Distortion problen

daddydoom · « **on:** 18 Apr 2012, 01:11 am »

I recently purchased my first MC cart and for the most part sounds wonderful, but on a few albums i get slight distortion in the right channel that i don't get with my other carts. I've checked and rechecked my set up and played with my anti skate a lot with no change. My question is could it be that the cart is so sensitive that the sound is on the albums or does it sound like a set up problem. Its not terrible but annoying.

A little more info: The noise only happens at the beginning and end of the albums and always on the same albums.

Any suggestions or comments will be greatly appreciated

neobop · « **Reply #1 on:** 18 Apr 2012, 02:12 am »

Could be azimuth.

These offending records, only a couple or many?

TONEPUB · « **Reply #2 on:** 18 Apr 2012, 03:13 am »

You mentioned always on the same albums....

Do you have anything that plays fine all the way through? What kind of table/tonearm and cart do you have? I agree with Neobop on azimuth, also what did you use to set overhang, VTA, etc?

daddydoom · « **Reply #3 on:** 18 Apr 2012, 10:44 am »

Thanks guys,

Neobop, Its only on a few records that i can here it, but i dont here it with my other cartridges. I have a fozgometer and it says i am dead on the money. I also have 2 digital meters for tracking, test records and other setup tools.

tonepub,
I have a modified Thorens TD 160 HD with the Ortofon 212d tonearm and the Ortofon winfeld cart. The other carts i use and dont get the noise are the 2M black and the Sumiko blackbird. I used a template the i got from vinylengine and tried the one that came with the test LP. No difference.

neobop · « **Reply #4 on:** 18 Apr 2012, 11:24 am »

The only thing that comes to mind is the replicant 100 tip on the Windfeld. The Black has a shibata and the Sumiko, an elliptical.
Have you tried slightly more VTF?
Did you align to the body or the cantilever?

It could be that the Windfeld is revealing groove damage or imperfections, the others don't. But it's odd that it's only in the rt channel.

Wayner · « **Reply #5 on:** 18 Apr 2012, 12:00 pm »

Try bringing the ass end of your tonearm up more. I've been reading lots on the virtues of a 92° rake angle, and your situation may improve by doing this. If it starts sounding to shrilly, you've raised it too far.......

Wayner

TONEPUB · « **Reply #6 on:** 18 Apr 2012, 01:56 pm »

If it's only a couple of records, you may have damaged or worn records. Usually an alignment problem will be evident on all records.

Any way you can listen to another copy or another pressing of one of the problematic titles?

That might settle it once and for all. Sounds like you've done everything else right!

ptmconsulting · « **Reply #7 on:** 18 Apr 2012, 03:37 pm »

The SRA/VTA for a fine line stylus can easily be set by ear. But here's what you need to understand about the groove walls vs the fine contact points of the stylus to make the adjustment.

- Low frequencies are represented as long swooping waves in the wall of the vinyl
- High frequencies are much sharper waves, they are essentially pointy but long from top to bottom of the groove like a knife edge.
- All waves in the vinyl wall are cut at an angle
- To set the VTA/SRA correctly you need to line up the fine line edge of the stylus to meet the high frequency knife edge waves in the vinyl wall.
- So what you really need to be listening for are clean transients on high pitched instruments, like triangles and cymbals and such.
- If you get that lined up cleanly then the bass and all else will follow. There is a misconception that higher means tinnier and lower means bassier. This may be true for non-fine line stylii but not necessarily for a Shibata and other fine line styli.

Wayner · « **Reply #8 on:** 18 Apr 2012, 05:30 pm »

The 92° rake angle helps to maintain stylus contact, regardless of stylus type. Maintaining contact without chatter, will stop the buzzing, reduce record wear and produce a well balanced top to bottom soundstage.

Wayner

TONEPUB · « **Reply #9 on:** 18 Apr 2012, 05:50 pm »

Quote from: ptmconsulting on 18 Apr 2012, 03:37 pm

The SRA/VTA for a fine line stylus can easily be set by ear. But here's what you need to understand about the groove walls vs the fine contact points of the stylus to make the adjustment.

- Low frequencies are represented as long swooping waves in the wall of the vinyl
- High frequencies are much sharper waves, they are essentially pointy but long from top to bottom of the groove like a knife edge.
- All waves in the vinyl wall are cut at an angle
- To set the VTA/SRA correctly you need to line up the fine line edge of the stylus to meet the high frequency knife edge waves in the vinyl wall.
- So what you really need to be listening for are clean transients on high pitched instruments, like triangles and cymbals and such.
- If you get that lined up cleanly then the bass and all else will follow. There is a misconception that higher means tinnier and lower means bassier. This may be true for non-fine line stylii but not necessarily for a Shibata and other fine line styli.

True. And again, before you start adjusting, I'd try another pressing of the same record. Eliminate the variable before you start tinkering! It will save aggravation later...

daddydoom · « **Reply #10 on:** 18 Apr 2012, 07:01 pm »

For the most part the records are quailty pressings and have been cleaned. Mofi and such and heavy vinyl. I was wondering if the noise has always been there, just the other carts didn't pick it up.

The problem i have trying a different copy is no one i know has a copy of any of the records that are the problem and really don't want to by another $50 record to find out.

I plan on recleaning some of the records to see if that might help.
This weekend I plan on trying some of the suggestions and will let you guys know how things went.

thx again

ptmconsulting · « **Reply #11 on:** 18 Apr 2012, 08:03 pm »

Don't forget to clean the stylus too

TONEPUB · « **Reply #12 on:** 18 Apr 2012, 08:20 pm »

Good call!

Sonny · « **Reply #13 on:** 18 Apr 2012, 08:36 pm »

I really think it's set up and not record...I had that problem too and my other cartridge tracked it fine, but the one that was having issues, couldn't. So it was not the record....

Try Azimuth and Anti-skate..normally when the distortion is on the right channel only, it's signals not enough anti-skate...

T

Wayner · « **Reply #14 on:** 18 Apr 2012, 09:13 pm »

In this case, since it's on the right channel (unless the left and right leads are switched), it too much anti-skate. Also, with an aging tonearm, are you sure your anti-skate even works? You said you changed the settings and there was no change. That would make me suspicious.

Also, did you do the simple test and flip your interconnects to the phono preamp and see if the problem followed you?

Wayner

orthobiz · « **Reply #15 on:** 18 Apr 2012, 11:02 pm »

Quote from: Wayner on 18 Apr 2012, 12:00 pm

Try bringing the ass end of your tonearm up more. I've been reading lots on the virtues of a 92° rake angle, and your situation may improve by doing this. If it starts sounding to shrilly, you've raised it too far.......

Wayner

Are you using a USB scope? Is there a reasonable setup for this?

Paul

Wayner · « **Reply #16 on:** 19 Apr 2012, 12:01 pm »

Zoom mode on my digital camera, mounted to a tripod. Take a picture, print it out, draw some lines and measure the angle of the stylus. Adjust accordingly.

Or, you can buy a USB microscope. Michael Fremer does this, but he got his info from others.

W

daddydoom · « **Reply #17 on:** 19 Apr 2012, 08:16 pm »

Wayner, while check settings i swapped the left and right rca's and the sound moved to the left channel.

I am not going to have time to mess with this until the weekend, but last night iwas doing some checking of the vtf and noticed that both of my digital vtf gauges had 2 different readings. I have the project gauge and the ortofon gauge that came with the tonearm. I have a calibration weight that came with the project gauge and both of them were right on the money, but when i check the cart i get a .4 difference. What would be causing such a big difference

Matt

Ericus Rex · « **Reply #18 on:** 19 Apr 2012, 08:20 pm »

Magnetism between the cart and some part of the plinth or scale?

neobop · « **Reply #19 on:** 19 Apr 2012, 10:10 pm »

Did you check the VTF with the anti-skate off?

When you get some time this weekend, I suggest using the (plastic?) Ortofon scale and setting at the max 2.8g VTF. If the noise is still there, give it another .2g. This won't hurt anything and at least you'll know if it's momentary mistracking causing the noise. I assume your cart is parallel with the record? If so you might try experimenting with the VTA, as Wayner suggests. Sometimes when the cart is a little low, I've gotten noise in the rt channel. I don't know exactly why this is, but it's happened with a couple of MCs. Hope it works out.