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11 hours ago, Bisguittin said:

I derive great daily pleasure out of the audio love of my life - a Goldmund Studietto. I was lucky enough to come by this creature about 30 years ago. When burglars removed all my gear in 1993, this was all they left. Too cumbersome I guess. Thankfully they didn't throw it on the floor. The funky slinky-spring suspension has been replaced by sorbothane hemispheres in a substantial overhaul which included a bespoke power supply. The arm is a Souther SLA3. Keen eyes will notice a cable tie (which I emphasize is ultra loose) - insurance against the cartridge free falling with calamitous effect, should the arm be enthusiastically lifted after a few wines. Cartridge is a Dynavector DV20x2L which feeds its signal to a modified Michell Iso.

20200518_213021.jpg

 

That's nice, early Golmund.
IIRC Goldmund had  their own (motor driven?) linear tracking tonearm.

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

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Yes. I never owned that. The plinth is set up for their linear tracker, but this has always toted the Souther. Occasionally Studios and Studiettos come up for sale in Europe or the US and reading between the lines one gets the feeling that often the accompanying Goldmund Arm has seen better days. Their durability was perhaps problematic.

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14 hours ago, andyr said:

Owen, I'm interested to know why you think an underslung c'wt causes VTF to vary more than a c'wt that is centrally on the arm stub would, when the cart goes over a warp?

 

And shirley a c'wt which is positioned right up against the pivot will have less inertia than one positioned away from the pivot - so if it does alter VTF... it will do it less?

 

Andy

Hi @andyr 

Rotational Inertia - yes, it is proportional to mass x distance from rotational centre, squared,.

However, at the stylus tracing audio frequencies that are of interest to us (> than say 12Hz), the stylus 'sees' the tonearm as being essentially 'rigid' - in an optimally-matched cartridge compliance - tonearm Effective Mass combo..

 

Underslung c'weights - it's geometry, perhaps a pic will illustrate this best.

(However, there may be other factors at play, c'wt fixing, decoupling,  etc & it will sound different or even better, as @mloutfie found.

eg. the Effective Mass of a tonearm is changed when the c'wt is moved or changed in mass, by any significant amount. )

underslung.jpg.0df904a461d5799ed173844d4629a246.jpg

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

 

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16 minutes ago, Owen Y said:

Unless the c'wt is 'hanging' - like the early Roksans....

 

roksan_tabriz_zi_3.jpg.5fb9d38dd50636bd698cf871187a6cb6.jpg

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

That's an interesting design. I can make that easily actually 

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59 minutes ago, Owen Y said:

Hi @andyr 

Rotational Inertia - yes, it is proportional to mass x distance from rotational centre, squared,.

However, at the stylus tracing audio frequencies that are of interest to us (> than say 12Hz), the stylus 'sees' the tonearm as being essentially 'rigid' - in an optimally-matched cartridge compliance - tonearm Effective Mass combo..

 

Underslung c'weights - it's geometry, perhaps a pic will illustrate this best.

(However, there may be other factors at play, c'wt fixing, decoupling,  etc & it will sound different or even better, as @mloutfie found.

eg. the Effective Mass of a tonearm is changed when the c'wt is moved or changed in mass, by any significant amount. )

 

 

underslung.jpg.0df904a461d5799ed173844d4629a246.jpg

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

 

 

Thanks Owen,

 

Sorry, I'm just as much in the dark as I was, before your post.  :o

 

I understand - and agree with - everything you said ... except the one sentence that I've put into blue text.  (IE. your pic doesn't help me.)  :(

 

Andy

 

 

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Posted (edited)

Sorry @andyr - I neglected to elaborate..

The c'wt's horiz distance from pivot, varies more significantly with tonearm up-down movement, when it's underslung - compared with an arm-axis mounted c'wt -  relative to the stylus up-down movement.

This is all only an occasional problem.

But of course, all your records will be flat  ;)

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

Edited by Owen Y

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Hi Owen,

 

given that the distance of the weight from the pivot doesn't change, the effective mass also doesn't change. The horizontal/vertical vectors, that you are focusing on, don't IMHO matter.

 

cheers

Grant

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Hi Grant - as VTF & c'wt balance result from vertical gravity force, the moment lever length is always the horiz. distance from the arm pivot (not the radial lever length).

 

Sorry if my terminology is a bit rusty, it's been a while since I attended physics classes ;) 

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

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31 minutes ago, Owen Y said:

Hi Grant - as VTF & c'wt balance result from vertical gravity force, the moment lever length is always the horiz. distance from the arm pivot (not the radial lever length).

 

Sorry if my terminology is a bit rusty, it's been a while since I attended physics classes ;) 

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

Yes but the practical effect given even a reasonable size warp would be less than one mm of difference, so of no concern 

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Posted (edited)

Here's my latest iteration. Currently fine tuning cartridge - tonearm combination.

20200508_001655.jpg

20200518_171123.jpg

20200518_173518.jpg

Edited by Gandra

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Posted (edited)

Hi Owen, 

 

I think that only applies to static tracking weight. As soon as the arm is in motion, the effective (inertial) mass is the dominant cause of stylus pressure changes, and this is constant as the arm moves, since the counterweight is a fixed distance from the pivot . The static weight imbalance due to the counterweight swing action would be minor by comparison, probably less than 0.1 g. But it doesn't need to be the way you have shown at all.

 

The big advantage of the under-slung  counterweight over the axial variety is being able to set the centre of static mass on the plane of the record surface and stylus tip. And the ideal way to take advantage of this is to also place the pitch bearing on the same plane. Then you also don't have the counterweight issue that you illustrate. Your drawing of course does not represent this, and has the pitch bearing too high and the counterweight too low.

 

cheers

Grant

Edited by Grant Slack

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3 minutes ago, Gandra said:

Here's my latest iteration. Currently fine tuning cartridge - tonearm combination.

20200508_001655.jpg

20200518_171123.jpg

20200518_173518.jpg

That looks stunning. What happened to the slate plinth?

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Packed away. Never know when / if it will be needed.  

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1 hour ago, Grant Slack said:

Hi Owen, 

 

I think that only applies to static tracking weight. As soon as the arm is in motion, the effective (inertial) mass is the dominant cause of stylus pressure changes, and this is constant as the arm moves, since the counterweight is a fixed distance from the pivot . The static weight imbalance due to the counterweight swing action would be minor by comparison, probably less than 0.1 g. But it doesn't need to be the way you have shown at all.

 

The big advantage of the under hung  counterweight over the axial variety is being able to set the centre of static mass on the plane of the record surface and stylus tip. And the ideal way to take advantage of this is to also place the pitch bearing on the same plane. Then you also don't have the counterweight issue that you illustrate. Your drawing of course does not represent this, and has the pitch bearing too high and the counterweight too low.

 

cheers

Grant

Hi Grant - I agree (& also with @Chill3) that the effect is small - but in high-end audio, we usually contend with this level of factors & we are talking about the near-static situation, when it comes to VTF.

 

However, when it comes to 'inertial' mass (Rotational Inertia ), as said, at the stylus tracing frequencies that are of interest to us (> than say 12Hz), the stylus 'sees' the tonearm as being essentially 'rigid' - as in an optimally-matched cartridge compliance - tonearm Effective Mass combo.

 

(Sorry, was not my intention to digress this nice  TT page & will refrain from adding further comment about this... as they say - YMMV  ;) )

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

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1 hour ago, Gandra said:

Here's my latest iteration. Currently fine tuning cartridge - tonearm combination.

20200508_001655.jpg

20200518_171123.jpg

20200518_173518.jpg

Beautiful 301! Is the plinth from the guy in Hungary? He does stunning work!

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1 hour ago, Gandra said:

Here's my latest iteration. Currently fine tuning cartridge - tonearm combination.

20200508_001655.jpg

20200518_171123.jpg

20200518_173518.jpg

I think I just came.....

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33 minutes ago, Doppelganger said:

Beautiful 301! Is the plinth from the guy in Hungary? He does stunning work!

Yep. Couldn't agree more. Beautiful workmanship, excellent communication, the whole experience was 100% positive. 

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2 hours ago, Owen Y said:

Hi Grant - I agree (& also with @Chill3) that the effect is small - but in high-end audio, we usually contend with this level of factors & we are talking about the near-static situation, when it comes to VTF.

 

However, when it comes to 'inertial' mass (Rotational Inertia ), as said, at the stylus tracing frequencies that are of interest to us (> than say 12Hz), the stylus 'sees' the tonearm as being essentially 'rigid' - as in an optimally-matched cartridge compliance - tonearm Effective Mass combo.

 

(Sorry, was not my intention to digress this nice  TT page & will refrain from adding further comment about this... as they say - YMMV  ;) )

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

 

Sorry, Owen - AFAIAC, you can't lob a grenade into this discussion and then back away.

 

My own understanding aligns with Grant's - iow, afaiac ... you have the wrong end of the stick.  In particular, Grant's comment ("The big advantage of the under slung counterweight over the axial variety is being able to set the centre of static mass on the plane of the record surface and stylus tip.  And the ideal way to take advantage of this is to also place the pitch bearing on the same plane. ") is much more important than minor differences in VTF over a warp (caused by an under slung c'wt) - if in fact your physics is correct.

 

Andy

 

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Recieved yesterday,  just tested tonight. With an Empire 1000ZE/X mounted it effortlessly tracked Tchaikovsky 1812 at 0.9g. :)

 

 

Has some cosmetic blemishes.  Will need a full recap and replacing the stock tonearm interconnects with better though that's about it. The pitting around the outside of the platter will be easily fixed with aluminum cleaner and I'll touch up the chips on the front corners.

 

20200519_205252.thumb.jpg.f3b204d37413dd681461412b18b419bf.jpg

 

20200519_205240.thumb.jpg.bc16c7e5c1b884c062f0f00390a6bd12.jpg

 

20200519_205224.thumb.jpg.3c149f1d7a976980a4e02410575778b8.jpg

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1 minute ago, MattyW said:

 

Received yesterday,  just tested tonight. With an Empire 1000ZE/X mounted it effortlessly tracked Tchaikovsky 1812 at 0.9g. :)

 

 

Impressive, Matt!  :thumb:

 

Andy

 

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9 hours ago, MattyW said:

Recieved yesterday,  just tested tonight. With an Empire 1000ZE/X mounted it effortlessly tracked Tchaikovsky 1812 at 0.9g. :)

 

 

Has some cosmetic blemishes.  Will need a full recap and replacing the stock tonearm interconnects with better though that's about it. The pitting around the outside of the platter will be easily fixed with aluminum cleaner and I'll touch up the chips on the front corners.

 

20200519_205252.thumb.jpg.f3b204d37413dd681461412b18b419bf.jpg

 

20200519_205240.thumb.jpg.bc16c7e5c1b884c062f0f00390a6bd12.jpg

 

20200519_205224.thumb.jpg.3c149f1d7a976980a4e02410575778b8.jpg

Nice pickup. Recently, I’ve been drooling over the micro seiki bl91 and kenwood DD’s on hifido... 

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16 minutes ago, crtexcnndrm99 said:

Nice pickup. Recently, I’ve been drooling over the micro seiki bl91 and kenwood DD’s on hifido... 

What I can't get over is how this has been the cheapest turntable purchase I've made. $630 couriered.  Arrived in 6 days from Japan once paid. Incredible table.

 

They actually had 5x of these listed when I bought mine. Did a search for a mate last night and they're all sold so the word got out fast that's for sure. 

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1 minute ago, MattyW said:

What I can't get over is how this has been the cheapest turntable purchase I've made. $630 couriered.  Arrived in 6 days from Japan once paid. Incredible table.

 

They actually had 5x of these listed when I bought mine. Did a search for a mate last night and they're all sold so the word got out fast that's for sure. 

$630 including postage?!? *Damn* son.. I figure places like Buyee must be incorrect when they quote $825USD for shipping a turntable.

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Posted (edited)
On 18/05/2020 at 6:30 PM, andyr said:

 

Owen, I'm interested to know why you think an underslung c'wt causes VTF to vary more than a c'wt that is centrally on the arm stub would, when the cart goes over a warp?

 

And shirley a c'wt which is positioned right up against the pivot will have less inertia than one positioned away from the pivot - so if it does alter VTF... it will do it less?

 

Andy

 

Hi Andy,

 

A low slung CW moves the COM lower. This makes the COM a pendulum lower than the pivot point so as the cartridge raises it has to pull the low COM pendulum.

 

This gives a good example

 

https://www.tnt-audio.com/sorgenti/in_balance_e.html

 

If you look at he uni pivot VTF raises 10% this is why uni pivots are sensitive to arm being horizontal to the LP. My Technics EPA100 (VTA on the fly) with Stanton 881s is not sensitive to adjusting arm height infact I tested over the whole VTA range and it is inaudible to me.

Edited by Warren Jones

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