the right for the left test tone. My scope measured 48 mV on the left and 820 mV on the right for the right test tone. A fractional adjustment using the SS Counter Intuitive got me to 790 mV / 44 mV on the left and 44 mV / 820 mV on the right.

I have a digital USB microscope coming today and I plan to look at my stylus. Looking at it with a 20x loupe seems to indicate that the stylus is not straight in the cantilever. This is a ClearAudio MC Concept cart and was $1000. It's still under warranty and I will get it replaced if my diamond is not properly aligned.

I think the Fozgometer may have just proved what I have suspected for months which is that the diamond is not in the cantilever properly. I will know more when I see it at 200x. I'll post a photo.

Aligning the cart parallel to the record surface isn't going to work if the diamond isn't in the cantilever properly. I am strongly suspecting that the azimuth the Fozgometer is giving me is more correct than simply a straight vertical.

Best regards and thanks to everyone for their input so far.

craigr

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 28, 2015 at 12:34:30
TimeConstant
 Thanks for sharing. Very interesting.

 

RE: Fozgometer different results UATLP vs HFNATLP, posted on July 28, 2015 at 12:58:22
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 > Aligning the cart parallel to the record surface isn't going to work if the diamond isn't in the cantilever properly.

Nothing is going to work well if the cartridge is defective. However, the Fozgometer does not measure the azimuth of the diamond stylus. It measures the azimuth of the electrical generator inside the cartridge body relative to the azimuth of the cutting head that produced the test LP.

I think the Fozgometer may have just proved what I have suspected for months which is that the diamond is not in the cantilever properly.

The Fozgometer has no way of determining the position of the diamond in the cantilever. It measures only the azimuth of the electrical generator inside the cartridge body.

Good luck,
John Elison

 

Page processed in 0.029 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]