PT Anni Inspired Project

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Capt Zach
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PT Anni Inspired Project

Post by Capt Zach » 16 Aug 2016 19:03

This thread will catalog my adventures putting together an Anni/Vector inspired PT. It will be slow moving since I don't have a regular space at the moment to setup and work on the TT. Plus, I'm sure there will be many technical hurdles to overcome.

Many thanks to those who have shared information, especially Tim Bissell, who was very generous with measurements.

The TT started as a non-working PT too, which I fitted a dc motor to. Pleased with the results, I'm slowly putting together the Anni Vector kit in stages.

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The hardest part of the project was fabricating an Anniversary-style, rear spring mount. I tried to get as close as I could. I wasn't able to communicate with Funk Firm in time to order the spring block, so I made one as well.

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Here is the inside in progress. I used the same motor as Funk Firm, and fabricated a mount from achromat material, and turned a pulley for it. I drew up CAD plans and had a company cut the end grain balsa and carbon separately and glued them together.

I did have a problem, with the new subchassis, the early bearing is barely tall enough to clear everything and work. I used half inch balsa on the new subchassis, so its thicker than the original aerolam. Does anyone know the thickness of the real Vector chassis?

PinkTrichard
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Re: PT Anni Inspired Project

Post by PinkTrichard » 17 Aug 2016 09:57

Looks interesting. I presume "the same motor" is the one used on the Saffire / K drive. Funk use several motors on different decks. Or do you mean the original Anni motor? What electronics are you using to run it?
Not quite sure what you mean by the "real Vector chassis". I lose the plot with Arthur and his model names, but I think "Vector" is both a solid turntable (without a "chassis" as such) or the name he gives to the patented 3 pulley idea. The laminated chassis similar to the one you have made (he has a couple hanging on the wall) is a different shape and I had never heard referred to as Vector. AK is busy with China atm, and hasnt replied to my question yet, but I am over on 21 September and will try to measure the trapezoid CF/balsa laminate sub-chassis in the factory then if I haven't heard before. I think it was pretty much the thickness of the aerolam original. If you are having a problem with bearing height then you could reasonably countersink a circle of CF under the bearing to make the endgrain thinner there - assuming you don't want to redo the chassis you have from scratch.

It would be interesting to compare our results - but I fear we won't have the opportunity now I am in France. I took the opposite approach to "reinventing Anni". The trilaminate may have been genius born of fortune, but the idea derived from a need to couple the bearing to the sub-chassis more securely. If you tighten too much on a PT chassis it crushes the aerolam. So the addition of an endgrain balsa element allowed a closer bearing coupling - but retained the "singing" characteristics of the aerolam - still with crinkly edge. The new bearing (which I have used on my project) enables a much better coupling than the original without crushing the aerolam (as well as being more stable) and so, for the moment, I haven't added the end-grain element - which "tuned" the sound as well as sorting out the bearing coupling.

Capt Zach
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Re: PT Anni Inspired Project

Post by Capt Zach » 17 Aug 2016 16:27

Thank you for the reply, that's very interesting. The motor is the Premotec 12V motor that I know was at least used on the later Anniversary's without a servo. I wasn't aware that Funk Firm used different types. At the moment, I'm running the motor from a simple dc controller group buy from pink fish media. A very simple, current feedback design. I'm working on tweaking it and will put it in a proper, Funk Firm style case.

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Its definitely less sophisticated than what they offer, circuit design is not my strong point.

I'm not sure what Funk Firm officially calls the CF upgrade subchassis for the PT's or if thy even still offer it, the Vector just refers to the addition of Vector drive as an additional upgrade. AFAIK, no one has directly compared the original Anni chassis alone to the newer CF, it would be interesting to note the differences if any.

I may opt to redo the chassis at some point if I can locate thinner balsa material. I had originally designed the motor cutout to accommodate a smaller Maxon unit. The amount of motor breakthrough with the Maxon was unacceptable, so I made a new mount for the Premotec and it was a huge improvement. However, the cutout is nearly the same size as the motor, so it barely clears.

I'd be interested in knowing more about the newer bearing, and how it differs from the PT model.

tim_bissell
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Re: PT Anni Inspired Project

Post by tim_bissell » 24 Aug 2016 21:00

Allscot in Glasgow, from whom I sourced my end-grain balsa, sell 3/8" (9.5mm) thickness as well as 1/2" (12.5mm).

My manual of mini-anni construction has moved, it is now at:

http://www.lotsov.info/pt-revival/index.html - the Allscot link (and other UK suppliers) are at the end of the document

By the way, for the rear suspension block I used the nylon block which connected the 'T' of the suspension mounts; I used a pillar drill to drill a (not too deep) hole into the side of the block, and self-tapped a small screw into the hole to hold the spring. the original brass suspension bolt with the hex head already fitted the threading in the nylon block.

Looks good so far, and I am very interested in your idea of a motor/controller project - especially your ability to get a pulley machined! - I have all the parts for a(nother) PT except a motor/controller

-- Tim

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Re: PT Anni Inspired Project

Post by tim_bissell » 24 Aug 2016 21:07

... and Arthur would be quick to tell you off for equating his Achromat material with foamed PVC ... like Champagne and sparkling wine they are similar materials but differ in the quality (size, density) of the bubbles! Having said that, the motor mounts may well be normal foamed PVC - that is certainly what I used for mine.

-- Tim

Capt Zach
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Re: PT Anni Inspired Project

Post by Capt Zach » 25 Aug 2016 16:53

Tim,

Very interesting! Thank you for the new balsa source. Would I be correct in assuming that what Funk Firm uses is closer to 3/8" ~10mm sheet?

I'm hoping that with tweaks the motor control will work acceptably well, it is far simpler than the K-drive though. I would prefer a servo if I had a choice. I wouldn't want to make a recreate the PT1 controller. It would be easy to make a new version of the Anniversary if I could had some detailed shots. The early servo motors are still easy to locate.

I've made a tool to turn the crowns on pulleys, so I can produce them in different sizes, although not as well as the real thing I would imagine.

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Re: PT Anni Inspired Project

Post by tim_bissell » 29 Aug 2016 22:43

My anni is in a box at the moment, but I have a feeling that the PCB is screwed into the controller case, and you have to remove knobs, transformer leads and DIN socket output leads to scan the underside.

I have just disassembled my PT/Funk Firm Vector to spray-paint the inner plinth (it has been raw MDF since I built it too late to paint last year) and measured the thickness with callipers; about 10.6mm thick, so the 9.5mm balsa is a good guess with two layers of thin 0.5 - 0.75mm pre-preg carbon fibre sheet.

-- Tim

Capt Zach
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Re: PT Anni Inspired Project

Post by Capt Zach » 31 Aug 2016 18:09

Cheers Tim, I understand. If you do find the time, even a simple photo plus a rough idea of the dimensions would be enough for me to start creating a new PCB. In the meantime, I will keep working on the simple controller and will share my results here.

Capt Zach
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Re: PT Anni Inspired Project

Post by Capt Zach » 14 Sep 2016 03:46

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The turntable with new acrylic top plate fitted. I included holes for the vector drive, whenever I'm able to add it. It helps a lot to know someone with a laser cutter.

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PT fully assembled with a Grace 707 tonearm, and my DIY achromat for testing. The Grace is ok for the time being. I'd like to eventually put together a new CF armboard with a different arm.

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