Nice going! 🙂 You seem to have used the copper space very efficiently.
Gotta love that Tango, huh? Gees that brings back memories...
Gotta love that Tango, huh? Gees that brings back memories...
PC board is finallly drilled!
I've been correcting/matching-up all the component part numbers on the PC board overlay & circuit diagram, and creating a parts list.
I'm short on some components, so I'll have to go shopping early next week before I can fill the board & test it.
I've been correcting/matching-up all the component part numbers on the PC board overlay & circuit diagram, and creating a parts list.
I'm short on some components, so I'll have to go shopping early next week before I can fill the board & test it.
This is now as 'final' as the theoretical circuitry gets; (though practical tests might show up faults that require modifications)
sp10pwm2.gif
Above pic is linked from my page4 in case you want the accompanying text. Certain component values are still not show - tests and calculations required to determine them.
sp10pwm2.gif
Above pic is linked from my page4 in case you want the accompanying text. Certain component values are still not show - tests and calculations required to determine them.
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Dang! I was soldering in IC sockets & pondering the wanderings of electrons and I discovered an oversight:
C16 has a DC offset on it = the RMS value of the phase pickup coil voltage, and I neglected to remove it anywhere.
In a way, it's being there can simplify things, since it eliminates the need for the 4053 analogue switch having a negative supply reference (Vee), and the op-amps then get a larger supply voltage.
The DC can then be removed by making R51 a capacitor/resistor series combination.
The TTL level shift circuit voltages change very slighty too (0v instead of -7)
C16 has a DC offset on it = the RMS value of the phase pickup coil voltage, and I neglected to remove it anywhere.
In a way, it's being there can simplify things, since it eliminates the need for the 4053 analogue switch having a negative supply reference (Vee), and the op-amps then get a larger supply voltage.
The DC can then be removed by making R51 a capacitor/resistor series combination.
The TTL level shift circuit voltages change very slighty too (0v instead of -7)
It seems I stayed away for just the right amount of time. This is very exciting to me, too. Will this controller work for a MkIII as well? If not, will there be a way of altering the electronics to run the MkIII? And, Steerpark, how do you plan to disseminate this work? As a kit, for example? Thanks in any case for your work.
As far as I can tell from the paperwork I have on the MkIII, my circuit ought to work - a few passive component changes to accommodate the much heavier platter. I have not actually studied 'numbers' so I won't promise it will yet - I'll have to look at the service data for the MkIII.
The main problem - if there is going to be one - would be the current drawn by the MkIII motor at startup. The L165 chips can handle quite a heavy current briefly, so I don't expect it will bother them, unless you did something like forcibly back-cue the platter while it was trying to run.
There is ALWAYS a way to alter electronics to do something you want
For now, my plan is to put it all on my web-page, circuit diagrams, pcb artwork, etc.
I had not really planned a kit, but depending on how much demand there is, I could possibly do that. And I have NO idea what people would expect to pay. My aim was to get an SP10 going for absolute minimum cost (a kind of 'show it can be done' experiment') since the motor cost me almost nothing, but if I bought all the components (rather than using from my accumulated store) it would add up.
Another main aim was to use universally available parts, that anyone, anywhere in the world could easily get - so a kit wouldn't really give you anything you could get from your favourite components dealer.
One friend was concerned that someone might lift the information off the web and use it commercially - i.e., THEY make up a kit and sell it. But one thing that really bugs me about 'public' projects in magazines & on the web is where they withold one critical component, like the eprom code that you then have to buy from them.
Progress so far:
Page 6 # testing
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I've found two Japanese web sites that seem to use the Kaneta circuit on an SP10 and an SL1200 motor:
Google Translate
Google Translate
These are translation-routed URLs. I have a little difficulty understanding the translated version!
Google Translate
Google Translate
These are translation-routed URLs. I have a little difficulty understanding the translated version!
^^^ What a load of rubbish!
I had a momentary lapse of reason. Putting any DC blocking element in the drive path will prevent the motor from self starting, no matter how long the time constant. It needs static DC voltages corresponding to the 3 phases to exist even when stationary, as if the 3-phase AC were frozen in time.
A workaround is to add a DC offset to the rectifier. But the offset is determined by the amplitude of the exciter oscillator, if that drifts, a DC error will result. So the offset is derived by rectifying the oscillator output, and feeding an adjustable portion of that back into the rectifier's otherwise unused non-inverting input.
Correction principle shown in the attachment.
Looking at the Kaneta circuit, I see no such DC correction. I think he just ignores the DC offset and lets it persist throughout.
Attachments
A sexy circuit suitable for generating PWM drive, without a microprocessor. Either for analogue purists or testing purposes - very linear.
sp10page4.htm#pwmpulsetrain
And there's a missing capacitor in my diagram one-post-back. The anode of the red diode goes to ground via 0.2uF
sp10page4.htm#pwmpulsetrain
And there's a missing capacitor in my diagram one-post-back. The anode of the red diode goes to ground via 0.2uF
I'm still here; I'm short of components for testing - no HEF4053! I'll be going into town to get bits to play with this week.
In the meantime I've been attending to my "ReVox Clone Amplifier" daydream, if anyone wants to see: ReVox Amplifier B24-something
In the meantime I've been attending to my "ReVox Clone Amplifier" daydream, if anyone wants to see: ReVox Amplifier B24-something
We're all still here too 🙂 Keep up the good work Steerpike - I'm seriously anticipating the final outcoming, and bolting it into my SP-10 Mk2 chassis!
Cheers, Jon.
Cheers, Jon.
Hope everyone had a great Christmas weekend and enjoying the Winter that is upon us.
Curious, Steerpike, do you have any developments on the SP10 MKII controller/power project?
It has now been 1.5 years since Steerpike and I first posted to this thread...
I'm hoping, very much hoping, something will finally develop into an excellent, functional/with options and isolated, controller and power supply unit.
Looking forward to future posts... everyone Enjoy!
Rick
Curious, Steerpike, do you have any developments on the SP10 MKII controller/power project?
It has now been 1.5 years since Steerpike and I first posted to this thread...
I'm hoping, very much hoping, something will finally develop into an excellent, functional/with options and isolated, controller and power supply unit.
Looking forward to future posts... everyone Enjoy!
Rick
Oh certainly things are happening! One bug that has kept me from putting up exciting new info on the PLL part is that when I went to get ICs before Christmas, I asked for 4035s and they gave me 4053s ! So next week when they open again after the holidays, I will be getting the right chips!
Meantime I have been adjusting component values in the 'drive' stage according to actual measurements.
These things happen - especially close to holiday time!!!!
Good luck and a very joyful New Year,
Brian
Good luck and a very joyful New Year,
Brian
Glad to see things still going forward.
How do you feel about how the design is coming together?
I know it is alot of work, and I really do appreciate all that your doing, as everyone else here... if there is something I can somehow help with, just let me know, ok?
Again, thanks!
Rick
So far I'm happy at how well it's working. All the test/prototype circuits have functioned as anticipated. That shouldn't be surprising, but often with stuff I'm experimenting with, I tend to rush it, and not think or calculate enough before going straight to harware. With all of you 'watching' though, I have to pay attention to the details on this one!
I think the circuit is rather an 'over-achiever' in some parts, when I look at the simplicity of some commercial designs. But for this project we don't have to concern ourselves with cutting a few dollars out of component costs. I don't like the prospect of having to go back and re-do a certain part because it doesn't perform - so I prefer to make each part work the best possible way that I know how, right from the start. (That's what audiophiles want anyway!)
Well, you are doing a great job!
We are all very appreciative of all the effort and work you have put into this!
Rick
We are all very appreciative of all the effort and work you have put into this!
Rick
A few dollars will not hurt. You have given a few people a lot of hope as the TT is in my view one of the absolute best as far as its potential is concerned. I am having a slate plinth cut to take just the motor and an on/off switch plus a carbon (solid) armboard.....a sort of updated Kaneta approach.