Perfect setup for AT-LP120 USB Turntable

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FileFixer

Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 01 Dec 2016 18:16

First what i have to tell you that Audio Technica is WRONG about his setup. Just forget it AT.

Second thing is to look that two important movie clips on Youtube and look what is precise physical measurement for your TT.

First movie clip:
https://www.youtube.com/watch?v=nK6xKQwp8K0

Second movie clip:
https://www.youtube.com/watch?v=H2l_ki3VmhQ

Ok, first step is over. If you have more time, try to elaborate where is Audio Technica wrong with his measurements which is more important for perfect setup your turntable.

Second step is to make "Lofgren B" protractor for cartridge alignment. Not Baerwald or Stevenson which is not adequate for your setup. Stevenson protractor is good if you trust Audio Technica measurements, but i dont`t trust them.

All measurement for distorsion you may check on Vinylengine tools...
https://www.vinylengine.com/overhang_sh ... =calculate

Protractor was plot with Conrad Hoffman Template Generator which is found here...
viewtopic.php?f=19&t=16849

Input values for Template Generator:
Spindle to Pivot Distance: 214.150 mm
Inner Groove Distance: 57.500 mm
outer Groove distance: 146.050 mm
Print as Lofgren B protractor

This is my setup result for AT-LP120 USB:

------------------------------Original AT---My setup
Maximum distortion %:--------1.579--------0.853
Average rms distortion %:-----1.008--------0.377

You can view that max distorsion better about double then AT and average distorsion is better above three times then AT.

The basic stuff for perfect setup is OVERHANG and VTF (vertical tracking force). AT recommended 15mm overhang that is defined in his Stevenson protractor but it must be 17.374mm and Lofgren B protractor.
In my research, Lofgren B protractor has optimal and low distorsion measurement in contrast to Baerwald or Stevenson protractors.

The plot distorsion on Lofgren protractor with 17.374mm overhang:

https://i187.photobucket.com/albums/x15 ... 6avzqf.jpg

Actually, my setup for AT440MLb cartridge is there...

Vertical tracking Force: 1.7g (real 1.4g based on measurement in first video clip "1:11")
Antiskating Force: 3.0g (bias setting based on very known audio track and VU meters with 1dB scale)
Overhang value: 17.374mm

With this settings i don`t have any sibilance, cartridge track grooves perfect above all LP records and i really enjoy in my AT-LP120 USB turntable.
Only may i have planing is swap internal RIAA preamp with preamp based on OPA2134PA Burr Brown OP Amps and i will try to thing that is better combination with this price evaluation turntable.
Ofcourse, damping all internal plastics with rubber is very possible stuff. I found very cheap and effective solution for this. ;)

Maybe your results is not same as my results but don`t hang it, just try to find best possible way to find best possible values for your TT and cartridge. It is possible, trust me.

Enjoy in sound.

FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 01 Dec 2016 20:24

You can view and compare more detailed graph for AT setup and My Customized setup on this graphs...
Audio Technica original measurement setup:
https://i187.photobucket.com/albums/x15 ... cwajo8.jpg

My custom measurement setup:
https://i187.photobucket.com/albums/x15 ... k2ql7h.jpg

Poinzy
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Re: Perfect setup for AT-LP120 USB Turntable

Post by Poinzy » 01 Dec 2016 21:19

I prefer to use an old RCA engineering manual to design my alignment protractors, but to each his own, I guess. Glad the above worked out for you.

BMRR
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Posts: 5790
Joined: 23 Aug 2013 03:48

Re: Perfect setup for AT-LP120 USB Turntable

Post by BMRR » 01 Dec 2016 22:04

FileFixer wrote:Antiskating Force: 3.0g (bias setting based on very known audio track and VU meters with 1dB scale)
This part does not surprise me. Hanpin's antiskating mechanism is very weak :|

FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 01 Dec 2016 22:12

BMRR wrote:
FileFixer wrote:Antiskating Force: 3.0g (bias setting based on very known audio track and VU meters with 1dB scale)
This part does not surprise me. Hanpin's antiskating mechanism is very weak :|
Yes it is malfunction on 90% of this TT. I found that my null point has above at 1g on AS spindle. This counter now is set to 3g but i think that is more above 2g when null point is above 1g.

FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 03 Dec 2016 00:50

This is comparision table with four different alignment. First is with Audio Technica protratcor, Then Lofgren A and B and last is Stevenson.
My TT is now align with Lofgren B protractor and result is much better when is align with AT protractor based on Stevenson.
But, i`m thinkig about Lofgren A alignment which is look light better then B variant?!
Lofgren A is better then B in Maximum Error and Maximum Distorsion, but it is a little worse, ie. almost negligible, in Average RMS Distorsion.
What you think what alignment is better, Lofgren A or Lofgren B?

https://i187.photobucket.com/albums/x15 ... y25axs.jpg

FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 03 Dec 2016 02:10

Plot for comparision between Lofgren A and Lofgren B alignment.

https://i187.photobucket.com/albums/x15 ... vi4og5.jpg

FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 04 Dec 2016 13:55

Today i was setup my TT on Lofgren A protractor. Sound is better on inner and outer grooves. In the middle grooves the sound has no sonic difference.
Plot shown difference in sound into middle grooves above 0,2% between Lofgren A and Lofgren B in benefit to Lofgren B alignment.
Both of them alignment is good in middle grooves but i decide to improve sound quality on inner grooves and outer grooves and i mean that Lofgren A alignment is way better then lofgren B.
For now i definitely stay on alignment of my TT based on Lofgren A prtractor.

I uploaded Lofgren A and Lofgren B protractors on my Box account and if you want to download it, just take it.

Lofgren A
https://app.box.com/s/gz7gkc7leuzwe790vzii5767qqf2zcnd

Lofgren B
https://app.box.com/s/rwrjcb6p8ki32ci3x5uabpj1fsp8vifh

If you want to listen great sound from your AT-LP120 USB turntable, just stay out from Stevenson alignment protractor (Audio Technica protractor). Trust me, i tried them all of them. ;)

Van_Isle
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Re: Perfect setup for AT-LP120 USB Turntable

Post by Van_Isle » 06 Dec 2016 06:52

What am I missing here? How can you achieve different pivot to spindle distances on this turntable?

FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 06 Dec 2016 12:20

Audio Technica says that it`s Effective Length was 230,5mm. If we calculate parameters based on his measurement, that Pivot to Spinde is not real 214,15mmm then 215,5mm. Audio Technica not say us what is Pivot to Spindle distance, it`s only say that Effective Length was 230,5mm.
For Lofgren A and B i was input real Pivot to Spindle value and it`s calculate parameters based on this values.
I was input wrong parameters only on Stevenson protractor and when i was input Pivot to Spindle that have 214,15mm then, i mean, result for Stevenson is worse then before.
Last edited by FileFixer on 06 Dec 2016 12:55, edited 8 times in total.


FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 11 Dec 2016 20:12

This is final result for my setup, all together in one A4 page. I was print this and laminate that i have for the future use.
All parameters inside calculator are copy from Conrad Hoffman template Generator protractor that i use to align my TT.

You can download full size image from this link...
https://app.box.com/s/3vo6kpcl3hvy3976vs4ybvte7p51hgpz

https://i187.photobucket.com/albums/x15 ... rbeoq2.jpg

FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 17 Dec 2016 12:03

Today i made new protractor with more control point on protractor and it is include graph showing tracking error and distorsion values.
You can download it from here... Just print on actual size and cut it.
https://app.box.com/s/1dgi232soci1d7e3yu3z030ojgzkd6fy

https://i187.photobucket.com/albums/x15 ... vhjesk.jpg


FileFixer

Re: Perfect setup for AT-LP120 USB Turntable

Post by FileFixer » 20 Jan 2017 02:49

I'm going to try this with my 120. Thanks for the info!
Dont forget to leave your opinion. ;)
I was searching threads on the 120 and boy, does Caffe Latte hate these things. He makes some good points, but still. The tt designer must have stole his wife. ;)
Hahahaha... Try to ask him. :D

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