Ok. No problem. Then I'll send the chip back to Ralph.
Thanks again for sharing this design.
Anders
Sent fra min E5603 via Tapatalk
I use a SMPS on all of our commercial products with no problems. They can be more sensitive to overloads, shutting down at the first sign of trouble, but with careful design, this becomes a non-issue. I'd leave at least 3dB of headroom (if your amps require 25W, use at least a 50W power supply).
On the positive side, they provide a well regulated DC output, which makes holding constant voltage at the output of the xfmrs much easier. They are virtually free of power supply ripple which linear supplies can suffer from, especially if not regulated. SMPSs are also much smaller and very efficient (green); in combination with a class D amp, this makes a huge difference: A class AB amp supplying a 25W motor will consume 50W and require a 100W supply. A class D amp supplying a 25W motor will consume 26W and require a 50W supply.
SMPSs are usually universal input (100-260VAC 50/60Hz) so they don't have to be reconfigured for different wall power. In the past, people stayed away from them, as some of them (poorly designed) were electrically noisy. The design of these supplies has progressed to the point where this is no longer an issue, even on cheap supplies.
Update on v1.02 firmware
I returned the phase adjustment to 1.5°/step. One of the peculiarities of using a 16 bit phase accumulator with an 8 bit DAC (PWM in this case), is that limited precision math can create different points where a carry occurs (and thus an additional phase step). For most frequencies, this isn't noticeable as the difference in phase shifts is usually in the mSec range. In certain cases, the math works out where it becomes quite noticeable and in the audio range where it could affect performance. Using a 16 bit phase accumulator in the SG4, a nasty phase spur will occur on either side of 81.92Hz, which is fairly close to the frequency needed for 45 RPM. The new firmware hasn't hit the field as of yet, so there will be no need to do another exchange. V1.02 will ship with the attenuator capability, but will retain the 1.5° phase adjustment of the original.
Sorry for the confusion.
I returned the phase adjustment to 1.5°/step. One of the peculiarities of using a 16 bit phase accumulator with an 8 bit DAC (PWM in this case), is that limited precision math can create different points where a carry occurs (and thus an additional phase step). For most frequencies, this isn't noticeable as the difference in phase shifts is usually in the mSec range. In certain cases, the math works out where it becomes quite noticeable and in the audio range where it could affect performance. Using a 16 bit phase accumulator in the SG4, a nasty phase spur will occur on either side of 81.92Hz, which is fairly close to the frequency needed for 45 RPM. The new firmware hasn't hit the field as of yet, so there will be no need to do another exchange. V1.02 will ship with the attenuator capability, but will retain the 1.5° phase adjustment of the original.
Sorry for the confusion.
Pyramid I'm just so happy to have this generator, I can stand to be "confused" like that all the time. 
One thing I'm not clear on is, what benefit does the adjustable phase angle give? I have no idea why anything other than the theoretical phase angle would be desirable. Since you have offered it there must be a purpose. Can someone explain the purpose and the method of properly adjusting the angles?
twystd
One thing I'm not clear on is, what benefit does the adjustable phase angle give? I have no idea why anything other than the theoretical phase angle would be desirable. Since you have offered it there must be a purpose. Can someone explain the purpose and the method of properly adjusting the angles?twystd
While 90° is the theoretical optimum shift for an AC synch motor (120 and 240 for 3 phase), in practice, if the mechanical components of the motor are assembled a few degrees off from optimal, it requires a corresponding electrical shift of the signals to align properly with the hardware.
I have done a 2 phase version of the Falcon PSU with 1° resolution; adjusting the signal 1° at a time was difficult to directly find the optimum phase relationship. Holding the motor in my hand, I would adjust the phase on either side until I could feel the vibration increase but that was usually 3-4° on either side of 90 (or some other phase). I would split the difference and set it for half way between the two, which could be 1 or 2 deg away from 90 depending upon the motor.
Having the ability to adjust the phase is a plus. Having the ability to adjust the phase in finer steps may or may not be an advantage. Unfortunately, using 0.5° steps created a problem that out weighed any advantage. 1.5° steps should be adequate for the job.
I have done a 2 phase version of the Falcon PSU with 1° resolution; adjusting the signal 1° at a time was difficult to directly find the optimum phase relationship. Holding the motor in my hand, I would adjust the phase on either side until I could feel the vibration increase but that was usually 3-4° on either side of 90 (or some other phase). I would split the difference and set it for half way between the two, which could be 1 or 2 deg away from 90 depending upon the motor.
Having the ability to adjust the phase is a plus. Having the ability to adjust the phase in finer steps may or may not be an advantage. Unfortunately, using 0.5° steps created a problem that out weighed any advantage. 1.5° steps should be adequate for the job.
Do cheap accelerometers have the resolution and speed needed to measure the vibrations? Not necessarily an absolute measurement, but enough the see if a phase change (or other variable) changes the vibration?
If so, that gives me an excuse to finally learn how to use that arduino I purchased.
https://www.adafruit.com/products/1231
There's also one with analog outputs, maybe useful for an oscilloscope?
If so, that gives me an excuse to finally learn how to use that arduino I purchased.
https://www.adafruit.com/products/1231
There's also one with analog outputs, maybe useful for an oscilloscope?
I sent them to Ted on Tuesday 22-Nov-16, he should have had them last Friday (day after Thanksgiving).
Ted? Have you sent them out?
For anyone in the UK/Europe, I received the chips from Bill(Pyramid) at the end of last week, I have shipped out all current orders, you should receive your order in the next few days.
I have a number of the new chips in stock, but I'm running short of boards. I'll order another batch as soon as I have further orders.
I have a number of the new chips in stock, but I'm running short of boards. I'll order another batch as soon as I have further orders.
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Found an interesting 60 WPC stereo amp for use with the SG4 to drive a turntable motor:
http://www.diyaudio.com/forums/anal...er-diy-turntable-motor-drive.html#post4909926
http://www.diyaudio.com/forums/anal...er-diy-turntable-motor-drive.html#post4909926
Thanks Rick. The SG4 is only the sine wave generator. It does not have the same resolution as the Eagle/Falcon (0.01Hz vs 0.000035Hz), so it is more like a 4 phase SDS. Because of the lower resolution (and the fact that it does not accept input from a tach), it is not suited for automatic speed adjustment; something that is still unique in an after-market controller and certainly at the price point of the Eagle/RR.
It is well suited for a DIY controller and it's hard to beat the price. The amp I linked to is also a bargain and together, they make a pretty decent motor controller for ~$100. Rest assured, your Eagle/RoadRunner is still a major step above what is offered here.
It is well suited for a DIY controller and it's hard to beat the price. The amp I linked to is also a bargain and together, they make a pretty decent motor controller for ~$100. Rest assured, your Eagle/RoadRunner is still a major step above what is offered here.
Well, I would have thought so but being a member of the obsessed audio kook community I had to be sure.
I have enough projects so that is a relief!
No question EAGLE and ROAD RUNNER, as I have said before, are as close to being perfect products than any I have ever purchased.
One hopes you cast your gaze on another area of audio!
I have enough projects so that is a relief!
No question EAGLE and ROAD RUNNER, as I have said before, are as close to being perfect products than any I have ever purchased.
One hopes you cast your gaze on another area of audio!
Good News
Just been playing about with the updated chip controller;
GREAT NEWS!
At least with my setup
I no longer need any resistor or NTC between the amplifiers and transformer.
As Bill (Pyramid) has modified the uP so the output voltage from the controller ramps up in about 0.6 seconds or so, the transformers, 60W toroidal in my case, no longer saturate and cause the amps to shut down..
The startup current from the PSU (24V) is about 3.6A, and I've set the output drop after 5 seconds to the maximum; in this case the running current drops to about 0.8A, but still with more than enough torque.
Once again thanks to Pyramid for an even more complete (and simpler) solution.
Just been playing about with the updated chip controller;
GREAT NEWS!
At least with my setup
I no longer need any resistor or NTC between the amplifiers and transformer.
As Bill (Pyramid) has modified the uP so the output voltage from the controller ramps up in about 0.6 seconds or so, the transformers, 60W toroidal in my case, no longer saturate and cause the amps to shut down..
The startup current from the PSU (24V) is about 3.6A, and I've set the output drop after 5 seconds to the maximum; in this case the running current drops to about 0.8A, but still with more than enough torque.
Once again thanks to Pyramid for an even more complete (and simpler) solution.
Yes Bill, I am using the Class D amps shown here:
100W DC 12V-24V TPA3116 Mono Channel Digital Power Audio Amplifier Board BTL Out | eBay
Still less than £5.00 each
I haven't tried switching between frequencies yet, as I shall only be using a single output, and using the mechanical switching on my TD124.
I'll check out the different outputs tomorrow and update accordingly
100W DC 12V-24V TPA3116 Mono Channel Digital Power Audio Amplifier Board BTL Out | eBay
Still less than £5.00 each
I haven't tried switching between frequencies yet, as I shall only be using a single output, and using the mechanical switching on my TD124.
I'll check out the different outputs tomorrow and update accordingly
Yes Bill, I am using the Class D amps shown here:
100W DC 12V-24V TPA3116 Mono Channel Digital Power Audio Amplifier Board BTL Out | eBay
Still less than £5.00 each
I haven't tried switching between frequencies yet, as I shall only be using a single output, and using the mechanical switching on my TD124.
I'll check out the different outputs tomorrow and update accordingly
Assume youavre using this amp for 230V output?
Which output transformer are you using? Same one per the parts list?
Hi there,
I'm using 12-0, 12-0 to 120-0, 120,0 60VA transformers. I've currently got them wired as 24 to 240 volts, but I'm only driving the transformer with around 12Vrms from the amps, so am getting around 120v for the motors I have, which are mostly 120V Papst 3 phase, delta wound.
I've got the generators set to drop the output down to about 75V once the motors are up to speed, as this is quite sufficient to provide the required torque and reduces what little vibration is left down to imperceptible levels..
I'm using 12-0, 12-0 to 120-0, 120,0 60VA transformers. I've currently got them wired as 24 to 240 volts, but I'm only driving the transformer with around 12Vrms from the amps, so am getting around 120v for the motors I have, which are mostly 120V Papst 3 phase, delta wound.
I've got the generators set to drop the output down to about 75V once the motors are up to speed, as this is quite sufficient to provide the required torque and reduces what little vibration is left down to imperceptible levels..