Transcoders are the best method of getting a component signal to VGA.

What they do:
Transcoders will convert a component signal directly to VGA.....no signal degrading or quality problems. What you put in is exactly what you get out. Therefore you get the highest quality image compared to any other type of converter out there.

What they won't do:
Transcoders will not upscale or downscale the image. For instance, if you feed in a 480P signal, and display it on a 1024x768 LCD, the image will be 640x480 and may or may not fill up the entire screen...this depends if your brand LCD will scale the image or not. Also, if you feed a 720 or 1080 signal into a 1024x768 monitor, it will not show up unless your monitor supports 16:9 resolutions and can scale.

If you don't want to build your own, you can buy the Vdigi transcoder for $60 at http://www.vdigi.com/
It was originally made for the Xbox, but will work with any component input.

How to build your own transcoder for less than $30:
A person by the name of Ken Gasper originally built and sold a transcoder called the XboxVga. He is no longer selling it, and the schematics have since appeared online:
Click to view attachment

However, there are a few things you need to change:
1. In the LM1881 schematic, R30 needs to be a value of 680K - not 340K
2. Some LCDs will only work with a horizontal sync input signal, not both horizontal and vertical. My CMV 520D only shows a picture when the vertical sync output to the VGA is disconnected.
3. You also need to be aware of AC getting through on 5V AC to DC power supplies. If you see horizontal green bands slowly moving up the screen, your power supply is letting some AC through. Either filter it, or use a better power supply.

Getting the parts:
I bought most of the parts at Mouser Electronics
The 4383 ampflier comes in surface mount only. You can buy a surface mount to through hole adapter for $6 at BrownDog There are other amps with similar characteristics out there that will work...I just don't know of any off hand.

The components parts list:
(1) LM1881
(1) MAX4383/448
resistors (1% tolerance):
(1) 5.76K
(1) 86.6
(1) 1.02K
(3) 75
(3) 2K
(1) 511
(1) 698
(4) 4.99K
(1) 931
(2) 80.6
(1) 1.78K
(1) 1.3K
(1) 2.8K
(1) 1.05K
(1) 549
(1) 442
(1) 887
(1) 680K
(2) 10
caps:
(4) .1uF
(1) 330pF

When I play my xbox, I get an interlace dsignal that look pretty bad, will this fix this like the vdigi does?

Yes, the circuit you build does the same thing as the Vdigi.

Good post.

Ive known that you could build these easily, just never bothered to research it. I already have most of the parts, would just need to pick up the amp and the LM chip.

Have you built it yet?

Yes, I have built one and it works great!!!

I have tried it on both my CMV 520D inside the projector, and my 17" CRT.

Do your monitors scale 480 well??

Have you compared it to a PC?

Neither monitor supports a 16:9 resolution, so 720 and 1080 do not show up at all.

I don't understand what you mean by "Have you compared it to a PC?".
Whatever you put into a transcoder is what you get out....the image quality is perfect.

Great! I have a little transcoder here that makes all white colours look like pink or red, so if this transcoder doesn't have these problems, I'll build one
Do you notice any problems using it?

I simply meant the quality comparison between the transcoder scaled (nevermind since your LCD doesnt scale) compared to the PC's scaling.

Forgive my ignorence but what does this replace? Is this used in conjunction with a pc?

I will have my pj hooked to my pc to play most things through it. Will I need this? And if so, how much am I saving compared to what it replaces?

Thanks

This is so you can hook anything that has component output to your projector, such as progressive scan DVD player, Xbox, HDTV tuner, etc. It has nothing to do with a PC.

This replaces converters such as the Avermedia and N6, which output a degraded picture.

Another good thing about transcoders is they are the cheapest of anything in this catagory. You can build your own for $30, or buy one for $60. A Viewsonic N6 will cost you $170.

hrlslcbr: The only tiny problem I have noticed is sometimes a horizontal row of pixels will be shifted over 1 or 2 pixels. This is only noticable in things such as game menus. While playing a game, or watching a DVD, you cannot notice. I don't know if it is caused by a faulty 1881 chip, or if I have a resistor slightly out of tolerance. I have not heard of anyone else who built one of these that has this problem.

I would have to say the picture quality of one of these is as close to perfect as you are going to get. The improvement from a N6 is massive!

Thanks, I may have use for this with my dvd then

Do you get 'wavy' lines or is it only some pixels that move from time to time?
There is another transcoder in the works at AVSForum, but I don't know how it'll compare to this. If I'd get better quality by building one, I'll surely do it.
Do you think you can take some pictures of the transcoder?
Thank you for sharing this with us.

No wavy lines. Just imagine a single horizontal row of pixels being shifted to the right 1 or 2 pixels. I imagine its due to some faulty component I put in there.

I don't have a digital camera yet, but really the transcoder isn't anything to look at. Just a Radio Shack project board with a mess of resistors and capacitors soldered all over the place, with RCA input and VGA output connectors.
I bought a little black box at Radio Shack to put it in, but haven't mounted it yet.

I don't think you will get better quality building a transcoder vs buying the Vdigi. They should work identical.....and I've researched the Vdigi quite a bit and never heard a single complaint about its quality. The Vdigi just has dip switches for some additional compatibility features (see their website).

Could you provide a link to the AVSForum thread on their transcoder?

This gets more confusing all the time.

I've got a Samsung 151MP, it has both a VGA and Digital TV input. Both inputs are the D sub 15 jacks that VGA uses.

I imagine that the Digital TV is a DVI-A that needs a DVI-A to VGA converter to work. Problem is that I can't find any DVI-A receivers to work with it.

So, if I buy this, I can use the regular VGA input. But will I be able to view HD stuff?

This is a very simple device. All it does is convert a component signal to the standard VGA that computer monitors can "read".
If you put 480P in, you get 480P out.
If you put 720P in, you get 720P out.
If you put 1080i in, you get 1080i out.
These devices only handle higher definition. 480i is not supported.

To be more technical, the sync signal on the component standard is carried on the green. Computer monitors need horizontal (and sometimes vertical) sync signals. So the transcoder takes the sync from the green and seperates it into seperate horizontal and vertical sync signals. The red, green, and blue information (the actual picture) stays exactly the same.

Here's the link: http://www.avsforum.com/avs-vb/showthread....threadid=310247
Someone posted some schematics some time ago on that thread, but I don't know if they work or not.

I had previously told people the CMV 520D LCD does not scale the 480P image out of the transcoder.

I was wrong.

I have been testing the projector from many different distances, and must have got confused when I moved the projector forward the same time I tested the transcoder.

A 480P signal leaving the transcoder fills up the entire screen on a 1024x 768 CMV 520D.
Sorry about the confusion.

I have a VDigi that's been collecting dust since I moved. Havn't built my PJ yet but I tested it out on my CMV. Looked like crap at first. A lot of grey lines everywhere. Then I swapped the component cable that came with the vidigi with my Monster one and it cleaned everything right up. Looks great. Can't wait to get my enclosure so I can test it out on the big screen.

I know it's not the best looking option, but I plan on using my xbox/xbmc as a portable HTPC untill I stop moving around so damn much.

Theres an easier/cheaper/better way to make a vga transcoder now...Its on my projects list, I'll post the schematics & PCB design when I get around to designing it...should be much better quality than what is currently offered.

Thanks for the information though, good to see some DIY Stuff

I was looking into these as a possible way to pick up a HD set top box and run component to one of these to vga on my projector, but it looks like I won't be able to do that either from what you are saying

Being that my LCD is only 4:3 native 1024x768 and 576p in 16:9 I was hoping my LCD would just display the info at this resolution, which appears not to be the case. Is there anyway to run component to a trancoder to a scaler then to a VGA based DIY projector.

Also will a transcoder in this method (hd box component out to a transcoder to a vga input on a DIY unit) work on one of minotens wuxga units? since its capable of 1080 etc?

Hey will something like this work,

The DVI HDCP converter receives DVI of signals as RGB or YPrPb from DVD Player or HDTV sources and changes the digital signals in a similar RGBHV signal. This can be attached directly to tube projectors or other displays without digital entrance.
The DVIHDCP processes input signals from 480i to 1080p with standard image repetition frequencies of 24 to 120 cycles per second.
The output dissolution corresponds to the picture resolution fed at the DVI entrance, it takes place only one digitalsimilar to transformation. The image repetition frequency stopped at the source appears at the similar exit.

http://translate.google.com/translate?hl=e...:en-US:official

Or will a xga projector again not know what to do with the resolution being thrown at it without a PC to scale it? And this thing is listed at about 500 canadian

From what I understand,

this thing passes through resolutions, it does not change it. If you feed it 480i your supposed to get 480i back out. So if you have a 720p source, and your monitor doesnt support 720p...sol.

Don't they have VGA resizing boxes?

I have just one question about the schematic. How is the decoupling capacitor connected? Is it connected from the Vcc to ground leads of the chips directly or am I wrong?

Also, just a tip if you're going to build this: you can get samples of both ICs at their manufacturers sites Maxim IC and National Semiconductor. It should save you 3-5 dollars. I haven't gotten mine yet, but the order process was pretty simple.

Maxim samples arrive quick and well packaged.

Expect about a week from the day you place the request for them to be delivered.

Awesome company, i use alot of their one wire bus devices in my kegerator API.

It is just supposed to be connected as close to the chip as you can get it. Since I used a Radio Shack project board, I put one side of the capacitor in the hole next to VCC of the chip and the other side in the hole next to ground on the chip. The capacitor ends up "stradeling" the chip.

MrWaxhead:
If your LCD does not scale 16:9 formats, then you can buy a seperate scaler to convert everything to 1024x768. I've seen a cheaper scaler mentioned a couple of times in the forum.

This DIY transcoder just got a lot simpler.

In September, National Semiconductor released a new IC called the LMH1251. Basically, its a transcoder on a chip. The best part about it: it handles a 480i component input. As a matter of fact it supports 480i, 480P, 576i, 576P, 720P, 1080i, 1080P.

Below is a simplified diagram I found in the data sheet:
Click to view attachment

More info can be found here:
Entire LMH1251 Datasheet

Vdigi is working on a new version of their transcoder. I wonder if it is based around this design?

Awesome find. I wonder how the quality of this compares to something like the vdigi.

Where there any specs given for those Zener Diodes, someone that builds this is going to need to know what voltage zener diode to drop in.

Also, the inverter coming out of the horizontal/vertical synch doesnt make alot of sense, why wouldnt they just invert it inside the IC?

***EDIT, nevermind I now see the attached data sheet, surely the information is in there, im just not digging into the 10 page spec sheet to find it, unless I decide to build one .....

It should be the same. As far as I know nothing has been built yet using this chip, but National wouldn't sell any if it didn't perform well. The major advantage this has over any existing transcoder, is the compatibility with 480i as well.

This is so new, I can't find any schematics on how to interface this with the required video amplifier other than what I posted from the data sheet.

So whos going to build the first one?

ill do it if you can find me a box to scale 1280x720 to letterboxed 1280x1024

I know nothing of the output quality, but here is a scaler for $190.

SCALER

190$ hahah i could get a new monitor supporting 720p for near that

Doh, I don´t know much about electronic circuits. I need some help with this board design, can anyone help?? I handmade drawing would be enough

I just scored a Vdigi on e-bay for $50.00. I'll try and post some pictures of the results.

Currently I am using my PC as input. I have a P4 2.4Ghz machine with an ATI All In Wonder 2006 card.

I'm running my PS2 through the ATI, with mixed results. I'm curious to see any difference between the HTPC and the Vdigi.

I'll be glad that I don't have to continually lug my PC from upstairs to the basement theater though!

someone post pics of their homebuilt. That would be cool to see.

drewbiedoo,
Let me know how your results with the vdigi compare. I am very tempted to buy a vdigi for myself to compare to the pvr-150.

Will do Dergrin-

I'm expecting the Vdigi to arrive in a day or two.

I also purchased a set of Monster brand component cables for my PS2. I read through some other forums, and compromising on the component cables apparently makes a huge difference.

The Monsters were well liked by most everyone who had them.

hey all, whats the best way to find out if your lcd supports 16:9?

Will this also work going the other direction? Will it transcode vga to component?



Thanks

Download powerstrip and try a widescreen resolution.

The best my xbox outputs is SVideo. Could this device be modified to accept svideo or is there and adapter I can buy/bulid to convert the SVideo to Component?

Thanks.

beekeeper-

I do not own an XBox, but have been searching around for information on 480p for my PS2. In searching, it appears that MS has much more support for component than Sony.

If you google for "xbox component cable" a ton of hits come up.

There are also lists of games that output 480p, 720p, 1080i. Here's a link to one such list:

http://www.hdtvpub.com/productdb/games/index.cfm

By the way, the Vdigi comes with an xbox component cable!

I received the Vdigi yesterday-

Now I am waiting on the monster cables to arrive. I expect them in any day now.

I am looking for a good DVD player with progressive scan and 3:2 pulldown. Does anyone have any recommendations or experience? I have a DVD player with component out, but it doesn't have progressive scan.

I will not be able to give a review of the Vdigi without the p-scan. (The vdigi requires progressive scan)

There are a lot of players out there, but 3:2 pulldown seems to be the elusive feature on many of these players. I would like to find a player with p-scan and 3:2 pulldown.

A lot of DVd players perform an up-conversion, but I haven't done a lot of research on what that is. I seem to remember a post regarding up-conversion and that it was more or less a B.S. feature.

Any help is appreciated.

Anyone have any pics of a homebrew vdigi??

It's hard to find MAX4383. Mouser or Digikey doesn't have this.
Anyone knows where to get one?

drewbiedoo,

How does the ps2 look with the vdigi? Do you see much of an improvement over the tv tuner card?

You can request a sample directly from the manufacturer.
4383 sample request

I used the 14 pin TSSOP package.
A 14 pin surface mount to through hole adapter can be found HERE.