VTA method???

[Thomas_AA]

Ok, but what you're bothered about or not is not relevant and not an objective argument. Lots of people aren't bothered about many things at all, but this topic is about how to set the ideal VTA/SRA, how to measure it or it's consequences and potentially how it affects sound.


You're concluding that VTA number from that picture with the measurements, not from the patent. The patent states that the sra should be 90 deg:

and the vta of the cantilever should be ca. 20deg, so that is not really a set value. Their main claim is on the SRA. What VTA comes with that depends on how the tip is glued in.

Without actual de music files we'll never know. Besides which type of music files is always very very important in these. Inner grooves? outer grooves? amount of modulation?
I see it like IGD. Lots of people claim it doesn't exist or doesn't occur on their setup. That is a consequence of either not having music where IGD occurs, or they don't know what to listen for, or are just plain deaf. It's easy to make a setup sound beautiful. It's not so easy to make a setup sound beautiful everywhere on every record.
I'm mainly interested in where things start to sound noticeably worse.

You have that stylus. I don't. So you have to do the measurements whether or not VTF is set correctly on their recommendation. Lots of manufacturers are often dead wrong.
What's the dynamic compliance of that stylus? (without brush)
1.0-1.5 with a brush down is very very low. You'd expect a compliance of well over 35.
Whether or not more VTF brings you within your desired SRA range....depends on your static compliance.
However I doubt playing with the VTF would bring that stylus in your first example with that 8degree SRA error (according to the measurements) into the right ballpark.
The original v15IV is rated at 25mm/N, so that means adding 1g extra VTF (wich of course is a huge amount), only ads 0,25mm extra sagging of the stylus. That would result in a lowering of only 2 degrees on the VTA if the cantilever (tip to fulcrum distance) is 8mm long (pretty standard). Certainly not enough for the stylus from your first example.
And that's for 1g extra VTF. Adding half a gram or even less won't really do anything. Or that jico stylus must have an insane high static compliance of like 75mm/N or more, but that's unlikely.
But I assume you haven't done such calculations yet?

Well, my concern is to use the cartridges and stylii that gets most out of the grooves with minimal distortion and not spend a fortune. The Shure/JICO combination is good at that despite the higher than normal VTA. With respect to the Ortofon replicant there are quite a few pictures available where SRA and VTA have been measured. And regardless of the patent there is no one showing 20°. Effective VTA is more like 26-27° or more, see e.g.

Ortofon Cadenza Bronze SRA

:-popcorn:

forums.stevehoffman.tv

My original stylus for the V15VxMR had only one parameter that was better than the JICO and that was channel separation above 10 kHz due to its higher resonance frequency. But hollow beryllium cantilevers are not made today. Speaking of the original Shure MR stylus, below is a picture of stylus angle and effective VTA. Around 26° effective VTA, 6° more than the target 20°. What does that tell you for an old cartridge like the V15V? Cartridges vary between 20-30° effective VTA, as I mentioned earlier. There is no way to adjust VTA to 20° of all these by tonearm height - my initial statement was to adjust for SRA and leave VTA as is. If you have correct SRA and it would be possible to adjust 6-8° to get correct VTA, SRA would be off and you suffer from high frequency loss.

Regarding VTF there is of course no fix for the VTA - more for getting closer to the ideal SRA around 92 degrees. Compliance is 22 so that makes me wonder why JICO specifies so low VTF. It tracks 100 µm at 1.45 g brush down and has below -60 dB THD at 1 kHz, 3.54 cm/s peak. Which is top notch figures.

BTW, the music excerpt was from the final of Mahler's 2nd symphony, crammed in last track inner groove of the record, i.e. one of the most difficult passages to reproduce by vinyl.

And another edit;

Without actual de music files we'll never know.

as noted earlier there is an example on the site I linked to with music file with and without 12° VTA IMD distortion.

 

[AvFan]

I don't (literally) see how the 22° and 26° lines were established. How was the cantilever pivot point established?

But does it matter? I don't think knowing the VTA is anything more than a meaningless rough double check of the setup. The view above is almost good enough to set SRA and then only make minor adjustments by ear.

 

[Thomas_AA]

I don't (literally) see how the 22° and 26° lines were established. How was the cantilever pivot point established?

But does it matter? I don't think knowing the VTA is anything more than a meaningless rough double check of the setup. The view above is almost good enough to set SRA and then only make minor adjustments by ear.

It's estimated by the geometry of the whole assembly and the error will be small even if pivot point is slightly off; I once checked the forward+upward movement of the stylus when lowered into a groove by a USB microscope to get the "arc". The cantilever itself is 22° but as we all know stylus protrusion exists to various degree, and adds ≈3-4°. It depends how much the cantilever tip is bent/stylus position.

I can play with changing the SRA from 94° to 91° which will adjust 3° VTA at the same time (knowing that stylus friction will reduce dynamic SRA about 0.5-1°). I will try with some home-made shims to see what it gives; tonearm height affects other things so I avoid that.

 

[AvFan]

I will try with some home-made shims to see what it gives; tonearm height affects other things so I avoid that.

The amount of extra iterative work created by using shims is unacceptable to me. One of my tonearm "must haves" is the ability to raise or lower the tonearm's pivot point on-the-fly. Yes, doing so changes the VTF but that is quick fix compared to installing a shim and then having to go through the entire alignment process again. Doing that induces more variables that could impact the sound than being outside the performance ellipse of setting the SRA visually by changing the tonearm's pivot height. Cartridge setup is fussy enough, why make it worse?

As a side note, earlier you linked a Hoffman thread re: the SRA of the Ortofon Cadenza Bronze that I posted in. In that thread I relayed a conversation that I had with Ortofon USA that setting the SRA for all the Cadenza carts was as simple as getting the bottom of the printed word "Cadenza" on the side of the cart parallel to the record surface. Seems simple and meets the manufacturer's design parameters.

 

[Thomas_AA]

The amount of extra iterative work created by using shims is unacceptable to me. One of my tonearm "must haves" is the ability to raise or lower the tonearm's pivot point on-the-fly. Yes, doing so changes the VTF but that is quick fix compared to installing a shim and then having to go through the entire alignment process again. Doing that induces more variables that could impact the sound than being outside the performance ellipse of setting the SRA visually by changing the tonearm's pivot height. Cartridge setup is fussy enough, why make it worse?

As a side note, earlier you linked a Hoffman thread re: the SRA of the Ortofon Cadenza Bronze that I posted in. In that thread I relayed a conversation that I had with Ortofon USA that setting the SRA for all the Cadenza carts was as simple as getting the bottom of the printed word "Cadenza" on the side of the cart parallel to the record surface. Seems simple and meets the manufacturer's design parameters.

It might sound a bit of work with shims, but once set, no need to do more, IMO. Since my tonearm design is pivot point at record surface to minimise warp wow, I am not keen on fiddling with tonearm height more than 0.5-1 mm or so.

And I agree, base setting should be as the manufacturer says (which usually is upper part parallell to record surface).

(The SRA tests I once did with 10 kHz test tones showed that max output, which is the measurement test method for SRA, was found at 0 mm and 1 mm height and got lower at <0 mm and >1 mm. The difference is small though, with a reduction on 0.3-0.4 dB at -2 mm and +2.5 mm)

 

[Fishead]

Highly interesting thread here and one that can be very helpful......I, for one, would like to know which tonearm you have that has "on-th-fly" raising and lowering of the pivot point?

 

[Thomas_AA]

Highly interesting thread here and one that can be very helpful......I, for one, would like to know which tonearm you have that has "on-th-fly" raising and lowering of the pivot point?

I have the Moerch DP-8 which has a knob for it on the fly, but I have removed it since it does not fit under the lid. It is possible however that I could use it just to find the fine-adjust SRA with the 10 kHz method, and then remove it again.

 

[AvFan]

Highly interesting thread here and one that can be very helpful......I, for one, would like to know which tonearm you have that has "on-th-fly" raising and lowering of the pivot point?

Both my tonearms have the feature: 1) Reed 3P has fine adjustment dial on top of the mounting column plus a lever that will move the column very quickly and 2) Jelco SA-750E that has an aftermarket micrometer as part of the mount collar.





Previously I owned a 10" Audiomods Series VI that had a micrometer that could adjust VTA/SRA on the fly.

 

[radiokom]

Highly interesting thread here and one that can be very helpful......I, for one, would like to know which tonearm you have that has "on-th-fly" raising and lowering of the pivot point?

I have Eminent Technolgy 2.5, Technics EPA-B500 base with various arms, Original SL-1210MK2. And finally, ELP laser However in this case SRA/VTA does not apply but very useful option to reproduce records damaged by those elliptical styluses.

 

[AvFan]

Just a reminder:

• For a typical 9" arm with an effective length of 230mm a 1mm change in pivot height changes the SRA by 0.25°
• For a typical 10" arm with an effective length of 250mm a 1mm change in pivot height changes the SRA by 0.23°
• For a typical 12" arm with an effective length of 295mm a 1mm change in pivot height changes the SRA by 0.19°

Some tonearms have very limited height adjustment so it is important to consider the height of the cartridge (e.g. taller carts like the Ortofon Cadenza) and the possibility of SRA adjustment when choosing the arm and the cartridge. A tall cart that requires a lot of adjustment may not work on all tonearms absent shimming.

 

[radiokom]

Just a reminder:

• For a typical 9" arm with an effective length of 230mm a 1mm change in pivot height changes the SRA by 0.25°
• For a typical 10" arm with an effective length of 250mm a 1mm change in pivot height changes the SRA by 0.23°
• For a typical 12" arm with an effective length of 295mm a 1mm change in pivot height changes the SRA by 0.19°

Some tonearms have very limited height adjustment so it is important to consider the height of the cartridge (e.g. taller carts like the Ortofon Cadenza) and the possibility of SRA adjustment when choosing the arm and the cartridge. A tall cart that requires a lot of adjustment may not work on all tonearms absent shimming.

Nakamichi Dragon-CT original tonearm has fluid damper and interchangeable arm wands, bet no high adjustment (I believe because of semi-automatic design). So this table was supplied with cartridge spacer kit. More than 15 years ago I replaced original arm with tangential ET-2.5 with high pressure manifold for shop compressor. But I have in collection original one too. Now with 2 wands

 

[AvFan]

Nakamichi Dragon-CT original tonearm has fluid damper and interchangeable arm wands, bet no high adjustment (I believe because of semi-automatic design). So this table was supplied with cartridge spacer kit. More than 15 years ago I replaced original arm with tangential ET-2.5 with high pressure manifold for shop compressor. But I have in collection original one too. Now with 2 wands

Interesting that the Dragon with all its automated adjustment won't allow pivot point height adjustment with the stock arm. I just wanted to remind folks that it takes pretty large changes in pivot height to make meaningful changes in SRA. 1° change in SRA takes between 4mm to 5mm of vertical change and that can become a problem in certain circumstances.

 

[Fishead]

Some very nice equipment discussed above.....the only arm I have where the tonearm base can be raised or lowered, thereby adjusting SRA is the Yamaha PX-3. I love that feature, and using headphones I can really tell the difference allowing a pretty effective adjustment to get the tone just right. Good stuff!

 

[radiokom]

Interesting that the Dragon with all its automated adjustment won't allow pivot point height adjustment with the stock arm. I just wanted to remind folks that it takes pretty large changes in pivot height to make meaningful changes in SRA. 1° change in SRA takes between 4mm to 5mm of vertical change and that can become a problem in certain circumstances.

Yes, Ortofon MC-20 was taken as standard, so you can use cartridges of that high or lower, with spacers. And it has 9" tonearm. For pivoted arm I would prefer 12" or at least 10" as Technics EPA. Jelco has some very nice 12" arms I plan install one on Nakamichi TX-1000 as second arm along with ET-2.5 as primary (if I will got one. Will ask Bruce Thigpen, maybe he have one with high pressure manifold left for sale).

 

[Thomas_AA]

Some SRA testing made here:

Fun with vinyl measurements

The speed fluctuation is about two percent, what kind of records it (Lyrec motor) could be used for cutting, gramophone?

www.audiosciencereview.com

 

[lini]

Just a reminder:

• For a typical 9" arm with an effective length of 230mm a 1mm change in pivot height changes the SRA by 0.25°
• For a typical 10" arm with an effective length of 250mm a 1mm change in pivot height changes the SRA by 0.23°
• For a typical 12" arm with an effective length of 295mm a 1mm change in pivot height changes the SRA by 0.19° (...)

Actually, that isn't quite true, 'cause in case of many radial-tracking arms the pivot axis for vetical motion is angled to be perpedicular to the length axis of the headshell, in order to avoid rolling, when riding over warps. Due to that, the effective nodding axis isn't the same as the virtual tonearm axis and actually is a good bit shorter - and hence the change in SRA will also be a good bit higher.

Greetings from Munich!

Manfred / lini

 

[AvFan]

Actually, that isn't quite true, 'cause in case of many radial-tracking arms the pivot axis for vetical motion is angled to be perpedicular to the length axis of the headshell, in order to avoid rolling, when riding over warps. Due to that, the effective nodding axis isn't the same as the virtual tonearm axis and actually is a good bit shorter - and hence the change in SRA will also be a good bit higher.

Greetings from Munich!

Manfred / lini

Yes, I simply did the arctan of 1mm/effective length. Can you provide an example calculation of a tonearm with that geometry? What specific brands of tonearm have that geometry?

 

[radiokom]

I have where the tonearm base can be raised or lowered, thereby adjusting SRA is the Yamaha PX-3. I love that feature, and using headphones I can really tell the difference allowing a pretty effective adjustment to get the tone just right. Good stuff!

Yes. I do exactly the same. On inner track. PX-3 is excellent table.

 

[mr_petit]

Some SRA testing made here:

Fun with vinyl measurements

The speed fluctuation is about two percent, what kind of records it (Lyrec motor) could be used for cutting, gramophone?

www.audiosciencereview.com

Why didn't you use an imd track/measurment?
A sweep is 1 frequency at the time, so there is per definition no IMD effect at all.
Or do you think that SRA effects don't manifest themselves mainly in IMD like most seem to think?

 

[lini]

(...) What specific brands of tonearm have that geometry? (...)

That's not a question of the brand, but rather a question of the specific models. For example, the classic SME 3009 family models don't sport that correspondingly angled vertical pivot axis, while the SME series V does. And for example all Technics SL-12x0Mky tonearms also do - and many more.

(...) Can you provide an example calculation of a tonearm with that geometry? (...)

I'll give you two simplified examples, combined in a quick & dirty drawing (*), that I just made with MS Paint:



In both cases I use a simple, hook-shaped, straight tonearm arrangement (in black), which makes things easier, 'cause in this case the actual and the virtual tonearm axis are the same (as are the headshell and the offset angle), and the length of the long part of the hook hence simply equals the effective length.

Well, and each red line (plus short part of the hook) would now show, what I call the effective nodding axis - on the right side in case of the correspondingly angled vertical pivot axis, on the left side in case of the vertical pivot axis being perpendicular to the arm tube instead. And each yellow line simple prolongs the vertical pivot axis to the rear end of the effective nodding axis, which one could also call the effective nodding pivot point.

So now it should be pretty easy to see, that on the right side the length of effective nodding axis = effective length * cos (offset angle), whereas on the left side the length of the effective nodding axis = effective length / cos (offset angle).

Well, and provided, that the initial tonearm orientation is horizontal and that one doesn't readjust for the slightly altered effective length after pivot height change, I'd calculate the change in SRA with arcsin (height change / length of effective nodding axis).

Greetings from Munich!

Manfred / lini


*) So never mind, that the angle of the red line on the left side isn't quite correct.