Famicom World

They say the guys over here are  "guys over at famicom are a bit clueless" -CombatRocked

That's not very nice  :-X

http://www.assemblergames.com/forums/showthread.php?44350-Famicom-AV-Mod/page2

It's mainly about people who used 80sFREAK's circuit and found that it didn't work right. I tried it myself and as calpis/kyuusaku said in that thread, it wound up having major sync issues with every TV I tried it on and it was fairly dim on top of that.

Rosser, don't bother, cool modders can't tune one stage amplifier.

The circuit is not the problem, bad modders are!

Quote from: 80sFREAK on March 02, 2013, 01:28:11 am
Rosser, don't bother, cool modders can't tune one stage amplifier.

"Cool modders" actually design circuits, ones based on principles that will work for everyone. Some of the proposed solutions here like 33 uF AC coupling cap are GUARANTEED to fail on standard 75 ohm inputs... There's been nothing posted which surpasses Nintendo's own cheap common-collector output. It's not even possible to since they themselves chose a tuned circuit which at least is verified working by MILLIONS of users.

There are only two options for more robust output and both require more active components:

-PNP common-collector -> level shift -> NPN common-collector with 75 ohm Re doubling as parallel source termination
-PNP input video amp or op amp with internal offset (Av = 2) -> level shift or 220 uF AC coupling cap -> series 75 ohm source termination

Hmm, never seen those posted. So is it so wrong to call 25 pages of "creative" solutions and other tuned voodoo nonsense clueless? How about all the paranoid shielding for jailbars when it's power rail coupled?

Quote from: 2A03 on March 02, 2013, 01:09:18 am
It's mainly about people who used 80sFREAK's circuit and found that it didn't work right. I tried it myself and as calpis/kyuusaku said in that thread, it wound up having major sync issues with every TV I tried it on and it was fairly dim on top of that.

And how come the 2 famicoms me and a friend got from 80sFreak directly work perfectly on several differentl tv sets ?
I keep reading things like that and I've come with 2 conclusions:
a. 80sFreak does some kind of voodoo magic and composite works
b. people that complain just make mistakes on the mod and/or can't mod at all

simple answer is this, if you were good at modding you wouldnt need to follow someone elses guide. You cant follow their guide correctly, thats your problem.

Quote from: keropiAnd how come the 2 famicoms me and a friend got from 80sFreak directly work perfectly on several differentl tv sets ?
...
people that complain just make mistakes on the mod and/or can't mod at all

Actually, if the mod has the 33 uF AC coupling cap it works because your TV has a non-standard high-impedance input and/or digital signal processing; older and higher end sets tend to have low input impedance and a simple comparator for sync detection, so this affects MANY people.

Perfect is subjective. In my opinion the perfect amp delivers 1.2 Vpp (1.0 for FC video) into 75 ohms with  minimal distortion, 100% DC coupling and 75 ohm series source termination & my definition just happens to be what's used in just about every modern video circuit.

Maybe I'll measure some of the amps posted around here.

hey
where are the video waveform pics taken from oscilloscore?
where i can definitely see that sync level was reduced by that high-pass filter (33uF + 75 Ohm) ?
hard to define what is wrong without them

i'm up to famiclone circuit that is very closer to sharp twin and exactly the first thing that kyuusaku mentioned (two emitter followers with voltage divider between them and pure 75 Ohm output impedance)

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Post Merge: March 02, 2013, 10:13:27 pm

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Quote from: kyuusaku on March 02, 2013, 05:25:58 pm
Maybe I'll measure some of the amps posted around here.

is it good?

Quote from: kyuusaku on March 02, 2013, 03:29:54 pm...

(http://cdn.epicski.com/6/64/64e01b38_butthurt.png)

2 keropi, well, yeah, it's kinda wodoo magic, you know, special spells and so on, which i explained in sticky thread. By the way, thank you for bothering with photos  :)

Quote from: VinylDracula on March 02, 2013, 03:58:21 pm
simple answer is this, if you were good at modding you wouldnt need to follow someone elses guide. You cant follow their guide correctly, thats your problem.

Correct, modder should understand, how it working, not just soldering whatever sits on the table/draw. The problem is, even there is a guide 95% will do their own way, obviously fail and complain.

Quote from: kyuusaku on March 02, 2013, 05:25:58 pm
Actually, if the mod has the 33 uF AC coupling cap it works because your TV has a non-standard high-impedance input and/or digital signal processing; older and higher end sets tend to have low input impedance and a simple comparator for sync detection, so this affects MANY people.

More than that i highly recommend to use ceramic capacitor. The problem is, when your friend 2A03 a.k.a Apolloboy complained about "bad picture", he does not posted any proofs or clear description what's wrong with picture. Ok, i turned on my remote view ability and gave him solution. He still trying to make shit storm. Oh, well, if that's all able to do, i'm off :)

Quote
Perfect is subjective. In my opinion the perfect amp delivers 1.2 Vpp (1.0 for FC video) into 75 ohms with  minimal distortion, 100% DC coupling and 75 ohm series source termination & my definition just happens to be what's used in just about every modern video circuit.

Maybe I'll measure some of the amps posted around here.

I'm affraid you actually have more 50 Ohms sets, just guess  ;D

Quote from: famifan on March 02, 2013, 10:07:06 pm
hey
where are the video waveform pics taken from oscilloscore?
where i can definitely see that sync level was reduced by that high-pass filter (33uF + 75 Ohm) ?
hard to define what is wrong without them

Don't scare them with too much science  ;D Give'em "ready to eat" solution, so they can make money on it straight away or they will call you faggot  ;D

Guys, no need drama, just some people have to accept - they are not perfect (i'm not perfect too  :P )

Quote from: famifan on March 02, 2013, 10:07:06 pm
hey
where are the video waveform pics taken from oscilloscore?
where i can definitely see that sync level was reduced by that high-pass filter (33uF + 75 Ohm) ?
hard to define what is wrong without them

I'll try to get a scope demonstration. In the meantime this is the concept:

Only considering the 33u C and 75 R, not the TV's clamp capacitor etc, you get -3 dB at frequency of 64 Hz. This means that Vsync's fundamental frequency component, 60 Hz is ~30% attenuated. Sync should have sharp rise and fall times but instead it will look overcompensated like this:

(http://img339.imageshack.us/img339/1808/fil39.gif)

Quoteis it good?

If the PPU outputs 2 Vpp then maybe it's good. I think it outputs 1 Vpp though so 0.5 Vpp will be delivered to the TV.. I'll check soon.

Edit: one problem with it is that the 220 & 2.2k point has a non-linear transfer so the signal is compressed and somewhat distorted. Since I think the signal is directly 1 Vpp out of the PPU we can't attenuate it at all to make a passive level shift... It must be active. I think 3 transistors may be the minimum necessary for a linear amp.

Quote from: 80sFREAK on March 02, 2013, 10:41:49 pmbutthurt

Maybe because I'm sick of watching mediocrity succeed? Everyone can't have such low standards or nothing would work right.

Quotehe does not posted any proofs or clear description what's wrong with picture.

Well considering the problem, it would be sync distortion.

QuoteI'm affraid you actually have more 50 Ohms sets, just guess  ;D

??? AFAIK no NTSC TV has 50 ohm inputs, all baseband inputs are 75 ohm (same for PAL), coax/cable TV is 75 ohm and most antennas are 75 ohm/300 ohm in the stone age.

Quote from: kyuusaku on March 03, 2013, 12:30:44 am
(http://img339.imageshack.us/img339/1808/fil39.gif)

You missing one thing here. Important thing

Quote
I think 3 transistors may be the minimum necessary for a linear amp.

It's very simple to make complicated things, but its very complicated to make things simple.

QuoteEveryone can't have such low standards or nothing would work right.

Unfortunately most people tend to use parts, which they have, not they should "Oh, it's just capacitor, i will solder this one".

QuoteWell considering the problem, it would be sync distortion.

Ok, so which exactly parts he used?

Quote??? AFAIK no NTSC TV has 50 ohm inputs, all baseband inputs are 75 ohm (same for PAL), coax/cable TV is 75 ohm and most antennas are 75 ohm/300 ohm in the stone age.

You never know ???

Well, if picture out of sync and dim, you have to change one value. That's all.

Quote from: kyuusaku on March 03, 2013, 12:30:44 am
Only considering the 33u C and 75 R, not the TV's clamp capacitor etc, you get -3 dB at frequency of 64 Hz. This means that Vsync's fundamental frequency component, 60 Hz is ~30% attenuated. Sync should have sharp rise and fall times but instead it will look overcompensated like this:

yep, i know it. Due to R and C tolerances cut-off freq. can be safely assumed to 60Hz. Just curious to see the actual waveforms

Quote from: kyuusaku on March 02, 2013, 05:25:58 pm
Actually, if the mod has the 33 uF AC coupling cap it works because your TV has a non-standard high-impedance input and/or digital signal processing; older and higher end sets tend to have low input impedance and a simple comparator for sync detection, so this affects MANY people.

Let me just comment on this... I have personally tested on:
a. LCD 37LH4000 LG
b. LCD LG TV/PC monitor, some cheap model that costed 150e
c. LCD Cheap chinese(?) one from a super market that was 1366x768
d. LCD 40" Sony Bravia something , don't have it anymore
e. CRT Sony Trinitron 14" 2 different models
f. CRT Philips 21"
g. CRT Comet 26"

so yeah, does the 1998 Comet  crt have signal processing? or the 14" ones? and what is the chance that ALL of them crt and lcd alike accept non-standard signals?
Apparently It only affects many people if they screw up their mod. There are people here that got machines from 80sFreak directly, don't you think they would complain at some point?  :crazy:

edit: added bravia

OK here's the setup:

(http://imageshack.us/a/img69/8738/setup1l.th.jpg) (http://imageshack.us/a/img69/8738/setup1l.jpg)

(http://imageshack.us/a/img850/5496/setup3d.th.jpg) (http://imageshack.us/a/img850/5496/setup3d.jpg)

(http://imageshack.us/a/img145/7508/setup2u.th.jpg) (http://imageshack.us/a/img145/7508/setup2u.jpg)

Just a common-collector amp with 100 ohm Re for very low output impedance. Go 75 ohm if you have the current to spare and you have the ideal 1 transistor amp. (Do use a large AC coupling cap.)


Here's Vsync DC coupled:

(http://imageshack.us/a/img221/7205/dc1n.th.jpg) (http://imageshack.us/a/img221/7205/dc1n.jpg)

Nice edges obviously:

(http://imageshack.us/a/img838/6638/dc2hm.th.jpg) (http://imageshack.us/a/img838/6638/dc2hm.jpg)

Here's 470 uF coupled:

(http://imageshack.us/a/img849/3606/220u1.th.jpg) (http://imageshack.us/a/img849/3606/220u1.jpg)

Also nice edges:

(http://imageshack.us/a/img834/9867/220u2.th.jpg) (http://imageshack.us/a/img834/9867/220u2.jpg)

I thought this was 44 uF but it was really 440 nF, shown for example:

(http://imageshack.us/a/img10/2899/44something3.th.jpg) (http://imageshack.us/a/img10/2899/44something3.jpg)

Just some line droop:

(http://imageshack.us/a/img685/2565/44something1.th.jpg) (http://imageshack.us/a/img685/2565/44something1.jpg)

Holy crap look at Vsync:

(http://imageshack.us/a/img837/4478/44something2.th.jpg) (http://imageshack.us/a/img837/4478/44something2.jpg)

Well here's 22 uF:

(http://imageshack.us/a/img24/6600/22u2x.th.jpg) (http://imageshack.us/a/img24/6600/22u2x.jpg)

(http://imageshack.us/a/img24/9586/22u1.th.jpg) (http://imageshack.us/a/img24/9586/22u1.jpg)

It doesn't *appear* too attenuated here, but it is (didn't bother measuring) the important thing is that the entire signal actually wobbles around Vsync which could definitely affect separation, particularly with AGC. The 470 uF doesn't show any of this (neither does 220 uF). I took a video of the wobble but I don't have anywhere to upload it at the moment.

Maybe this hasn't been the most effective exercise but at least anyone can see that there is a difference.

Sync wasn't attenuated to -3 dB is since while 60 Hz, it doesn't nearly have a 50% duty cycle, so there's less 60 Hz power.

Note: if source impedance is increased (as in every mod) the effects should be worse since the source will create another time-constant. I'm not going to bother building every amp, too much time spent already.

sweet  :pacman: :pacman: :pacman:

what is the 15kHz noisy thing? jailbars?

Which pic?

Jailbars are every 8 pixels so I don't think that's what you're seeing.

Quote from: kyuusaku on March 03, 2013, 11:27:39 am
Just a common-collector amp with 100 ohm Re for very low output impedance. Go 75 ohm if you have the current to spare and you have the ideal 1 transistor amp. (Do use a large AC coupling cap.)



Here's 470 uF coupled:

Hold on, where is 220uF? ???

Quote
I thought this was 44 uF but it was really 440 nF, shown for example:

Well, noone need to read after line above  ::) If you still want to read

Quote
Well here's 22 uF:

In the previous post you told about 33uF and now toying around 22uF, what is that? Turning things up side down? ???

Quote
It doesn't *appear* too attenuated here, but it is (didn't bother measuring)

So "yes" or "no"? ???

Quotethe important thing is that the entire signal actually wobbles around Vsync which could definitely affect separation, particularly with AGC.

It's obviously, if

Quote
I thought this was 44 uF but it was really 440 nF, shown for example:

QuoteThe 470 uF doesn't show any of this (neither does 220 uF).

You still missing one important point

QuoteMaybe this hasn't been the most effective exercise but at least anyone can see that there is a difference.

Nice try.

QuoteNote: if source impedance is increased (as in every mod) the effects should be worse since the source will create another time-constant. I'm not going to bother building every amp, too much time spent already.

Sounds like you realised you failed and don't want to fail one more time.

I beleieve, that you are nice guy, but please, again PLEASE, do not touch soldering iron until a) you will able to read values of components with 100% accuracy b) understand, what components are and how do they working c) don't be offended, study hard and you will rewarded.

*Sigh* here we go again with the master of pretension...

QuoteHold on, where is 220uF? ???

Do you really need a picture of 220 uF? I can still take more shots.

QuoteWell, noone need to read after line above  ::) If you still want to read

Uhh they're two "22"  tantalum caps I found, their size suggests they could be 22 uF, without a capacitance meter how am I supposed to know?

Don't assume I have everything on hand. If you really knew about components yourself you can extrapolate information from my examples. 33% isn't much in the frequency domain, plus these caps have 10-20% tolerance themselves.

QuoteIn the previous post you told about 33uF and now toying around 22uF, what is that? Turning things up side down? ???

I don't have any 33 uF caps, the closest I have is 22 uF. Or maybe you'd like me to waste 6x 220 uF in series to appease you?

QuoteSounds like you realised you failed and don't want to fail one more time.

&&

QuoteI beleieve, that you are nice guy, but please, again PLEASE, do not touch soldering iron until a) you will able to read values of components with 100% accuracy b) understand, what components are and how do they working c) don't be offended, study hard and you will rewarded.

*Sigh* If only your actions matched your wisdom. Maybe you'd like to give a Fourier analysis of the FC's sync and show how little your higher impedance amp is affected by 33 uF....

I chose 100 ohm to be fair. Clearly the visible distortion doesn't bother you @ 22uF, maybe you think 33% will make a difference on a 1 pole filter...  Personally I've seen *100uF* cause sync havoc on the Neo Geo AES, and that's with a very tiny (<20 ohm) source impedance from a push-pull amplifier. How is 100 uF with a Fc of 21 Hz causing problems? High amplitude 60 Hz screen flashing effects in games--FC games do them too.

It's much easier to just say this forum is clueless and be over with it. I'm the one who first said it by the way, any others are just agreeing, no need to be hard on anyone else.

Good, so please stay away with your theories.

/thread

@ kyuusaku

yes, there are some muppets at other places that did a half-assed job like you and somehow came to the conclusion that the people here are clueless...
I still haven't seen your comment on the sets I tested my machine and found working excellently, how come? Or are you just ignoring this little fact since it won't work with your theory?
Oh, and go to the other places to see shots of the Philips + 37LH4000 sets. Somehow clueless persons produce the better results.

Quote from: kyuusaku on March 03, 2013, 12:19:37 pm
Which pic?

Jailbars are every 8 pixels so I don't think that's what you're seeing.

they are on every pic except on 440n

Quote from: keropi on March 03, 2013, 11:55:22 pm
@ kyuusaku

yes, there are some muppets at other places that did a half-assed job like you and somehow came to the conclusion that the people here are clueless...

Half assed job like me? What in the world are you talking about? I never constructed 80sFREAK's amp, I didn't have to build it to see its flaws and talk shit about it. What I constructed here isn't meant to be a work of art, I wired in some components point-to-point to demonstrate the signals. I understand basic amplifier topologies enough to know that what I constructed already has better performance than *any* FC A/V mod proposed online and that is why this community is a joke for technical insight... Try to be a little open minded, tone down the bromance and not focus on sides.

Also really?? I seem to recall you valuing my assistance on ASSEMbler numerous times regarding your PCE RGB amp, oh and your N64 RGB amp... Guess those were just more wasted keystrokes.

QuoteI still haven't seen your comment on the sets I tested my machine and found working excellently, how come? Or are you just ignoring this little fact since it won't work with your theory?

I have no idea what circuits your TVs contain (I haven't even heard of many of the brands!) and it's irrelevant. The standard termination for consumer baseband video signals is 75 ohms to ground. You can look it up. The fact is that most TVs, especially newer ones like yours, are very forgiving. And yeah, a lot of your TVs certainly do have digital signal processing which has been widespread in CRTs since the mid 90s.

Just because you THINK something works doesn't mean it does. Perhaps your eyes will lead you to believe you have a "perfect" amp since it works on 50 out of 50 TVs and 100 out of 100 FC games, but as soon as you come across an edge case you'll know the truth; the PPU generates a really shitty video signal so a TV will probably lose sync before you can visually distinguish an anomaly.

There's no question 33 uF causes the signal to droop, it's apparent in the 22 uF picture. What maybe isn't apparent to you, because I haven't uploaded the video, is that Vsync makes the entire signal wobble due to insufficient coupling. I tested a 100 uF cap and there's still too much wobble!

So I've defended my position plenty, I have and can gather more evidence to support my claims but any more time on this subject is seriously an exercise in futility. If you want to learn more, read video amplifier datasheets, I'm sure some of them will explain why they all suggest 220 or 470 uF coupling caps. 80sFREAK without any evidence of his own to bring WISHES I were disingenuous, but at this point he's got his trollface on--something he resorts to in practically every discussion we're both involved in.

BTW, the people at ASSEMbler are predominantly clueless too. Feelings less hurt?

Quote from: famifan on March 04, 2013, 12:36:23 amthey are on every pic except on 440n

I think you're talking about the overshoot. Part of that is really there, part is exaggerated by my unideal 75 ohm probing solution and improper source termination.

Edit: If you mean during Vsync, those little pulses are colorburst! The PPU strangely doesn't shut it off for the front and back porches

Sounds like "cool modders" and "genius designers" so badly wants to know "what's inside of the cat". Nothing special, just one stage amplifier.

kyuusaku, you are still here? Geez, looks like you enjoying your butthurt ::)

Quote from: kyuusaku on March 04, 2013, 05:09:58 am
[...]
Also really?? I seem to recall you valuing my assistance on ASSEMbler numerous times regarding your PCE RGB amp, oh and your N64 RGB amp... Guess those were just more wasted keystrokes.

Yes, in a sense they were.
Apart from the n64 modification that the original modder got me confused, the PCE RGB amp was a huge failure.
I and everyone that offered help wasted our time. Like this amp here, there was some pretty words about how amps "should work"  and how 73x4 is better than the transistor-based amp. The result after 1 month of having my pce gutted and with orders of TI chips and resistors/caps was something INFERIOR than the transistor amp that you people bashed.
Guess what? Several other people on dedicated PCE forums lol'ed pretty hard with the assembler thread. You were quick to prove the old amp a piece of crap but somehow noone dared make the "correct" one that was superior.

I have an open mind, I always want to try new things but when all that "science" produces is an inferior but "correct" solution then sorry: I'll pass. Same thing you are doing here. There is a perfectly working solution that only fails when others with questionable skills construct it. The thing works from ultra-cheap OEM tv sets to LG/Sony ones. Yet you are somehow not satisfied.
OK I can understand that, perhaps there is a different and better solution. Then you go ahead and make some scope readings which is nice. But not with the mod you are claiming to be crap. That's half-assed to me , sorry.
What I would really like to see is when you and everyone else that knows his stuff come and give a complete, proven and correct solution, be it a PCE 73x4 amp or a superior famicom one. Something that works and is jailbar free. Not something that people need to turn down brightness to hide bars. 80sFreak with his "wrong" way does not need any tricks, either prove him wrong with a better/equal solution or just stop.

And I was never ungrateful to anyone that helped me, just go look on the assembler threads. I didn't even say a word when the 7314 amp was mediocre after spending time/money on it. Everyone helped from the good of their hearts and that was awesome. And I'll thank you again in the future should you give me any help on a problem I have, I am not a petty man. But that doesn't mean that because you helped me once I am not entitled to a different opinion especially when I have something right before my eyes that looks great.  That's what I came not to like on assembler, the constant bashing of other works that sometimes just don't deserve it. And I am not talking about you on this one... you have proven to be miles better than those I talk about by just writing here - no matter what the outcome was.

Quote from: keropi on March 04, 2013, 07:25:49 am
Guess what? Several other people on dedicated PCE forums lol'ed pretty hard with the assembler thread.

Have you ever noticed that lazy and ignorant people mock those who try and attempt intelligent discussion?

QuoteYou were quick to prove the old amp a piece of crap but somehow noone dared make the "correct" one that was superior.

You try designing a discrete DC coupled amplifier... It's not easy, that's why I didn't post anything at the time. Every FC amplifier we're talking about here is EXTREMELY simple since it does not have voltage gain, it's basically the same thing as your beloved inefficient PCE amp. That's the main reason this discussion is so retarded--fan boys to dead simple circuits, most of which don't make any sense.

QuoteSame thing you are doing here. There is a perfectly working solution that only fails when others with questionable skills construct it.

80sFREAK's part choices have failed for numerous people, and I have shown why. You're being delusional, there's little question they built the circuit "correctly"--there are only 4 parts and apart from switching resistors there's no way they could build the circuit wrong and still see ANY video.

QuoteOK I can understand that, perhaps there is a different and better solution. Then you go ahead and make some scope readings which is nice. But not with the mod you are claiming to be crap.

Once again you don't understand, I did scope readings with an amp BETTER than the one I'm claiming to be crap. I didn't have the 33 uF capacitor which is an obscure value. Tests with a 100 uF cap show the same problem. The whole point wasn't to build 80sFREAK's circuit, it was to show the high-pass filter effect to famifan.

Quoteis jailbar free

Jailbars have NOTHING to do with the video amp. At best the video amp can only hide them by filtering them, intentionally or unintentionally.

Quotewhen I have something right before my eyes that looks great.

You are being a petty man here--defending to the death something that you don't understand, just because it's what you have invested in. As I already explained FC video amplifiers will all "look great" because 1) all of the amps in use are basically the same concept 2) the PPU output is very different from normal video, there are so few brightness levels you'd never notice 3) TVs do they best the can to fix many of the problems with bad amplifier circuits.

Quotea superior famicom one

Here's a parting gift:

(http://img40.imageshack.us/img40/4632/giftjt.png)

-3 components
-75 ohm source
-high linearity
-minimal Vsync distortion

The downside? It consumes 60 mA instead of 15 mA like the ideal amplifier. Similar to the other amplifiers it also delivers the wrong amplitude.

Simple enough for you 80sFREAK?

Gosh, kyuusaku, please, stop it, your butthurt will burn our planet  ;D

Stop freaking out locals by this nonsence, draw complete equivalent circuit. It will help you. Your theories are nice, but not complete to be correct.

I'm getting boring of this "battle" ::)