SS diode replacements

dgta · 31st October 2011, 01:46 AM

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?

kem69 · 31st October 2011, 02:12 AM

Try 220R to 400R resistor... 5 to 10W...

Defiant · 03:48 AM

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

dgta · 31st October 2011, 05:41 AM

Yes that datasheet does. Thank you.

OTOH, I'm not really thrilled with tube rectifiers in my tube tester

yagoolar · 31st October 2011, 07:08 AM

Use PSUD 2 software to simulate power supply condition.

Defiant · 31st October 2011, 08:31 AM

Quote:

Originally Posted by dgta

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

dgta · 31st October 2011, 01:05 PM

Quote:

Originally Posted by Defiant

What kind of tester?

Hickok 752

Quote:

Originally Posted by Defiant

Are they vacuum rectifiers or mercury vapor?

One of each. Merc is easy. That's why question about 5Y3

Defiant · 1st November 2011, 08:21 AM

Quote:

Originally Posted by dgta

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?

dgta · 1st November 2011, 01:22 PM

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).

quadtech · 1st November 2011, 02:48 PM

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

31st October 2011, 01:46 AM	#1
dgta diyAudio Member Join Date: May 2011	SS diode replacements 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?

31st October 2011, 03:39 AM	#3
Defiant diyAudio Member Join Date: Oct 2011 Location: Mesa, AZ	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 Last edited by Defiant; 31st October 2011 at 03:48 AM.

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31st October 2011, 02:12 AM	#2
kem69 diyAudio Member Join Date: Jan 2010	Try 220R to 400R resistor... 5 to 10W...

31st October 2011, 05:41 AM	#4
dgta diyAudio Member Join Date: May 2011	Yes that datasheet does. Thank you. OTOH, I'm not really thrilled with tube rectifiers in my tube tester

31st October 2011, 07:08 AM	#5
yagoolar diyAudio Member Join Date: Oct 2004 Location: Mazowieckie, Jozefoslaw	Use PSUD 2 software to simulate power supply condition.

1st November 2011, 01:22 PM	#9
dgta diyAudio Member Join Date: May 2011	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).

1st November 2011, 02:48 PM	#10
quadtech diyAudio Member Join Date: Oct 2007	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

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