EngineerNate's Sony TTS-4000 Build
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Igor_SPb
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Nathan,
About C5, C6. I looked at my turntable and the original capacitors have a capacity of 10 microfarads, as in the circuit diagram.
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Thanks Igor! I've learned a lot since I worked on this table. I think I ended up putting 4.7uF for C5/6. They're there for DC blocking so a smaller value simply raises the cutoff frequency a bit. If I remember right I had an issue with one of those traces so I'll probably leave them be for now.
I found some higher output Vref chips since I worked on this. Might be fun to try that route again. Looking forward to the results of your experiment.
I found some higher output Vref chips since I worked on this. Might be fun to try that route again. Looking forward to the results of your experiment.
Igor_SPb
New Member
Looking forward to the results of your experiment.
Ok. Now I can say that this precision Zener I bought is more stable than MC7809 voltage regulator that I installed about 3 years ago. Now the voltage is stable at 8.69 volts at any time when the turntable has just turned on and after 10 hours of continuous operation. It is installed one instead of three diodes. Maybe there is some change, but my voltmeter has only two digits after the comma and cannot measure any difference.
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Which model zener is it?
Igor_SPb
New Member
Д818ЕОС metall case. TempCo similar to http://audiokarma.org/forums/index....y-tts-4000-build.814038/page-13#post-12458311
But price about half dollar
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totem
Addicted Member
Igor is your Table a TTS 4000 or the TTS 2250?
Nate does your TTS 4000 have a multi voltage switch or trans?
We'll see how stable it is, long term then. They use them as shunts, rather than references for active series regulation in these TTs, which is stressful.
Igor_SPb
New Member
Totem, my turntable is TTS-4000 and it have a multi voltage switch.
Igor_SPb
New Member
Pio, of course, I will observe how stable it is within time.
Mine has a multi-voltage switch as well. I'm guessing it just changes the taps on the transformer?
Yup, iirc.
Igor_SPb
New Member
Pio, I hope so.
I turned on the motor in the morning, and immediately went away on business, returned after about seven hours and the speed of the table changed. I adjusted the speed again, after that five hours have passed and now the rotation is absolutely stable. I started counting when one pitch would run away, but after fifty turns I was tired of it, the pitch remained in place. The temperature inside the motor rose and stopped at around 32*C. I put the sensor of the digital thermometer inside on the wires.
I have some thoughts on how to eliminate possible temperature drift, I will write about this a little later.
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totem
Addicted Member
As does the the TTS-2250 which was a drive only designation, I have a sense that if sold with a plinth the PS 2250 may
not be multi voltage but only a guess. I have not been able to confirm though.
Igor_SPb
New Member
Option 1.
Make and install a pre-heater under the board that will maintain a constant temperature, as in some professional precision instruments. I will do it.
It may be worthwhile to remove power transformer from the motor, since it is the main source of heat, at the same time there will be less vibration in the motor.
Option 2. If it will be necessary.
We can divide the 9 volt line into two, the first one will power the microchip and the timing chain, and the second one will be powered by a microcontroller, which will smoothly change the reference voltage instead of the console's manual adjustment knob. There, output voltage is about 2.5 volts and the current consumption is less than one milliampere. The microcontroller will receive a signal about speed from the motor frequency generator. Thus, we do not change the control circuit itself, but only add smooth automatic regulation of the reference voltage with heating. + option 1.
But for the second option I do not have enough knowledge, I will ask for the help of my friend, who knows the electronics and computers well.
If the problem is solved with the help of these options, the question may arise whether it is necessary to install precision parts. My IMHO is necessary. Original parts installed even in the most critical places have a very bad temperature coefficient, this does not change the speed smoothly. Now my turntable rotation is very smooth.
By the way, instead of R37 thermistor, I just installed a jumper.
What are you thinking about this?
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Iirc, the strobe lamp is linked to line freq, which varies slightly but is supposed to be zero sum difference long term. That doesn't serve us well here, trying to guage small drift trends. Perhaps a closer tolerance quartz clock time base driving a LED strobe lamp.
Igor_SPb
New Member
I know about it and I controlled the rotation also with the help of the TV screen, and there the frequency is super stable, as far as I know.
Of course, I will make a strobe with a quartz stabilization, the parts have already been ordered. The scheme is on vinylengine.
Frame rate from analogue CRT TV?
Igor_SPb
New Member
Pio,
The flicker 60/120 hertz from a plasma TV.
On top of the original platter, I put another platter with pitchs for the stroboscope, this way I can see two readings at once, from the built-in light (50 hertz) and from the outside (60). Both platters have four pitchs 33/45 for 50/60 hertz.
It's funny to see how the pitchs of 45 revolutions run at different speeds from 50 hertz and from 60 hertz. Both (50 and 60 hertz) 33.3 speed pitch lines runs the same. In fact, with a flicker frequency of 50 hertz, it is impossible to get the correct speed 45 on the strobe.
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