Poll: are A/V jacks "cheating"?

[JohnCT]

Just wondering what everyone thinks. Adding A/V jacks takes all the tuned circuits out of the loop, hence my ambivalence about adding them.

Does anyone *not* install them because they think it's a more pure experience to run the TV as built?

I don't know if I'm wording this correctly but I'm inclined to think it's kind of cheating a bit.

Very interested in hearing some thoughts on this. Thanks!

John

[decojoe67]

Originally Posted by JohnCT

Just wondering what everyone thinks. Adding A/V jacks takes all the tuned circuits out of the loop, hence my ambivalence about adding them.

Does anyone *not* install them because they think it's a more pure experience to run the TV as built?

I don't know if I'm wording this correctly but I'm inclined to think it's kind of cheating a bit.

Very interested in hearing some thoughts on this. Thanks!

John

My repairman mentions that with finicky sets like the early Philco's, but I always shoot it down. I do like a set working as it was from the factory. Even with the HV, he has mentions modern replacements. I would only have these mods done if it was a rare set and there was no other choice. For me it's starts to lean towards just installing a modern chassis and storing the original away. I've accepted these early TV chassis' with all their quirks.

[bandersen]

I've never installed them and yes I do see it a bit as cheating. It's removing half of the circuitry from the TV and just turning it in to a monitor. I like the novelty of having to tune in and adjust the controls.

[Yamamaya42]

You sometimes have limited choice, nobody fixes tuners anymore as far as I can find, and if the IF section is out of tune, and you don't have known GOOD calibrated equipment to align it, (sweep marker generator, etc ) and the know how to use it w/o making it worse off than when you started, A/V direct input may be the better choice.

[Electronic M]

Lean towards RF but there's Merritt in both approaches depending on the situation.

With the number of sets I own even wired RF with cheaper cabling is wildly impractical save for a few sets so most of my collection gets signal from a cluster of BT modulators feeding tuned dipoles with enough TX power to cover my block.

On my 21CT55 I was leaning towards going with video input (I built and successfully tested the tube amp box for it) until I found I could get the reciever chain to pass color and work by adjusting the osc slugs for each channel.

Last year me and a friend bought and split up a 17" predicta...my friend wanted the tuner (the one in his was wrong and shot) and speaker and the rest became mine....I mixed and matched with my keeper and ended up with one with good RF and cosmetics and a second ugly one with no tuner that I converted to a monitor to sell (sweep would die after a few minutes so it wasn't exactly a great set).

I have an RCA TM21, Contact CYB, and 3 other tube Broadcast/industrial monitors that never had RF/IF/Audio....I do have one IIRC conrac tube rack mount tuner and a HH Scott lab grade rack mount tube amp, but that isn't enough to go around.
I also have some tube Setchell Carlson and Admiral School TVs/monitors that can take either input.

Then there's installing an input just for the fun of it...some sets are just asking for an input such as a early 50s RCA that has an RCA audio input and an RCA jack marked video....That set needs an input so that jack can live up to expectations.

TLDR version: it is nicer to have RF but sometimes you gotta do what you gotta do to get/keep a set running.

[hfrazier]

I feel that if they can be added in in a reversible manner then it's not a big deal.
Although, what's even more fun is making a RF modulator media server - I just finished adding my Raspberry Pi-powered media player with RF Modulator and it works quite well going through the original tuner of my Zenith!

[dtvmcdonald]

Aligning a CT-100 to a perfect state with cheap equipment is possible. I've done it with
a cheap Eico sweeper and an old RCA signal generator. I set the marker frequencies
by watching them on my SDR.

I've also done and checked alignments using a broadband noise generator and that same SDR loosely (like 0.5 pF) coupled to the appropriate spot in the TV or radio. The noiee generator consists of a Zener diode and a one transistor emitter follower.

You just have to figure out how to use the equipment to sort of follow instructions
designed for other methods.

As I like to point out, that while the CT-100 has probably the best tube color TV IF response, there is at least one other TV that really truly is as good: the TRK-12.
Yes, you read that right.

[Kevin Kuehn]

I'd sure rather see an old TV used as an A/V monitor than gutted for some other application. For nostalgic sake most people wouldn't know the difference.

[Phil Nelson]

I can relate to both points of view, and I have followed both paths at different times, with different sets.

Most of my TVs are restored to be operational "front to back," just as the designers intended. But in a handful, for whatever reason, I ended up installing jacks to inject audio and video.

In my Admiral 24C15 console, I made the A/V connection switchable, so you can either plug in a VCR or DVD player directly, or flip the switch and watch whatever comes in through the antenna (for example, from my in-home TV transmitter). This article describes the switchable setup:

https://antiqueradio.org/A-V_AdapterForVintageTVs.htm

When I got rid of that Admiral set, the switchable input was a nice selling point!

I also built an A/V adapter for my RCA CT-100, based on a design from the 1956 RCA Broadcast News. The adapter requires no hardwired connections to the CT-100 and it has a switch to toggle between direct input and an antenna signal:

https://antiqueradio.org/VideoAdapte...Television.htm

In another case, my DuMont RA-102, I experimented with direct input, using a preamp/video inverter, but I ended up not installing it. In part, this was just a fun experiment, but it also helped me evaluate my TV's condition. The preamp/inverter worked, but its picture wasn't dramatically better than the alternative (i.e., the native picture was pretty darned good!). The RA-102 also has more historical importance than most of the TVs in my collection, so I put the injector aside and left the factory wiring alone.

https://antiqueradio.org/DuMontRA-10...Television.htm

There's more than one way to skin a cat! And with a little forethought, you can make a direct input switchable, or at least easily reversible. If I sell a TV where I have installed an A/V input, I'll include a note explaining how to uninstall it and restore the factory connections.

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html

[MadMan]

Nonsense. We all want to preserve these old things. You don't preserve something that performs a useful function by allowing it to become irrelevant. If adding AV jacks or a media server is what it takes, then so shall it be. Obviously, we should not be modifying it in some irreversible manner.

[decojoe67]

Now that it's explained and shown I'm more in agreement. Now I regret parting with my Philco 48-1000. The audio was troublesome and my repairman suggested a direct input. Something made me feel that it was lame way to solve the issue. I actually traded that set because of that. If it was now I wouldn't have.

[cj_reha]

I don't think so...as someone who has limited experience with TVs and even more limited experience with servicing tuner and IF circuits, I would absolutely add A/V jacks to a set requiring a video IF alignment or some other such problem requiring test equipment I don't have at the moment.

[wa2ise]

Be careful if the TV in question is a "hot chassis" design.

I've placed a Channel Master CECB inside a TV set:


For details on this, go to my web page http://www.wa2ise.com/radios/tv.html and scroll all the way to the bottom.

[MadMan]

So wait, is injecting video as simple as hijacking the grid of the video amplifier tube? I feel like I tried exactly that on my Admiral, and though it worked, the video looked like crap. I was under the impression that a transistor was needed to make the video signal inverted first. Or something like that.

[AlanInSitges]

I don't think it's cheating anymore than running a DVD player through an agile modulator is. I mean, technically if you aren't receiving an OTA signal from a commercial analog transmitter the chain is broken.

If your enjoyment comes from knowing that all the electrons are flowing, the coils are resonating, the capacitors are capacitating, and that whole marvelous Rube Goldberg contraption has all its parts working in harmony, then using the tuner is the only way to go.

If seeing the absolute best picture you can on that set is what you enjoy most, then running the Y half of an s-video output from an HDTV box or DVD player into the video stage is the most "true" option.

MadMan depends on the set, if it has one or two video stages, remember the output from the video detector is negative.