When replacing a vacuum tube rectifier with SS diodes, how do you accurately reproduce the voltage drop of the vacuum tube? I can't find much data on voltage drop vs current, in my particular case for a 5Y3GT. Datasheet only gives one point, 50V drop @ 125mA.
Anybody have any info on this or do I need to create my own data from testing? Is the drop linear with current?
Anybody have any info on this or do I need to create my own data from testing? Is the drop linear with current?
This sheet shows the entire curve for the 5Y3GT. Also, thermionic rectifiers follow the 3/2 power law, so you can calculate the voltage drop from a single data point with acceptable accuracy.
OTOH, the best way to reproduce the voltage drop of a tube rectifier is to use a tube rectifier
OTOH, the best way to reproduce the voltage drop of a tube rectifier is to use a tube rectifier
An externally hosted image should be here but it was not working when we last tested it.
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Yes that datasheet does. Thank you.
OTOH, I'm not really thrilled with tube rectifiers in my tube tester
What kind of tester? Are they vacuum rectifiers or mercury vapor? The latter types look neat, but they are noisier than any SS diode and don't like having anode voltage applied until they are fully warmed up. I wouldn't even hesitate to replace a merc rectifier with a silicon diode and a 12-14V zener
Hickok 752
One of each. Merc is easy. That's why question about 5Y3
Is the replacements of the tube rectifiers a PHOGE mod, or is there actually a good reason for doing so?
Don't know what or who PHOGE is, but yes, there are several good (to me) reasons.
1. I don't like dissipating 25W in a box full of electronics with zero ventilation
2. I don't like waiting for tubes to warm up.
3. I don't like having a consumable device that can't be tested ( only have one tester)
4. I might leave it on for hours and it wastes electricity. Most of it in the heaters.
Oh, wait, I found what PHOGE is:
Pulsed homogeneous orthogonal field gel electrophoresis (PHOGE).
1. I don't like dissipating 25W in a box full of electronics with zero ventilation
2. I don't like waiting for tubes to warm up.
3. I don't like having a consumable device that can't be tested ( only have one tester)
4. I might leave it on for hours and it wastes electricity. Most of it in the heaters.
Oh, wait, I found what PHOGE is:
Pulsed homogeneous orthogonal field gel electrophoresis (PHOGE).
There are some nice pics of the guts of a Weber copper cap here
Close call with a Weber WZ34 - AudioKarma.org Home Audio Stereo Discussion Forums
Close call with a Weber WZ34 - AudioKarma.org Home Audio Stereo Discussion Forums
Progressive Hacking of Otherwise Good Electronics. It is derived from POOGE
So, add ventilation.
The 5Y3 is directly heated and warms up in about 3 seconds.
Get a couple 5Y3's, test them so you know they're good, and put them aside for the tester. Then, if you suspect it is wearing out you can replace it with a known good tube and test the suspect tube. If the suspect tube tests good, put it aside for use later. Most rectifiers last a very long time, so you shouldn't need to replace it very often.
Thats what nuclear power and solar/wind is for. The filament in a 5Y3 only burns 10 watts, which is a tad less than a 60-watt equivalent CFL and way less than the computer you're using. Besides, it keeps you warm on a cold day
Anyway, since tube rectifiers aren't a linear resistance, a silicon diode with an inline resistor will not match the voltage drop at all values of current. Whether this is important in a Hickock tester, I don't know. The curve is especially non-linear at low current levels where I imagine most testing takes place. Depending on what you pick for a static operating point, a resistor of 500-750 ohms in-line with a 1N4008 should adequately replace each side of the 5Y3.
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