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Old 6th January 2003, 01:23 PM   #11
dhaen is offline dhaen  Europe
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The basic answer is that since R=V/I, then 2.2 ohms on one, and 4.2 ohms on the other. Though it does puzzle me why they are so different. Did you measure them under the same conditions?
Measure again across the tube pins with the tube plugged in, and then calculate the value required:
R=(V - 5)/1
In reality, the loading will change, so the final value will differ slightly.
Both at least 5 watt rating. (10watts better). They will get very hot.

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Old 10th January 2003, 11:26 PM   #12
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Sorry it took so long to reply, I went back to work, nuff said!

Anyway, the measurement for the 300b heater volts was taken with the tubes not in the socket, hence the high voltage readings.

As I found out, the tube needs to be in the socket to complete the circuit and get a true volt reading.

After some trial and error experiments I now have the voltage to 5.2 and 5.3 volts DC on the heaters using a 1 ohm 10 watt resistor on each rectifier circuit, testing the volts with the tubes in place.

I ordered two 1.2 ohm 12watt resistors to correct the voltage hopefully closer still to 5 volts exactly. I installed two new 16v 10k uF electrolytic caps in the supply, eliminating the 10v caps.

The PWT was built and tested at 117v for a 380-0-380 volt output, but a 120.89 volts a/c wall socket volts it reads much higher at around 400-0-400 volts output, hence the B+ is higher hovering near 500 volts, the PWT barely gets warm and the OPT is cool to the touch after an hour of being on. No smoke, yet!

It does sound, well, magical. A muscian friend, who's ears I trust implicitly called them "demon amps". He was listening to recordings he has listened to numerous times in the past and was absolutlely impressed with the fact that he was hearing information he has never heard before on other amplifiers.

I'll try to post a pic of the wiring, later today.
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Old 10th January 2003, 11:32 PM   #13
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Hi Paul,

Congratulations once're almost there.

Guess that amp has found a permanent home.

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Old 10th January 2003, 11:38 PM   #14
dhaen is offline dhaen  Europe
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Well done Paul
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Old 11th January 2003, 12:02 AM   #15
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Hi again,

Here is a link to the pic of underside.
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