The Mongrel

[Harry Dalek]

As much as I like tubes I have little experience with them beyond audio devices and deflection amplifiers. How those guys designed all the RF/IF stuff in radios and TVs is beyond me. They were talented and imaginative!

I always wondered how they worked out Scanning on a CRT in the first place ,i know they would of wanted the result in their head and copy mechanical scanning so how but making it work with circuits must of been a bit of trial and error not like you could even read a book on how to do it right at the start .

I am surprised you have not built much with Valves !

Always liked Vacuum tubes glowing in the back of the old b/w set in the 60s never knowing how they worked ,all we used to do was when it stopped lighting up just pull it out and replace with out to much thought on the marvel these things are .

I have been doing a lot of CRT stuff since your help with the Anderson monitor and using tubes for one is on my to do list ,something else in this field to learn .

Time to plunder some valve/tube scope circuits, the Heathkit stuff I have here is probably a good starting point...I may go quiet on this for a few days as I think it through...the 'Phantasron' circuit looks promising..."Some users have considered the operation of this time-base to be fantastic; hence the name phantastron." No, it's not April 1st...

That's ok can't do much anyway till the weekend work and family birthdays rest of the week .



The Phantasron is the circuit i would of used here i have it on page 2 ,I was reading on Hans page about he swapped to it after a friend redesigned he's time base and being pleased with the new scanning linearity.

Many valve/tube Tektronix oscilloscopes used the Phantastron circuit, if they used it, it must be OK...

Steve A.

I didn't know that but good enough for them it sounds good to me !

My plan was use as much as i could that may already have been designed for NBTV and what i have handy ,there's very little really in the way of NBTV Vacuum tube circuits.

This is what i found a bit is yours too ! I was going to start it off with this one of your video inverters

6SL7 Inverter 1.gif (4.8 KiB) Viewed 8441 times

6SL7 Inverter 2.gif (4.92 KiB) Viewed 8441 times

6SL7 Inverter 3.gif (4.48 KiB) Viewed 8441 times

Then i was going to use Jean-luc's design sync sep

SYNC SEPARATION.JPG (34.11 KiB) Viewed 8441 times

I was going to use Hans Phantastron circuit out of he's scope adjusted to vertical horizontal scanning so ramp generators

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As you know i wanted to use Jean-luc's deflection amplifiers but that went to pot noticing yours and was a better design not just saying that i can see it .

32 Line 'Club Standard' 3.gif (12.05 KiB) Viewed 8441 times

Now we come to Power supply which i should of should of put first as its a good thing to get out of the way here i am stuck a bit some variation in circuit needs and what range for the CRT go for close to mid or close to higher range data CRT needs ?...Since i am now fine with using 1n4007 1000v diodes making the power supply will be easier and a bit more space i know its more logical to do it this way .
Least the New Transformer is something i don't have to worry about powering this thing .

Modulation i am fine if you want to work this out ,as mentioned easiest is just put the primary of a transformer between the control grid voltage and CRT control grid and drive the modulation from the secondaries from the video amplifier sure works , Jean-luc went spot wobble so that's another way, up to you Steve if you have another idea can try all more than one if you like .

So i thought i would put what i had on mind here and it might help you work out if any thing here is a good or not so good idea for the monitor ..

[Steve Anderson]

What came first? The chicken or the egg? Do you say these are the voltages and currents you have to work with, or these are the voltages and currents I need? A blend of the two is what is best, though not always achievable. However, that's the aim here...given what we have to work with...iterative as ever...

Steve A.

[Steve Anderson]

I am surprised you have not built much with Valves !

Well, some, but not to the extent of building my own TV or radio. It's been either where I have an interest, (audio), or where needs must, CRT deflection. Though these days that maybe a moot point. Often just for the novelty of it, something different...and as you know I tend to go for a blend, a hybrid...

Steve A.

[Harry Dalek]

What came first? The chicken or the egg? Do you say these are the voltages and currents you have to work with, or these are the voltages and currents I need? A blend of the two is what is best, though not always achievable. However, that's the aim here...given what we have to work with...iterative as ever...

Steve A.

Yes no longer 12 volt dual supply any more ! i haven't looked at your selected valve's data yet but didn't think they could all have different operating ranges ,seem to always be the same in a radio or what ever i think ?
so designing the dc supply or designing the circuits first i see your point !

[Steve Anderson]

It's not greatly different (sometimes) with all semi devices, though they're much easier to deal with.
The crux of the matter, actually there's two...use of a CRT and all-tube.
The alternative is what Albert did with his Niptrix (I think that's what he called it). Solid state, but with bucket-loads of LEDs to wire up. The nearest I've done to something like that was an audio level warning device where the display changed from green (OK), to amber (at a certain level below maximum) to red (at or more than maximum). Intended for concerts and the like.

But that was only 88 LEDs per display, I built four prototypes, so a total of 352 LEDs. Alberts was 1,536 for one display...

My meagre effort is below...

Steve A.

[Harry Dalek]

Well, some, but not to the extent of building my own TV or radio. It's been either where I have an interest, (audio), or where needs must, CRT deflection. Though these days that maybe a moot point. Often just for the novelty of it, something different...and as you know I tend to go for a blend, a hybrid...

Steve A.

Well have to have a want or need make some thing your can't buy is always good point for me .

i rather keep it mostly Valve it can be Hybrid its is the Mongrel now ! your point before about the power supply or circuits first will be interesting to see how this will evolve.

The CRT power supply would be easier ? i have seen you have a few versions done for the DG7 32 i noticed you steadily increased the range to it for Hans DG 7 scope power supply ,brighter display ?

Any case i see with what i have on this transformer theirs going to be some voltage multiplying even for this low voltage crt ?

[Harry Dalek]

It's not greatly different (sometimes) with all semi devices, though they're much easier to deal with.
The crux of the matter, actually there's two...use of a CRT and all-tube.
The alternative is what Albert did with his Niptrix (I think that's what he called it). Solid state, but with bucket-loads of LEDs to wire up. The nearest I've done to something like that was an audio level warning device where the display changed from green (OK), to amber (at a certain level below maximum) to red (at or more than maximum). Intended for concerts and the like.

But that was only 88 LEDs per display, I built four prototypes, so a total of 352 LEDs. Alberts was 1,536 for one display...

My meagre effort is below...

Steve A.

The attachment SPL Meter 1.jpg is no longer available

I ended up buy a few of these Led blocks a few years ago but never did any thing with them i think i was planning a low def audio scope ,hats off to you and Albert that's a hell of a wiring job ! so easy to make a wiring mistake

[Steve Anderson]

...that's a hell of a wiring job ! so easy to make a wiring mistake

Planning, thinking ahead and doing a drawing beforehand, then you stand a fighting chance...the same for everything...
I thought of those 'blocks', maybe for NBTV but not the the concert audio level warning device. The guys on stage are looking out into stage lighting, often they cannot see if the have an audience or not. So these needed to be really bright, and they are, absolutely blinding in the workshop, just about right when used in a venue. In the short video below you can see the camera is struggling with their intensity...

Those 'blocks' are multiplexed so each row or column is only on for one eighth of the time, OK at home but not in a stage environment.
I later added a peak hold and slowed down the reaction speed...

Sometime later I changed the LEDs to Red/Green in the same package, with both on you get a yellow.

Steve A.

video_20180102_101920.mp4

(13.52 MiB) Downloaded 181 times

[Harry Dalek]

...that's a hell of a wiring job ! so easy to make a wiring mistake

Planning, thinking ahead and doing a drawing beforehand, then you stand a fighting chance...the same for everything...
I thought of those 'blocks', maybe for NBTV but not the the concert audio level warning device. The guys on stage are looking out into stage lighting, often they cannot see if the have an audience or not. So these needed to be really bright, and they are, absolutely blinding in the workshop, just about right when used in a venue. In the short video below you can see the camera is struggling with their intensity...

Those 'blocks' are multiplexed so each row or column is only on for one eighth of the time, OK at home but not in a stage environment.
I later added a peak hold and slowed down the reaction speed...

Sometime later I changed the LEDs to Red/Green in the same package, with both on you get a yellow.

Steve A.

video_20180102_101920.mp4

Watching the video that brightness would sure get anyone's attention ,can get all 3 colours in an Led these days we are very lucky for devices these days JLB would be jealous !
I don't recall you showing this project before !

[Harry Dalek]

Here's another vacuum tube video modulation idea the results look ok ,can't say i like the construction style but .
http://danyk.cz/elmon2_en.html

Home made Television 1967

my-five-inch-tv.pdf

(525.64 KiB) Downloaded 189 times

[Steve Anderson]

I don't recall you showing this project before !

Well, I didn't see the relevance to NBTV/SSTV, so no real point in publishing it here, also at the time it was covered by a "Non-Disclosure Agreement" between the client and myself. i.e. commercially secret. It has been vastly improved since, and that I legally cannot go into.
Likewise 90% of what I do is covered by some legal document whereby I must not divulge any commercially secret information. I was covered by the UK 'Official Secrets Act' for my work at Decca Radar in the 70s! It was extended to cover the 2012 London Olympics, it expired in 2020. (Actually 2018, bad memory).

So a lot of what I do outside NBTV/SSTV I cannot publish here, or anywhere else...until whatever agreement expires...most of it isn't relevant here anyway. So you're not missing out on anything really...

Steve A.

[Harry Dalek]

I don't recall you showing this project before !

Well, I didn't see the relevance to NBTV/SSTV, so no real point in publishing it here, also at the time it was covered by a "Non-Disclosure Agreement" between the client and myself. i.e. commercially secret. It has been vastly improved since, and that I legally cannot go into.
Likewise 90% of what I do is covered by some legal document whereby I must not divulge any commercially secret information. I was covered by the UK 'Official Secrets Act' for my work at Decca Radar in the 70s! It was extended to cover the 2012 London Olympics, it expired in 2020. (Actually 2018, bad memory).

So a lot of what I do outside NBTV/SSTV I cannot publish here, or anywhere else...until whatever agreement expires...most of it isn't relevant here anyway. So you're not missing out on anything really...

Steve A.

Can always go in off Topic but see your point ; )
Here on this project i am interested to see what you come up with ,not easy i know and some thing you have not done before makes it harder more thinking head scratching and time .
Some of the posts on the Valve circuits i posted up are more for help ideas its always nice to have an example ,might not use it as i am sure you rather try your own design .
My end i am thinking more placement of whats coming panel and such .

[Steve Anderson]

Harry, the circuit you posted Wednesday (Aug 18) looks a promising start...it can be simplified in the PSU as there's no PDA in the DG7-32. Can you confirm the tubes in the bottom row are 2xECC42s/ECC85s and 2xEF86? (The original is somewhat blurry...)

Yes, agreed on the construction style...could do with a 'haircut', though many say I should have one too...(my hair in the Avitar is real)...

Steve A.

[Harry Dalek]

Harry, the circuit you posted Wednesday (Aug 18) looks a promising start...it can be simplified in the PSU as there's no PDA in the DG7-32. Can you confirm the tubes in the bottom row are 2xECC42s/ECC85s and 2xEF86? (The original is somewhat blurry...)

Oh that's good ! i recall your saying no need to reinvent the wheel ! so if some thing been designed and works for a similar use pinch the idea it i say
if you click on the photo its much larger than what's displayed i need that my self these days my eye's not what they used to be ! i have a whole set of glasses for different distance work close closer silly close then i get the PC microscope for crazy small

What i make out for the Tubes are Left to right 6CC42 ECC85 .EF80,6CC42 ECC85,EF80 ....may be i have some thing i can substitute if not whats already been selected

Yes, agreed on the construction style...could do with a 'haircut'

A for end idea working but D for construction a wiring mess really should try and keep the plastic coated wiring to a minimum but if needed bundle them to one side neatly


,

though many say I should have one too...(my hair in the Avitar is real)...

Steve A.

[/quote]

I could not work out if that was you ! between you and Klaas i don't know what to think ! may be i need do one

[Steve Anderson]

OK, a pair of ECC85s and a pair of EF80s, that makes more sense than EF86s...I forgot about clicking the image, yet I often mention it! Your 6BX6s are the same as EF80s, just with US type number instead of European. As for the EEC85s, I think you have substitutes (or near) for them...I'll check.

Assuming this was for standard 625/50 (European language used on the circuit and 230V transformer primary) there'll need to be a few changes to component values for 32/12.5, I'll re-draw the circuit with suggested changes tomorrow....(Friday).

I assume you're not bothering with audio? Though it's no hassle if you are...

I sent you some 630V or 750V capacitors a few years ago, I think they were 1uF or 470nF, can you try and find them and let me know? They could be very useful here...

Steve A.