What if i have 9V battery with BC107? It has Ic=2mA and Vce=5V which seems that supply voltage would be inefficent to handle it. How to do calculations for such constraints where i cannot use other supply voltage? I know this is not efficent, but for sake of calculations.

Even tho English isn’t my mother language I have understood all of your explanations regarding tubes subject ! You are such a wonderful teacher my friend! Thank you so much!! I’ve downloaded that manual, thank you for that too!

7:15 I assume this is to impedance match? If so, why is this important?

Thank u sir, great electronic school class.

Hi Tom great video as usual. Haven't heard from you a while and miss your videos; sure learned a lot ad hpe you are still doing ok. I recently got given 4 old tube radios from a friend so I went from about zero to 4+. I want to restore them and was wondering if you have a good low-cost place to get the film capacitors from? Anyway, hope you get back to YouTubing again! 73...

Can you fix the bad ones, by charging them up?

Circa 1935 Alan Blunlein wrote a paper calling this ultra linear operation a distributed load amplifier. Williamson allowed a little grid current. This gave 1.5 extra watts. Quad used cathode windings. Ultra linear needs more care than triode especially if using loop negative feedback including the output transformer . 1972 GEC book of designs went into detail. Matching networks to the ultra linear taps for example.

Really a superb video. Great incremental approach to teach the increasing complexity along with schematics, use cases, and physical pictures of tube components. I've watched numerous tube tutorials and this one is really substantially better. So I subscribed :)

At 12:21 you say you set F to 7. It clearly shows that you set F to 8 in the video. Can you verify the discrepancy?

I don't think the UAF42 is out of date, it depends on what you are trying to do with it. Like you mentioned, the center frequency can be controlled by a digital potentiometer and can have a very high Q. What you did not mention was that there is also a high-pass and low pass out in addition to the bandpass which is useful if you are trying to isolate multiple frequencies. Thanks for the video, I'll have to check out your others.

Great video. I have one of these B&K 700s. Would you happen to know anyone that could restore it?

The neximage5 is a solar system imager, so it does not have the larger chip/wider field and sensitivity needed for deep space objects. You might try a basic thread on 1.25' .5x focal reducer which helps with field of view and sensitivity making the scope faster, 8"f5 1000mm focal length.

The mirror of the DS 114 is anything but corrective, it is spherical and there are bird jones "corrector " lenses in the focuser tube. It is 1000mm right? Condolences on that one, one of the ubiquitous bird jones scopes that beginners are advised against buying. But if you only use it at low powers for dsos, it can be accaptable because it cant go very wide like it's better 114 f4 parabolic cousins can do, but those need premium eyepieces to get sharp wide fields

Imagine owning a 22" celestron pacific Schmidt cassegrain

I can only think of one 40" refractor and I don't think any bigger were made, and if so only the one 40" remains. The Yerkes

I have one of the generic moon and skyglow filter, I think it is an astromania or svbony but it has no brand on it. I also have the original baader version. I don't remember if i did a critical comparison, but I can say the baader is not as dark of a purple color and hence passes more light than the cheap one.

The #21 orange is good for mars. Otherwise only the very light filters, the light yellows and light/pale blue filters are the only ones I ever liked to use. And actually the baader neodynium moon and sky glow filter is excellent on jupiter as it also acts as an RGB intensifier. The contrast booster version of the filter, which added a yellow tint to help with chromatic abberations in achromat refractors, is an excellent mars filter in all types of scopes. Back then, stacking the moon and sky glow filter with the baader fringe killer (chromatic abberation filter), or other fringe killer filter, tended to lessen the yellow tint of the fringe killer, giving a more neutral color while still reducing purple fringes. This led to the development of the baader semi apo filter, which does what the stack of the MSG/FK filters did. I find it to have a slight green tint . I have a 2" version that I will probaby sell because my 4"f10 refractor has low enough CA, that I preferred the unfiltered view because of the green tint and about 5% light loss of the filter. I decided to keep it for a time because i got a cheap beat up omni 102 f6.5 refractor tube, but that turned out to be out of collimation and useless for planets, then it effectively got stolen when it was in my van with other scopes, mounts and music gear, that got unfairly impounded and I was prevented from getting it out in time. So I still don't have nuch use for that filter

I have a 1991 10" lx premiere, which is an lx6 with an f10 optical tube rather than the horrible f6.3 optical tubes. I got it to replace my stolen c11/g11, and it was a straight across trade for the g11 tripod, weights and my guidescope hardware that the thieves didn't know to steal, so it was essentially free. It came with the dec motor and 4 or 5 of the old super plossls. The superwedge and fork in general is much harder to setup and transport than the c11/g11 which broke down into lighter components. It isn't quite the same but for the trade at zero.cost I cant really complain

While i like some of the components in that 2" kit, I dont think it is a good value. The only filter that you need is the moon filter, and the diagonal is not dielectric, just a standard aluminum. The eyepieces are only 3 element modified wide angle kellners. Meade also sells the exact same kit now. They are all made by GSO. Buying a dielectric diagonal and a better 40mm like a 38mm Q70 or william optics 40mm swan was a better way to go. The SvBONY eyepieces use glass lenses, only the aspheric series has a single plastic lens, the rest are glass. Others watching this should know that the 2" kit is trash in fast scopes, and even the Q70 type eyepieces are not sharp to the edge in fast scopes. That is where the meade ultrawide, and other nagler clones like the ES82 and panoptic and panoptic clones ljke the es68, are needed for sharp to the edge performance. Other "internally barlowed" designs can also be sharp to the edge, such as pentax xw, vixen LVW, hyperion, and many of the planetary long eye relief designs. But wide field kellner konig and erfle variants are only good in slow scopes, f7/f8 and slower. For even slower.scopes like SCT, these eyepieces perform reasonably well. Note that the 26mm in the kit is only 56deg and could have fit in a 1.25" housing. But even though the 32 and 40mm are advertised to also be 56 degrees, they are actually wider at about 65degrees. In fact, the 40mm has a wider true and apparent field than the 42mm GSO superview, which is advertised at 65deg but is actually more like 60-62 in the 42mm and around 52-55deg in the 50mm. The 3 element kit eyepieces actually do have good contrast and light throughput due to having less glass, which is helpful for faint DSOs. I used the 40mm e-lux (kit ep that I got used by itself) often as an outreach eyepiece that lived in my 8" meade lx200R ota case. I now have an older astrola branded version of the same eyepiece, that is filling the hole in my set, where a nicer japanese made 40mm superwide that uses the maximum 2" field or very close to it, like a UO MK70, TV widefield, or meade 4000swa, the one I used to own, would be. I had all my equipment stolen from storage in 2018, and replaced some of it with less expensive vintage stuff, like a powerstar C8, and a 10" meade LX premiere (f10 version of LX6) to replace my c11/g11 setup. That 26mm 5 element smoothside meade super plossl is indeed excellent and I was lucky to get it (and a few others) with the used 10", and the 26mm celstron/vixen silvertop plossl with the c8. But I generally prefer my 65deg LVWs, 82-84 deg meade UWAs and lone nagler (I had more in my pre storage theft days), and my 28mm megaview (82deg UWAN/PWA type) and 20mm WO XWA 100deg. I also have a 24mm ES68 that I mainly got for my 1.25 limited xt6 dob, orion ST80, and meade 114 lightbridge (which got lent/lost, refusal to return), as well as my etx90 ota. But I can also use it in my bigger scopes as I have a hole between my 28mm and 20/22mm eyepieces. Sometimes exit pupil size is more important than true field of view, and even though the 24mm es68 is much narrower field than 20mm XWA, sometimes you need a little more brightness. One of my regrets in my previous pre 2018 incarnation was selling my 23mm axiom lx (same as 24mm UWA/es82 so really it was 24mm) because it had the same true field as my 20mm ES100 (I especially miss my 14mm ES100, but the 20xwa is significantly better than the 20mm es100, and the 28mm megaview is close enough to the 31 nagler for me to be very happy, other than the 3mm focal length difference and wider true field of the 31)

Panoptic doesn't rival nagler, it complements it, both invented by Al Nagler. Also, naglers and panoptics have never been $100 except when the 4.8mm type 1 nagler was cleared out in 2004 for $105. Typically.naglers go for $300ish to $700. But some nagler clones are in the $100 range, or used to be before explore scientific doubled the price of their 82deg eyepieces after cutting off meade and celestron from selling their same versions of the eyepieces made by JOC who owns Explore scientific. But some are still $99 like the excellent UWAN type now sold by several brands in 4mm 7mm 16mm and the excellent alternative to the 26 and 31mm naglers, the 28mm UWAN, which ranges from $200 for the stellarvue, to $300ish for the meade PWA. All are made by the same manufacturer who made the original william optics UWAN 20 years ago.

Nagler has always owned televue, he didn't work for orion or any other telescope company since he started televue in the mid 70s

Ma means modified achromat, which is basically a kellner with a wider field

I appreciate this honest and direct presentation of the NTSC television servicing industry. Thanks. I will view it again and share it elsewhere. In particular, your recommendation of many Sencore products shows the efforts design and manufacturing engineers and technicians made to provide effective instruments for consumer electronic products before the digital age. (btw - I wrote the instruction manual for the TF46 Super Cricket)

To follow up on the video. I grew in my Dad's TV shop "Hoffmann's TV' in Mandan, ND, and spent many hours looking at those Sams Photofact schematics with the waveforms of the signals. Unfortunately, he never learned to 'scope' the signal, relying instead on how the relative voltages appeared, according to his training with aircraft radio with tube-type equipment during World War Two. Those highly informative and informational diagrams were very influential when I was preparing Sencore instructional manuals for products in the mid-1970s.

Some corrections are needed. The Sencore PS163 was/is my favorite scope of the time, from the early 1970s. First of all, it was 'dual-trace', meaning that a service technician could observe both the input and the output of an electronic product in a way they could compare the entire system, rather than the typical single-trace scopes from Heathkit, RCA, and even Sencore (PS148), as well as the more expensive engineering products from HP, Tektronics, and others. In its design the PS163 was based on several circuit boards for the dual-channel inputs, the time-base synchronization board, and the high voltage board for the CRT. Unique at the time were the 'clip-on' probes that allowed a technician to connect to a measurement point without having to hold a pointed probe while viewing the screen and twirling the dials. I also appreciated the definite "click" of those dials and buttons of the PS163, compared to other products. I worked at Sencore in the early 1970s and sold many PS163s in the Mid-Atlantic and the MidWest regions at the time. I also produced the screen waveforms for a Sencore booklet that described NTSC television signals from front-to-back in a typical color television set of the day.

I bought my first slide rule as a junior in high school, a Pickett 10” LogLog, 1967. I already knew how to use it, because I had been playing around with my father’s slide rule for a couple of years. I used that slide rule until I bought the HP-35, just a couple of weeks after it hit the market. Now I have a small collection of slide rules, various brands and lengths, and a circular slide rule too.

Get in touch. We have same interests and I am in Bastrop Tx

Are u in cent Tx. I am in Bastrop cent Tx

The crowhurst amplifier. Very good audio author and audio expert

Pleasecall a horse a horse nthis is the norman crowhurst amplifier

Great content sir! thanks for posting,

15:40 "as good as hobbyist can afford" that's the same stuff even highest quality electronics producers can do, offcourse these days it's mostly cheapest lytics in cheapest devices... ie there are no better quality lytics than japanese

so amazing information thanks for you

Still have my N1725 that I purchased in Fall 1967 as a Freshman Physics major at U of Md. Although generally used it, I was seduced by the department’s 4 station Wang calculator (labs) and then later by the Univac 1108 timeshare at UOM. Recently got back into the N1725. You are right about addressing the mathematical fundamentals. How much I have forgotten!

Great video series. I'm new to electronics and found your video very handy. Thank you.

I like that curve tracer!! Gary Grove , Minneapolis, MN 73's

Great explanation! Thanks for sharing!

This is the best video about this topic on KZfaq! Couldn't be any cleaner. Thank you!

Any updates about Tom ? I learned a lot from his videos. I hope he is safe and okay.🙏🙏🙏

Silly doug

Ahh, I built that exact radio in college around the time you made this video and I'm brushing up for a job interview tomorrow. Incredibly useful, thanks for your upload!

Very good explanation of basic operation. I have a question about turning it on and off. Is there a correct way to turn it off? I mean, how do I properly turn off the scope? Is it the same way as normal PC?

Wow. You are an awesome teacher.

Thanks for the video. Almost the perfect video for me. If only you had tested a push pull output transformer of known impedance with the AD2 to see if it is able to estimate the input impedance accurately? Could be great to use the AD2 to test transformers of unknown impedance.

is the video producer dead?

is the producer of this video dead?

Is the producer of this video dead?

My idea of a legacy oscilloscope is my trusty Tek 475. An IBM “surplus” item, new about 1973 and still in spec. I also have a Rigol MSO5354 amongst others. Finally disposed of all my vacuum tube era test equipment. Parts too hard to find!

GOOD..!!

So electrons can move in the vacuum inside a tube just not through a wire?