Good day everyone,
I'm using TV damper diodes (EY80) for HV rectification in my preamp and power amp. They all have their own separate heater winding, and I left them floating. I was unsure how I should ground them.
Is that bad? They have been running for a year now without problems, the amps are dead quiet.
Thanks!
I'm using TV damper diodes (EY80) for HV rectification in my preamp and power amp. They all have their own separate heater winding, and I left them floating. I was unsure how I should ground them.
Is that bad? They have been running for a year now without problems, the amps are dead quiet.
Thanks!
Why do you want to grounding it?
The cathode on HV potential, the cathode-filament maximum potential only 650V.
The cathode on HV potential, the cathode-filament maximum potential only 650V.
I've been using 6/12CT3 dampers and running from a filament supply common with the audio tubes. I have a DC elevation circuit on the CT for the benefit of the audio tubes. So far no issues. Not sure if you need a CT when dedicated to the dampers. You could connect one side of the heater supply to the B+ similar to how normal 5V rectifiers are done as long as the filament transformer has a reasonable hipot voltage rating.
You can check the specs sheet. I had 6AX4's floating in an amp for years without any issue, then during a service I grounded them with a 3W 100 Ohm resistor.
Don't bother grounding them. There is no need. All that grounding will do is ensure a large potential between the cathodes and the heaters. But even this should have no impact on noise in a power supply rectifier circuit.
Checked out the specs on the PY80 - https://frank.pocnet.net/sheets/030/p/PY80.pdf which the Philips EY80 datasheet refers to. Pretty impressive.
The heaters can be elevated up to 650VDC positive relative to cathode. I won't worry too much about a ground reference.
The heaters can be elevated up to 650VDC positive relative to cathode. I won't worry too much about a ground reference.
If you are using a separate heater winding for the EY80, it's usually better to connect the heater to the cathode.
Yes, of course the heater is rated to withstand the DC voltage, but they can fail because of the stress, and there can be some leakage current.
OTOH, even the cheapest (dual bobbin) transformer can withstand thousands of volts P -> S, and is very unlikely to break down, even in a lifetime.
Yes, of course the heater is rated to withstand the DC voltage, but they can fail because of the stress, and there can be some leakage current.
OTOH, even the cheapest (dual bobbin) transformer can withstand thousands of volts P -> S, and is very unlikely to break down, even in a lifetime.
What Rod said. I referenced the damper diode heaters in an older amp I built during a service, because I was working on it anyway. How much does a resistor cost? That said, the amp had been running for 8+ years and the 6AX4's were still very good (as can be expected).
So if you happen to be doing a service, I would do it.
So if you happen to be doing a service, I would do it.