TRUE POINT AUDIO - DC Motor Controllers - Anyone Tried One?

[SONDEKNZ]

I recently stumbled upon a new (to me) name - TRUE POINT AUDIO - a specialist UK company offering some pretty interesting looking options around DC motors and their control.

Presumably, their products are a direct alternative to the LINN RADIKAL, MOBER, ORIGIN LIVE type offerings - for driving turntables.

They offer an interesting solution including a power supply that is not directly connected to the AC-mains - dubbed MIDAS (Mains Isolated Dc Advanced System) - evidently relying on a juiced-up capacitor to provide supply.

The gear looks well thought-out and nicely finished.

Has anyone tried TRUE POINT AUDIO? If so, please share your feedback.

https://www.true-point.audio/tpa_audio_dc_Motor_Kit.htm

 

[david ellwood]

There’s no mention of how its servo works.

looks like you’d have to come up with your own motor mount and pulley solution.

 

[Wine Man]

I am using a Midas PSU with a PT Anniversary - it replaced the 30 year old original Pink PSU and simply plugged into the deck where the old one did and worked with the original motor. I was very pleasantly surprised at the noticeable improvement on the original Pink PSU. There is now a 'Midas Plus' which I have on order so I will share my thoughts when it arrives. These units can be used with Michell decks amongst others, best to enquire with Truepoint about specific turntables.

 

[Vinny]

True Point Audio are a sideline project for the owner of an engineering company - a bit like SME was orginally, and Tiger Paw. Originally the company just sold parts for, and overhauled, PT decks. In particular they offered a service to swap the positions of the ball and ceramic cup spindle bearing parts, so that the cup sits on the spindle, not inside the platter.

Prices for those parts and service were horrendous. I haven't checked for 3-4 years, but you can get comment over on VE via the PT forum.

The common, and highly regarded, drive motor/controller replacement for PT decks is one taken from a cheap Technics(?????) deck, complete with timing strobe. You can pick up one of the decks for peanuts (£20-40) on the Bay when they are runners but in otherwise p-poor condition. Details also over on VE. I have a spare/salvaged motor and controller if of interest.

 

[palasr]

This appears to be a power supply for brushed DC motors. My experience with various DC controllers for brushed motors has been fairly dismal (this includes the utterly crappy OL unit). The problem is long term drift due to thermal changes both in the motor and the controller circuitry. Brushed DC motors need some type of servo sensor (ala the Radikal) to maintain long-term speed stability; they cannot run open-loop. This problem can be more easily solved (albeit more expensively) using a brushless DC motor which incorporates a gearhead with built in Hall effect sensors thus providing constant feedback regarding the speed (and position) of the motor - the control electronics are essentially built into the motor itself. Maxon supplies a wide variety of such configurations. This is also the solution so elegantly devised and implemented by Technics many eons ago.

I'd give it a hard pass.

 

[SONDEKNZ]

...The common, and highly regarded, drive motor/controller replacement for PT decks is one taken from a cheap Technics(?????) deck, complete with timing strobe. You can pick up one of the decks for peanuts (£20-40) on the Bay when they are runners but in otherwise p-poor condition. Details also over on VE. I have a spare/salvaged motor and controller if of interest.

A very interesting thought...
Feel like elaborating? If so, probably worthy of its own thread.
I'm keen; just curious to understand how much DIY fabrication is required - for an LP12 transplant.

 

[Vinny]

Feel like elaborating?

To be honest, I sold the PT1 maybe 3, maybe 4 years ago and had done some research over on VE while I had it. I did buy a Technics deck with no cart' and a broken lid as a drive donor/insurance against motor failure. I just cut the whole assembly, motor, controller etc., in one piece, out of the plastic base of the Technics (I am assuming that my memory about it being a Technics is correct based on the comment from @palasr above).

I honestly don't remember much more than what I have posted here and so far as I can see there is no way to search part or all of the forum over on VE, but link below if you'd like to browse, or ask Tim Bissell for a steer - he is the PT guru over there.

So far as being suitable for use on an LP12 - you would need far better knowledge/experience than mine to judge if that was likely to work. The major difference between the LP12 and both the PT decks and the Technics, is platter weight. Would this matter/be a showstopper? Personally, I have no idea.

I do know that the Pink Linnk supply, which I have had from new on my LP12, is an adaptation of the Anniversary PSU/motor, albeit a complicated battery supply.

The only serious question about a DIY job, would be around mounting of the motor on an LP12 - it might be simple, maybe not - the rest would be no great task as it would be basically putting everything else in a box and fitting some cable.

Pink Triangle / Funk Firm- Vinyl Engine

 

[Alun Rains]

I believe that Richard Johns on the LP12 Facebook forum has one if these in his LP12. He was very pleased with it and I did look into them.
However eventually I went with the External Zeus from Valhalla Electronics instead as it was far cheaper.

 

[SONDEKNZ]

I am using a Midas PSU with a PT Anniversary - it replaced the 30 year old original Pink PSU and simply plugged into the deck where the old one did and worked with the original motor. I was very pleasantly surprised at the noticeable improvement on the original Pink PSU. There is now a 'Midas Plus' which I have on order so I will share my thoughts when it arrives. These units can be used with Michell decks amongst others, best to enquire with Truepoint about specific turntables.

Very cool!
I’m very keen to read your thoughts on how the MIDAS technology changes the sound of your deck, if at all.
Exciting!

 

[9designs]

Begs the question why aren't there more battery based PSU, if we want a clean DC wouldn't that be better? Then it charges up when the deck is not in use. Perhaps based around a laptop battery and charger with speed sensing closed loop?

 

[Paul R]

Begs the question why aren't there more battery based PSU, if we want a clean DC wouldn't that be better? Then it charges up when the deck is not in use. Perhaps based around a laptop battery and charger with speed sensing closed loop?

DC motors are (surprise....) dc sensitive. Battery voltages change as they discharge. So you would need a regulator. In which case you gain nothing from the use of a battery other than it always being flat when you want to use it.

As pointed out above, the problem with DC motors isn't supplying them with clean DC, it's matching the level of that DC to the current need. Whatever the quality of your regulation, without feedback from the actual platter rotation the speed of the turntable will vary across a side. Not to mention from morning to evening and as a weather front comes through.

 

[cobbers]

The common, and highly regarded, drive motor/controller replacement for PT decks is one taken from a cheap Technics(?????) deck, complete with timing strobe. You can pick up one of the decks for peanuts (£20-40) on the Bay when they are runners but in otherwise p-poor condition.

Did one some years ago - worked perfectly fitted into an LPT - a bit slower on startup coming to speed - just getting it into the space available was the only real problem.

 

[9designs]

DC motors are (surprise....) dc sensitive. Battery voltages change as they discharge. So you would need a regulator. In which case you gain nothing from the use of a battery other than it always being flat when you want to use it.

As pointed out above, the problem with DC motors isn't supplying them with clean DC, it's matching the level of that DC to the current need. Whatever the quality of your regulation, without feedback from the actual platter rotation the speed of the turntable will vary across a side. Not to mention from morning to evening and as a weather front comes through.

All that accepted, but it seems some go to great length (expense) to turn a noisy AC supply into DC, regulate it, add close loop feed back etc... Why not start with a "clean" DC signal in the first place? With nothing to pollute it, then regulate and control that?

 

[wiresandmore]

Begs the question why aren't there more battery based PSU, if we want a clean DC wouldn't that be better? Then it charges up when the deck is not in use. Perhaps based around a laptop battery and charger with speed sensing closed loop?

My PT Anniversary has a battery PSU like this (although it’s a burglar alarm battery!)

 

[chartz]

There’s only one way to make a servo motor: a dented wheel. Panasonic (FG Servo) put one within their motors and it worked perfectly.
Regulating a standard brushed motor is not possible.

 

[wiresandmore]

Also, I’ve found True Point great to deal with. There can’t be that many PT decks in circulation, it’s great that someone is making spares and looking after them.

 

[Pkay]

Also, I’ve found True Point great to deal with. There can’t be that many PT decks in circulation, it’s great that someone is making spares and looking after them.

I agree with you. I have a PT fully updated by Charles and I much preferred it over my Kuzma Stabi which I onsold.

Charles has been great to deal with and it is great to have someone around who is willing and capable of keeping the PT going.

 

[hp1]

The pink triangle decks use a tachometer which sends the motor speed back to the controller to control the speed, the old pt 1 used a portescap motor with an ac tacho while the anniversary uses a premotec motor with a tachometer.

 

[Vinny]

The PT1 that I had, I completely stripped down to component parts. There was nothing at all complicated about it and no component except the motor that would cost more than very little to make, if I had had to replace anything.
I did replace the suspension springs - a few pence each from a spring supplier - details over on VE again. The packman retainers could be punched from any scrap of thick plastic film.
The ceramic bearing cup was absolutely fine, but to make a new one, for anyone set up to do so, would cost just a very few pennies, actually probably less than a penny - I have not handled tonnes of PCA (what the cup is made from), but I have handled many, many kilos in the form of lamp (arctube) parts and a colleague made reasonably complicated expeimental parts using mild steel tooling that he turned on the lab' lathe. You'd want to either fill a furnace with the green parts, or piggy-back on another laod of some other parts.

One oddity that did strike me as verging on insane was the platter levelling adjustment. There are 3 and they are lengths of studding with a nyloc nut on the end which sit in holes on the sides and rear of the frame and allow the studding to be turned using a small bespoke box spanner. Turning the studding moves wedges which change the height of the suspension springs. I removed the nylocs, cut a small slot across the ends of the studding and then replaced the nuts. Adjustment was then possible using a small and very ordinary screwdriver.

 

[Alex M]

The pink triangle decks use a tachometer which sends the motor speed back to the controller to control the speed, the old pt 1 used a portescap motor with an ac tacho while the anniversary uses a premotec motor with a tachometer.

I understand Funk now use a current feedback circuit to regulate the motor speed. I had my PT TOO converted to full Vector operation about fifteen years ago, and this incorporated the "K-Drive" controller for the DC motor which used this principle.

It seems to work very well, since my deck sounds far more stable than it did with the AC motor, although at least some of the improvement must come from the motor's new position on the subchassis.

Alex