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Sideways Uni-Pivot Arm, SUPATRAC Blackbird, formerly "Ekos Killer (Price?)"

Thanks fellas, this is great feedback. I agree that the inertia adjuster looks complicated and to some extent spoils the simple lines of the arm tube. It's about the fourth iteration of inertia adjuster so far. There are a million ways to do it, and I like the suggestion of a rubber girdle - that's worth looking into. It would be trickier to install and adjust, but some might be prepared to tolerate that bearing in mind that it only needs to be adjusted as often as you install a different kind of cartridge. I'll keep thinking about it.

If you have a badly warped record without excessive bass content, removing the inertia adjuster and compensating the counterweight can help the arm to track better, so there might be occasions where the ease of use of the current version is appreciated, but from reactions I'm beginning to think that how it looks might trump ease of use.

There are other aesthetically surprising tonearms out there:
vertere_1024x1024.jpg


Thinking cap coming out of cupboard.
 
^ That's trying too hard for my taste.
Your's looks way better to me.
And I like the tree frog platform and would generally stick to your original way of doing things
for the most part.
If it makes sense to you, just leave it like that.

If John Bicht could have made internet surveys how people would like his arm to look like,
god knows what the original Mission 774 would look like today.

I also like your rope ladder CW a lot, but apart from that I think your initial design
is pretty much spot on perfect.
 
Yes, the Vertere has its own style, which I appreciate, but it's a bit of a mess, and the circuit-board depth of the arm cantilever doesn't inspire confidence if, like me, you think stiffness is critical to accuracy and energy conservation ('dynamics'). I'm sure if you stress it, it will bend visibly. I can't discern any flex at all in the Blackbird arm tube. However, some designers seem to think absolute rigidity isn't required, so the proof is in the pudding.
 
torstoi said:
I like the tree frog platform and would generally stick to your original way of doing things for the most part. If it makes sense to you, just leave it like that.

If John Bicht could have made internet surveys how people would like his arm to look like, god knows what the original Mission 774 would look like today.
Click to expand...
Yes, sonddek knows what he's doing and he's right to prioritise performance over aesthetics. My two suggestions would likely have some dampening effect, but the tree frog platform on its long hangers might be prone to vibrate at a microscopic level, so maybe some experimentation is in order.
 
laughingboy said:
Yes, sonddek knows what he's doing and he's right to prioritise performance over aesthetics. My two suggestions would likely have some dampening effect, but the tree frog platform on its long hangers might be prone to vibrate at a microscopic level, so maybe some experimentation is in order.
Click to expand...

Yes, the rigid coupling of the inertia adjuster was a design consideration. It is steel, so the claws are reasonably rigid, and the heat-shrink covers are compressed when it is pushed down onto the arm so that it grips quite firmly. Like every aspect of an arm's design it's a compromise, but I think the improved ease of use over the previous device is probably worth any small sacrifice in resonance behaviour. The previous type is also available so you can listen to them and decide which one sounds better. I wouldn't like to try to say which is in use in a blind test.

The arm will work perfectly well with the weight held a little higher, so I'm open to all suggestions. There may be a viable way to insert an inertia adjuster into the near side (signal wire) tube and move it along with a magnet without tangling with the signal wires, but I haven't worked that out yet.

As always, there is nothing to stop you blu-tacking a black plate to the top of the arm if you want a cleaner look and are not worried about warp-riding.
 
Is the hanger a fixed mass or a platform to add mass to tune? is there reason to vary height of the mass or just its position along the arm?

Some cantilevering affair may work better aesthetically (thinking triangles are a theme here) but be more prone to resonance depending how its damped.
 
Puggie said:
Is the hanger a fixed mass or a platform to add mass to tune? is there reason to vary height of the mass or just its position along the arm?
Click to expand...

It's a fixed mass, but I'm just about to ship inertia platforms with a hole in the middle so that additional weight can be bolted on. You can't vary the height of the mass except by bolting on additional mass above or below the platform. My assumption is lower is better, because the low pivot means that the arm is always a little top heavy.
 
SteveH said:
No I'm not a trade member. Where do I say I am?

I have a "bug up my ass" because PFM has three separate subfora for "Trade" discussion. I never visit these as I'm not interested in people peddling their wares to me. The OP is a trade member describing a product he manufactures and sells, with numerous posts extolling it's virtues etc. Ergo, AFAIAC it should be in a trade subform. That's where other trade members are obliged to post when visiting customers for installations etc. I view that as differential treatment.

I have zero horses in this race: I don't own a turntable and will never develop a tonearm in a million years. I wish the OP every success with his business. Truly.
Anyway, whatevs - if TonyL is content to keep trade content here, then that's his prerogative.
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I agree with some of the things you say.. But we are clearly in a minority and that's life. Can I suggest my easy solution? Just put the OP on your ignore list and you won't see the thread again. Works flawlessly..... As long as you are logged in.
 
sonddek said:
It's a fixed mass, but I'm just about to ship inertia platforms with a hole in the middle so that additional weight can be bolted on. You can't vary the height of the mass except by bolting on additional mass above or below the platform. My assumption is lower is better, because the low pivot means that the arm is always a little top heavy.
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Very interesting arm, which arm board fitings do you cover? I was thinking Rega type on my Transrotor.
 
So far Linn, SME, Jelco, VPI, but Rega will be out very soon as it's very similar to the VPI/Jelco version.

I'm also experimenting with silver/grey finish, which might be preferred on a Transrotor. I will post pictures of the Rega mount and alternative finish here.
 
The website got a bit stuck in the past so I've just updated it with a little more information for the curious.

http://www.supatrac.com

There's much more to do, but for the time being that'll have to do as it has taken a few days. I know there are some rough corners like file sizes and some of the pictures could do with a friendly brush, but I'll get there.

Please let me know what you think.
 
sonddek said:
The website got a bit stuck in the past so I've just updated it... Please let me know what you think.
Click to expand...
It's massively better. Well done.

Three minor things:
  • the curtain menu that appears when you click on the 'hamburger' icon could do with disappearing when a site visitor clicks outside it (not just disappearing by clicking on the 'hamburger' itself). I don't know how to do this with pure CSS though.
  • You probably want more contrast on the hamburger background, as it almost disappears against the predominantly white background as you scroll down. You could change your view's background colour and leave the hamburger as it is. Alternatively, you could change the hamburger color to black at all times, but you'd want to change the first 'hero image' to one where the SUPATRAC logo is black, too. Say, the one with the Coltrane LP on impulse label.
  • It would be nice to offer visitors a way of manually speeding up the cycle of your 'hero images' (pictures with review quotes). As it is, if visitors want to read all the reviews, they have to sit and wait. Making the images a 'carousel' would be a good idea. Sticking with pure CSS, something like this.
 
laughingboy said:
It's massively better. Well done.

Three minor things:
  • the curtain menu that appears when you click on the 'hamburger' icon could do with disappearing when a site visitor clicks outside it (not just disappearing by clicking on the 'hamburger' itself). I don't know how to do this with pure CSS though.
  • You probably want more contrast on the hamburger background, as it almost disappears against the predominantly white background as you scroll down. You could change your view's background colour and leave the hamburger as it is. Alternatively, you could change the hamburger color to black at all times, but you'd want to change the first 'hero image' to one where the SUPATRAC logo is black, too. Say, the one with the Coltrane LP on impulse label.
  • It would be nice to offer visitors a way of manually speeding up the cycle of your 'hero images' (pictures with review quotes). As it is, if visitors want to read all the reviews, they have to sit and wait. Making the images a 'carousel' would be a good idea. Sticking with pure CSS, something like this.
Click to expand...

Thanks - great feedback - cruder attempts at all of your suggestions are now live except I haven't time today to code the carousel so it's just point'n'click for next slide for the moment.

BTW, I set the slideshow speed using a square-root algorithm from the number of words in the quote you're reading, but it's impossible to account for different reading speeds.
 
sonddek said:
BTW, I set the slideshow speed using a square-root algorithm from the number of words in the quote you're reading, but it's impossible to account for different reading speeds.
Click to expand...

crikey that's clever. Works pretty well for my reading speed too (although I suspect I'm slower than many).

great looking page.
 
pickwickpapers said:
crikey that's clever. Works pretty well for my reading speed too (although I suspect I'm slower than many).

great looking page.
Click to expand...

Thanks. In fact, calculating the reading delay is quite trivial:
Code: 
3000 * Math.round( Math.pow( quoteText.split( /\s/ ).length, 0.4 ) )
 
Works pretty well for my reading speed too (although I suspect I'm slower than many).
Click to expand...

In fact, due to your comment I've just reassessed it and I think it's a bit more accurate now using a switching delay of 3 seconds plus a root of the product of word length and byte length. If you can be bothered, please let me know if it's now too fast...
Code: 
3000 + ( readtime * Math.round( Math.pow( quoteText.length * quoteText.split(/\s/).length, 0.44 ) ) )
 
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