Hi-Fi News Test LP Distortion.

[admin_exported]

Hi all, First post so please take it easy on me. I am trying to set up my secondhand Ortofon MC30 Supreme cartridge on an Audiomods tonearm fitted to a Roksan Radius 5 turntable, I have set the overhang and cartridge alignment spot on using the Hi-Fi News test LP, tracking weight is set to 2grms using an ortofon gauge. Now to the problem, i think that there is some distortion at the top end of the frequency range, using the 20Hz to 20KHz sweep on the test LP and looking at the tape record output on my pre-amp (MF A3CR) with an oscilloscope i can see lots of distortion above about 10KHz. Seeing as it would be unlikely that the distortion is recorded on the test LP then it would seem that i have a knackered stylus, does this make sense? or is there something that i am missing? Any thoughts would be appreciated.

 

[stevieg330]

Hi,

Sorry, I may be missing something but how do you set cartridge alignment and overhang with the test record? I Have it and can't think how you could do this. There is an azimuth test but that is for setting the vertical alignment.

You need to be setting overhang and cartridge alignment with a protractor, preferably a good one. I use an Avid Rega version which for me, works perfectly. There are also ones you can download and print out which will get you going as well.

I would suggest that you spend some time getting the overhang and alignment spot on with a protractor and see if your distortion problem disappears.

Good luck

Regards

Steve

 

[Anonymous]

Hi Steve,

Sorry, should have said - using the protractor supplied with the test LP - and not using the test LP.

I am confident that the cartridge alignment is correct, a thought occurred to me last night, could it be that the cartridge cannot track the higher frequencies of the frequency sweep test due to the level recorded onto the record but it is OK on the 300Hz tracking tests?

Does this make sense?

Cheers,

Dean.

 

[shooter]

- using the protractor supplied with the test LP -

Is it the right protractor for your arm?

You can download one from Vinyl Engine for free, it will only be a printed vertion but it will give you an indication if the cart is set up nicely.

If all is well then have a read though the below link, it seems the 300hz test is a pig.

http://www.tracertek.com/media/news/newscartridge.pdf

 

[stevieg330]

Hi Steve,

Sorry, should have said - using the protractor supplied with the test LP - and not using the test LP.

I am confident that the cartridge alignment is correct, a thought occurred to me last night, could it be that the cartridge cannot track the higher frequencies of the frequency sweep test due to the level recorded onto the record but it is OK on the 300Hz tracking tests?

Does this make sense?

Cheers,

Dean.

Hi Dean,

Perhaps it was me being dim, I forgot that there was a protractor with the record. Having said that and bearing in mind I also have a Rega arm, I could never get the alignment right with this protractor. If I remember correctly the main problem was that the sound got distorted towards the centre of the lp. Since I have had the Avid one I have no problems at all with distortion or any other issues, so it may be as as been said that the supplied one isn't perfect for your arm, certainly I couldn't get it right with my RB300.

I would have a look at the Vinyl engine ones and check the alignment with one of them although I couldn;t get it spot on with those either.

TBH I wouldn't get too hung up on some of the tests on the record, as you have been told some of them or real 'torture' tracks whch don't have a lot to do with the real world, especially the bias tracks, bands 8 and 9.

The point is do you get distortion while playing 'normal' records and if so does it happen on the outer or inner tracks, either or which would point to incorrect alignment. Is the anti skate set up properly?

HTH

Regards

Steve

 

[Anonymous]

Hi Shooter,

My Audiomods tonearm uses the Rega armtube which i believe makes it a 9" arm, i am using the two point technique suitable for 9" arms protractor section and have set up the overhang to 17.25mm as specified for the audiomods tonearm.

The cartridge looks nice and square in the headshell and also looks correctly aligned on the 2 points of the protractor.

If i check the tracking ability with the test record it tracks the 300Hz +14dB section OK but struggles with the +16dB track.

The problem is a horrible waveform above about 10Khz (maybe a bit lower) on the 20Hz to 20Khz frequency sweep track, at lower frequencies the waveform is good.

I am wondering if it is just that the cartridge cannot track the higher frequencies at the recorded level on the disc?

Any thoughts would be helpfull.

Cheers,

Dean.

 

[shooter]

Have you played an LP yet, but not the test one?

Does it track on on all the bands, inner, middle and outer?

Any sibilance?

The stylus could be dirty or worn, do you know the history of it?

And remember the 300hz is a beast of a test...

 

[Anonymous]

Hi Shooter,

Yes it does seem to track OK on all parts of an LP with no noticable increase in distortion on inner tracks, it just seems to me that the top end could be a bit sweeter.

I do understand that the 300Hz tracks are a torture test for the cartridge and I have cleaned the stylus very carefully.

I brought the cartridge off the site that should not be talked about and know that i was taking a risk doing this, i have been using it for about 3 months, during this time i have learnt a lot about cartridge set up by reading various forums and articles.

I would say that i have only come back to using a turntable again about 9 months ago after about 30 years of CD only, the truth is that i seem to be playing records far more than I do CD's now (and enjoying it).

I could be worrying to much about the distortion on the frequency sweep track but it would be nice to know the cause.

I have just remembered that I also have an AT30E cartridge somewhere, I will try to find it and do the same test with this.

I will post the results when done.

Thank you all for the responses.

Dean.

 

[stevieg330]

Hi Shooter,

My Audiomods tonearm uses the Rega armtube which i believe makes it a 9" arm, i am using the two point technique suitable for 9" arms protractor section and have set up the overhang to 17.25mm as specified for the audiomods tonearm.

The cartridge looks nice and square in the headshell and also looks correctly aligned on the 2 points of the protractor.

If i check the tracking ability with the test record it tracks the 300Hz +14dB section OK but struggles with the +16dB track.

The problem is a horrible waveform above about 10Khz (maybe a bit lower) on the 20Hz to 20Khz frequency sweep track, at lower frequencies the waveform is good.

I am wondering if it is just that the cartridge cannot track the higher frequencies at the recorded level on the disc?

Any thoughts would be helpfull.

Cheers,

Dean.

Hi Dean,

A couple of things, you mention that the cartridge is sitting squarely in the headshell but that may not be perfectly correct. My cartridge actually sits slightly skewed inwards as per my protractor so it sitting square is not necessarily right. As I said before I could not get satisfactory alignment with the protractor supplied with the record.

Secondly out of all the cartridges I've used I have only had one that could play the 300hz +16db bias setting without distortion and even then only at maximum tracking force. I think it's very likely that you will measure distortion with a scope when playing this track and the one after it even more. You're probably right that your cartridge can't deal with this one although that doesn't mean there is anything wrong.

But the reality is that under normal conditions your cartridge will never see this sort of level so I think you may be reading too much into it. I've been told many times that as long as the cartridge will track the first two bias settings ok then there is nothing wrong.

Again, as long as you are not getting distortion on normal play then imho there is nothing to worry about.

Cheers

Steve

 

[Anonymous]

Hi all,

As suggested by Steve I ordered an Avid Rega protractor, turned up this morning.

Set up the cartridge using this and it has improved the sound quality a lot, the top end is much better and sounds brighter (louder?).

It would seem that the protractor supplied with the test record does not work with the Rega arm correctly, BUT it could allways be me being a bit thick!

Thanks all for your help and suggestions.

Dean.

 

[stevieg330]

Hi all,

As suggested by Steve I ordered an Avid Rega protractor, turned up this morning.

Set up the cartridge using this and it has improved the sound quality a lot, the top end is much better and sounds brighter (louder?).

It would seem that the protractor supplied with the test record does not work with the Rega arm correctly, BUT it could allways be me being a bit thick!

Thanks all for your help and suggestions.

Dean.

Hi Dean,

Did you find that the alignment was much different with the Avid protractor? Also, as I said previously my cartridge is actually skewed very slightly with the front pointing inwards, does the MC30 do the same or is it fitted square?

Glad you think it has improved the sound as it's not the cheapest protractor around. I really couldn't get on with the one supplied with the record nor the freebies from Vinyl engine but this one, for me works a treat.

Cheers

Steve

 

[shooter]

Is the cart tracking the 300hz sweep now?

 

[Anonymous]

Hi Steve and Shooter,

Yes, the cartridge is now further back in the headshell by about 3mm but it does appear to be fairly square.

The 300Hz torture test tracking is about the same but there is definately less distortion in the higher frequencies on the 20Hz to 20Khz sweep track.

It now sounds much better, I played 4 Lp's last night and still wanted to play more, my wife put a stop to that!

This vinyl lark's good isn't it!

Again, thanks for your help.

Dean.

 

[sirlordcomic]

I'm using an AT33PTG/II on a Series 5 Audiomods at 2g VTF.

I can't can't passed 1 second on that +18 track, it just skips all the way out.

I used a Feickert protractor and I have adjusted anti-skate to no distortion on either channel in each of the 3 test tracks which are +12?

I think I had some carts that could play that last track, not sure. Grado wood bodies? Soundsmith Voice?
Can't remember which. Also, it was on MG-1 Airbearing then....