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Old 12th February 2013, 10:45 PM   #61
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I am not of a different opinion, I just did not mean _slow_ charge of "electrolytes". Slow charge and time delay are completely different things. I use resistor in primary exactly for "slow charge of electrolytics", limiting inrush current. After electrolytics had been charged up to 70% of the voltage the relay shorts the resistor and stays on until power is not removed and electrolytics discharged.
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Old 13th February 2013, 04:30 PM   #62
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Originally Posted by Wavebourn View Post
I am not of a different opinion, I just did not mean _slow_ charge of "electrolytes". Slow charge and time delay are completely different things. I use resistor in primary exactly for "slow charge of electrolytics", limiting inrush current.
I have to sharpen my written English.....the concept was:
By the delay of the +B voltage the in-rush current limiter was implied.......

During the delay-period the idea was to have "a slow charge of the capacitors" and that the heaters during the same delay had reached max. before the full +B voltage was connected.
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Old 15th March 2013, 09:29 PM   #63
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I received boards today, smallest one is for slow start/surge charge limiter. Bigger one is for rectivier. Originally it will rectify 400+400V. The biggest one contains rectifiers for negative bias and filament of preamp tubes, also voltage stabilizers for -72V (bias), +12.6V (filaments), +270V (screen grids) and +400V (preamp and driver).
Also, the longest board will have on it couple of 20 uF film caps, shunt for 800V B+ power. It contains star ground and all output voltage pads.


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Old 15th March 2013, 09:36 PM   #64
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Also, the longest board will have on it couple of 20 uF film caps, shunt for 800V B+ power.
Shunt for 800V B+? What is that?
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Old 16th March 2013, 12:35 AM   #65
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Shunt for 800V B+? What is that?
It shunts 800V B+ on AC by 10 uF film cap, directly to the star ground. Such way output tubes are powered as if from 10 uF film caps (20 uF/2), but rectified AC is actually smoothed by 470uF/2 electrolytic cap + 10uF film.

All power supplies at their outputs are interconnected at the star ground. Such "zero volt reference" eliminated the "sonic difference" between rectifiers and power cables.
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