Buzzing on azimuth adjustment track (Hifi News Test LP)

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Faye_108
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Buzzing on azimuth adjustment track (Hifi News Test LP)

Post by Faye_108 » 17 Aug 2019 06:55

So I'm currently in the process of aligning my new Hana-SL cartridge on a Technics SL-1200.
In lack of any other tools I am using the Hi Fi News Test LP for azimuth alignment. Track 5 on side B consists of a mono signal with the left and right channels out of phase. Apparently the goal is, when engaging the mono switch (which sums the left and right channels), to adjust azimuth until I hear minimal output from both speakers.

For the moment, even though the output is much less compared to "stereo mode", it is far away from minimal output. No matter how I adjust the azimuth, I always hear practically the same level of output in "mono mode". It may be, because azimuth fine adjustment is very difficult directly on a headshell (I tested 2 azimuth adjustable HS and they are both very prone to indentations of the inner aluminium barrel caused by the screw), or it may also be because this method for adjusting is debatable in general.

But there is another symptom that I don't understand at all and which is my main concern:
When I play the track in stereo, I hear even output from both speakers without any distortions.
But as soon as I engage the mono switch, a clearly audible buzzing appears. It is not constant, but present on most of the track. Adjusting anti-skate has zero effect. I also tried to adjust VTA and VTF, but with zero effect.

What may be the source of this buzzing?

wart
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Re: Buzzing on azimuth adjustment track (Hifi News Test LP)

Post by wart » 18 Aug 2019 10:18

Hearing is not the right tool for azimuth. Hi Fi news can be used roughly to check it. You will have to find proper tool in order to do it - oscilloscope or Fozgometer or just don't care about it.
Buzz if mono switch activated - normal. You can't void it with cartridge adjustments. You can read this for hints
https://forum.polkaudio.com/discussion/ ... mono-vinyl

If you want fluent mono - get mono cartridge.

ChrisfromRI
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Re: Buzzing on azimuth adjustment track (Hifi News Test LP)

Post by ChrisfromRI » 20 Aug 2019 04:26

Let me start by saying I am unfamiliar with the particular test record and methodology you're using. However, I can share how I do this, in this post, and it should give you a better understanding of what we're trying to accomplish.

I first align a cartridge for perfect visual Azimuth alignment using a front surface mirror. This allows me to see that the cartridge is mounted vertically - as a starting point:

https://live.staticflickr.com/65535/482 ... be99_h.jpgZYX Fuji Azimuth 2 by c f, on Flickr

I then use the Analogue Productions Test Record for observing the accuracy of this initial setting, because that's the test record I have for this. On its 2nd track it has a 1 KHz signal recorded on only the left channel groove wall, and then on its 3rd track it has a 1 KHz signal recorded on only the right channel groove wall. For observing that my initial Azimuth setting provides low cross-talk I have used a Fosgometer (be careful because these often arrive mis-aligned from the factory and you first need to align them with other test equipment before using them), an Oscilloscope, and most recently the stereo VU Meters on my tape deck with the preamp "Tape Out" setting selected, and the deck input set to "Source" and not "Tape". All three visual aids work equally well and have plenty of dynamic range for observing the amount of cross-talk when playing these tracks. The goal is that the cross-talk will be low and reasonably close to the same for both channels. Accordingly, I will explain the method using the stereo VU meters as I believe it is the easiest method to visualize and understand.

When playing the 2nd track, which only has modulation on the left channel, I advance the gain of BOTH channel inputs on the deck until the left channel modulation is just barely pinning the left channel VU meter, and I observe and note how much the right channel VU meter has advanced off of its zero signal position (it should be low on the meter scale but show some cross-talk signal). Then I play the 3rd track, which has only modulation on the right channel, and advance the gain of BOTH channel inputs on the deck until the right channel modulation is just barely pinning the right channel VU meter and I observe and note how much the left channel meter has advanced off of its zero signal position. The goal is that both unmodulated channels have about the same response above the zero signal level! There will always be some measurable cross-talk, and what we're trying to do with our Azimuth setting is to achieve close to the same level of cross-talk on both channels, and it should also be low on both channels.

If you started with the mirror as I recommend you do and one channel has more crosstalk than the other, then either the stylus is misaligned on the cantilever, or the internal alignment of the generator inside the cartridge body is misaligned. A slight twist in the cartridge's physical Azimuth as viewed in the mirror will then be necessary to get the two levels of cross-talk closer to the same level as each other. Loosen the headshell Azimuth bolt, give a slight twist, and check your result as previously described.

Hopefully you can find similar tracks on your test record, and a visual aid as I described for checking the level of cross-talk on each channel. In my experience cartridges from the larger cartridge manufacturers require little more than the mirror alignment, and the test record almost always shows very close to the same level of cross-talk if the mirror image was straight up and down. OTOH, re-tipped and small company hand made cartridges tend to have greater incidences of misalignment.

ChrisfromRI
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Re: Buzzing on azimuth adjustment track (Hifi News Test LP)

Post by ChrisfromRI » 22 Aug 2019 07:04

According to my Fozgometer Instruction Manual your HiFi News Test LP has tracks 4 & 5 on Side 1 for adjusting Azimuth, and track 3 for checking Channel Balance.

ChrisfromRI
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Re: Buzzing on azimuth adjustment track (Hifi News Test LP)

Post by ChrisfromRI » 25 Aug 2019 03:20

How is this going Faye_108?

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