Planning to put together a power supply for a 26 pre.
I'll be using a RGN 1064 mesh anode rectifier. It requires 4 volts on it's heater, but I can only find transformers at 5 volt.
Calculations on a dropping resistor on the 5v secondary are pretty easy as the filament draw is a tick over 1 amp (1.1A). 1 volt drop @ 1 amp = 1 ohm @ 1 watt.
My concern, since the rectifier is directly heated, is the potential sonic degradation that might be incurred using this method, if in fact it does degreade the sound. There will be a voltage regulator of some sort downstream after the LCLC filter ( still undecided and playing around / looking at S.S. or tube based regs), so if the dropping resistor effects the over all sonics it might just be extremely minimal if at all ?... But I have no experience in this area.
I would be using a separate transformer for the heater so it would be possible to do something on it's primary to not have to worry, but I have little if no knowledge on how this would be done....
Probably the "best" way would be to deconstruct the beast and unwind, but that is beyond my current skill set and I would mostlikely destroy the part and create a pile of scrap from what had been a good part.
Soooooo...... this post.
Thanks fella'a
JD
I'll be using a RGN 1064 mesh anode rectifier. It requires 4 volts on it's heater, but I can only find transformers at 5 volt.
Calculations on a dropping resistor on the 5v secondary are pretty easy as the filament draw is a tick over 1 amp (1.1A). 1 volt drop @ 1 amp = 1 ohm @ 1 watt.
My concern, since the rectifier is directly heated, is the potential sonic degradation that might be incurred using this method, if in fact it does degreade the sound. There will be a voltage regulator of some sort downstream after the LCLC filter ( still undecided and playing around / looking at S.S. or tube based regs), so if the dropping resistor effects the over all sonics it might just be extremely minimal if at all ?... But I have no experience in this area.
I would be using a separate transformer for the heater so it would be possible to do something on it's primary to not have to worry, but I have little if no knowledge on how this would be done....
Probably the "best" way would be to deconstruct the beast and unwind, but that is beyond my current skill set and I would mostlikely destroy the part and create a pile of scrap from what had been a good part.
Soooooo...... this post.
Thanks fella'a
JD
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