Get off my LAWN! "Grumpy Old Farts"

[GonePlaid]

I never knew he owned a Honda.

 

[Passinwind]

ETA: P.S. Is there a place where I can get a picture of a cross-section of a vacuum tube (e.g., a 6L6GC)? I want to get a feel for its dimensions and relate that back to electron beam optics. I'm trying bit by bit to understand these things from the ground up. Thanks. (A cursory search for this yielded me nothing.)

Just download everything here: Technical books online

If it's not there it probably doesn't exist.

I'll do a quick scan through some of the pdfs I've hoovered off that site, but it may take me a day or three to get to it.

 

[Haroldo]

O, I thought you were talking about delivering DNA inside cells, that viral vector.

A gif is a series of images. Can malware code be imbedded inside images? Yes. There would have to be a trojan horse that could unpack and assemble the virus from code in the images. There are far easier ways to accomplish this.

Virus scanning software on your computer is a good investment. It looks for identified code segment markers that indicate the presence of something undesirable.

I use this product: Malwarebytes Cybersecurity for Windows, Mac, Android & iOS

Since a gif is a loop, it does present a small load to the Computer, slowing it down but not in a meaningful way.

That was my suspicion, tho' I (obviously) wasn't sure. My computer is and has been for a long time loaded up with anti-virals.

I can live with the graphic loops, tho' not always with the loops' content.

Thanks.

 

[Haroldo]

Just download everything here: Technical books online

If it's not there it probably doesn't exist.

I'll do a quick scan through some of the pdfs I've hoovered off that site, but it may take me a day or three to get to it.

Thanks. I'll blast through these in a day or so.

 

[LBS-bass]

I never knew he owned a Honda.

 

[beans-on-toast]

ETA: P.S. Is there a place where I can get a picture of a cross-section of a vacuum tube (e.g., a 6L6GC)? I want to get a feel for its dimensions and relate that back to electron beam optics. I'm trying bit by bit to understand these things from the ground up. Thanks. (A cursory search for this yielded me nothing.)

ETA (further): PPS. Are all tubes in this day and age driven by indirectly heated cathodes? Is it always the case that schematics ignore the filament circuits? More thanks.

Invalid Link Removed

Not to scale but the components labelled.

See Link Removed for images of different tubes of the same type. Here is an example.

Schematics often show the heater pin connections at the power transformer heater winding circuit. This is separate from the plate, screen, cathode, grid connections.

The 6.3V heater connections are at the bottom right with the exception of the 5AR4 rectifier tube. In the case of the latter, there is a separate 5V heater winding on the power transformer.

Rectifier tubes can be directly heated (for example, 5U4GB), or indirectly heated (5AR4), depending on the type. Both types can be found in amps with tube rectifiers. Indirectly heated have a slow turn on which is good for the capacitors. In directly heated cathodes, the heater filament itself is the cathode and emits the electrons directly. In indirectly heated tubes, the heater is separate, heat generated by the filament is applied to the cathode, heats it to the point where it boils off electrons.


The Rectifier Tube



Small signal tubes such as the 12AX7 used in amps are indirectly heated.

 

[the slug]

The Yogi Bear pronunciation?

my one son's nickname is boo boo I would always call him "hey boo boo". that was a good show

 

[Haroldo]

Invalid Link Removed

Not to scale but the components labelled.


View attachment 3492210



See Link Removed for images of different tubes of the same type. Here is an example.

View attachment 3492216

Schematics often show the heater pin connections at the power transformer heater winding circuit. This is separate from the plate, screen, cathode, grid connections.

The 6.3V heater connections are at the bottom right with the exception of the 5AR4 rectifier tube. In the case of the latter, there is a separate 5V heater winding on the power transformer.

View attachment 3492284


Rectifier tubes can be directly heated (for example, 5U4GB), or indirectly heated (5AR4), depending on the type. Both types can be found in amps with tube rectifiers. Indirectly heated have a slow turn on which is good for the capacitors. In directly heated cathodes, the heater filament itself is the cathode and emits the electrons directly. In indirectly heated tubes, the heater is separate, heat generated by the filament is applied to the cathode, heats it to the point where it boils off electrons.


The Rectifier Tube



Small signal tubes such as the 12AX7 used in amps are indirectly heated.

Thank you. My background includes a lot of ion source design and operation - there, too, you find both directly and indirectly heated cathodes. (Also, rf and electron cyclotron resonance driven sources. Different kettles of fish, entirely.) I am in a period of re-education.

One of my questions was prompted by the "500V 6L6" thread in the Amps sub-forum and the included Peavey 65 schematic which didn't (if memory serves) include the heater circuit.

 

[beans-on-toast]

Thank you. My background includes a lot of ion source design and operation - there, too, you find both directly and indirectly heated cathodes. (Also, rf and electron cyclotron resonance driven sources. Different kettles of fish, entirely.) I am in a period of re-education.

One of my questions was prompted by the "500V 6L6" thread in the Amps sub-forum and the included Peavey 65 schematic which didn't (if memory serves) include the heater circuit.

I’ve used a mass spec and other diagnostic equipment in the distant past.

The 500v 6L6 thread is over thought. The limiting factor in this case is heat dissipation. If the tubes are running too hot, simply blow a fan onto them. The amp needs to be serviced by a tech: contacts cleaned, tubes checked, biased. The amp was designed to run at 508V at 120VAC+/- some spec. Let’s be conservative and say 10%. The amp will be within the design operating specs with 6L6GC tubes installed. If concerned, use NOS tubes. No problems as far as I can see.

Schematic posted below, the heater circuit and connections are there

 

[Haroldo]

I’ve used mass spec and other test equipment in the distant past.

The 500v 6L6 thread is over thought. The limiting factor in this case is heat dissipation. If the tubes are running too hot, simply blow a fan onto them. The amp needs to be serviced by a tech: contacts cleaned, tubes checked, biased. The amp was designed to run at 508V at 120VAC+/- some spec. Let’s be conservative and say 10%. The amp will be within the design operating specs with 6L6GC tubes installed. If concerned, use NOS tubes. No problems as far as I can see.

Yerp. Tho' sometimes it seems what is proposed in threads such as that could function as great self-education projects. I can see the lure of becoming a tech as a hobby/avocation. The question, I guess, is it possible to do so safely. I know it's really inefficient to do that. If done safely, and given time and money (mistakes will be made), I think that sort of autodiactic behavior is not a bad thing. Thoughts?

 

[Passinwind]

They just don’t show the heater connections in that schematic. This is more the exception rather than the rule.

Sometimes the filament supply string is on the power supply schematic rather than the main board one.

 

[beans-on-toast]

Yerp. Tho' sometimes it seems what is proposed in threads such as that could function as great self-education projects. I can see the lure of becoming a tech as a hobby/avocation. The question, I guess, is it possible to do so safely. I know it's really inefficient to do that. If done safely, and given time and money (mistakes will be made), I think that sort of autodiactic behavior is not a bad thing. Thoughts?

Of course anyone can do it. If you want a good basic introduction to tube amps, consider this book:

Guitar Amplifier Electronics: Basic Theory

 

[Haroldo]

Of course you can do it. If you want a good basic introduction to tube amps, consider this book:

Guitar Amplifier Electronics: Basic Theory

Thanks. Tho' I was initially thinking about other folks and in general terms, it might be more likely I was thinking about myself.

 

[beans-on-toast]

Thanks. Tho' I was initially thinking about other folks and in general terms, it might be more likely I was thinking about myself.

I started figuring out and repairing tube radios, alone in the basement, as a five year old kid. I lived through it although I do have some nice soldering iron burns.

 

[beans-on-toast]

Sometimes the filament supply string is on the power supply schematic rather than the main board one.

I just rechecked, the power supply and the heater connections are on the schematic, bottom right.

 

[Haroldo]

I just rechecked, the power supply and the heater connections are on the schematic, bottom right.

View attachment 3492467

And so they are. I never flipped the thing and never looked down.

 

[Haroldo]

I started figuring out and repairing tube radios, alone in the basement, as a five year old kid. I lived through it although I do have some nice soldering iron burns.

I am mightily impressed. That sort of behavior really has served as a launching pad for so much of tech.

 

[GonePlaid]

I am mightily impressed. That sort of behavior really has served as a launching pad for so much of tech.

Just read-and reread-the tube discussion y'all are having.

 

[Haroldo]

Just read-and reread-the tube discussion y'all are having.

As our California-based, bass playing friend always says (paraphrasing here), 'I thank you for your indulgence'.

 

[GwenOnBass]

View attachment 3492300

And (no potentially virus-payload sort of animated .gif, sorry!) reminded of where in the Bible we are told of PMS: Mary rode Joseph's ass all the way to Bethlehem.

***

Used to be a good hack was recognized as a good hack. Not really sure when good hacks became malicious hacks.
The Story of Mel

is an inspiring tale that I suspect shows up in some form on every platform that can be hacked, all things bass included.