Fun with vinyl measurements

[Thomas_A]

What do you mean by that?

The record slides quite easy on felt and since almost all records can be adjusted for centering by nudging the rim by the finger (the center hole is often a bit bigger than the spindle), it can be done with reasonable accuracy just by watching the grooves or the tonearn. Takes a sharp eye and a few seconds to do.

 

[Balle Clorin]

..I find it very difficult to do...takes me minutes .. so I do not bother

But I clamp all records, nudging while spinning is not possible

 

[Thomas_A]

..I find it very difficult to do...takes me minutes .. so I do not bother

But I clamp all records, nudging while spinning is not possible

Yea its much easier to spin and watch it when you nudge. A bit of practice and it works quite well.

 

[Thomas_A]

No measurements here but a bit Swedish history from a 1965 years vinyl...

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

 

[morillon]

No measurements here but a bit Swedish history from a 1965 years vinyl...

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

mp3!!!




;-)

 

[Thomas_A]

mp3!!!




;-)

Yes... but 320....no space on dropbox also...

 

[mackat]

This is the test tone before the frequency sweep on the CA-TRS-1007. What does it mean when one channel looks "smooth" and the other not so much?

I have seen variations of this while testing different cartridges.

 

[morillon]

This is the test tone before the frequency sweep on the CA-TRS-1007. What does it mean when one channel looks "smooth" and the other not so much?

I have seen variations of this while testing different cartridges.
View attachment 394170

fft? l vs r....
(protract? as? efforts.... )


(
hello... did you have the opportunity to observe the w&f of your turntable and its speed control finally...? ;-)
)

 

[mackat]

fft? l vs r....
(protract? as? efforts.... )

I’m not quite sure I understand what you mean by this?

(
hello... did you have the opportunity to observe the w&f of your turntable and its speed control finally...? ;-)
)

Which turntable are you referencing?

 

[morillon]

I’m not quite sure I understand what you mean by this?

Which turntable are you referencing?

the observation in fft would be interesting.. perhaps linked to a relative defect of protraction, or linked to the adjustment of the antiskating vs the level of this signal... so have you explored these subjects a little when you observe this? just some ways that can be explored... ;-)


my apologies... I confused you with madrac....

 

[Balle Clorin]

The uneven

This is the test tone before the frequency sweep on the CA-TRS-1007. What does it mean when one channel looks "smooth" and the other not so much?

I have seen variations of this while testing different cartridges.
View attachment 394170

The is normal when the record is not totally flat, I see the tone channel may be affected mor then the other. This is low requency resonance, try a sub filter ant it may look clean

 

[Thomas_A]

This is the test tone before the frequency sweep on the CA-TRS-1007. What does it mean when one channel looks "smooth" and the other not so much?

I have seen variations of this while testing different cartridges.
View attachment 394170

Can you zoom in and also, make spectrum of L and R separately? It works if you split the stereo channels.

 

[USER]

Can anyone help me understand how something like this affects a turntable? @JP?

When I got this deck I thought I would go through the motor adjustments as they seemed relatively straight forward. It had started out like the following and improved with motor lubrication, head adjustment, etc. However I got stuck on the final adjustments and ended up screwing things up. Essentially I could not get the amplitude anywhere near 15V.

I tried to find someone to service it but he had trouble as well and says that the adjustments don't work out like how the manual states so it makes sense that I ran into problems. He thought everything was OK as his shaknspin results are good, but my own measurements are the ones posted up top.

Certainly this goes to show how limited W&F measurements are for repair and maintenance, but I am curious about what is going wrong. Do the issues only manifest in the the wow and peak results?

 

[Balle Clorin]

I suggest to look at the Excel data from Shaknspin, much more useful than er WF values.
I adjusted my 21F by using the oscillosope as the manual advises. For my Sony 212 I scrwewd it up to I tried toget the two voltages same at target, but the y interacted someway, I finally got it right by doing gradual adjustements, very small. First one potemeter then the other, one at the time. if I tried a full adjustment on just one i it failed

 

[morillon]

It is often good to change the potentiometers when it becomes too difficult to find a setting.. (and don't forget to change the chemical capacitors and often the tantalums) ;-)

 

[JP]

Can anyone help me understand how something like this affects a turntable? @JP?

View attachment 394841

When I got this deck I thought I would go through the motor adjustments as they seemed relatively straight forward. It had started out like the following and improved with motor lubrication, head adjustment, etc. However I got stuck on the final adjustments and ended up screwing things up. Essentially I could not get the amplitude anywhere near 15V.

View attachment 394846
View attachment 394844View attachment 394845
I tried to find someone to service it but he had trouble as well and says that the adjustments don't work out like how the manual states so it makes sense that I ran into problems. He thought everything was OK as his shaknspin results are good, but my own measurements are the ones posted up top.

View attachment 394847

Certainly this goes to show how limited W&F measurements are for repair and maintenance, but I am curious about what is going wrong. Do the issues only manifest in the the wow and peak results?

1:10 probe? What are you getting?

 

[USER]

1:10 probe? What are you getting?

Yes. I was getting around 3V if I remember correctly. It was a while ago, so a bit hazy. But the difference was significant. I turned the unit on and let it run while the tech was manually spinning it I believe.

It is often good to change the potentiometers when it becomes too difficult to find a setting.. (and don't forget to change the chemical capacitors and often the tantalums) ;-)

Unfortunately this was due to adjusting potentiometers. Do you mean to replace the potentiometer?

I suggest to look at the Excel data from Shaknspin, much more useful than er WF values.
I adjusted my 21F by using the oscillosope as the manual advises. For my Sony 212 I scrwewd it up to I tried toget the two voltages same at target, but the y interacted someway, I finally got it right by doing gradual adjustements, very small. First one potemeter then the other, one at the time. if I tried a full adjustment on just one i it failed

It was the tech's shaknspin so I don't have any access. I think I am going to do as you did and just tweak until I see a positive change.

 

[morillon]

Unfortunately this was due to adjusting potentiometers. Do you mean to replace the potentiometer?

I don't understand...


if using a drop of product "for electrical contact" * in the old carbon type PCB potentiometer etc. is not enough... it is often preferable to replace them new, it doesn't cost much...
classic problem with many old potentiometres in many situations...
I'm not saying that it's the problem here, just that it's a classic precaution or something to do if you have adjustment problems. too delicate to opt for, or not possible...

** ! need specials precautions in tuner , hf, etc

 

[Balle Clorin]

Yes. I was getting around 3V if I remember correctly. It was a while ago, so a bit hazy. But the difference was significant. I turned the unit on and let it run while the tech was manually spinning it I believe.


Unfortunately this was due to adjusting potentiometers. Do you mean to replace the potentiometer?


It was the tech's shaknspin so I don't have any access. I think I am going to do as you did and just tweak until I see a positive change.

I see now that my writing was not clearly. I had 2 pots to adjust. To make 2 voltages/sinus on the scope to X volt. Both interacts on the result, so I adjusted a tiny amount on one and then the other, alternating. If I tried to correct one sinus curve/voltage fully , and then the other, I never got both values right. This was a Hall motor on the Sony PS212

I find this useful for quick unweighted WF check while adjusting.

The NAK T-100 software is also useful for online measurements during adjustment, if test record can be used.

 

[JP]

Yes. I was getting around 3V if I remember correctly. It was a while ago, so a bit hazy. But the difference was significant. I turned the unit on and let it run while the tech was manually spinning it I believe.

Platter removed though per SM, which would run the motor open loop.