Hi Guys,
Sorry Im posting on behalf of my friend, he's got some Sveltlana Sv 811 & 573 tubes on hand & would like to know what's the best approach to build a quite filament supply. Think the crux of it is the 4A rating.
Thanks in advance
Sorry Im posting on behalf of my friend, he's got some Sveltlana Sv 811 & 573 tubes on hand & would like to know what's the best approach to build a quite filament supply. Think the crux of it is the 4A rating.
Thanks in advance
You speaking of smps supply Lampie ? Think I read something like this but can't recall where. Do wonder if it would affect SQ.
Thank you again
Thank you again
I use a 500kHz sine wave without disturbing harmonics and center tap transformer to eliminate noise.
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Interesting would it be too much to ask if you'd mind sharing a schematic ?
So its a 500 khz sine wave generator of sorts ?
Looks kind of complex.
Thank you again.
So its a 500 khz sine wave generator of sorts ?
Looks kind of complex.
Thank you again.
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I based this on a David Berning Zotl as he described it in his Patent:
Tube amplifiers for high-end audio by The David Berning Company
I used his MicroZotl schematic as a starting point.
http://davidberning.com/images/microZOTL/microZOTL_Manual.pdf
Tube amplifiers for high-end audio by The David Berning Company
I used his MicroZotl schematic as a starting point.
http://davidberning.com/images/microZOTL/microZOTL_Manual.pdf
If you wanted to go down the DC heated route, you might not need to look much further than Rod Coleman's filament regulators:
Rod Coleman DHT Filament Regulator
4 Amps is a kit option and they are very quiet (they sound good too).
Rod Coleman DHT Filament Regulator
4 Amps is a kit option and they are very quiet (they sound good too).
Hi CV
I've bought some for my future build but didn't realize that Rod have them available for high ampere usage.
Thks
I've bought some for my future build but didn't realize that Rod have them available for high ampere usage.
Thks
DC on DHT is a nogo. The one side of the heater (cathode) has a lower voltage then the other side and therefore bias voltages are nowhere the same. Please look how a triode is build and you will agree. With indirectly heated tubes DC power is fine but not always required as these are more quiet in general.
Hi Lampie, wow a question on behalf of my friend becomes learning new things for me.
Thank you kindly
Thank you kindly
There is so much information to be found but to select the correct one is sometimes difficult.
Most of the information found on the web is sales driven and therefore needs to be filtered out.
Most of the information found on the web is sales driven and therefore needs to be filtered out.
Rod Coleman is an electronics engineer and his solution is tech driven as is Guido Tent's solution. Both make a buck. But that doesn't make the approach invalid. Distortion goes down. The only DC approach that is suspect is the low impedance one.
I do not want to be disrespectful towards anyone for that matter. I only find that in most cases only part of the "truth" is revealed when checking info on the web (understandable when trying to sell a product). In many cases even incorrect information (mainly unintentionally).
Fortunately for us DYIers there are reliable sources to be found as well (Including here on diyaudio).
And to guys like Nelson Pass, John Broskie, Stephie Bench, the late Allen Wright and many many more.
Fortunately for us DYIers there are reliable sources to be found as well (Including here on diyaudio).
And to guys like Nelson Pass, John Broskie, Stephie Bench, the late Allen Wright and many many more.
Ofcourse. I just wanted to counter your statement that DC on a DHT is a no go. The devil is in the details.
Well Lampie 🙂. I am more of a cut and paste builder. My theory doesn't go much further than ohm's law. So I can't answer your question. Apart from the fact that the filament is a resistor and therefore I suppose there is potential difference accross the filament. My point is that even if there is field shift. There are products with Rod's boards and EML tubes (who wrote the info you referred to in this thread) that have won best of show prices. (Using DC)
If their tubes have problems it doesn't mean this is a general issue but in reality that seller doesn't know what he is talking about!
Rod Coleman has actually bought EML 300B's and he is running them with his regulators if I am not wrong. No troubles.
Instead if you buy KR tubes their expert (a REAL one) will tell to use DC regulated supply for best performance and life!
DC supply is simply the best way to run DHT's. I have been using it for more than 15 years and never had a problem.
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