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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

Showing 2 responses by dougdeacon

dougdeacon
3,338 posts
 
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.
dougdeacon
3,338 posts
 
Thanks Tom. Lugnut and I are both right? Must be a good day! BTW, what would we hear with a non-optimal anti-bias setting? Channel/image imbalance? Harsh HF's in one channel?

David,
I was talking about the bias tracks but certainly didn't state it clearly, thanks. It's just like you said. Hey, wanna swap one of those bum cartridges? I've got an ADC XLM that should track at .75g on an Illustrious. Deal?

I didn't bother with the HFN record after my last cartridge realignment. I'm either getting lazy or pretending I can hear like Twl!
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