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Ronan Regulator for DHT http://dcaudiodiy.com/phpBB3/viewtopic.php?f=5&t=2081 |
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Author: | ratbagp [ October 8th, 2021, 6:08 pm ] |
Post subject: | Re: Ronan Regulator for DHT |
Another possibility is the LT1085 version of the D-Noizator. See post 1985. https://www.diyaudio.com/forums/power-supplies/331491-noizator-magic-active-noise-canceller-retrofit-upgrade-317-based-reg.html ray |
Author: | David McGown [ October 8th, 2021, 6:54 pm ] |
Post subject: | Re: Ronan Regulator for DHT |
Ray, Thanks for the suggestion, but I am not sure how this can apply to a DHT filament CURRENT regulator providing 5VDC/1.5A for 300B. It could potentially apply to the voltage pre-regulator to help clean it up before going to the current regulator, but any circuit would have to be sensitive to the fact there is substantial current being supplied. I have to say, if I wanted that level of complexity, I would just give Rod Coleman the business and figure out a way to make it all fit. Just trying to keep it simple, small and good enough. I know ultrasonic AC with hum balance pot is another way as well. David |
Author: | ratbagp [ October 8th, 2021, 10:19 pm ] |
Post subject: | Re: Ronan Regulator for DHT |
If you are open to the high frequency AC solution, read Alex Kitic's methodology in his RH813 amp. I used it in my GK71 amp adding extra turns to obtain 20 VAC. For 6.3 VAC, you would need to reduce the number of turns. It seemed to work for me and it did not require a hum pot. By the way, for 115 volts, I used a 560 uf 200 volt cap to get rid of the buzz. Also note that after powering off, the caps do not discharge. http://rh-amps.blogspot.com/2014/06/rh813-flagship-project.html I am currently rebuilding my GK71 amp since I had to disassemble it for the trip to Oz. ray |
Author: | dberning [ October 10th, 2021, 11:26 pm ] |
Post subject: | Re: Ronan Regulator for DHT |
Aside from proper balanced heating of the tube and freedom from hum, high-frequency ac heating does not cause the electromigration issues that dc heating can. |
Author: | SoundMods [ October 11th, 2021, 10:41 am ] |
Post subject: | Re: Ronan Regulator for DHT |
dberning wrote: Aside from proper balanced heating of the tube and freedom from hum, high-frequency ac heating does not cause the electromigration issues that dc heating can. In the interest of clarity, David -- could you explain "electromigration?" |
Author: | tomp [ October 11th, 2021, 11:16 am ] |
Post subject: | Re: Ronan Regulator for DHT |
As I understand it, a DC current can cause molecules of the filament metal to migrate over time. It is similar to a plating process where metal molecules move to a charged metal plate. Different process but a similar result. It causes thinning in part of the filament which then has greater dissipation and earlier failure. |
Author: | SoundMods [ October 11th, 2021, 2:53 pm ] |
Post subject: | Re: Ronan Regulator for DHT |
tomp wrote: As I understand it, a DC current can cause molecules of the filament metal to migrate over time. It is similar to a plating process where metal molecules move to a charged metal plate. Different process but a similar result. It causes thinning in part of the filament which then has greater dissipation and earlier failure. Does this only apply to direct-heated triodes where the filament serves as the cathode as opposed to the filament heating a separate metal cathode? |
Author: | Roscoe Primrose [ October 11th, 2021, 3:02 pm ] |
Post subject: | Re: Ronan Regulator for DHT |
SoundMods wrote: tomp wrote: As I understand it, a DC current can cause molecules of the filament metal to migrate over time. It is similar to a plating process where metal molecules move to a charged metal plate. Different process but a similar result. It causes thinning in part of the filament which then has greater dissipation and earlier failure. Does this only apply to direct-heated triodes where the filament serves as the cathode as opposed to the filament heating a separate metal cathode? Yes. Except for the triodes part Roscoe |
Author: | tomp [ October 11th, 2021, 3:42 pm ] |
Post subject: | Re: Ronan Regulator for DHT |
It applies to any metal through which the DC current flows. If it is a direct heated cathode, it will be affected. If it is an indirect heated cathode only the filament wire will be affected, but if it fails the tube is toast anyway. |
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