Diamond Stereo Width Issue

[PMST]

Recently I've upgraded to a second VR but having an issue.

I do all my own iRIAA in the box, my chain is simple, and is identical for both lathes. It is:

AUDIO PLAYER - AMP - CUTTERHEAD

On my original VR i use Myshank Synthetic diamonds and doing my own iRIAA works very well, but Souri's diamond has a much narrower stereo image, almost mono, I've swapped the heads around on the lathes, also audio players and nothing is changing. I've attached audio to hear, first the original audio file, then a recording of a cut from my MS synthetic, then a recording of Souri's.

Has anyone else ever had this issue or possibly got an explanation?

- Note.... Please ignore the wow on souri's cut, I'm waiting for a power lead for my motor and platter

[2bitcomputer]

Interesting.
To my ears, the stereo width decreases AND the balance shifts left on the Souri diamond.
Is that what you hear?

Are the cuts on exactly the same equipment - head, main unit, TT, signal chain?
If yes, then I would be interested in the hours of use on each - souri's sounds older, and I believe sharpness/integrity of tip is essential for good verticals.
And then I would want to check orientation of diamond to blank - is the diamond perfectly vertical and is the cutting face perpendicular to the groove?

[PMST]

The equipment is all the same, player, amp, turntable, playback, recording interface, however the head is the only different thing, one is the new head with Souri diamond with my newer VR, the Myshank is in my older, although I can't see a head changing the stereo image like this, its just two tweeters after all, nothing else that can change the imaging at this point in the chain (I assume?) Signal is the same file, coming form the same player and amp.

I've got another shank diamond on its way so I will be trying that in the head this time and will go from there!

[2bitcomputer]

I have an old semi-blown pair of headphones that do exactly the same thing to a stereo image, they narrow it and pan/move everything left.
I mean exactly - Kinda freaky that you would post mp3s with the same sounding problem!
Anyways, I have used a mix of myshank and souri diamonds over the years and never noticed (with my good headphones ) the kind of problem you have here.
Have you measured the impedance of all 4 channels of the 2 heads and is there any difference between them?

[PMST]

No measurements yet but getting to that in the coming days once I finish my current workload

[PLD]

I can't really see how a stylus could cause this, but the two tweeters on my head are definitely imbalanced. I'm not sure if it's the tweeters themselves or perhaps the glued cones/joins causing the problem, but I could hear a marked difference just by putting pink noise through the head and flipping between the channels. I ended up having to alter the EQing/level going to one side to counteract the problem.

[markrob]

I assume you are talking about the sound you hear from the head in the room, not what is recorded in the grooves. In this case, you will hear a major difference in the audio when you play noise or music in both channels together or each separately. This is because the two drivers are purposely wired in reverse polarity. So you will hear some acoustic cancellations when both are driven. In the end, you really only care about what is recorded, not the sound in the room from the head.

Mark

[PLD]

Oh, certainly. However there was a difference in what was cut as well between left and right, noticeably in the upper midrange, and the left channel needed some boosting in a couple of areas to even things up. Especially apparent on material that was mono, or close to.

[PMST]

So after running tests, I can only think that I have been sold a total dud of a head. Using the same diamond, on the same lathe, with the same audio, all the same, my new one just sound like shit. When changing diamonds I noticed the pivot to hold the diamond is drilled completely off centre, almost impossible to get the stereo imaging even close. The overall sound is gritty, distorted and awful stereo imaging.

Please excuse the bad quality pictures, I couldn't get it to focus on the part I wanted, but you get the idea. Fingers crossed Souri will take it back and send a replacement.

[PMST]

The lathe also came with an unusable clamp, as you can see the drill started, then retracted, when into a second place, and came out in the centre of the clamp, totally off center. Seems to be the same issue as with the pivot to hold the diamond, just drilled wildly off from its mark

[PMST]

Fingers crossed it's a one off and doesn't happen to anyone else, Souri has always been great to me in the past so hopefully i can just return this one and get a replacement, luckily i still have one head thats sounding great!

[2bitcomputer]

So it is a new VR bought directly from Souri?

[PMST]

Yes brand new from Souri about 3 weeks ago

[tragwag]

oh man, yeah my two heads are pretty different. one of them needs a few dB on one side to even the volume

[PMST]

oh man, yeah my two heads are pretty different. one of them needs a few dB on one side to even the volume

Ah ok good to know! I suppose this is tricker for me as I don't use the main unit.....