Headroom distortion in fp3

[gkantermd]

Just received a pro-ject turntable with blue point no. 2 cartridge and a pro-ject phono preamp.  Have noticed what I think is headroom distortion particulary but not exclusively on passages of piano chords ( Best  of Dianna Krull). Had not noticed this in past with cd. Any thoughts...new tubes with greater headroom or has my beginner soldering now made itself noticble?  Thnx.

[Laudanum]

Just a thought, it might not be the FP3 at all.  Have you tried the Phonostage directly into your amp?  Im running one of my turntables into Seduction - FP3 - Crack headphone amp.  Originally run directly into the Crack from Seduction.   I hear no increased audible distortion with FP3 in the signal path.  But thats not necessarily apples to apples as I have no idea what the gain of the Project phono stage is or the output of your blue point cart.  The FP3 input can always be padded down with resistor but I have a feeling that you may possibly be hearing cartidge mistacking.  I'll let the experts chime in, they are better equipped to help nail down these things.

[gkantermd]

Thanks for the quick response.  I'll check the phono amp gain tonight.  I do know that the blue point is a moving coil with significant output.  I checked the tracking, antiskating and weight of the cartridge and all seems ok.  Will try the direct input into the amp which is old Carver.

[Laudanum]

Are you using the MM input setting of the phono stage?   Just checking specs, the Blue Point 2 is a very high output MC, 2.5mv, as you mention.  Designed to be used with an MM phono stage or the MM settings of a switchable stage.  If you are aware of this already, I apologize.   Im not sure what the gain of your stage is in the MM setting but at 40db for example, or a bit higher,  I wouldnt think you would overdrive the FP3.  I dont when using a 4.0mv or 5.0mv cart with Seduction (40db gain) going into the FP3.   You could also potentially overdrive your Amplifier with FP3 but I doubt that's the case seeing how you arent doing so with your CDP which I would think probably still has a higher output voltage than the phono stage with the Blue Point 2 ... assuming the MM setting and around 40db of gain.  So I would check the settings of the phono stage of so equipped to make sure it is set to MM and if that's already done, check direct from phono stage into your amp as planned.  That will atleast narrow down the cause.

[Paul Joppa]

The level control in Foreplay is at the input, so the amplifier circuit sees just enough input to produce the output desired. It is capable of more than 10 volts output, which would seriously overdrive almost any power amplifier. Bottom line, it's nearly impossible to exceed the Foreplay's available headroom.

As others have suggested, if you have a phono preamp with high gain (e.g. a MC input) you might overload that.

[gkantermd]

Good point. Initially had it set to MC but switched to MM.  No change in distortion headroom.  I will check the gain tonight and also try the direct pug into the amp.  Again, thanks.

[fullheadofnothing]

Your problem is probably cartridge related. If it's new, it may just need some time to break-in (at least 50 hours). You may need to track a bit heavier (you are more likely to damage your records and your stylus by tracking too light). Your anti-skate could be incorrect. Your vertical tracking angle could be incorrect (you can try lowering the back of the arm). It could be a problem with the particular record. Is it only audible as the stylus gets closer to the label? Improper impedance loading can also cause sibilance, but that HOMCs are usually designed for the 47K MM load.

Are you new to the madness that is turntable setup? It can be maddening at times, but when you get it dialed in, it's so much better than digital.

[Grainger49]

Let me start with an appology for our hobby, the vocabulary sucks. 

I'm not quite locking in on "headroom distortion."  Can you express that differently.

For instance poster Paully has heard all sorts of distortion over the years, 10+ years, that we have known each other and he has finally sussed out the source of it.  He is extremely sensitive to anti-skating/inner groove distortion.  He now has a SLT arm and it is all gone.  Hopefully this will also help his migraines.  (I got rid of 90% of my migraines after retiring, it was stress.)

I would really like to help you in your quest for clean vinyl sound.  It has such a great potential. 

If you answer the other questions and mine we can probably get you where you want to be.

And welcome to the Bottlehead Community!

[ALEXZ]

Hi,
Just a guess that may help with troubleshooting: is  there any repeatable patern in the distorted tracks location - on the edge of lp or near centre , or it's totally random ?  
 

[gkantermd]

This is really really embarrassing. First I want to thank all who have offered their help. I have learned a lot from your advice. Now the silly stuff. I should have added that there was one other amplifier in the line between the vinyl and my ears...my new high gain hearing aids!!!!!! dOH. Switched back to my older ones and voila...no more distortion.  Hope you all enjoy the laugh as I the relief. Long live Bottlehead.

[Paul Joppa]

Oh, that's hilarious! Thanks for posting. It's funny because we have ALL had similar dOH! experiences, many more than we will admit to.  :^)

[Laudanum]

Now, that is indeed "headroom" distortion !!!   :-)

[Grainger49]

Found the distortion by the popular elimination of components.  Often a good troubleshooting technique.