[orthobiz]

Wow, Wayner! Great analysis, all of this turntable stuff can get murky....

Paul

[neobop]

Hopefully, every time you change your VTA, you re-align your cartridge........It is the hypotenuse of a triangle and as you raise or lower the back end of the toneram (from a previous cartridge alignment) you have now made the pivot to stylus distance shorter.

What you might think is a change from adjusting the VTA (SRA), you may have just been experiencing the sound of something different, not necessarily better, just different.

I have re-thunk the entire SRA debate. I have to ask myself why I would not want to have the contact surface of the stylus be anything but vertical? Any slant of the stylus adds a time element to the playback, as any other contact angle other then perfectly vertical is going to smear time together during playback.

A stylus "rake" angle was used during the dead wax cutting process, much like a machinist would add "kerf" to the cutting tip of a lathe. This "kerf" simply kept the cutting tip from chattering (which causes skip). The modulations in the vinyl can be nothing other then completely vertical in nature (from a side view) or the vinyl would not cleanly pull out of the the stamper.

'ner

Hi Wayner,
I'm not sure about that.  I'll say why. 

The hypotenuse is a long side in a right triangle.  Arm height is the shortest side.  In order effect a small degree of change in SRA, a large change in height is necessary.  Thus, a small change in height will have little affect.  I think the same holds true for the relative position of the end of the hypotenuse (stylus) in relation to the other side of the 90° angle (record). 

"It is the hypotenuse of a triangle and as you raise or lower the back end of the toneram (from a previous cartridge alignment) you have now made the pivot to stylus distance shorter."
I think you just misspoke here and know the distance gets shorter as the arm goes higher, and longer as the arm goes lower, but that's not my point.  Once SRA is very close (91.5°), it usually requires a very small change in height to "dial in".  According to my measurements the change in alignment is virtually imperceptible with a change of < 1.5mm approx.  This is with arms 235 - 240mm eff length, possibly a little more for a Loefgren alignment.  I say approx. because I don't trust the Sony height calibration, the Unitrac doesn't have it, and the Victor 7045 isn't in service yet.  Those are the only VTA OTF arms I own.  Your 1200 is probably better for that than the Sony which is down at the moment.  The damn semi-auto function had the arm out of level and going sideways with height adjustment.  You should have seen the azimuth.  Maybe I can just remove that crap from the arm and tighten it up, or I'll have to replace the arm.  If you took measurements of the alignment change per mm of height, I'd be very interested in results.

I think you'll find this of interest:
https://forum.audiogon.com/discussions/interesting-phenomena-in-the-cutting-room

Regards,

[orthobiz]

So what's the rake on mono records? Is it the same?

Paul

[vinyl_guy]

So what's the rake on mono records? Is it the same?

Paul

I don't know. Send an email to Fremer and I'm sure he will tell you

[Wayner]

For a 9" arm, 1/4 1° of change requires 4mm of arm height adjustment. This will definitely affect the cartridge alignment, because the tonearm is a fixed distance and if the back of the tonearm length has been raised or lowered, the stylus distance (measured on the record's surface) will change.



Wayner

[neobop]

For a 9" arm, 1/4° of change requires 4mm of arm height adjustment. This will definitely affect the cartridge alignment, because the tonearm is a fixed distance and if the back of the tonearm length has been raised or lowered, the stylus distance (measured on the record's surface) will change.



Wayner

Yes, but you're talking 0.25° of SRA change = 4mm height for 228.6mm hypotenuse.  You computed SRA change, but not distance change of other side of right triangle?  Your calculations support what I'm saying.  I asked if you took measurements for alignment change per mm of height for your 1200.  I had no expectation of an answer or a specific answer, rather a possible  discussion of alignment change, new nulls, and implications.
neo

[vinyl_guy]

My understanding is with a 9 inch arm, a 4 mm change in VTA equals approximately a one degree change in SRA. It is what I found when I measured and adjusted my cartridge.

[Wayner]

You are correct. I was thinking about 1/4° equals 1 mm of height adjustment. My bad. 4mm for 1°, 8mm for 2°, and 10mm for 2.5°

So it is very obvious that most tables could not reach the 92° rake angle, if they measured 90° now.

[Wayner]

So one would have to ask oneself, why would the record industry and the hifi establishment want an ideal arm angle that most table are not made to approach, as the ideal settings for playback? Would it not be the easiest for the general consumer at large to simple set the arm for "level"? In the long run, I believe the level arm produces the SRA that the cartridge manufacturer wants you to use. Almost everyone can judge if an arm is level (with needle in the record groove), requiring no special tools, or a USB microscope or some other CAD program to draw lines and try to guess where the contact ridge is. It should not be this complicated, nor do I think that it is.

I also have read many articles on the subject and the conclusion is, no one can actually tell where the sweet spot is, and for all practical purposes, it was right under their nose.

I'm not saying that you should not fiddle with such things. I have, but in the end, I went back to the parallel arm. It just makes a whole bunch of sense to do it that way.

'ner

[SteveRB]

So one would have to ask oneself, why would the record industry and the hifi establishment want an ideal arm angle that most table are not made to approach, as the ideal settings for playback? Would it not be the easiest for the general consumer at large to simple set the arm for "level"? In the long run, I believe the level arm produces the SRA that the cartridge manufacturer wants you to use. Almost everyone can judge if an arm is level (with needle in the record groove), requiring no special tools, or a USB microscope or some other CAD program to draw lines and try to guess where the contact ridge is. It should not be this complicated, nor do I think that it is.

I also have read many articles on the subject and the conclusion is, no one can actually tell where the sweet spot is, and for all practical purposes, it was right under their nose.

I'm not saying that you should not fiddle with such things. I have, but in the end, I went back to the parallel arm. It just makes a whole bunch of sense to do it that way.

'ner

I tend to agree.

[sunnydaze]

Perfectly said, Wayner.     

Lotta folks round here obsess and sometimes make things needlessly complicated.  In the process, they scare away folks that otherwise are leaning towards dipping the toe into the vinyl waters.

None of this stuff is brain surgery.  Just use common sense.  Start w/ arm level, fine tune from there, up and down,  using your ears.  Exactly what I suspect you'd do anyway, even if you had the nifty technology to actually see the angles.

Doing this -- combined with siteing on a solid level surface,  using a synergistic arm / cart combo, and employing patience and care in setting up mount distance, null points, and VTF -- pretty much guarantees an excellent  result.  At least that's my experience.

[Wayner]

I have nothing but the highest respect for vinyl_lady. I know that Laura will pursue this until she is happy with the results, one way or another. She is one person here that does use her knowledge, but also common sense and will find the answer that fits what she is looking for.

On a side note to all of this, I'm one of the guys that sprung some cash for the SAS stylus from JICO. I bought one for my Shure M95HE and I must say, WOW! However, I have noticed that while some LPs easily show an expanded universe of sounds, others do not, and it does have me puzzled. Part of this SRA equation also needs to address the differences in record thickness, if we are to be true to a certain angle (and I guess that means all of us). Do I have a record of VTA positions for my LPs.....no. Should I.....I'm starting to wonder. I do wonder if the tweaks we are all looking for are actually very, very tiny steps while most of us (me too) are busy making the big leaps.

Tonight I'm going to start with a record that I know has out of this world sonic holography. I'm going to measure the record's thickness and translate that to another LP that may be of a different thickness, but seems to lack the sonics that I think it should have. I am then going to fiddle with the Technics's VTA.

'ner

[neobop]

You are correct. I was thinking about 1/4° equals 1 mm of height adjustment. My bad. 4mm for 1°, 8mm for 2°, and 10mm for 2.5°

So it is very obvious that most tables could not reach the 92° rake angle, if they measured 90° now.

Wayner,
This keeps getting better, at least as far as supporting my contention about alignment change, not SRA alone.  You said, "For a 9" arm, 1/4 1° of change requires 4mm of arm height adjustment. This will definitely affect the cartridge alignment, because the tonearm is a fixed distance and if the back of the tonearm length has been raised or lowered, the stylus distance (measured on the record's surface) will change." 

I said, "Once SRA is very close (91.5°), it usually requires a very small change in height to "dial in"."  

I'm not disagreeing with the height/SRA thing, I'm saying the resultant alignment changes are less severe than implied.  If that is true, then a small change in arm height will not mess up your alignment much.  Exactly how much is easier to measure (I think) than calculate. 

I'm not sure how much the intervening height of the cart on the hypotenuse, will change the distance on the record.  This gets complex and I'll try to measure the change.  I'll use a Chpritz straight line protractor to find the new nulls.  This is a bit of a PIA.  That's why I asked you in the first place, maybe you have already done this.  This isn't a right/wrong thing.  It's a question of degree.
neo

[Wayner]

I can draw it on my CAD and measure a 1/4° vta change if you want. It might be fun to know. I think I'll do the Technics pivot to stylus distance in my Lofgren B alignment. So thats 233.282mm for my arm.

[Wayner]

1/4° change resulted in a .00009" difference. I thought it would be a little more then that.

1° change resulted in a .0015" change.

2° change resulted in a .006" change. This one would be significant. The others, we can't see that small.

So I will eat some crow, and say that small changes will have an effect that we can't deal with. However a drastic 2° change will require a re-alignment.

Make sense?

'ner

[vinyl_guy]

I have nothing but the highest respect for vinyl_lady. I know that Laura will pursue this until she is happy with the results, one way or another. She is one person here that does use her knowledge, but also common sense and will find the answer that fits what she is looking for.

'ner

Thanks Wayner. You know the respect is mutual.

As I mentioned when I posted the pictures of the stylus, Michael Fremer's seminar at RMAF got me wondering how close my SRA was to optimal for my cartridge which according to Lyra is 92 degrees. I also wondered if I could improve the sound I was getting from vinyl. When I first installed the Atlas and about 6 months before I measured SRA, I started with the tone arm level and adjusted by ear. I got to a point where I was tired of adjusting and just wanted to listen to music and it sounded pretty good--better than with my previous cartridge, so I called it good. Measuring SRA was as much a curiosity as it was to fine tune the VTA/SRA and see if I could get more out of my cartridge. For me, mission accomplished--it was worth the few hours I spent one afternoon. I was able to use the USB microscope to get closer to 92 degrees and bring the music more into focus. Color me very happy with the results.

[neobop]

1/4° change resulted in a .00009" difference. I thought it would be a little more then that.

1° change resulted in a .0015" change.

2° change resulted in a .006" change. This one would be significant. The others, we can't see that small.

So I will eat some crow, and say that small changes will have an effect that we can't deal with. However a drastic 2° change will require a re-alignment.

Make sense?

'ner

That's outstanding!!  Thanks Wayner you saved me quite a bit of tedium.   I use magnification for alignment and .006" = 0.1524mm still isn't a whole lot.  I usually use Loefgren A, but I suspect that for either of those alignments you'll just wind up with slightly different nulls. 

No crow necessary, we're both right.   BTW, check out that Agon link above.  Atmasphere is a guy named Ralph who makes Atmasphere electronics.  He's been mastering and cutting - doing high quality recordings.  You'll get some answers as to why a cutter head might vary VTA/SRA.  I suggest you ignore the posts by a dude named Raul.  Waste of time.
neo 

[G Georgopoulos]

  I suggest you ignore the posts by a dude named Raul.  Waste of time.
neo

Neo, I read your posts and it's full of B.S....

[neobop]

Hi,
I've read some of yours and you seem a lot like Raul, the self-appointed arbiter of all things audio, but I wouldn't make such a statement without reading more of your utterances.  They don't interest me.   You're probably more knowledgeable than Raul but that's not hard to do.

Brilliant nonspecific attack  BTW.
neo

[G Georgopoulos]

Hi,
I've read some of yours and you seem a lot like Raul, the self-appointed arbiter of all things audio, but I wouldn't make such a statement without reading more of your utterances.  They don't interest me.   You're probably more knowledgeable than Raul but that's not hard to do.

Brilliant nonspecific attack  BTW.
neo

Neo you're ranting again about personal attacks,you have shown disrespect to a fellow vinyl person,we're a community of vinyl people here,we shouldn't behave like you did,have i ever disrespected you or commented bad at you before,no!!!,kind regards...