A Thought for a new Hagtech product

Julien43 · « **on:** 25 Sep 2004, 02:25 am »

I have just started searching for a DIY AC motor controller for My P3. I bet there is a market out there, of 'philes wanting to upgrade these popular Rega tables. The design doesn't have to be limited to Rega. The popularity of these units, combined with the ever present desire to upgrade makes me think Mr. Hagerman's aptitude, applied to such a device would be a fruitful endevour. Offered as a "Half Kit" and finished product, it would allow enthusiasts' on both sides of the fence to enjoy Jim's talents. I posted a request for a DIY design on AA.
Here's the url: http://www.audioasylum.com/audio/tweaks/messages/108202.html
Wadda think Jim. I know your a busy man, but I honestlly believe your efforts would be well rewarded!

hagtech · « **Reply #1 on:** 25 Sep 2004, 03:23 am »

Julien,

A fine idea! It has crossed my mind in the past. Not sure how big the market is. Need to learn a little something about ac motors. But it doesn't look that hard.

What features would you like to see? I am thinking of variable phasing between coils for minimum cogging. Wonder if that could be auto-nulling. Maybe AC regenerated from batteries? Or is wall supply ok? Variable speed control?

What tables would be appropriate? Rega? Linn?

jh

JoshK · « **Reply #2 on:** 25 Sep 2004, 04:47 am »

Forget AC, make it a DC controller/regulator and you got yourself a real TT project!

No seriously, most of the better motors out there these days are DC. DC motors can be had for <$100 that together with a DC motor controller will give you excellent results.

hagtech · « **Reply #3 on:** 25 Sep 2004, 05:19 am »

DC is done already. At least the proto. We'll be showing it at RMAF. To be used (and sold) in Galibier and Redpoint turntables. They have similar motor pod housings. I designed them a motor control board to fit inside.

Suppose I could do something similar for other tables. Gimme some specs! What features you want? Size? For which tables?

Circuits I already have debugged are the regulator, battery charger, strobe, and fuel gauge.

jh

Brian Clark · « **Reply #4 on:** 25 Sep 2004, 07:42 am »

For starters, Garrard 301 & 401 - 16watts

Brian

penance · « **Reply #5 on:** 25 Sep 2004, 10:48 am »

Jim

Any more info on the DC controller?

I'm building a TT based on Scheu components (platter/bearing/motor)
The motor is a DC PLL design and operates between 9v and 12v.
Would your board suit that?
I currently have a jung based super reg lined up for it, but i would rather use that in my pre than for a TT motor.

JoshK · « **Reply #6 on:** 25 Sep 2004, 01:12 pm »

I have a Teres TT. It has a DC motor and it uses a feedback circuit from its strobe. Mine has given me a lot of grief. I was looking for a project to do motor controller like the Origin Live Motor upgrade, that has a pitch controller knob and button to switch between 33/45. That would be cool!

Marbles · « **Reply #7 on:** 25 Sep 2004, 01:56 pm »

Quote from: JoshK

I have a Teres TT. It has a DC motor and it uses a feedback circuit from its strobe. Mine has given me a lot of grief. I was looking for a project to do motor controller like the Origin Live Motor upgrade, that has a pitch controller knob and button to switch between 33/45. That would be cool!

Josh, have you upgraded the Teres motor to the 1/2 tape pulley?

Did you know the Teres motor has 33/45 capabilities? To make it 45, just hold the button down for 3 seconds

Julien43 · « **Reply #8 on:** 25 Sep 2004, 10:32 pm »

Jim,
I’m not technically knowledgeable, so I can’t comment on design parameters. As far as features:
1) Variable speed, it would be a nice selling point with one caveat. I’d like to have the ability to bypass the variable speed for greater accuracy (without a strobe)
2) AC regeneration, seems to be a popular concept (ie: PS Power Plants) perhaps another selling point.
3)Batteries? Great in theory, but is it practical for driving a motor?

Your mention of designing a controller for a turntable manufacturer, and your penchant for making your designs available as kits made me think this might be something you would be interested in.
Thanks for reading my post!
Julien

gnnett · « **Reply #9 on:** 25 Sep 2004, 11:16 pm »

I have an early Origin Live DC motor that uses AC and would like to convert to batteries.

So what details do you need to know about the motor?

1/2 kit would be ideal.

Regards

Gnnett

JoshK · « **Reply #10 on:** 26 Sep 2004, 02:17 am »

Quote from: Marbles

Josh, have you upgraded the Teres motor to the 1/2 tape pulley?

Did you know the Teres motor has 33/45 capabilities? To make it 45, just hold the button down for 3 seconds

Yes and yes.

My problems are still there. I even had sent the motor back once to fix it, but that didn't do it.

JoshK · « **Reply #11 on:** 26 Sep 2004, 02:22 am »

I will caveat my statement by saying that I haven't tried the battery supply, I am using the default AC supply. Maybe a cool regulator with pitch between a battery supply and a DC motor would be cool. Hmmm....

hagtech · « **Reply #12 on:** 26 Sep 2004, 03:03 am »

The dc controller I just did is custom for the Galibier/Redpoint tables. I won't be selling that one as a half-kit. It uses a dozen batteries, which lets it drive those big tables to 78rpm. Had a proto run (no wires) for three straight days on one charge.

I'm thinking of a smaller, more generic board for a half-kit. Something a bit more flexible. That's why I appreciate your comments as to a feature set.

jh

Julien43 · « **Reply #13 on:** 26 Sep 2004, 07:31 am »

I am, most pleasantly, surprised (honored actually) that a designer of your stature would even entertain a product suggestion from me. Jim, you are too kind. All I can say is "Thank YOU"

gnnett · « **Reply #14 on:** 27 Sep 2004, 07:54 am »

I suppose there are more AC syncronous turntables out there and hence more "potential" customers.

However, among those willing to void warrantees, diyers, my guess is there would be a preference for either scratch build, or motor replacement. Then I think DC becomes preferable.

In which case I hope more "likely" customers for the latter.

On this basis here is my DC motor controller list, for what it is worth:

1. 33 and 45 rpm.
2. Voltage (range) able to be changed (not switchable) for motor options, ie: upgrade of motor does not require new ps, just a change of components or component values. (Origin Live and Scheu to start with)
3. Similarly current scaleable to address such changes in motors.
4. No feedback.
5. Board must be square so no one can say they have a Redpoint or Galibier equivalent motor controller.
6. And maybe just one tube somewhere just for show.

I would be happy to send my OL motor if needed for prototyping and while the last item is optional, item 5, I think is probably quite important.

Regards

Grantn[/b]

Julien43 · « **Reply #15 on:** 27 Sep 2004, 08:46 pm »

Being an analogue neophite, I was unaware of the superiority of DC motors. Gnnett makes a very valid point about the nature of this being a DIY project. I must agree that I would seriouslly consider a motor upgrade. What is killing me is I just bought the P3 motor upgrade because I bought a used Planar

eweitzman · « **Reply #16 on:** 28 Sep 2004, 01:33 am »

If I understand it correctly, the main advantage of certain DC motors (per Wilimzig's article in Sound Practices) is that they have very flat speed-torque curves. That is, the motor can increase the torque almost instanteously when there is a slight drop in speed due to increased amplitude in the record groove.

So this leaves the problem for the controller: what's the best way to ensure this performance? Is it to be able to deliver sudden bursts of current to support the torque demand? Or constant voltage? Or not interact with increased back EMF from the motor when current draw increases? I personally don't have a clue, just guessing here. But a great solution to this problem might find it's way into a great controller kit/2

- Eric

Marbles · « **Reply #17 on:** 28 Sep 2004, 01:39 am »

Quote from: JoshK

I will caveat my statement by saying that I haven't tried the battery supply, I am using the default AC supply. Maybe a cool regulator with pitch between a battery supply and a DC motor would be cool. Hmmm....

I never ran mine off AC, I bought the battery when I bought everything else.

I did run into a tape slipping. I replaced it and it was fine.

JoshK · « **Reply #18 on:** 28 Sep 2004, 03:19 am »

I am not dissing Chris' product. I think this is more of a one bad one and I think it can be rectified to better suit my preferences with such a motor controller that we are discussing. I never quite liked the strobe feedback mechanics myself and would prefer something seemingly more constant.

BWentler · « **Reply #19 on:** 28 Sep 2004, 01:44 pm »

I'm using a Teres Audio DC motor to drive my VPI HW19 mkIV TT. That setup, motor/sensor, is great since you can fit it for many different TT's. The thing with Teres motors is the housing is to designed to match a Teres TT. If you have a TT that is very short, you could not use the Teres motor without either rising your current TT or placing the Teres motor on a different stand.

I would suggest a half kit that the end user could determine the how the motor needs to be mounted/housed. By using some sort of external sensor, will insure correct speed no matter what TT the motor is connected to.

I also have the battery supply optinion. This is a great "next step" in upgrading your TT and/or the DC motor upgrade.