Jelco VTA adjuster

snap, crackle and pop
scho2684
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Re: Jelco VTA adjuster

Post by scho2684 » 14 Jul 2018 15:07

Wow...this is actually capable of VTA on the fly
This one runs so smooth, it feels like a bearing on itself.
Unfortunately I dont have much time over this weekend, but I will report back, as this is something special!
Easy VTA Improved.jpg
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scho2684
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Re: Jelco VTA adjuster

Post by scho2684 » 15 Jul 2018 16:27

What for me wasn't a issue, but for the maker it was, was the fact that there was a "wobble" during adjustment with the MK1 unit I got first and where this topic started with.
For me no point because I am only looking for repeatable elevation settings when I change cartridge.
VTA on the fly was not my goal when I purchased this thing.

Anyway, the maker insisted that I send it back and so it happened...

He also mentioned that the MKII was almost production ready, cost a little more but I would get more rigidity in return.
The 90 GBP didn't hurt anymore, the MKII costs 30 more, and so ... (...)

Yesterday it came, and I must say that I am pleasantly surprised!
The thing feels so good that with this small (mechanical!) Review, VTA on the fly is now the approach.

The difference with the first version is that the lift part (that is fixed to the arm pillar) is now accompanied by 2 pins in 2 sliding bearings.
This ensures that the "tilting moment" is minimized.
In the first version, the pen of the micro meter was the only point of contact with the rest of the structure.

So lets take a closer and very critical look (the Jelco arm for which this device will be used most is of a quality that only quality things should be attached to it, both ends that is):
There is a base that is fixed on your turntable.
In this base there are a total of 4 bearings, 2 that hold the pen of the micrometer, which drops onto a pointy headless bolt that has been screwed in from below.
Then further to the hole where the arm pillar comes in, there are 2 sliding bearings where the 2 pins come in which are attached to the lifting mechanism.

1. It can be taken apart without force (I dont know whether that was meant to be :roll: ):
Deasembled 01.jpg
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2. 2 Bearings on top of each other hold the micro meter pen, pointy screw underneath:
Deasembled 02.jpg
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3. The 2 sliding bearings to catch any tilting of the arm:
Deasembled 03.jpg
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The lifting mechanism consists of a collar that is fastened to the arm pillar by means of a small lock-in hex bolt
The micrometer is fixed at the end of this collar, and now also equipped with 2 stainless steel pins to accommodate the tilting moment.

4. The 2 stainless steel pens that drop into the 2 sliding bearings:
Deasembled 04.jpg
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The fit is of "laboratory" quality and there is really nothing that rattles or feels loose.
The fitting of the arm pillar is also very precise, turning the locking screw loose there is hardly any movement to be observed when you try to move the arm base.

Some observations:
The drop point, the pointed Allen screw that has been screwed in from below, is not fixed.
If you have turned 20 times up and down, it may well be that the Allen screw has also been moved a few moments.
Maybe I fix that with Lock-Tight or so.

The arm pillar of my 750D runs above a bit tapered outwards, which means that I do not get the collar completely at the top.
No problem with me, I have enough space to miss that few mm.
Maybe I put a bit of blue-Tac in between, or I'll leave it that way, we'll see.

No pictures of a completely assembled table, I still miss my bearing, but the outline is almost exactly the same as the MK1 version, and I have already photographed extensively at the start of this topic.

The video is made with 2 cameras and consists of 2 parts:
1. 2x hand slap to synchronize the two videos, then unlock, arm up, lock, unlock, arm down, lock.
2. unlock, slightly push and pull on the arm base to see if there is movement when the lock screw is loose.
You actually see the image of the head moving a little, but that is almost entirely due to the fact that the camera that shoots the head is not on the turntable itself. See the photo of the setup for the movie ...

Judge for yourself, but I think this is a very pretty accurate device.

5. The movie setup:
Movie setup.jpg
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6. The movie to prove how rigid this thing is (any movement at the base will be largen quiet a bit at the headshell):

Pryso
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Re: Jelco VTA adjuster

Post by Pryso » 21 Jul 2018 19:38

Thanks for all this information scho. I'm considering the purchase of a SA-750E and my research found an accessory collar to stabilize the mounting post. Apparently there can be some play in the stock arm mounting. Anyway, it appears your adjuster may provide two benefits -- measured VTA settings AND stabilized mounting.

If so, it looks like a "must have" with those Jelco arms.

scho2684
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Re: Jelco VTA adjuster

Post by scho2684 » 21 Jul 2018 20:35

Indeed, the stock collar is not that stable...
A very good alternative is the Ammonite collar which is higher and has a more aggressive "recess" (I don't know the correct term) in the hole where the pillar goes.

I think the Ammonite is the most stable collar that money can buy.
But like on anything, I do have a criticism, I think the pitch of the thread of the fixing nut is a bit to large.
It would be better to have a smaller pitch...

This VTA adjuster is obviously a compromise (like anything else) however if you only have one arm on which you switch cartridge every now and then, then this is the VTA adjuster to go in my opinion...
The fact that the arm is still stable even with the fixing nut loose, makes VTA on the fly possible.
The compromise is not in stability (is at least as stable as the Ammonite) but in the fact that you create more resonance candidates...

Pryso
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Re: Jelco VTA adjuster

Post by Pryso » 21 Jul 2018 21:55

Good further info.

I'm looking for a second arm but want interchangeable headshells on both to facilitate numerous cartridges (MC, MM, mono, even 78). So repeatable VTA will be a big advantage, once that height is established for each cartridge. The Jelco looks like the one so far.

scho2684
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Re: Jelco VTA adjuster

Post by scho2684 » 22 Jul 2018 09:11

Yep...
Than the combination Jelco / Easy VTA is certainly worth looking for...
The Easy VTA is actually suitable for any arm with a 18mm pillar, given that there's enough space (a bias weight on that side of the arm might be in the way)

ajsds66
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Re: Jelco VTA adjuster

Post by ajsds66 » 07 Feb 2019 12:56

Very nice review from The Ear Magazine.

http://www.the-ear.net/features/vta-made-easy

cats squirrel
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Re: Jelco VTA adjuster

Post by cats squirrel » 07 Feb 2019 14:31

I have also bought one recently, to use with my LAD Jelco variant. Can confirm the excellent build. Mine is black, and contrast well with a 'silver' arm and carbon fibre head shell.

scho2684
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Re: Jelco VTA adjuster

Post by scho2684 » 07 Feb 2019 15:23

Nice review from Ear!

ChrisfromRI
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Re: Jelco VTA adjuster

Post by ChrisfromRI » 07 Feb 2019 19:18

I recently bought the Jelco TS-550 which is the current oil damped model of the 750, and they improved the mounting collar in the new version. In fact it is now quite like those aftermarket "upgrade" mounting collars.

Over the years some private labeled variants had this fixed a long time ago, such as the Graham Robin that was manufactured by Jelco to a very high standard for Graham. The Robin's mounting collar is very nice.

WRT on the fly SRA/VTA adjustment, I do have that feature on my Graham 1.5, and I rarely use it. I just set SRA/VTA for a mid-thickness record...

scho2684
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Re: Jelco VTA adjuster

Post by scho2684 » 08 Feb 2019 10:13

ChrisfromRI wrote:
07 Feb 2019 19:18
I recently bought the Jelco TS-550 which is the current oil damped model of the 750, and they improved the mounting collar in the new version. In fact it is now quite like those aftermarket "upgrade" mounting collars.
Different subject but the 550 is quit a different arm if one only look to the specs:
Effective mass TS-550 9.2 gr vs. the 13.48 gr from the SA-750D...
ChrisfromRI wrote:
07 Feb 2019 19:18
WRT on the fly SRA/VTA adjustment, I do have that feature on my Graham 1.5, and I rarely use it. I just set SRA/VTA for a mid-thickness record...
Without questioning the quality of this VTA adjuster (it is really good and well thought of) currently I have placed back the Ammonite collar for that very reason of that last additional note in that review.
At this time I dont switch so much from cartridge, so its a bit of a overkill now for me, but I will place it back if I for whatever reason will be switching cartridges a lot...

But from all aftermarket adjusters available, this is definitely the one to go for...

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Re: Jelco VTA adjuster

Post by ChrisfromRI » 08 Feb 2019 20:57

I believe the big difference in the effective mass between the 550 and the 750 is the headshell they come with. Of course Jelco makes several different headshells of varying mass from 9 to 17 grams for these tonearms. So you can vary effective mass by which one you use. My 550 is a 9 inch model using the 12 gram headshell (versus the stock supplied 9 gram headshell), and an aftermarket IsoKinetic counterweight.

42826

I happen to own another of the 750 arms on my re-plinthed Lenco L75, in the 12 inch length and also with the oil damping, and it seems extremely similar from a construction standpoint as the 550. They adopted a single new two-tone color standard (Chrome with Black) instead of multiple solid colors used in the past. Also, the new counterweight is two piece with a sliding section allowing it to cover the same full range of cartridge weights as the two independent counterweights they supplied in the past (a light one and a heavy one). The new models all seem to come with an improved mounting base which looks to me very much like what Ammonite did to improve stability over the old mounting base.

https://www.jelco-ichikawa.co.jp/cn3/tonearms.html

I also have a 12 inch 350 on my SME wide base Thorens TD125 turntable where I passed on the need for oil damping, and frankly the extra mass of a longer 12 inch arm seems to have mitigated my need for the oil damping.

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Re: Jelco VTA adjuster

Post by ChrisfromRI » 09 Feb 2019 04:19

For anyone in need of more repeatable SRA/VTA adjustments these micrometer mounts are certainly an option, however, I found that simply taking a stack of business cards and using those was also a repeatable way to perform this adjustment. First, slip as many business cards into the space between the tonearm base and the tonearm's cueing mount as will fit. Then loosen the grub screw that secures the arm height adjustment. If you want to try a slight raise in height just add a business card and retighten, and if you want to a slight decrease pull out a business card and re-tighten. Adding or removing more business cards allows for larger variations of heights. Remove the card stack before listening tests. If you ever want to get back to where you started simply return to the original number of business cards you started with. I always found this method very accurate to get to the correct SRA/VTA for a mid-thickness record, and then left the adjustment alone.

scho2684
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Re: Jelco VTA adjuster

Post by scho2684 » 09 Feb 2019 08:51

But that is not a on the fly solution, with this thing you have...
You can adjust height while listening, or even when you are measuring with a test record.
Point is that once you have loosen the fixing screw the whole construction remains very stable (see video in first post on this page) and there is not a single other device (or method) that I know of that does that.

From that perspective its a very accurate and wonderful constructed device.

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Re: Jelco VTA adjuster

Post by Hugo » 09 Feb 2019 09:53

ChrisfromRI wrote:
08 Feb 2019 20:57
............. I happen to own another of the 750 arms on my re-plinthed Lenco L75, in the 12 inch length and also with the oil damping, and it seems extremely similar from a construction standpoint as the 550. They adopted a single new two-tone color standard (Chrome with Black) instead of multiple solid colors used in the past. Also, the new counterweight is two piece with a sliding section allowing it to cover the same full range of cartridge weights as the two independent counterweights they supplied in the past (a light one and a heavy one). The new models all seem to come with an improved mounting base which looks to me very much like what Ammonite did to improve stability over the old mounting base.

https://www.jelco-ichikawa.co.jp/cn3/tonearms.html
The collars that Jelco supply with the new TS and TK series arms are actually identical to the old collars, except for colour (the new ones are silver). I’ve just taken a few photos to show the two collars – the silver one is from a TS-550S and the darker one from an old SA-750D (my poor photography makes it look black, but it is grey).

https://drive.google.com/open?id=0B7Cb9 ... RwbGYwRTFJ
https://drive.google.com/open?id=0B7Cb9 ... 5VcXZfWmxB
https://drive.google.com/open?id=0B7Cb9 ... dLSmZwR25Z

I do agree with your point about using stacks of business cards to quickly set arm height to suit different cartridges, headshells etc. Getting VTA/SRA right does matter very much and of course there is always scope for fine-tuning between LPs by anyone inclined to do that, but on the whole I find that once the ideal arm height has been established once, and usually by ear, further tweaking does rather tend to get in the way of the music.