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This whole thread is unnecessary and propagates the myth that delayed B+ is needed. I was surprised that it’s become an official pcb for sale by this forum.
I think you should rethink this. Well I am even sure
Triac with electronic stuff is not equal to "zero crossing SSR". Don't believe simple members but take it from TE:https://www.te.com/commerce/Documen...v&DocNm=13C3206_AppNote&DocType=CS&DocLang=EN
As said, many new developments have no benefit but drawbacks. Let's call it by the correct name then. Now I am off to the lab developing wireless mains power.
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horses for courses, some amps particularly with too many filter caps can sure use them, but for tube amps, can do without and in most cases an NTC is enough...
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I think you should rethink this. Well I am even sure
https://www.te.com/commerce/Documen...v&DocNm=13C3206_AppNote&DocType=CS&DocLang=EN
As said, many new developments have no benefit but drawbacks. Let's call it by the correct name then. Now I am off to the lab developing wireless mains power.
tried the solid state switch maybe 20 years ago, did not like it, my EI traffo went bussing, never tried it again after that...
I think you should rethink this. Well I am even sure
https://www.te.com/commerce/Documen...v&DocNm=13C3206_AppNote&DocType=CS&DocLang=EN
As said, many new developments have no benefit but drawbacks. Let's call it by the correct name then. Now I am off to the lab developing wireless mains power.
Yes they say exactly the same as I said; I found out the hard way. I didn't have that paper, thanks for finding it.
Jan
Tony, you DO know that the subject of this thread has nothing to do with transformer inrush current, right? The thread got hijacked somewhere along the way. Or people just read sloppy.
Jan
dc resistance of transforer secondaries reffered to primary and any other resistances in series form a time constant wit filter capacitance....these forn the inherent delays...
looking at tube power amp designs you can see high resistances used..
even a famous Sansui tube receiver employed such tricks...
these issues are very well know even in the 70's by engineers designing them...
it is only that now some diyers have become aware...always a welcome thing...
looking at tube power amp designs you can see high resistances used..
even a famous Sansui tube receiver employed such tricks...
these issues are very well know even in the 70's by engineers designing them...
it is only that now some diyers have become aware...always a welcome thing...
Delays? Do you have an idea of the value of those delays? Can you give us some numbers then?
I think you are confused.
In the discussion for the B+ delay, we are talking about a delay that is long enough to make sure that the heater is at temperature and emission has stabilized. A few tens of seconds.
Edit: for those who are wondering: 1 ohm and 1000uF is 1millisec time constant.
Jan
I think you are confused.
In the discussion for the B+ delay, we are talking about a delay that is long enough to make sure that the heater is at temperature and emission has stabilized. A few tens of seconds.
Edit: for those who are wondering: 1 ohm and 1000uF is 1millisec time constant.
Jan
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Sure, but it is good form here (actually is in the rules) to not hijack a thread. Sort of common decency.
Of course, if you are confused about what the subject of the thread actually means, you may be excused. At least, until it has been explained to you.
Edit: for those wondering: Threadjacking is the practice of taking over a thread by posting off-topic replies such that the original topic becomes diluted or lost. From rule # 1.
Jan
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Interesting read. I had no idea. However, been using SSR relays to control both power amps ( AR-D76 Dynaco ST0 & MKIII preamps etc) since 1980I think you should rethink this. Well I am even sure
https://www.te.com/commerce/Documen...v&DocNm=13C3206_AppNote&DocType=CS&DocLang=EN
As said, many new developments have no benefit but drawbacks. Let's call it by the correct name then. Now I am off to the lab developing wireless mains power.
with zero ill effect. In fact works like a dream. I guess the initial surge is
absorbed with no ill effect.
Using conventional relays will randomly act at zero crossing some times.
That is called denial of facts but please go on. It is the absolute worst of solutions but that is fashion in some circles. The zero ill effect is probably that nothing has died yet, then the SSR is overdimensioned. It does not work like a dream as you have not looked with scope what happens and guess stuff. It works but less OK for all parts involved. If overdimensioned and stressed stuff does not die that is not OK but "mediocre" or "bad" compared to solutions that don't stress parts and also work OK.
In engineering the rule of thumb is to use zero crossing SSR's only for ohmic loads. Like halogen heaters in copy machines etc. Why would I know? Well I made the error in switching neon lighting in a building with overdimensioned SSR's thinking it would work out OK. It did. It "worked like a dream" for a while Some got noisy, some neon ballasts started to make noise, SSR's started to die... Oh oh after investigation it turned out to be that zero crossing SSR's are better not used on reactive loads. Then someone got a light shock when changing a neon tube. After a while the SSR's leaked enough for electric shock and some neon tubes lighted up lightly when off. Disapproved solution, not safe.
So please measure your AR-D76 Dynaco ST0 & MKIII preamps and check if they are completely unpowered when OFF. Another drawback compared to the already mentioned ones.
There is nothing a tube rectifier won't solve
In engineering the rule of thumb is to use zero crossing SSR's only for ohmic loads. Like halogen heaters in copy machines etc. Why would I know? Well I made the error in switching neon lighting in a building with overdimensioned SSR's thinking it would work out OK. It did. It "worked like a dream" for a while
Some got noisy, some neon ballasts started to make noise, SSR's started to die... Oh oh after investigation it turned out to be that zero crossing SSR's are better not used on reactive loads. Then someone got a light shock when changing a neon tube. After a while the SSR's leaked enough for electric shock and some neon tubes lighted up lightly when off. Disapproved solution, not safe.So please measure your AR-D76 Dynaco ST0 & MKIII preamps and check if they are completely unpowered when OFF. Another drawback compared to the already mentioned ones.
There is nothing a tube rectifier won't solve
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Now you had me surprised as these were AFAIK not available last time when I did a project with SSR's. Good development!
Solid State Relay - 1 phase Peak Switching | Solid State Relays | ECD Controls
One sees that simple solutions often have the better specs so I would look critically to these peak switching relays when using them and check what happens. Some modern solutions are not as nice as they are presented. I really like LT4320 ideal rectifiers and still use these with pleasure. Someone here pointed at the 6 MHz charge pump in these.... I don't have an issue with it in reality but this info is NOT in the datasheet...
I dare to say that a simple old fashioned good quality power switch and an NTC to the primaries are the best way of switching on transformers in all its simplicity and when all plusses and minuses are added up. Further surge reduction can be done at the secondary side. Complex EE wet dream smart solutions often miss a few essential things here and there.
Solid State Relay - 1 phase Peak Switching | Solid State Relays | ECD Controls
One sees that simple solutions often have the better specs so I would look critically to these peak switching relays when using them and check what happens. Some modern solutions are not as nice as they are presented. I really like LT4320 ideal rectifiers and still use these with pleasure. Someone here pointed at the 6 MHz charge pump in these.... I don't have an issue with it in reality but this info is NOT in the datasheet...
I dare to say that a simple old fashioned good quality power switch and an NTC to the primaries are the best way of switching on transformers in all its simplicity and when all plusses and minuses are added up. Further surge reduction can be done at the secondary side. Complex EE wet dream smart solutions often miss a few essential things here and there.
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NTC on the primary of the mains transformer with a delay tube to prevent driver tubes lighting up like a flash bulb to extend the filament life and a damper tube between the central tap of the mains transformer H.T. to ground is all that's needed. No silicon stuff that in 5, 10 or 20 years is unobtainable. 50 year life expectancy. Soft start filament and B+ and easy on the B+ capacitors with no voltage overshoot if values are selected properly. Easy.