405 easy converter kit - does it make sense?

[oldeurope]

Good morning,
I wanted to make a kit for an easy analogue standard converter.
But after the expected very low cost aurora I stopped the development.

I noticed that people in the forum want to build their own converter.
The low cost aurora is not available, so may be it makes sense to make
a kit?

The kit contains three (or four) PCBoards.
1. The UVB at the input. It contains a sync sep. , DC restorer, and colour
trap. It feeds the other two boards with signal.

2. A clock board. It gets H- and V- sync from the UVB and generates
the three clock frequencys for the delay ccds. And the V- sync replace
pulse.
It contains two 4046 one 4049, 74LS51, 74LS221 and some Flip Flops.

3. The analogue board with the interpolator and the switched delay
ccds. It gets it's vision signal from the UVB. At the output you have 405.

4. Another UVB to drive the npn modulator transistor.

It will be a bit easier than the MK I (yes that is possible!), because
I made a fundamental mistake at the V- sync there.

What do you think?

The link gives you infos in the UVB :

https://www.vintage-radio.net/forum/...ead.php?t=6753

Kind regards
Darius

[jim_beacon]

Darius,

I would certainly be interested in a kit of boards! Is it wortyh including the delay line chips as well? I've noticed some people have had difficulty in sourcing them.

Jim.

[oldeurope]

Originally Posted by jim_beacon

Darius,

I would certainly be interested in a kit of boards! Is it wortyh including the delay line chips as well? I've noticed some people have had difficulty in sourcing them...

Jim.

... for very low cost.

I think the kit compleatly will cost 160 Euros or so.
The main problem is that some people think a PCB solves all
their problems.

Kind regards
Darius

[Sean Williams]

Hi Darius,

I would be interested too - My attempts at doing a PCB for your original design also stopped when the low cost aurora was announced - I didnt get too far, as I am at the limit of my understanding with this sort of stuff!


I would agree with Jim regarding the delay lines, and to a point agree with your comment regarding costs to get them!


Look forward to hearing more

Sean


Happy Darius Modulator owner

[oldeurope]

Originally Posted by m1ecy

Hi Darius,

I would be interested too - My attempts at doing a PCB for your original design also stopped when the low cost aurora was announced - I didnt get too far, as I am at the limit of my understanding with this sort of stuff!


Sean


Happy Darius Modulator owner

Hi Sean, the MK II and III are difficult to understand because they have
an automatic input signal detector and automatic signal switching.
And the sync is splitted from the vision signal and a compleatly new
generated sync is added at the end.
This is nice to have, but not essencial.

Kind regards
Darius

[Sean Williams]

Hi Darius,

My understanding of Television in general is not that great, however, I am learning all the time.

I would be glad to assist in any way I can with the production of an affordable standards converter kit - I understand and respect the designers/suppliers of currently available models, and their pricing, but unless you are seriously engaged in collecting, the added expense of a ready made converter is prohibitive.


Plus of course, it is much better to build these things yourself - you learn how it works and what to do when it stops

Cheers
Sean

PS, More waxies here for you - will send them out after the weekend.

[high_vacuum_house]

Hello there,
I would also be interested in a kit of boards plus the "difficult to get" IC's.
I am currently saving for a convertor and I would love to buy and build a kit.

Many thanks,
Christopher capener

[channel405]

Hello Darius,

Yes I would be very interested in a converter kit too. The more parts included with it the better though but I realise this would increase your workload!

Out of interest, could you just gives us a few specs on the converter please like the 405 output resolution or frequency response, will it deliver the full 3Mhz do you think? What about interpolation by an analogue converter, can it be as good as a digi one?

Thanks, Tim

[ppppenguin]

Originally Posted by channel405

What about interpolation by an analogue converter, can it be as good as a digi one

Darius's converter uses 2 line interpolation which should give almost identical results to digital 2 line interpolation. You will not have jagged diagonals and curves!

The Aurora converter uses 3 line interpolation which is slightly better in theory but is difficult to see in practice. The BBC Research report on the subject reckoned that the 3rd line was useful - you could see the difference in the carefully chosen test pictures in the report. Unless I had a side by side comparison of 2 and 3 line interepolation I doubt that I could tell the difference.

[oldeurope]

Originally Posted by channel405

Hello Darius,

Yes I would be very interested in a converter kit too. The more parts included with it the better though but I realise this would increase your workload!

Out of interest, could you just gives us a few specs on the converter please like the 405 output resolution or frequency response, will it deliver the full 3Mhz do you think? What about interpolation by an analogue converter, can it be as good as a digi one?

Thanks, Tim

Hi Tim, a kit (Bausatz) includes all parts. You get 3MHz with the cxl5506
and 1,5MHz with the cxl5508. And the 1,5MHz at 405 is better than the
resolution of a vhs tape at 625 and you accept it on a big screen.
m1ecy has a demotape from my converter.
Watch it to find out if it is good enough for you.

I noticed that digital converters are not that complicated as I expected.
In the digital arrangements the interpolator is a difficult thing.
Maybe it is not a mistake to combin a digital converter and an analogue
interpolator. The trick that makes the analogue converter so easy is
the dividing of the line frequency by 1,5. 625lines/1,5= 416,666...lines.
This causes that the artefacts you have without an interpolator
are not standing still like in a digital 405 converter. Moving things
are well noticed and so a good interpolator is essencial for the analogue
converter.

Kind regards
Darius

[Sean Williams]

Hi Tim,

The tape I have from Darius is in my somewhat uninformed opinion, absolutely great, there appears to be no loss of definition, and images appear sharp and in correct proportion.

To be honest it seems just short of witchcraft to me that any of this stuff works at all


You are quite welcome to borrow it and see for yourself the great results from this design of converter.

I look forward to owning one myself!

Cheers
Sean

[oldeurope]

Good evening,
I started drawing the schematic for the clock board in eagle.
Than I can route the clock PCB.
With the UVB- PCB and the Clock- PCB most work is done.
The rest analog with the three delay ccds can be made on a
vero board I think.

Kind regards
Darius

[ppppenguin]

Darius

Congratulations on offering to do a kit for a converter.

May I suggest that you do the whole design on a single PCB. This should be less expensive than multiple PCBs and easier to assemble.

[Courtney Louise]

Darius,

What a great Idea and I am sure it will be very very very very popular with the people here...

Thanks for all your great efforts in this field of the hobby and I am sure it will give many more old TV's a home with those of the group whom havent ventured out into the world of vintage tv due to lack of anything to watch..

Thanks again

Andi

[channel405]

Hi Darius and M1ecy,

Yes the specs for your bausatz sound pretty impressive! I am very intersested in this in kit form. Well done Darius.

Thanks M1ecy for the kind offer to borrow your tape for evaluation. I would like to take you up on that offer if I may.

Tim

[oldeurope]

Originally Posted by ppppenguin

Darius

Congratulations on offering to do a kit for a converter.

May I suggest that you do the whole design on a single PCB. This should be less expensive than multiple PCBs and easier to assemble.

Good morning,

Hi Jeffrey,
1. Making the UVBs I noticed that there is a big difference between
a vero board and a PCB. To get the same size like a vero board
you definatly need a multilayer board. So on a standard PCB you need
two or three times of the size of a vero board. SMD does not make the
board smaller, except IC's.

My software is only able to make 10cm X 10cm.
The clock board will be loaded with:
3x 74LS221
1x 74LS92
1x 74LS51
2x 74LS73
2x 74HCT4046
1x 74HCT4059 (this is a biggi!)

2. I expect that mabe 10 people will build one,
so the PCBs must be usefull for other applicationes to.
Than it is possible to produce more and keep it cheep.
The UVB is existing and tested.

3. The colck board can be screened seperately and this makes
it less noisy.

4. You are free in the choise of delay ccds, because they are not
on board.

I have soled (and I am still selling) UVB- kits in ebay. The interesting
question is: Are people able to build it and do they get good results and
what must I do to make sure that they get success. This is a learning
process for me.

Kind regards
Darius

[humorist2751]

Greetings to all.

There is a long (and more or less noble) history of projects in electronics magazines being laid out on stripboard/veroboard. I see nothing inherently wrong with that, though it does need a somehat greater attention to detail from the would-be constructor. Not a thing to tackle when you aren't at your best (not that any assembly work should be done under such circumstances).

The real bugbear for me, when I looked into building one of Darius' Standards Converters, was the lack of a physical layout; this was left as "an exercise for the reader". Nothing wrong with that per se, as Peter Scott proved by building his own device largely to Darius' design; but it was this part of the process (deriving a physical layout), plus of course the "hens' teeth" rarity of the requisite delay elements, that informed my decision to buy one of Malcolm Everiss' excellent Domino machines.

That said, I would be interested in a kit form of Darius' design; at a minimum, it would have to contain any dedicated (i.e. non-vero) blank boards, plus the elusive delay elements; but the sine qua non (for me) would be full physical layout details. Of course, the kit could well contain "everything but the kitchen sink" (or even including it), so that one need not purchase so much as an additional resistor or capacitor - but it would have to contain the first three items I mention in order to have wide saleability, at least insofar as such a rather esoteric item can be said to be widely saleable in the first place!

Just my two denarii worth.

[Nickthedentist]

Originally Posted by humorist2751

The real bugbear for me, when I looked into building one of Darius' Standards Converters, was the lack of a physical layout; this was left as "an exercise for the reader"...

I don't collect vintage TVs so this is a bit academic.

I too have absolutely no problem with building projects on Veroboard so long as a layout is suggested. I can (and do) design my own, but it can easily take longer than actually putting the whole thing together.

So do include a suggested Veroboard layout, Darius, for those of us who are inherently lazy

Nick.

[Paul Stenning]

There is also a much better chance of the finished item working if it has been built following the same layout as the original one. If people have to devise their own layouts it cauld result in problems due to parts being too close together, ground connections being too long, decoupling caps being too far away from ICs etc.

I think if veroboard is the way you are going it would be a good idea to include details of your layout so that people can follow that.

[oldeurope]

Good morning,
the schematic and the layout is generated automaticly when I build
something.

I don't have a layout and the schematic comes when the
thing is finished.

I don't know the layout and I have to measure out where which pin
is connected. Now I have to look at the MK III logic how the IC's
are conected. Than I'll draw a modified schematic for the kit and
route a PCB.
I have a pic of the down side of the MK II board, maybe it helps.

Kind regards
Darius