CurtPalme.com Home Theater Forum

[mp20748]

A picture of my best Low-Noise Moome card mod.

And a picture of a Certificate of Participation of one the workshops I attended that really taught on noise and interference and how to design for best results.


The original Moome design was very well done, which shows the digital side of things were very well designed. On the analog end, there was room for improvement, and that's exactly what I've done here. My best work so far, considering that I've greatly improved on keeping the projector noise out of the Moome's video stage, to even better isolating the Moomes digital noise from being a problem in the analog section. The measured results are far better than expected for a mixed signal board design. The end results are stunning, especially on the low end of things with near zero hash noise.

[mp20748]

I wanted to get back to this to comment on a few other things, that I really like about the board design (Moome Card) and that much attention was giving to lowering the noise on the board before my attention to it. If you notice, the two 270uf/16v volt aluminum caps are not being used on the buffer supplies (removed). They were not needed after my changes to the board. My approach to lowering the noise resulted more in my ability to trace the noise to it's source, and with circuits like this (mixed A/D) special techniques had to be both learned and developed in order to better isolate the source of the noise. ANd as I may have been mentioned before, I use three different pieces of test gear to help me wit the process. But the noise and interference Workshops/Classics are critical here, because as they say in the Workshops, "Noise and Interference is a technology of its own" and because of the complexities involved in really dealing with it, you would definitely have to spend a lot of time marrying yourself to the art that's involved.

A scope by itself is a powerful piece of gear, but when using it for noise, it's really limited. Because it'll only let you see the signal itself. The noise is harder to see because almost anything in or near the testing point could be the source of a noise (or distortion) shown on the scope screen. Because noise can be ambient (close by) or even riding on the ground. So without a good procedure or special technique, you'll find yourself dealing with it better at the last analog stage. Using high bandwidth chips or transistors makes for a better or sharper image, but will also increase the noise problem. And that is why it's very important especially when using high bandwidth chips to make sure you also address any associated noise.

Now here is the point with the final analog (before buffer) filter stage or network, that it's design is ONLY supposed to address a part of the noise band (notch) or as a low-pass filter (high frequency stripper). These goals depend on the DAC and what they're requiring for a filter network. And when that';s done right, the signal should be good, but here is where the problem becomes more complex, and that is when you have other noises or more noise than what the DAC's filters were needed for. And that is why there is much to do with mixed board designs and making sure you address any and all noise problems on the board. And when dealing with CPU, DACs, or any other digital chip with a clock, the potential for noise problems will exist. And again, the noise I'm talking about here are seen seen as lines and jaggies or any other obvious distortion. Though a keen eye may spot a smaller part of them.

I'll get back to this later, and since this noise is mostly known to be an analog problem. That is not always the case, and I'll prove that later as I've taking my cheap $39.00 Blu Ray with the only connectors on the rear and applied some of what I've learned in the Workshops, to make it perform better. Because with any of the poorly designed digital video devices, if not designed right with noise (and not only interference) as a concern. The image would have problem with this same noise (hash) that I've been running down. The digital video chips and circuits work best, when they are properly designed for best noise performance, and with almost all of them, there are always these particular resistors that they put near the chips.




Last week or so I posted some shots on the "shootout" thread, in those shots I used a Moome card that was not fully modified thinking someone would notice the noise in it. One of the shots is below. See if you can tell what the noise is. Look at the other shots that I posted (not on that same batch) as a reference:

[mp20748]

[mp20748]

Actually the shots show a lot, but being able to or attempting to explain what they show doesn't make sense to me. You may not understand afterwards. And for sure there are differences between the shots, but of course you would have to be familiar with the movie and understand why they are being posted.

[Mr Jaeger]

[gregstv]

Give it a go Mike. We are all very interested in your work and knowledge. If any of use lean a small amount from what you explain it's a good thing.

[mp20748]

[cmjohnson]

One of you has a red push going on, or the other has a blue push to deal with. To start. Why don't you both run a D65 calibration and try again?

[cmjohnson]

Mr. Jaeger, please do be careful when saying dumb things like that. I've been rather deeply involved with electronics and projection
CRTs for a VERY long time, and I'm not exactly uneducated abouth these things.

I'm not on Mike's technical level. Or a number of others. But for you to say I don't understand is ABSURD.
I understand just fine. I understand that you're posting irrelevant screen caps and talking about a subject
that you have shown NO evidence you are actually competent in as of yet.


But I can tell you that there's no point in posting a screen capture NOT from a projector in this thread,
when the point of this thread is not even to compare screen captures anyway.

You joined this forum less than two years ago and have managed to rack up an awesome 13 posts to date,
of which 10 of them are from the last 10 days. This is hardly anything to support the idea that you have any level
of technical expertise or knowledge that might make it worth listening to you.

You have no street cred here, in American street talk terminology.

You might be able to improve the membership's opinion of your knowledge if you were to make the effort to post your bona fides.

Until you build a reputation for competence, you won't have a reputation for competence.

Frankly I'm wondering whose troll account you really are. The way you talk (OK, type...) seems....familiar.

[Curt Palme]

The ban hammer is about to come down. Seems like some Europeans have nothing better to do than troll. That's why I left the 'yepp' post up. I do know a past forum member that was banned that used that all the time.

I have no problems with querys on people's mods, but trolling and flaming isn't allowed, period.

[Curt Palme]

The ban hammer is about to come down. Seems like some Europeans have nothing better to do than troll. That's why I left the 'yepp' post up. I do know a past forum member that was banned that used that all the time.

I have no problems with querys on people's mods, but trolling and flaming isn't allowed, period.

[Mr Jaeger]

Not interested in trolling in any way, just to inform and maybe help.

[cmjohnson]

Then try to actually do that.

Give some INFORMATION that is HELPFUL.

You can start by telling us what your relevant technical credentials are.

[Mr Jaeger]

[gjaky]

[cmjohnson]

I've said before that I consider screenshots to be of limited utility. Consider the amount of compression and loss of data that occurs between the original image and the one on your computer monitor right now.

They aren't totally useless, however. Well made screenshots can show some qualitative differences between images.

[racerxnet]

[cmjohnson]

I agree with that. Consistency of color should be a given. If you are going to post screen shots of ANYTHING that is to be used for purposes of comparison, please be sure you've calibrated your display device first, and don't mess with the settings to make it look subjectively better to you.

I don't post screen shots, right now I have no dog in that fight, but I can tell you that I prefer a slighly more vivid interpretation and enjoy movies that are most colorful and/or make use of color in creative and exciting ways. Examples: Pleasantville. Starts out in black and white, makes color part of the theme of the movie as it develops. And it's gorgeous. And then, Jingle All The Way, colors are full tilt.

[mp20748]

[mp20748]

I've been trying a few different Blu-Ray players, but will be getting back to my Pany this evening. And I'll also be getting back to my Moome card version and will re-post some of what I've already posted to bring things into perspective..

[mp20748]