the 1954 Limiter!!

[MidnightArrakis]

looks more like heaters are just in wrong spot and plate and cathodes are drawn wrong...so yeah...

eesh....6sk7 look confusing....

[looks more like heaters are just in wrong spot] -- Where??? How???

[plate and cathodes are drawn wrong] -- OK, so I made an error!!! Let's see your impeccably redrawn version, OK???

[6sk7 look confusing] -- Created and drawn per the "1963 RCA Receiving Tube Manual". Please indicate and/or show what it is that is confusing. THANKS!!!










>> Updated schematic is attached for new "shredding" comments!!!

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[MidnightArrakis]

MidnightArrakis,​

Excellent!

opacheco

[Excellent!] -- Newly updated schematic is available. See my earlier response.

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[scott2000]

Let's see your impeccably redrawn version, OK???

Why would I take time to draw something out when you are the one offering up a condensed version to reflect Dave's mods to the 1954 Limiter? It's great that you're doing that. It's all kinda there already anyhow.

I do think it would be cool to have a professional schematic of his mods.
The original 1954 Limiter input and the Federal Am864 output are already known and simple enough. Dave's drawing is as well... trying understand the reasoning for some of the routes.
Maybe could ditch the heater connections to free up some space ?idk...
Thanks for doing this..

 

[MidnightArrakis]

I think we need to add one ground connection in the side chain tube rectifier/time network. Please check my attached pic.

opacheco

[I think we need to add one ground connection in the side chain tube rectifier/time network] -- I didn't tie the bottom heater connection to GROUND because I don't see a "connection junction point" where the switch "OFF" position crosses over the heater output line. So, while you can see a "connection junction point" at either end of the .1uF capacitor and another pair of "connection junction points" at either end of the 390-Ohm resistor, I just don't see the same "small black blob" at the crossover junction location where the "OFF" position crosses over the heater connection. Tough call, huh???


However, with that said, I just happened to see this small note as I am writing this response to you that is barely visible located at the very, very bottom of the hand-drawn schematic:


SO!!!.....I guess I will now go back into my schematic and connect one side of all of the 6.3VAC heater tube pins to GROUND and call it a day!!! Although I am not personally crazy about connecting one side of an AC voltage to GROUND, even if it is on a transformer secondary. I would think that running the filament AC voltage as an isolated set of connections to all of the tubes would be preferable. Are there any members out there who are more knowledgeable about these things than I am have any comments, recommendations and/or suggestions? It would be appreciated!!! THANKS!!!

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[MidnightArrakis]

Maybe could ditch the heater connections to free up some space ?idk...
Thanks for doing this..

[Maybe could ditch the heater connections to free up some space?] -- Perhaps you may be unaware of the fact that there is a significant difference between a "hand-drawn" schematic and one that is created using a modern CAD-system, especially when a PCB-design will be the end result of going through the schematic drawing process. What this means is.....should a PCB-design be the end result of an electronic CAD-created schematic, then all of the component pins need to be shown -- AND -- connected to "something" in order for the correct "netlist" data file to be generated so a PCB can be accurately and properly designed. It is as simple as that.

In other words.....should I ever happen to get around to actually building this "1954 Limiter", my approach would be to design one or more PCB's as is necessary in order to actually build this!!! And, I do things in this manner only because I am a combined "Mechanical Designer" -- AND -- a "PCB Designer". So, my approach to designing a piece of electronic equipment is to try and figure out how the entire schematic could be designed as one or more PCB's. I'm not worried about trying "to free up some space" while creating a CAD-designed schematic. I am trying to just make sure that everything is connected correctly so a nice PCB can be designed. That's just me!!!

[6sk7 look confusing] -- When "hand-drawing" a schematic, you can create your schematic symbols just about anyway that you want to create them. However, when using a modern schematic CAD-program, while you can also create any schematic symbol as you "willy-nilly" want to, there are now guidelines and standards for schematic symbol creation. And, as I have mentioned in my Post #121, all of my vacuum-tube symbols were created using the "1963 RCA Receiving Tube Manual" as my standard.

So, while using the "Receiving Tube Manual" tube symbols may not look as straightforward as the simpler "hand-drawn" symbols, the "Receiving Tube Manual" symbols are at least more technically correct not only with their visual presentation, but also by showing all of the symbol pinouts as are needed for a device to be correctly and entirely connected within a circuit. While you may not agree with it, the world today is a bit different than it was 60+ years ago when these schematics were first designed. I am just trying to adapt these vintage schematics into today's world so they can be possibly built again using today's technologies.

That's about it!!!

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[scott2000]

I guess I will now go back into my schematic and connect one side of all of the 6.3VAC heater tube pins to GROUND and call it a day!!!

The heaters in Dave's circuit are DC afaik. Would have to go back an read through..
Possible there is some confusion about the 3 way switch operation where a 6.3VAC signal is used for tube balancing and Dave just wrote what was in the article's drawing as it related to the heaters of the original. Not sure...

Switch function is mentioned in the article. It's unclear but maybe Dave's 6.3vac is also used to power a jewel light or something ..but maybe there is a tube with ac heaters. But the bridge dc heater supply is clearly there in his drawing...

 

[MidnightArrakis]

The heaters in Dave's circuit are DC afaik. Would have to go back an read through..
Possible there is some confusion about the 3 way switch operation where a 6.3VAC signal is used for tube balancing and Dave just wrote what was in the article's drawing as it related to the heaters of the original. Not sure...

Switch function is mentioned in the article. It's unclear but maybe Dave's 6.3vac is also used to power a jewel light or something ..but maybe there is a tube with ac heaters. But the bridge dc heater supply is clearly there in his drawing...

[The heaters in Dave's circuit are DC afaik / a 6.3VAC signal is used for tube balancing] -- And.....this is one item that I find to be rather confusing in Dave's circuit. There is one set of a 6.3VAC voltage used to power the tubes filaments, yet there is another separate 6.3VAC used as the "Balance". Then, to somewhat further complicate things as you have pointed out which is different than the original, Dave's circuit has the heaters running off of a DC voltage.

The schematic you included in Post #126 is the first time I have actually seen the original schematic and seeing it certainly cleared up one previous point of confusion for me.....that there actually is a "connection junction point" at the location where the switch "Limit Off" point connects to the GROUND of the "Balance" 6.3VAC connection. So, that's a good thing. THANKS FOR THAT!!!



In any case, I find this whole section of Dave's schematic to be rather confusing:



However, I already have some PCB-mounted 6.3VAC @ 6A transformer for the heaters, several 30,000uF @ 35V PCB-mounted capacitors and a small box filled with PCB-mounted 10-Amp bridge rectifiers.....so, whenever I may get around to designing and building this thing, I already have some of the more "weird" components all ready to go!!! And.....it looks as though it could easily fit within a 2U rack-chassis. YAY!!!

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[davemascera]

[The heaters in Dave's circuit are DC afaik / a 6.3VAC signal is used for tube balancing] -- And.....this is one item that I find to be rather confusing in Dave's circuit. There is one set of a 6.3VAC voltage used to power the tubes filaments, yet there is another separate 6.3VAC used as the "Balance". Then, to somewhat further complicate things as you have pointed out which is different than the original, Dave's circuit has the heaters running off of a DC voltage.

The schematic you included in Post #126 is the first time I have actually seen the original schematic and seeing it certainly cleared up one previous point of confusion for me.....that there actually is a "connection junction point" at the location where the switch "Limit Off" point connects to the GROUND of the "Balance" 6.3VAC connection. So, that's a good thing. THANKS FOR THAT!!!

View attachment 118807

In any case, I find this whole section of Dave's schematic to be rather confusing:

View attachment 118809

However, I already have some PCB-mounted 6.3VAC @ 6A transformer for the heaters, several 30,000uF @ 35V PCB-mounted capacitors and a small box filled with PCB-mounted 10-Amp bridge rectifiers.....so, whenever I may get around to designing and building this thing, I already have some of the more "weird" components all ready to go!!! And.....it looks as though it could easily fit within a 2U rack-chassis. YAY!!!

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Hey, sorry I didn't answer this. Yeah, the 6.3AC heater does indeed hit the 'balance' switch (it wouldn't work otherwise) before hitting the rectifier and becoming DC.

 

[MidnightArrakis]

Hey, sorry I didn't answer this. Yeah, the 6.3AC heater does indeed hit the 'balance' switch (it wouldn't work otherwise) before hitting the rectifier and becoming DC.

>> Would it be asking of you too much to review the "electronic version" schematic that I have posted in Post #121 and kindly inform me of any additions/changes/deletions/updates to it? I would really like to come up with a final and completely accurate and correct version of this schematic that can be "100% TRUSTED"!!! Is that possible for you to do?

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