Rega P8 bias problem?

Hi I have a problem with a fairly new P8.

Not used it for a week and today putting a new LP on and the bias has failed. When I lower the arm down the centrifugal source throws the stylus and arm out to the edge and off the LP. I have checked the tracking force and there is no problem - balances as usual and sets and lowers. I have used the slider to set the bias from 0 right up to 2.0 and nothing changes. it still throws the arm outwards as soon as the stylus touches the groove. I have obviously emailed the UK dealer for advice but I wonder if anyone on here has had similar and there is something obvious that I am missing?


Your Bias is too high - not too low… :wink:

Bias counteracts the natural tendency for the arm/cart to go inwards.

Have you checked the azymuth, in the case you don’t use a Rega cart ?
With Rega Protractor

Silly question perhaps but are the deck and platter perfectly level? Use a proper spirit level for this.

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Thanks all. I have now removed the P8 turned it upside down examined it and there is nothing to adjust or play with.

I have re connected it , reset everything and now it is once again working correctly, even at the 2.0 max setting. I am now running it at the 0.25 I originally had an it is playing well.
Very strange.

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Ah,I imagined centrifugal force.
However it is now working. If it tracks Joni through to the end of side 1 ‘Ladies of the Canyon’ with nary a skip or miss, then I’m happy.

All good and now listening to a new to Miles album. Excellent.

The Physics means that the drag on the Stylus (pulling forwards), acting around the Arms pivot, causes an inward rotational force. Not outwards.

Bias (aka Anti Skating) is intended to provide an opposing turning moment, causing the Arm to rotate outwards (*). Ideally the net force should be zero.

Somehow, you clearly had your Bias set on Maximum… :thinking:

You other problem is with music. You need more Pink Floyd… :wink:

(* - If Bias is left ‘on’, checking Tracking with a set of Scales can be fraught, with the arm continually going outwards…)

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Not set on maximum at any point. Its been sweet since I set it up some many months ago. Today it simply didn’t operate as normal.

Joni as the test, and now Miles. Dark side perhaps later. :slight_smile:

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I am offering you an explanation based on the facts your report & Physics.

You tell me then - WHY did your Bias not operate correctly today…? And now suddenly does…?

I am just suggesting you may have had it set incorrectly. YMMV, etc.

Out of here…

The supplying dealer has suggested that the cart wires could have dropped onto the surface. My removing turning upside down and general resetting could have moved them again. It’s a possibility. I hadn’t thought to look at that.

You make some good suggestion, I confirm that wasn’t the case. Thanks for your help.

Thanks to the excellent replies on here and a bit of internet knowledge I now understand. :slight_smile:
No centrifugal force of course. The vinyl is spinning, not the stylus. DOH!
Friction on the stylus pulls on it, the constrained arc pulls it inwards.
Incorrect antiskate bias will result in the stylus either running against the left or right sidewall of the groove. No amount of normal bias will cause the arm to move so directly to the outside of the turntable, especially as at rest there was no movement.
I think the ‘dropped’ or even clumsily caught by me cart wire seems to be the most logical explanation, and something I will have to look for if it happens again. There is enough spare for this to happen.
I am now looking for a flat test record to try and set the antiskate to a central point. The azimuth I will leave for another day.

I cannot offer a better explanation than any of the comments above, but my RP6 suddenly developed exactly the same behaviour not too long ago. Nothing in the system had changed in any way and, as far as I can tell, neither my wife nor the cats had touched the TT.

Everything seemed to be level and there was no obvious cause for the needle to act like a lemming on the edge of the records. Since I could find no solution, I dismantled the Fraim rack, dusted all the shelves and then reassembled it all with the usual attention to cable dressing. The problem seems to have disappeared and everything has been working fine since then.

I put it down to gremlins.

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Had the same problem when I got my P3. Only to find out that the cart wires were touching the record surface when the arm was put down. I just had to push the cart wires up a bit.

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Make sure that the main bearing oil has not flowed out due to inverting your P8.

Good point to check. Thanks.

I am now just running some setting tests (anti skate) using “Third encounters” sound track. It is an orchestra in full avant garden mode, with sweeping overlaid dramatics, and underlying almost hidden lighter themes. A true cacophony of sound that tests separation and left/right with just a slight lean or turn of the head. Mrs Bruss says I look like a dog when listening to it, well I think she means just when listening to it. :slight_smile:

It doesn’t matter providing you know that she likes dogs!

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…I agree…setting bias by ear seems to me to be the best way. When I hit the right value, it’s pretty obvious.

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