| Electronics > Projects, Designs, and Technical Stuff |
| Planning to build benchtop 500V tube PSU, help needed. |
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| Emo:
Be careful while selecting the regulator tubes. Often tubes have a maximum voltage between cathode and filament. In push-pull configurations special versions were produced like the FAMOUS EL84 and the EL86. Both the same specs except for the cathode to filament voltage. An other way of solving this is to have a floating filament supply specific for those regulator tubes. Made one myself decades ago with regulator valves. Still working Eric |
| Wolfgang:
Hi, agreed the mximum voltage between cathode and filament is an issue. For the pass valve, the heater should float around the output. I tried two ways: - pass valve heater sitting at the output voltage in a center tapped heater transformer - Make the whole regulator floating. This automaticall solves the problem above. You could use valves with a higher maximum voltage between cathode and heater, like the PL519. Here you have 250V, the EL84 has 100V only. Much fun Wolfgang |
| 001:
--- Quote from: Wolfgang on December 14, 2018, 04:52:51 pm ---- Make the whole regulator floating. --- End quote --- Can You illustrate it with tube circuit? |
| TERRA Operative:
--- Quote from: Wolfgang on December 14, 2018, 03:18:02 pm ---You need two 450V caps in series with equalizing resistors. No big deal. --- End quote --- Ah yep, I completely missed that one. Easy enough to do and caps are cheap. --- Quote from: Emo on December 14, 2018, 03:50:15 pm ---Be careful while selecting the regulator tubes. Often tubes have a maximum voltage between cathode and filament. In push-pull configurations special versions were produced like the FAMOUS EL84 and the EL86. Both the same specs except for the cathode to filament voltage. An other way of solving this is to have a floating filament supply specific for those regulator tubes. Made one myself decades ago with regulator valves. Still working Eric --- End quote --- --- Quote from: Wolfgang on December 14, 2018, 04:52:51 pm ---Hi, agreed the mximum voltage between cathode and filament is an issue. For the pass valve, the heater should float around the output. I tried two ways: - pass valve heater sitting at the output voltage in a center tapped heater transformer - Make the whole regulator floating. This automaticall solves the problem above. You could use valves with a higher maximum voltage between cathode and heater, like the PL519. Here you have 250V, the EL84 has 100V only. Much fun Wolfgang --- End quote --- I managed to get my hands on a bunch of 6005W tubes for the regulator tubes (Basically a shock and vibration resistant version of the 6AQ5), are they safe to use as per the original design, or is there something (like the PL519 or similar) that would be better to use instead? The 6AQ5/6005W has a max cathode to heater voltage rating of 200V I'm also interested in how I would make the reguator floating too. |
| 001:
6aq5 so crappy try TV tube it is rugged and cheap |
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