Weird Pre-Echo Type Distortion

I've noticed a bit of weird distortion from my V15VxMR just lately with a couple of lp's.

This is with my BC13 Help and Mofi Abbey Road (which I won here on the forum fundraiser Thanks!)
What happens is that loud sounds eg. guitar, in left channel are heard first (about a second earlier) in a quiet distorted form in the right channel.

Is this down to the groove wall being too thin on the original lacquer and distorting the adjacent groove while cutting is taking place?

After a quick trawl through the archives, I just checked out this thread http://www.stevehoffman.tv/forums/showthread.php?t=66032

Note the last line of the last post

"Also, I wonder if stylus length has anything to do with how much groove echo is audible?"

Maybe what I hear is due to the Shure stylus reaching deeper into the groove?

Anything I can do?

JJ

 

There's nothing much you can do.

This pre-echo is part of the manufacturing process; it can be due to cutting or any of the plating stages (which is why they need to be done slowly). It only really annoys me on headphones.

It's due to the modulations of groove B having moved the walls of groove A a little. I suspect it's worse (louder) towards the top of the groove, where the walls of adjacent grooves are closest, and that means those with line contact or micro ridge styli may be more affected.

 

Thanks Mikey,

this is not the pre-echo I am familiar with, that is where you hear faint music undistorted in both channels a couple of seconds before the track starts for real.

This is distorted and loud enough to be heard while the track is playing, and therefore is quite distracting. As I said, it only seems to be sound exclusive to the left channel which is heard distorted in the right.

I guess this is still a form of pre-echo but it's a particularly unpleasant one, I would try to post some clips if I knew how.

I never got this with the old cart, Im not going back tho that one was a terrible tracker of inner grooves.

JJ

 

It sounds weird - does it only happen on a few records or is ita general prob?

 

Hi there,

thanks for replying, you're not wrong, it does sound weird.

I have only noticed it on these two lp's so far, but I haven't played my entire BC13 using the Shure yet. (I want to redo my Needledrops)

It is very noticeable on "You've Got To Hide Your Love Away" the acoustic guitar on the left, kind of pre-echoes distorted in the right channel, same with that Mofi, Abbey Road, where it is noticeable on the intro to "Here Comes the Sun".

I'll try and get some clips posted later, I'm at work currently.

Regards
JJ

 

Check out your stylus, it could be skewed.

 

Steve,

when I get home from work in an hour or so, I'll needledrop what I hear and as you say report back.

When you say "Play a real record", I trust that is what you mean.

Regards

JJ

 

Oh right I guess you can have too much of a good thing.
I've not noticed it with anything else yet, because I have mainly been interested in re-doing my Beatles cd's.

Surely even you wouldn't describe the Mobile Fidelity Abbey Road as "wacky pressed", "wacky eq'd", maybe .

JJ

 

Right Here Goes, you will need headphones to really hear it,

BTW, it is a kind of echo, not Pre-Echo. It was late when I first noticed it last night, maybe the Gorts can change the thread title to Weird Vinyl Distortion.

First, "Here Comes the Sun" Intro MOFI, hear the distortion in the right channel.
http://www.yousendit.com/transfer.php?action=download&ufid=F1CAB1EA4F3966AC

Next "Here Comes the Sun" Intro BC13, no distortion.
http://www.yousendit.com/transfer.php?action=download&ufid=FF4AB9A65480E6E3

Now "Here Comes the Sun" Outro MOFI, hear the distortion in the right channel at the end.
http://www.yousendit.com/transfer.php?action=download&ufid=A1A1929301D629C6

And "Here Comes the Sun" Outro BC13, no distortion at end.
http://www.yousendit.com/transfer.php?action=download&ufid=DAEDC8B91B015FBD

Then "You Got to Hide You Love Away" BC13, hear the acoustic guitar distorting in the right.
http://www.yousendit.com/transfer.php?action=download&ufid=0DC165DA42BF2618

Finally "If I Needed Someone" BC13, strong sound from the left but no distortion in this case.
http://www.yousendit.com/transfer.php?action=download&ufid=55E513F11F9AF136

I know what you said earlier Steve but these are the records im listening to at the moment.

I've not noticed it on any other records, many of which are 180-200g modern pressings.

Peharps there is is nothing wrong and I happen to have a couple of duff pressings, I just don't know. I'm still fairly new to vinyl.

CHeers

JJ

 

Do you have the brush down on your V15? If so, try it with the brush up (remember to adjust the VTF to compensate)...

 

The brush makes no difference, I thought it was reading the groove at first.

It wasn't.

Thanks anyway.
JJ

 

Anyone?

 

I checked out a couple of the clips. The distorted crosstalk (as well as loud, fuzzy pre- and post-echo) in the right channel sounds like both my V-MR and VxMR did when the azimuth was off. When looking down the length of the cartridge at eye level from front to back, the cantilever should appear to rise straight up from the record surface. If not, any distortion or anomalies will be exaggerated. You've already check the tracking force and anti-skating, right?

 

I hear a difference, but not enough to be able to say anything's wrong.

I did have to use headphones, and play the clips loud. I wouldn't normally listen at the level necessary to hear the crosstalk/distortion. I'd be more worried about all that low frequency noise that's present on all the recordings. Souds like the turntable motor.

There have been instances of out-of-spec shure styli with bad crosstalk; a lot of your problem may be azimuth (vertical) alignment, as seen from the front. This may not be easy to adjust on your table.

 

Thanks guys for the advice,

So it seems I have three problems.

1. Pre/post echo, I'm guessing the problem on HCTS.
2. Crosstalk, on YGTHYLA.
3. Motor Noise

For 1&2 i'll first try the TF and ant-skate. Then I have an unused spare stylus, i'll s'pose I can crack that open and try. Then failing that, I believe the azimuth can be adjusted on the RPM4 (Uncle Ants?)

As for 3. the motor noise, dunno what to do about that, could be inherent in the design.

I'm going to be away this weekend so it may be next week before I can report back, fingers crossed, and thanks again.

JJ

 

Your BC13 issue of Help - is it a UK pressing? What are the matrix numbers? Just want to check if I have the same pressing.

 

Ocdman,

its a bit late here to check now (2:06am!).
Lucky I got day off work t'moro.

I'll check in the morning, its from 1986 (on the paper inner sleeves), pretty sure it uk pressing although I bought 'unplayed' used from USA.

Why d'you ask?

JJ

 

Even though you didn't have the problem with your old cartridge, there could still be a problem down (or up) in the groove on that pressing. I was curious so I wanted to check it out. I have several copies but if I don't have the one with your matrix numbers I won't bother to dig them out.

 

Thanks for the offer of checking Ocdman.



I couldn't sleep anyway, trying to bore myself to sleep watching Big Brother, it's not working! You should see oddballs they got in the bb house this year!

Anyway the matrices are YEX 168 - 4 and YEX 169 - 4. With HTM inscribed as well.
Are these early enough to be from tube cut lacquers, if so the metal parts may have been a bit worn by the mid 80's I guess?

JJ

 

JJ.. you're not going to get more than about 30dB of separation on a vinyl record, and I think you're probably getting that. The mofi seems to have slightly better (lower) signal in the wrong channel, probably due to more modern electronics during cutting, though it does sound less like the guitar on the left. CD / digital playback has quite a different set of compromises, but (80dB+ ) separation is one of the good points.

The ProJect turntables have the motor suspended on rubber bands; check that it's free to bounce, and isn't touching anything like the shelf underneath (sometimes extra feet help)

 

Yes it can be adjusted - if you go here:

http://www.project-audio.com/inhalt/en/manual/manual_rpm5.pdf

Its the manual for the current RPM5 not the 4, but the bit on adjusting azimuth is the same ... I wouldn't do it unless you have to though. Setting the stylus down on a small mirror can help in seeing whether its perpendicular or not.

I doubt you would be getting much motor noise,... unless you didn't undo the shipping screws.

 

Thanks Uncle Ants,

I think azimuth will be a last resort, tho the stylus may have a very, very slight lean. I've only noticed the problem on 2 lp's so far.

I may try the new Stylus, first.

Also the motor has always been audible, even though it floats freely on its band, and doesn't touch anywhere. I suppose that's one of the advantages of the more expensive decks with separate motors.

If you've heard any of the clips, do you think the motor noise is typical of an RPM4?

Cheers JJ

 

I just did that now. Uh no, I don't think it is typical ... Its quite noticable though.