Azimuth and the Fozgometer

I've regularly been able to reproduce the minimal crosstalk position (as measured by a Wally Analog shop) when adjusting by ear (and yes, the final adjustments are VERY small). The Fozgometer is faster, easier to use and less expensive than Wally's device, but unless it's more accurate it wouldn't seem to offer much value for me.

It would be fun to play with, but I personally wouldn't drop $250 just for that. YMMV of course...

I agree with Doug. Someone once told me in my Shure cartridge days (when we eyeballed everything!) that unless the cartridge was obviously "tilted" ;--) it would be "just fine". So for me, everything was "just fine" for many years.

John, the track I use on the Cardas record is No. 3 on Side 2. It's actually 32 concentric (independent) grooves, so you can drop the stylus into any one of them and it will provide a continuous signal of out-of-phase white noise. If you can set your preamp to "mono", you can take a signal out of one (either L or R) of the main outs starting with the main volume at minimum until you find the best meter range setting (unfortunately the tape outs on most preamps will remain in stereo even when the preamp is set to mono ;--) Then you adjust the azimuth for the lowest meter reading. If yur preamp doesn't have a mono setting, then you can put a 'Y' connector on either the main outs or the tape outs and hook the meter to the 'combined' leg of the 'Y'.

Does anyone have any experience using an oscilliscope to set azimuth?

the only problem with the whole 'minimal crosstalk' approach (which i have used) is that it's only close to optimal. i have found that i can eyeball azimuth typically as close as when i measure minimal crosstalk.

dead on azimuth is where the phase is aligned, not gain. the image snaps in based on phase being equal in each channel.

i suppose that the Fozgometer must somehow measure phase.

i have the new Talea tonearm with dynamically adjustable azimuth. i know of no other arm which allows one to adjust azimuth while listening. i watched the arm designer use this to dial in azimuth and it really works.

I agree with Mike, that phase is everything in azimuth adjustment -- however, from my reading of the Fozgometer instruction manual:
http://www.musicalsurroundings.com/Manuals/Fosgate/FozgometerManual.pdf
it only measures L or R crosstalk levels (separately of course which is good) and L vs. R cartridge output levels (balance) AS MEASURED THRU YOUR PHONO PRE. I mention that little detail here because that fact makes it important to know if your phono pre is in perfect balance first! Now, that's easy enough to find out by running JUST the left OR right tonearm lead/signal thru one and then the other channel of the phono pre and making sure the output of each side (measured thru the tape output on your preamp) is the same. The Foz can balance the signal for you internally which is nice; otherwise, if any of the cartridge, the record, and/or the phono pre are not each in perfect balance, that CAN be adjusted with the preamp's balance control, EXCEPT you'll then have to take your readings from the preamp's main outputs, not the tape outputs. Just remember, results with the Foz or any measurement device depend on/assume the L and R signal are the same strength, whether your testing is crosstalk-based or phase cancellation-based.

It's recommended the Foz also be used with a test record -- one with which I am unfamiliar, so I don't know if it contains an out-of-phase mono track. The Cardas record does, and it was cut by Stan Ricker, the best in the business, so I would rely on its accuracy: i.e. that both channels are precisely cut at the same amplitude, AND that there is a minimum of left/right phase cancelling crosstalk in the grooves themselves.

Both measurement techniques -- crosstalk levels or degree of phase cancellation -- will provide dependable result if set up and carried out with good experimental technique ;--) however I prefer the phase cancellation method because I feel it's more precise (i.e. the cancellation is either complete, or it's not) while the crosstalk method involves some subjective judgement (as implied in the Foz manual.)

Yes, you can use an oscilloscope as your measuring device; and if you're measuring crosstalk, it's essential if you don't have a Foz. But if you have a Cardas (or other) test record with a L/R out-of-phase track, and a mono switch on your preamp, then any device (including your ears!) will do just fine ;--))
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