CurtPalme.com Home Theater Forum

[jbmeyer13]

While in D.C. this past weekend I had the opportunity to make a brief trip out to Mike Parker’s to see his PJ and the latest round of modifications he's been working on. Mike’s PJ fires onto a 1.3 gain 8’ wide screen which is nearly identical to my set up with the exception that my screen is 9” smaller. This gave me an excellent frame of reference to see and understand the improvements he has made. I had a chance to see his modified chain with both an 02 and prototype 03 VIM.

02 VIM

I’ll admit that I was somewhat skeptical because Mike doesn’t have his set up really dialed in. With that said the low end performance was still very evident. I brought along a copy of Harry Potter and The Deathly Hallows Part 2 which is a benchmark disc for separating the men from the boys when it comes to ultimate low end performance. On the VIM’s he’s altered the signal path, cleaned up the noise in the process and is able to display deep blacks without compromising details.

03 VIM

This is where I was left dumbfounded. An 03 VIM has superior BW but is quite noisy in stock form. Mike has done a LOT of work to this board but the minute he pulled up a 1:1 test pattern (1920 x 1440/60hz) from his generator the difference was blatantly obvious. The 1:1 lines were razor thin; literally half what they were on his 02 and the low end was not compromised in the process. Since I have a stock 03 VIM on loan from Nash I can attest to the difference these modifications make; the sharpness makes you think you’re looking at LUGS. There is still a bit of noise which I believe Mike said was attributed to the belly fans and the annoying faint line on the right side of the image is still evident (this is a separate form of noise generated by the CLM) but these issues should be rectified shortly.

Conclusion

Once Mike resolves the minor issues (belly noise and faint line) I believe his modified 03 VIM may be the best possible performance attainable from a Marquee. I’ll let Mike explain how he’s going to accomplish this but suffice it to say that the headroom that comes with the lower noise floor and increased bandwith really makes it possible to display a sharp 2D image with such depth that it seems like you are watching 3D. I’m very excited to see the finished product.

[Nashou66]

Nice write up Justin. Now you know why I want my 03 vim back ! lol

Nashou

[jbmeyer13]

I'd tell you I'm keeping it but you are holding my CVA and VDM hostage..LOL

Then again we both no you don't really need this VIM or that Red C-element I need;-)

[mp20748]

Thanks for coming over Justin. It was a real pleasure having another eye on the screen. And your visual insight was also very helpful to me.

And that's what made me pop in that 03 VIM, which I had no intention to do originally, but the conversation lead me to trying out a VIM that's not even my VIM. The 03 VIM I put in had the "mini board" that i was installing on the "Super Vims' a few years ago, but since the difference was slight, I discontinued doing them. The mini board that I attached to the VIM's (both 02 and 03) replaced the video switching section of the SD5401 chip. The SD5401 chip remained used for DC restoration only, but the video switching was all being done on the mini board.

Now, the difference in an modified 03 VIM and an 02 VIM varies depending on who is using it. The 03 VIM has a flat out higher bandwidth, but it's also noisier because of that higher headroom. So an 03 stock VIM could get fairly close to 200mhz. Stock that would be 200mhz of noisy bandwidth, which will not produce clean and clear images and lines.

My 02 VIM as had been demonstrated has been modified to go slightly beyond 200mhz. this is not a flat bandwidth because I am applying a bit of peaking to make that happen. A little peaking is good, but only if it's a little. the more you peak, the more you can add distortion at the higher frequencies. Think of it as if adding a treble control on a top end audio system.

What was a very low noise 02 VIM in action coupled to my High Bandwidth neck boards. And before putting in the 03 VIM, I was thinking that the LCP CRT's was the reason I was not able to properly resolve the 234mhz test pattern. I knew the neck boards were not going to be a problem for it. But after sticking in the 03 VIM, it became obvious that the extra everything was because of the neck board and special (mini board) modified 03 VIM combination. wow!!!!!!!

I had already put in a few 03 VIM's that i have here, but did not notice a difference when trying to resolve the 234mhz pattern, so I did not give thought to the 03 VIM or any VIM being a bottle neck for the higher performance. But putting in the 03 VIM had me wonder why was this particular VIM different, and that's when I remembered it had the mini board attached. And I have since confirmed that the difference is the mini board.

What both Justin and I was watching when he put in his Blu Ray was the amount of depth that was in the image. And what was also noticed was the level of low end performance. These two virtues are not new to me, but the difference that 03 made was huge. And before I forgot, sharpness was unbelievable. The entire image became alive with everything in the image being clearly visible. Something that would make more sense on a digital setup.

What I really liked was the black level performance was at a whole different level, that I've only seen in professional B/W photos. I'm still tripping on this.

Anyway, and here's something I've mentioned before; the only way to truly experience native 1080P HD on a CRT display, you would need to be able to 100% resolve and display that source. And as Justin had also experienced, that is when you get to really experience what 2D looks like. And once you really experience 2D, you'll have no interest or desire to play with 3D (cartoons and such). A true 2D image is something to behold, because a well done 2D image has incredible depth in it.

[stridsvognen]

Thanks for sharing Justin.

Nice to get new eyes on this.. I have Mikes 02 and 03 vim here, and neck boards, and can confirm most of whats written here, i prefer the 02 vim on my setup for now, reason is the noise on the 03vim, but its clear to me it have higher bandwidth, so when put up my contrast to make my prefered light level its blooming to much.

One thing is sure.. there is no way back to stock boards for me..

Hoping to get the right match for the 03VIM so it will step up to the next level..



I like to thank Mike for the effort to make all this possible

[jbmeyer13]

Hey Kurt,

I'm sure Mike can chime in later and correct me if I'm wrong but my guess is that once he dials in everything you will likely have to send back to him both your 03 and the neck boards. I think the VNB's need to be matched to the VIM based on differences in the architecture of the 02 and 03 VIM's. I remember we were looking at one of the colors on the 1:1 and Mike mentioned how a single resistor change on the VNB will determine the ability to attain true 1:1.

Stock Marquee boards are all a little different so there's something to be said for matching components. Squeaking that last little bit of performance out comes down to very subtle differences. Mike's comment about having just the right amount of peaking would also suggest the potential need to test a complete chain together rather than separately. While your VNB's and 02 work great now, I'll bet some changes will be needed to those VNB's to attain optimal performance with the 03. Again, Mike can confirm but that is my gut feeling.

Lots of moving parts in this equation and as Mike and I saw a small change can make a huge difference. IMO, most of the time the changes we may see when modding can be subtle in nature but this time around it was of significant magnitude. I hate saying that because it sounds like such a cliche but it really is true on this occassion.

[CIR Engineering]

I'm really glad you got to go by Mike's place Justin. And I'm glad the two of you had some fun together as well. I knew if you two could start talking on the same level good things would probably come of it.

craigr

[CIR Engineering]

[jbmeyer13]

[CIR Engineering]

[mp20748]

I knew I was going to get Craig's attention when I mention 3D..


Some of the upgrades or later changes can be made by some of you guys yourself. I can make it so that you'll be able to balance the neck boards to any of the later version VIM's. The same process won't work with stock boards.

I've even done a change for DC restoration, that you can do yourselves and even do so to your liking..

But in order to get that real profound image depth, you would need to both balance the neck boards and make a change to the DC restoration circuits. When this is done, the image has a certain clarity to it, that allows you to see imperfections even on the far walls and objects. You'll also be able to see the most deepest black and at the same time be able to see all thing dark and black in a room.

[mx83toy]

[mp20748]

Guys, if you have a second (hopefully modified) VIM (either 02 or 03) try this:

if you're able to pull up pins 11 and 14 on each of the three SD5401 chips, and once you have them out of the way, put a small jumper on the circuit trace where pins 11 and 14 were soldered.

Put that VIM in your projector and let me know if you're able to see the difference in sharpness and bandwidth increase.


Or you could check out the two shots I posted below. I'm sending 1920X1440 /60hz directly into my Marquee using RGBHV:


The RED is using the jumper, when done it by-passes the video section of the SD5401 switch.




The Green is without the jumper, with the signal going through the video section of the SD5401 switch.



I am using my modified 02 VIM. The RED is not really brighter, it's more intensified that its hard to capture it with the camera. Now I know why the VIM with the mini board was better.

With the jumper on the red, my Marquee is 100% resolving 1920X1080P /60hz.

[mx83toy]

Mp thankyou for sharing this information with us I appreciate it... I'm pm'ing you about my boards in a sec

[Nashou66]

MIke what would the effect be on the 03 vim, if you have one not moded it be cool to see what happens there as well.

[Nashou66]

I remember the old discussions we had on using a fast switching single channel chip that was at least lower than 3ns, the sd5401 I think is 1 ns. The chip we were looking at back then was a DGxxx somethingoranother. What did you end up going with on the daughter board?

Nashou

[mp20748]

[Nashou66]

I found something in my Mod folder that we looked at but cant remember why we never went this route. it was using a relay but not sure if there was a fast enough switching relay for off and on. The internal video is turned of and on at 1ns if I remember correctly.




Nashou

[mp20748]

Relays may be worth trying out.

[mp20748]