Azimuth&Bias on HIFI test record


I bought a used Grado cartridge on the 'Gon. When I go to set it up, everythings runing smoothly VTA, tracking force, alignment. I then listen to the HiFi test record to test azimuth and bias. Concerning azimuth, the text suggests that the test tone should disappear, when the amplifier is switched to mono, because the signals will cancel each other out. Now my question, should there be dead silence or just a reduction in the test tone? On my set-up, when I push the mono button the tone is greatly deminished but, not completely gone. Concerning bias, on the test record they have you listen to a test tone. Supposedly you adjust your bias/anti-skate to smooth out the high frequency test tone. On my system the tone seems to modulate. Do I increase the bias until the tone stops modulating? Would like any advice from those that have experience with using test records. The Grado Platinum is mounted on a RB300 which is attached to a P3. So what's the scoop Analog elders?
colitas
Azimuth can best be confirmed with a mirror. The object is to have the cartridge perfectly perpendicular to the record. I'm no setup guru and could be wrong on this but it seems to me that if azimuth were wrong then the relationship between the arm and the platter is off which would be unusual with better tables.

Bias is a booger. Test records give dubious results, IMHO. If you don't have access to a proper blank track on a test record, which I believe is the best way, carefully cue the stylus on the outermost area of an lp. There is a small hump on all older recordings at the edge. What you are trying to do is que the stylus between the hump and the lead in groove. If the cartridge climbs the hump and goes off the record you have too much anti-skate.

Next, as the record is playing look closely at the cantilever and its angle in relation to where it exits the cartridge body. If the cantilever is obviously at an angle to where it isn't aligned with the cartridge body then you have too much or too little anti-skate. Playing a cartridge like this will eventually skew the cantilever permanently.

So, now you have it set up to not jump the hump and the cantilever remains centered in the cartridge body. You may then experiment by ear in minor adjustments to acheive equal left and right volume adjustments.

I believe the absolute best way to check bias is to use an oscilliscope to determine if the signals are of the same amplitude left and right. I've never known anyone that has done this however.

Hopefully Twl will chime in and write a clearer explaination than this attempt.
Colitas, The HFN bias test tone varies from inaudible (good) to a steady "buzz" (needs adjustment) to a rough or warbly buzz (dangerously near mistracking). Unfortunately, bias force increases as the arm tracks across the record. So there's no "perfect" antibias setting, just a good compromise. As a rule, the anti-bias scales on Rega arms are off. Most people set it somewhat lower than their measured VTF.

Is there an azimuth adjustment on an RB300? I didn't know that. On my system switching to mono reduces the signal to a whisper, but not total silence.

Great post Lugnut. Agree about bias tracks on the HFN record. Why are they all near the inside? Tracks 1 & 2 are pretty useless anyway, they should have included just tracks 3 & 4 and duplicated them near the outer edge.

I've never looked to see if different antibias settings cause a visible change in cantilever angle. Might depend on the compliance of the cartridge. I suspect low compliance carts could be significantly mis-biased without displaying much visible deflection of the cantilever. You'd only know by stylus and/or groove wear.

Maybe Twl will straighten us out.
An old fashioned way to check azimuth is to scratch or use a marker to draw a line perpendicular to the bottom of a small pocket mirror. Then, IF your platter is level, slide the mirror up near the cartridge and view from the back side. If the cartridge has a perpendicular side edge it should line up with (be equidistant to) the scribed line. If the cartridge isn’t “square” it’s up to the eyeball for a manual setting, though even some of those have a vertical line on the front of the cartridge body. For anti-skate, I go with my ears, but Lugnut is correct that the only perfectly “accurate” way is to use a ‘scope. Oh, and I have seen it set using a ‘scope and having it subsequently fail the HiFi test record gauntlet!

Doug, did you mean azimuth test and not bias test with respect to the HiFi record when you say "Colitas, The HFN bias test tone varies from inaudible (good) to a steady "buzz" (needs adjustment) to a rough or warbly buzz (dangerously near mistracking)."?

My understanding is that there should ideally be no tone using a mono signal when doing the azimuth test. For the bias test, there should be a rock-steady tone and any "buzzing" indicates improper bias. If it is supposed to be silent, I can't get any of my cartridges past the first bias track! Ha!

Maybe we are mixing terms here. I just wouldn't want anyone that is using the test record for the first time to be confused.