I'm so glad
I'm so glad
I'm glad I'm glad I'm glad 

I finally finished a book
You cannot view this attachment.

It took me about a year but to be fair progress slowed during the summer (I cut grass on the side and it gets pretty crazy)
You cannot view this attachment.

So you're thinking yeah that's real dope and all but it's not like you're fixing any amps 

Ok I'm getting to that so the good part is this book is next 
You cannot view this attachment.

And check it out
You cannot view this attachment.

 

So I'm stoked I actually started the second book at one time and made it to the zener chapter then realized I better do the other book first 

The first book was really cool but got kinda crazy at the end the last chapter I was measuring rise time and tilt 

You cannot view this attachment.

I'm hoping in about six months or so when somebody reports the E B C voltages I may have somewhat of a clue 🧩   

And ya knew it was coming 

A parallel LCR circuit
You cannot view this attachment.

You cannot view this attachment.

It really helps to actually do stuff.  I wasn't getting the results I needed so I had to try and fix it.  Turned out I was using the 1k resistor that was called for previously when I fact a 100k resistor was needed.

 

Seems like it's always darkest before the dawn  I'm so ready to be done with this book I literally have like 25 pages to go and still slugging it out 

Anyhow the assignment was to put together the circuit
You cannot view this attachment.

Then calculate the resonant frequency and adjust signal frequency until the voltage across the resistor is maximized.

So I did everything
You cannot view this attachment.

and on the scope display the top is Vr and the bottom is Vin
You cannot view this attachment.

So I had calculated 50.33 khz and ended up with this
You cannot view this attachment.

So I really like how in this field the experiments closely match the calculations 

So now I somewhat can start to comprehend how an old radio tuning capacitor can pull in a radio station but what bothers me is that is only one variable.  Or rather someone tuning in a station isn't adjusting a capacitor AND inductor.
Anyway don't want to open a can of worms 

Ok now it makes sense why in another thread I suspected a tube and G1 had me check for heater voltage ⚡

I bet many innocent tubes are wrongly accused and framed 

Hi Mr Joe afaik pretty sure nothing like that existed...however that is an excellent point in that there is or was a plethora of natural gas, propane, pipelines, petroleum in the area. 
I got lucky for some reason I never had to explain to law enforcement why I was sitting in an old heap behind a business by myself at 0200 

In contrast (apparently) TV tube heaters are (were) in series

You cannot view this attachment.

I guess my job now is to find out if my tube amp heater circuit is like an old TV or the 📻 radio in TV's car 🚗

 

About forty years ago when I was still in college and working part time the university had afternoon/evening classes I guess it was geared towards working older people 

So anyway I was a 🦇 vampire staying up all night doing homework and playing guitar 🎸 etc and my routine had me going to bed 🛏� at about 0530.  I had found that Casper the friendly ghost 👻 came on like at 0500 and that was my SOP.

So what does all that have to do with anything? 
At night in the small town it got quiet with the exception of an audible hum 
Sometimes I would have the windows open I was in an upstairs room at the end of the house.  This (real or perceived) hum/pitch/monotone frequency tormented me to some end.  In fact I made a few nocturnal excursions around town looking for it.  I would drive around to different areas and shut the engine (slant six 66 Dart) off and sit and try to determine where it was coming from.
Spoiler alert: I never did find it or find out anything.
When I told my dad about it he said there was a composer that went crazy because of constantly hearing 440 or something 

I'm glad you were nice
I actually got scared when I saw you replied 

 

Ok I tried it 
You cannot view this attachment.
I got lucky I guess 

Might be time to buy a lottery ticket 

Well I got into somewhat of a pickle 🥒

I have three chapters to go in my little book before I can go on to the cool second book that has me playing with transistors and diodes and stuff but I hit a 🛣� roadblock.

The third from the last chapter was on bandpass filters so I ran into trouble with the impedance calculations of inductors and capacitaters and resistors in parallel.  Meanwhile I was like "what is all this j and theta crap" 

I tried to get through it but ultimately admitted defeat and went back to a chapter in a book a did a few years ago so I'm midway through that.
You cannot view this attachment.

So all good it should be rewarding to get to the lab portion and see 🙈 how the 🥼 experimental 🧪 results compare.

There is a post by one of our esteemed members from near Australia 🦘 🌏 where he told someone what frequency to expect from a potentiometer and capacitater  so I may play around and see if I can figure out how he calculated that   

Ok I went and redid the experiment this time using my scope to measure the voltage drop across the resistor at different frequencies and got some good results 
(bottom left)
You cannot view this attachment.


gratuitous scope pic

You cannot view this attachment.

 

So all I need now is a gif of Keanu going
"DUDE.....your meter can't handle it "

 

Here is an 🥼🧪 experiment I just did

I was really impressed how the measured hung right in there with the calculated

Unfortunately at 50 khz it went out the window
You cannot view this attachment.

Here is the "schematic" 

You cannot view this attachment.

I know

I should have remeasured everything with my scope.   

Well....I wasn't gonna mention it but since you brought it up 

I was reading this the day before yesterday and of course I instantly remembered you talking about your car radio

You cannot view this attachment.

Diagram and text Art Margolis

Well....you knew I was gonna do it 

Amp in playing mode
You cannot view this attachment.

You cannot view this attachment.

Amp on standby

You cannot view this attachment.

You cannot view this attachment.

 

Holy cow 🐄🐮

Seeing the difference between LED and incandescent bulbs