A unipivot made from scrap

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IslandPink
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#301 Re: A unipivot made from scrap

Post by IslandPink »

You've done a load of work there, well done. Takes me ages to swap a cartridge !
It's a really encouraging that you can hear all the differences clearly, says good things about the arm.
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#302 Re: A unipivot made from scrap

Post by Ant »

Well the dr feickert jig makes setting up an(other) cart pretty quick.
It was expensive but worth it for the amount of use it gets when setting up stuff for other people aswell

The only arseache i have with the tools ive got is the digital stylus force gauge which is about 1/2" thick so it cant just sit on the platter.

Its pretty old, i must have had it 20 years but its accurate. I did also buy an el cheapo chinese one that was really thin, but it was rubbish and would give 3 different readings if you put the stylus on it 3 times.
I could do with replacing the old one with one more practical, but its another thing i just dont get around to.

The most useful thing is the perspex azimuth gauge i got, just a series of horizontal and vertical lines on a clear block, it allows me to quickly set azimuth using a part of the cart body or the cantilever as a datum to match to the lines. Can also be used to set the vta quickly if put behind the arm tube or the headshell then adjusting the arm height so the tube or headshell lines up with the horizontal lines.
It was only a couple of quid, but has proved to be really useful.

I roughly set up petes 2m blue while mi dad was here earlier, and it took about 5 minutes with the perspex block and a normal stevenson protractor. It only took about 10 minutes to tweak it in when i listened to it abit later.

Need to figure out how to bodge an arm lifter onto it, i can get a rega one or a project one
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Greg
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#303 Re: A unipivot made from scrap

Post by Greg »

Ant wrote: Sat Aug 21, 2021 9:57 pm Well the dr feickert jig makes setting up an(other) cart pretty quick.
It was expensive but worth it for the amount of use it gets when setting up stuff for other people aswell

The most useful thing is the perspex azimuth gauge i got, just a series of horizontal and vertical lines on a clear block, it allows to quickly set azimuth using a part of the cart body or the cantilever as a datum to match to the lines. Can also be used to set the vta quickly if put behind the arm tube or the headshell then adjusting the arm height so the tube or headshell lines up with the horizontal lines.
It was only a couple of quid, but has proved to be really useful.
I agree. The Dr Feickert protractor is a brilliant tool and simple to use. I jointly own one with a couple of friends and we have all found it invaluable for cartridge and arm set up.

I’ve not heard of the azimuth gauge you use before now and see they are readily available on eBay. It looks really useful, so I’ve ordered one. Thanks for the heads up.

You seem to be making great progress with your arm. A giant killer on the horizon?
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Nick
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#304 Re: A unipivot made from scrap

Post by Nick »

It was only a couple of quid, but has proved to be really useful.
Though does assume the stylus is perfectly aligned on the cantilever.
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#305 Re: A unipivot made from scrap

Post by Ant »

Yes it does, a microscope is the only real way to tell if it is aligned in the cantilever properly in the first place
I have a basic microscope that ive used to look at stylii before but it only goes up to 200x so wasnt all that useful other than being able to see signs of wear after a clean

Re a giant killer, who knows, i dont have another current production arm to compare it to.

Id also need a pair of the same cartridges and a pair of the same turntables to make any meaningful comparison
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Nick
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#306 Re: A unipivot made from scrap

Post by Nick »

Yes it does, a microscope is the only real way to tell if it is aligned in the cantilever properly in the first place
And even then what matters is how the stylus is aligned in relationship to the coils or magnets (MC or MM). Measuring with a text disk is IMHO the only way to be certain.
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#307 Re: A unipivot made from scrap

Post by Ant »

Plus it depends if an arm has adjustment for azimuth in the first place, otherwise you're stuck with whatever it ends up as depending how the arm is mounted and how well aligned the bearings are

Its a blummin minefield
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Nick
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#308 Re: A unipivot made from scrap

Post by Nick »

Plus it depends if an arm has adjustment for azimuth in the first place
You can always add packing to the headshell/cartridge
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izzy wizzy
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#309 Re: A unipivot made from scrap

Post by izzy wizzy »

Ant wrote: Sun Aug 22, 2021 2:57 pm Its a blummin minefield
Too right!

I think the ability to get the thing in roughly the right place quickly is a huge step. And then as we all know, there is much to be gained by the last few tweaks to make up for, in many cases, the errors made by a human putting the thing together in the first place. An arc protractor gets me there as fast and accurately as I ever have with whatever alignment I fancy. The Dr Feickert protractor is meant to be fantastic.
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#310 Re: A unipivot made from scrap

Post by Ali Tait »

It is, and does make it easy and I’m very happy with it. The Smart Tractor is on another level though, but not cheap!
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#311 Re: A unipivot made from scrap

Post by Ant »

I think the smartractor is about 400 quid last time i checked? Something like that, the 160 i paid for the feickert was abit hard to justify if it was just for my own use, but given the intended use i decided to spring for it. 400 odd was just too much at the time

Before I got the dr feickert jig i had the clearaudio one and i thought it was crap. It had 4 different sets of null points and none of them were quite right for me. Sold that one quickly and got back what i paid for it so that was ok. I havent tried the project one, i think that one was abit cheaper than the feickert one

I usually go with stevenson because i prefer it, with its 60.325 inner null, but being able to easily go with lofgren or baerwald with the feickert is very useful. Ive set up carts for people to all 3 before when ive been asked to set them up to specific alignments
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vinylspinner
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#312 Re: A unipivot made from scrap

Post by vinylspinner »

I co own a Smartractor with Greg, it is a great bit of kit to have, a bit fiddly at first but very good once you get the hang of it.
I probably wouldn’t buy one just for personal use, it’s one of those tools that only gets used occasionally, at £400 it isn’t cheap, the Dr. Feickert is quick and simple to use, regret selling mine last year.
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Greg
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#313 Re: A unipivot made from scrap

Post by Greg »

Yes, I meant SMARTractor.
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#314 Re: A unipivot made from scrap

Post by izzy wizzy »

I've had a Dennesen Sountractor for about 35 years but reckon I get better results with a custom arc protractor printed on heavy paper. Don't know why.
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#315 Re: A unipivot made from scrap

Post by Ant »

Decided to do some bias measurements based on the james kogen paper with this arm.

The bias weight itself weighs 2g, so i had a look to see what i was getting with its distance from the bearing centre as close into the housing as possible.

Lashed the scales to a piece of aluminium bracket so i could measure it, and got 0.14g which corresponds to about half a gram of bias. Pulling it as far out as possible got me up to 0.21 which is about 0.7g of bias.
Less than half of what i thought i was getting.

Obviously not a useable range, so i shoved a nut and bolt through the bias nut-on-a-string to make up a 4.5g bias weight.

Right into the housing i now got readings corresponding to just over 1g, then about 4mm further out readings corresponding to about 1.7g so ive set it to that for now for a 2g tracking weight as i find i prefer it set a little less than equal to the tracking weight

Going out to the end of the bias arm again gives reading corresponding to about 3g, so a 4 to 4.5g physical weight for the bias weight will give a practical range

The graphs on kogens paper are a bit difficult to see on a pdf on a phone, hence the 'about'
Next i need to do some measuring of how far apart the divisions need to be for a 0.25g advance per division so there is a visual aid on the bias arm to set the bias

Onwards!
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