Cetla416a, do you have anymore details on what you are thinking of making?
The CT link is typically used for a fuse location in a full-wave rectifier with capacitor input filter, as the link sees current pulses that reach zero level - which aids in the operation of the fuse when asked to blow.
If you are using a choke input filter, then the link current does not normally reach zero level, so the fusing scenario is a little more nuanced. Similarly for the use of a standby or time-delay relay contact switch in that link.
I'd suggest at least adding series ss diode protection to the 83 anodes, to avoid any chance of arc-back or flashing. This form of modern protection was not available back in the day, so wasn't discussed in vintage books/articles.
The CT link is typically used for a fuse location in a full-wave rectifier with capacitor input filter, as the link sees current pulses that reach zero level - which aids in the operation of the fuse when asked to blow.
If you are using a choke input filter, then the link current does not normally reach zero level, so the fusing scenario is a little more nuanced. Similarly for the use of a standby or time-delay relay contact switch in that link.
I'd suggest at least adding series ss diode protection to the 83 anodes, to avoid any chance of arc-back or flashing. This form of modern protection was not available back in the day, so wasn't discussed in vintage books/articles.
When ss where for the first time avaiable i tougth of it as a really big step forward, nowdays ppl want to use mercury rectifiers...
i am just glad the lovely smell of selenium rectifiers has not made comeback yet...
but who knows...time will tell
i am just glad the lovely smell of selenium rectifiers has not made comeback yet...
but who knows...time will tell
Selenium rectifiers have a huge voltage drop, and they age even sitting on the shelf, totally unusable even if you have a NOS.
Thinking about safety...if you post here asking questions, you do not know too well what you have to do, so better use MV when you get some experience and are confident about what you are doing.
Thinking about safety...if you post here asking questions, you do not know too well what you have to do, so better use MV when you get some experience and are confident about what you are doing.
I finished my amp a couple of months ago. 2A3 SET based on fi/Lofton-White circuit. Using 5U4GB, 5931 and 5V3A rectifiers. LCLC PS filtering.
If you have a separate filament winding available... Maybe adapt this delay as a soft start (play with the 10W resistor value) or to just delay HV completely at the primary of the HV transformer by omitting the 10W resistor? A simple RC delay with few parts that can fail over time. Overrate Q1 and use a high-quality long-life C1 and a not-cheap relay and a fixed resistor for R1 and it should be ultra reliable, no? An NPN used in this way is statistically more likely to fail open not closed (if it does fail), further protecting the 83 as the relay wouldn't close if Q1 does fail.
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I run 866A MVs with their separate filament transformers coming on at start-up. 120 seconds later an octal Amperite NO relay switch closes and supplies mains voltage to the PT. Works nicely and is simple to implement. If I need to condition a new pair of 866 tubes I just pull the relay and let the rectifiers cook away for 30min.
In addition to the above, I have ALL my gear plugged into Manual Reset GFCI receptacles. Prevents those dreaded hot-starts.
Manual Reset GFCI
Manual Reset GFCI
I love the octal Amperite NO relays. I use a 6NO30 in one of my circuits. I use it to switch a relay with multiple contacts. Once this relay is switched ON the 6 volts to the Amperite is switched off, so I have no problem when the amplifier is switched OFF and ON again.
I noticed the octals are very hard to find nowadays. I would like to have a spare one.
Regards, Gerrit
I noticed the octals are very hard to find nowadays. I would like to have a spare one.
Regards, Gerrit
At high power levels 83 compared to other tubes, will keep the supply voltage more stiff( the voltage will not sag so much being a low drop voltage tube). Any amp at its power limit generates IMD. An amp with MV at this limit generates less IMD.
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No delay required, the 82 & 83 were designed from the ground up to function without waiting for the filament.
I get the sense that many spend hours reviewing spec sheets for OPTs, Rs, Cs, Etc but won't take the time to open a .pdf tube sheet.
I'm 92 finally, I've got a vile of Hg in a drawer by my desk since I can remember.
And a small length of Indium used in a Zone Refining experiment
These daze the far greater danger is simply taking a walk, depending upon the jurisdiction you are in..
I did screwup a couple of weeks ago, I fell off my tractor, it pinned me under one of the rear wheels
Sh*t happens when & were we least expect it.
I'll scan & post the original 82 & 83 spec sheets tonite from the 1933 RCA Cunningham song book.
Then post it. It will be a .jpg for all to marvel at.👍
I get the sense that many spend hours reviewing spec sheets for OPTs, Rs, Cs, Etc but won't take the time to open a .pdf tube sheet.
I'm 92 finally, I've got a vile of Hg in a drawer by my desk since I can remember.
And a small length of Indium used in a Zone Refining experiment
These daze the far greater danger is simply taking a walk, depending upon the jurisdiction you are in..
I did screwup a couple of weeks ago, I fell off my tractor, it pinned me under one of the rear wheels
Sh*t happens when & were we least expect it.
I'll scan & post the original 82 & 83 spec sheets tonite from the 1933 RCA Cunningham song book.
Then post it. It will be a .jpg for all to marvel at.👍