With the latest design I sent you, the 0-4V scale out of the external DAC is good enough as output voltage is scaled then and proportional to the reference.
For the current feedback, that's ok, let me study what is the best way to do it and I will send you an update schematic.
I absolutely agree with you on the pre-discussion as there are here people who are more expert for sure than me on drive system that can give a hint on the mechanical design.
So until there won't be enough input to decide if my basic idea is a good solution or not, we will wait to do any further implementation both HW and SW.
I think your approach is very wise and I take that as good input.
I don't see why people wouldn't want to use a tachometer, it makes no sense.
The only reason why I wouldn't see it being used as if they wanted no compensation at all.
They will be able to detach the tachometer and regulate the speed from the user interface and adjust it with a strobe.
My thinking is that if people don't want feedback at all because maybe on listening session they prefer it without it, then I don't see why they would want to have current feedback which is even way more intrusive.
anyway, maybe the control signal can go to the uC with a jumper that can either be shorted or not, or maybe even better enable current feedback or not through the UI that controls either a small relays or a mosfet.
Something I will have to decide once I get into the design phase, when the design will be commented enough to make us feel confident of the concept design.
😎
EDIT: to be hones, so far I don't see much participation! Hopefully we will get more inputs as we go. If you guys think it is better open a new specific thread for this such as "New DC motor drive and control system development" could help improving visibility, I can do that and we can start on there.
The only reason why I wouldn't see it being used as if they wanted no compensation at all.
They will be able to detach the tachometer and regulate the speed from the user interface and adjust it with a strobe.
My thinking is that if people don't want feedback at all because maybe on listening session they prefer it without it, then I don't see why they would want to have current feedback which is even way more intrusive.
anyway, maybe the control signal can go to the uC with a jumper that can either be shorted or not, or maybe even better enable current feedback or not through the UI that controls either a small relays or a mosfet.
Something I will have to decide once I get into the design phase, when the design will be commented enough to make us feel confident of the concept design.
😎
EDIT: to be hones, so far I don't see much participation! Hopefully we will get more inputs as we go. If you guys think it is better open a new specific thread for this such as "New DC motor drive and control system development" could help improving visibility, I can do that and we can start on there.
you can use all the quality parts you like it will make no odds. it's how these parts are implemented. Technics belt drive turntables are DC and the reason they used DC way back in the 70's was cost and quality. using DC allowed Technics to manufacture cheep plastic record decks for the masses that sounded very very good and this was due to the DC motor.
rim drive or belt drive it makes no difference, they will both rotate at the same speed given size of pulley. so spin at 300rpm as that is the largest target area and it will be up to 250rmp people to get a new pulley to which they can use the 300rpm one. it's about shaft speed and pulley/platter diameter, nothing more nothing less.
more people will come on board as the project matures and by saying that you want to use the best of the best will put a lot of people off that could potentially be of service to the project. not many people are going to fork out $1000min on a motor or is this project just so you can have something you want.
rim drive or belt drive it makes no difference, they will both rotate at the same speed given size of pulley. so spin at 300rpm as that is the largest target area and it will be up to 250rmp people to get a new pulley to which they can use the 300rpm one. it's about shaft speed and pulley/platter diameter, nothing more nothing less.
more people will come on board as the project matures and by saying that you want to use the best of the best will put a lot of people off that could potentially be of service to the project. not many people are going to fork out $1000min on a motor or is this project just so you can have something you want.
Biblio I think you need to change a little bit attitude here and being more positive.
I am designing this for free instead of keeping it to myself, I am not charging anybody, neither are the other guys here and you would only benefit by being good and give your contribution.
This is obviously something I initiated with of course a precise interest on it and a specific goals. The motor I am looking for is probably $300-400 and not $1000+.
Technics and TT from the 70’s with all due respect are not up to level and they need lots of modification to get in the ballpark, which are changing the cheap and worn parts. Few of these many vintage tables are really worth investing time on it, But this is another story.
Are you trying to say that belt or RIM drive makes no difference because platter spins with both methods?
Belt stretches everybody knows that, while direct drive will give you more dynamic and that is why these Technics and others have an advantage over many other tables.
The project cannot mature if there is no participation on it. Prototyping is really expensive both on mechanical and HW side. Beside its expense, spinning more revision will burn a lot of time for who is designing it and puts all the efforts on creating the physical model and put it together.
Obviously for who sits there and watches and waits for the Christmas gift, it doesn’t cost anything nor make any difference if project needs unnecessary re-spin then change again because it wasn’t thought well upfront.
I believe the advice Pyramid gave was really wise and worth fully consider. Maybe people get more interested and excited in this project if we open up a new thread.
I will do that! In order to have a clear cut and avoid any confusion from other users who try to read this thread which started with one topic a took a totally different direction.
That way, anybody who is interested in DC motor and doesn’t mind spending a little extra $$ for motor, which is specifically interested in RIM drives and also has more real estate to place an extra motor box right by their table, can participate.
Also people who are not interested on pulling through but that have good inputs to give are obviously more than welcome in
I will open up a new thread and recap a little bit what’s discussed here, post the design concept and the email from Maxon.
Anybody who is interest please join the other thread. This one can be continued on the original thread on how to modify/hot rod the Hurst motor.
Thanks to all.
i am excited in the project and the prospect of a decent priced DC motor upgrade.
i'm not trying to be negative i'm just trying to bring reality in to the equation.
and yes it makes no odds what the end user uses to drive the platter the motor will work in both cases belt or rim it makes no odds. you personally will be using rim drive but the same motor/supply can be used for belt as well with no modifications apart from the pulley.
a $300-400 will do just fine, people can use others and that's the good thing about DC.
i'm being good and giving contribution, errrmmm DC motor idea....
chill fluffy bunny, i mean no harm and i'm well up for the project. think of me as a devils advocate 🙂
i'm not trying to be negative i'm just trying to bring reality in to the equation.
and yes it makes no odds what the end user uses to drive the platter the motor will work in both cases belt or rim it makes no odds. you personally will be using rim drive but the same motor/supply can be used for belt as well with no modifications apart from the pulley.
a $300-400 will do just fine, people can use others and that's the good thing about DC.
i'm being good and giving contribution, errrmmm DC motor idea....
chill fluffy bunny, i mean no harm and i'm well up for the project. think of me as a devils advocate 🙂
ahahaha...that sounds good, now I get your intentions 😛
Yes my intent is to make the control so that people can use it with a variety of different motor and pulley combinations without changing a bit.
I am preparing the new post so you guys stay tuned...and I am glad you are in for the project 😉
Yes my intent is to make the control so that people can use it with a variety of different motor and pulley combinations without changing a bit.
I am preparing the new post so you guys stay tuned...and I am glad you are in for the project 😉
as promised, here is the new thread....sorry for the delay but I have been super busy as usual.
Please feel free to post and follow this subject at the link below:
http://www.diyaudio.com/forums/anal...dc-drive-system-tt-rim-drive-starts-here.html
Please feel free to post and follow this subject at the link below:
http://www.diyaudio.com/forums/anal...dc-drive-system-tt-rim-drive-starts-here.html
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