Jewel Bearing Carbon Fibre Uni-Pivot

[Cressy Snr]

I’ve decided to make a new thread about Ant’s uni-pivot arm, because having it in the previous thread with its unfortunate ‘scrap’ title is IMO inappropriate, given the quality of what he has developed. I’ve been using this arm for the past week or so at my place and it is frankly superb.

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The arm currently carries a Dynavector DV20X2 high output moving coil cartridge and is the arm previous to his latest version.
The pivot housing carries a sapphire single-point bearing and on this version there is no lift/lower device. However this is not a problem as the finger lift sits well above the record surface and I have added my own little touch, in the form of an orange plastic bead, so that I can see where the lift is in low light conditions. You can literally just grab hold of the finger lift and not send the arm careering across the record. It is definitely the best hand cueing experience I’ve had with an arm and uni-pivots are usually a complete PITA to hand cue. The bead is functional as well as adding a bit of 1950s atomic age retro chic to the look of the arm.

Soundwise the whole thing is neutral, controlled and throws a nice image with plenty of width and depth. It does not get flustered when the going gets busy and it tracks like a train. Frequency range is wide and stable, and surface noise is well suppressed.The overall presentation is clean, detailed, musical and dynamic. It’s a cracker of a pickup arm and deserves wider exposure.

[Paul Barker]

I woont that one!

lifting the mayware is like driving a Triumph Herald that needs new shocks!

[simon]

Is that the same arm I tested? It was very good, I'm tempted.

[Cressy Snr]

Is that the same arm I tested? It was very good, I'm tempted.

Dunno, you’d have to ask Ant.

Edit: rambling removed for clarity of Ant’s answer to Simon’s question.

[Ant]

No it wasnt that one, the one you tested was quite a bit earlier

[simon]

Oh right, time flies when you're busy at work!

[Cressy Snr]

Picked up my own Lenco from our Ant this afternoon, with the CX unipivot fitted, plus a new armboard:

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My Audio Technica ATVM95EN has been fitted. It sounds excellent on the CX arm.

[Thermionic Idler]

Watching with interest. I want to build a second system for the office with a Quad 34 preamp. I already have a GL75 ready to go in a new plinth and I'll need an arm and cartridge to go on it. The idea is to use the same deck to run demos at Owston, because transporting the Garrard literally requires a team of professional movers experienced with pianos.

The low-output version of that Dynavector looks like a good match with the Millett phono stage too.

[Cressy Snr]

Well, it’s a superb arm. I only have the second prototype. Ant has the later one, which has a lift/lower device.

I had a small issue with the longer length of the CX unipivot compared to the SME 3009 arm. I terrified myself when hand cueing it, due to the proximity of the speed change lever to the cartridge when swinging the arm over a record from the rest.
The missus had a 1960s red necklace, made up of different sized plastic beads and kindly allowed me to destroy it. A bit of careful drilling later and I ended up with a small bead at the end of the fingerlift and a larger one to replace the speed change lever handle:

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Very atomic and very retro. I love it.
The ‘$tateside’ badge is not fixed, I’m just weighing up the aesthetics of that particular item.

[Cressy Snr]

Been pimping up the Lenco this week:

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Put some nicer feet on it and sprayed the platter black as the cream paint was looking the worse for wear due to me not priming the metal properly in the first place. It now looks a lot better.

I shortened the wires coming out of the armtube and made up some red sleeves for the tags:

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Polished up the lateral balance weights with a bit of brasso:

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[Cressy Snr]

Nice:

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[simon]

That's pretty groovy Steve

[Cressy Snr]

Been wanting to try this for ages and have finally got around to it:

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Straight underhung arm with no offset as per the VIV Rigid Float and the arm on the Yamaha GT5000 high end turntable.
I moved the arm away from the chassis so as to be able to create an underhang of around 14mm from the centre of the turntable spindle.
I can compare the conventional arrangement to the straight arm simply by changing which hole the arm is mounted in.
Reading about this stuff on the internet proved a waste of what's left of my life as the debate is completely polarised, with so much noise around the issue that trying to find any reliable information is futile.

I've listened to half a dozen LP sides so far and can't find anything to complain about in terms of mis-tracking or end-of-side distortion. Dynamics and bass are pretty cracking too. Pitch and rhythm are also spot on.

[Cressy Snr]

Well I've had the cans on nearly all day and can't fault the sound. The under-hang needed tweaking a few times, in order to eliminate the skating force. If the under-hang distance is too far from the centre spindle, the arm skates both outward from the run-out grooves and inwards from the edge; not what you want and a worse situation than the normal inward force pulling across the disc presented by a conventional over-hang and offset tonearm.

There is a sweet spot in the under-hang range, where the arm stays still wherever it is placed on the spinning platter. This coincides with the best tracking performance and the best sound quality, and will be different depending on the arm being used. I finished up with an under-hang of -10mm for this particular arm.

We'll see how it goes for a few days and whether I decide I want to return to the conventional arrangement. At the moment, I can't see that happening but, as always, time will tell.

[Cressy Snr]

Link to review of VIV Rigid Float tonearm.
It’s the review that got me wanting to have a go at it.

https://www.stereophile.com/content/spi ... ha-tonearm