The State of DACs for the MiSTer and Direct Video

[antoniovillena]

I had one more test for the day, I tested one of the Mister Addon's Analog I/O boards. To be clear there appears to be two versions of the Ref 6.1 analog I/O board, on the dac test results sheet, the Mister Multisystem shows what the what I call "high" version looks like. The Mister Addons board in the sheet shows the "low" version. A delta of 140mV at 100 IRE is just crazy imo for a "reference" design. I think the low version might actually be worse then the AG6200. It starts going darker sooner, at 50 IRE, then flatlines around 2.6-2.7 gamma, which is very dark! Also the highlights are darker as well, it maxes out around 83 nits at 100 IRE, again noticeably dark. Worst of all you don't know what you'll get, high or low voltage i/o board, its a lottery... we need vendors to step up and test their products and document what were getting, is that too much to ask?

Hi. I am interested to add my IO BOARD to the spreadsheet. I will send one unit. Please contact me by PM or email.

[CMR]

I wonder if the difference in IO boards might have something to do with the resistor packs not being soldered well enough. I had this issue with my first IO board (v5.5) with the audio not having stereo output. I managed to fix it by reflowing the resistors for it.

[thorr]

I am looking forward to seeing Antonio's tested. It should/might be better than all the others because it has full range RGB capabilities.

[Peredonov]

Probably useless for most MiSTer users, but it would be interesting also to see Jim Drew's (CBMStuff) IO board's analogue video tested. This board seems to be of better quality than the standard IO board, and the manual for it specifies "three 6-bit linear R2R ladders to provide a 18 bit (6-6-6) DAC color output. The each leg of the resistor ladder is connected directly to the FPGA chip."

[KnuckleheadFlow]

http://tinyurl.com/dacanalysis

Just wanted to say I appreciate your efforts here.

Canceled my order for the Tripp Lite P131-06N (didn’t know it’s the AG6200 and that can be had for less if I’m gonna settle). Tried to order a Vention HDMI to HDMI+VGA but apparently Vention won’t sell to Canada? On their Ali Express store it’s not available to be shipped to my address.
Found the last StarTech HD2VGAA2 on sale at BestBuy.ca for $32, so I hope it’ll be good enough.

Btw, any idea why the Vention with the Lontium does so much better than the Ontens with the same? Is that ‘_ex3’ a lower spec version or something?

[jd213]

I think the only Vention adapter known to have good measurements was the one with both VGA and HDMI outputs, and that one has been out of stock on Aliexpress for a while.

[KnuckleheadFlow]

I think the only Vention adapter known to have good measurements was the one with both VGA and HDMI outputs, and that one has been out of stock on Aliexpress for a while.

Ah ok. Yeah that’s the one I was going for. I thought it was some weird regional restriction when it said it can’t be shipped to me.

[KnuckleheadFlow]

So I finally got a StarTech HD2VGAA2 after some tomfoolery where the Best Buy seller didn’t ship the adapter for over a week and then shipped me some no name $10 amazon special instead (money refunded right away). Of course first thing I did was take the StarTech apart, not turn it on.

Seems this one has an ITE IT6693, instead of the IT6695. I can’t find much about it online. No mention of it in the 6695 data sheet I got from ITE, but the 6695 is mentioned as a drop in replacement for the 6693 in the dongle reference design they sent along with the data sheet. I emailed the rep that sent it about what the difference is, hope it’s not lower spec or anything. Maybe it just doesn’t have 5V tolerant inputs of the 6695?

Edit: No functional difference according to the rep: “IT6693 has been EOL, and replacement product is IT6695, the function is exactly the same”

Digital audio goes to what appears to be a Cirrus Logic CS4344 24 bit DAC. Don’t have any experience with that but it seems decent enough from a little quick googling.

[NuclearMonster]

Thank you for this analysis. I wanted the Icy Box IB-AC502 device based on the report and the only place to get it seems to be from grooves dot land in Germany. Fortunately it arrived here in Hawaii after just two weeks for only $4 in postage. I am surprised to see there are no screw terminals for the VGA side, but the Icy Box DAC works very well from a brief testing. It’s replacing the Rankie adapter in my direct video setup, which was so poorly shielded it made a terrible interference sound into the VGA-SCART cable every N milliseconds. This model of the Icy Box doesn’t carry audio, but that’s OK since I’ve switched to using optical and I’m happy to have better video quality and a video DAC that doesn’t require power.

[Sumolx]

I've also purchased the Icy Box IB-AC502 and it seems to be the Rev A model that I have received. However, I am running into an issue with my arcade monitor and that it does not lock onto the vertical sync with this adapter. Based on the spreadsheet, this adapter shouldn't require an mods, but I do see the picture rolling perfectly vertically.... i can almost lock onto it but with no success on the main menu. Same applies to when I start a game like Street Fighter Alpha 3. Via Analog IO module, everything is displayed correctly. Am I missing an ini setting besides enabling direct video?

[GeCe]

I've also purchased the Icy Box IB-AC502 and it seems to be the Rev A model that I have received. However, I am running into an issue with my arcade monitor and that it does not lock onto the vertical sync with this adapter. Based on the spreadsheet, this adapter shouldn't require an mods, but I do see the picture rolling perfectly vertically.... i can almost lock onto it but with no success on the main menu. Same applies to when I start a game like Street Fighter Alpha 3. Via Analog IO module, everything is displayed correctly. Am I missing an ini setting besides enabling direct video?

Enable composite sync if you don't combine H and V sync

[Sumolx]

I've also purchased the Icy Box IB-AC502 and it seems to be the Rev A model that I have received. However, I am running into an issue with my arcade monitor and that it does not lock onto the vertical sync with this adapter. Based on the spreadsheet, this adapter shouldn't require an mods, but I do see the picture rolling perfectly vertically.... i can almost lock onto it but with no success on the main menu. Same applies to when I start a game like Street Fighter Alpha 3. Via Analog IO module, everything is displayed correctly. Am I missing an ini setting besides enabling direct video?

Enable composite sync if you don't combine H and V sync

For the Jamma spec I have the settings set to rgb and composite sync and all works fine with analog io but when I enable direct video to use the hdmi to vga adapter the image just scrolls slowly across the screen and I'm unable to lock on.

If I was to describe it... it's like the direct video vertical sync is way off when compared to analog io. I have to adjust the v-hold quite a bit just to get the image to scroll slowly across the screen. This applies to the main menu and any core I load up. When the core loads up I then have to adjust v-hold again as it is significantly off as well.... I can get close to locking in but it is way off compared to analog io v-hold adjustment.

Edited...
Just purchased the ugreen adapter based off the ag6201 and going to see how it works.

Edit #2
Why does analog io and direct video resolutions differ?

IMG_5264.jpeg (5.79 MiB) Viewed 13199 times

[mr-box]

i just got the Icy Box does not work for component still need to add the diode (1N4148) and a 330ohm resistor which blows ass . anybody have any ideas how to make it work with out breaking the case on it

[Sumolx]

The ugreen ag6201 is also behaving the same way.... unable to lock in the vertical scrolling.... the direct video signaling is not identical to analog io so it's not usable for my setup which is an Arcade CGA monitor via RGBs.

[kitty666cats]

Welp, I made an account here just to make a new topic to tell people about a HDMI to component that works perfect with the MiSTer, meaning people don’t need to waste time modding HDMI to VGAs. I cited numerous tweets from Mike Chi confirming as much, maybe the topic got flagged for posting links to his Twitter (might have posted a link to Amazon, if so that’s probably what got it flagged).

I’ll just post a photo of the ones to look out for - Mike even said he used one of these (they have a Lontium chipset) connected to a MiSTer when he was testing and calibrating the RT5X!

1_yxlINAV.jpg (159.42 KiB) Viewed 11521 times

[sonic68010]

I’ll just post a photo of the ones to look out for - Mike even said he used one of these (they have a Lontium chipset) connected to a MiSTer when he was testing and calibrating the RT5X!

I'm so frustrated trying to get Component working on MISTer. What settings do you use w/ this converter?

[rsn8887]

What about this?

https://misteraddons.com/collections/co ... -to-analog

[ackmangogo]

Found another DAC with silicon image receiver chip, sil9135, cro-dac11 from Imagenics.
Seems like same chip on hdfury 3, according to specs.
https://www.drhdmi.eu/dictionary/hdfury-3.html
https://pdf1.alldatasheet.com/datasheet ... I9135.html

https://imagenics.co.jp/pdf/products/c_cro-dac11.pdf
https://drive.google.com/drive/folders/ ... KLJylmBUnM

[jd213]

It has a MSRP of 80,000 yen though ($536 USD at current exchange rate), so one could probably buy several HDFury3's for that price.
https://imagenics.co.jp/products/cro-dac11/
It also doesn't work for HDCP sources (not that you would need it for MiSTer, but it's nice for systems like PS3).

[ackmangogo]

Bought one on yahoo auction about 5000 yen, about HDCP, a cheap splitter will roll the dice.

[rezb1t]

So I bought a ICY BOX IB-AC502 after reading the results and I must admit, I’m disappointed. Sure, the black levels and color accuracy are good, but this dac completely stops outputting video for multiple seconds on resolution changes, making it completely unusable for games like Castlevania: Bloodlines for Genesis. On top of that, it won’t even display interlaced video in either of the existing Genesis cores…

If you’re considering this dac, I recommend buying a different one instead. I received a benfei adaptor that seems reasonably ok. It doesn’t handle PAL video output in the MegaDrive core but that’s the only flaw I could see

[akeley]

So I bought a ICY BOX IB-AC502 after reading the results and I must admit, I’m disappointed.[...]

Crap, I bought this one as well, though won't be able to try it out for some time as it's elsewhere. Just my luck, I guess. Did you try Amiga core? This one uses res changes quite frequently (also ao486)...

[thorr]

I bought it also, but haven't tried it yet. Fortunately the HDMI to component/VGA box I use works really well and I didn't really need the Icy Box one anyway. They don't make the one I have anymore as far as I know.

[rezb1t]

So I bought a ICY BOX IB-AC502 after reading the results and I must admit, I’m disappointed.[...]

Crap, I bought this one as well, though won't be able to try it out for some time as it's elsewhere. Just my luck, I guess. Did you try Amiga core? This one uses res changes quite frequently (also ao486)...

Same story with the Amiga core unfortunately, it affects every core, whenever the resolution changes the video gets blanked out for a few seconds. For most games this probably isn't that big of a deal, and it does display a very nice image. The newer Benfei with the CS5210 listed in the document doesn't have this issue, an easy way to test is to go to one of the cores and load up the 240p Test Suite and try changing between 480i and 240p. With that, the Benfei changes resolution instantly and my PVM never loses sync, even if I go back and forth really fast. The only issue with the Benfei is that if I go to the MegaDrive core and switch to PAL mode, I get a rolling picture. This also happens with the older Genesis core. Thankfully this isn't a big deal to me, but it's a shame there's a drawback.

I really hope one day we can have an affordable DAC that tests well here, but also has no sync issues with any of the cores and switches resolutions immediately. MiSTer Addons has the Reflex Prism coming soon which I'd like to test, it would be nice if that was the solution.

[ackmangogo]

So I bought a ICY BOX IB-AC502 after reading the results and I must admit, I’m disappointed. Sure, the black levels and color accuracy are good, but this dac completely stops outputting video for multiple seconds on resolution changes, making it completely unusable for games like Castlevania: Bloodlines for Genesis. On top of that, it won’t even display interlaced video in either of the existing Genesis cores…

If you’re considering this dac, I recommend buying a different one instead. I received a benfei adaptor that seems reasonably ok. It doesn’t handle PAL video output in the MegaDrive core but that’s the only flaw I could see

Tried with similar ITE IT6692FN chip dac, same issue

[jd213]

Have you tried the old Genesis core? When using the Benfei or Moread (CS5210), my PC CRT doesn't like the 320x224 modes in Castlevania Bloodlines and other Genesis games over Direct Video + Forced Scandoubler when using the Nuked core, but it works fine on the old core (non-Direct Video with the Nuked core also works fine). I'm guessing this might be more related to the core than the DAC, though.

[rezb1t]

Have you tried the old Genesis core? When using the Benfei or Moread (CS5210), my PC CRT doesn't like the 320x224 modes in Castlevania Bloodlines and other Genesis games over Direct Video + Forced Scandoubler when using the Nukey core, but it works fine on the old core (non-Direct Video with the Nukey core also works fine). I'm guessing this might be more related to the core than the DAC, though.

Yep same issue with the older Genesis core. You’re right that the current release of the MegaDrive core has sync issues with some CRTs, however I think I fixed this in the latest unstable version(I am MP2E on GitHub).

The reason I say I think instead of being more certain is I only have 2 CRTs to test on. If you could test the latest MegaDrive unstable core found on MiSTer Nightlies and report back, I would appreciate it! If there is still an issue, I will attempt to fix it.

[jd213]

Thank you, that does indeed seem to fix the issue on my Mitsubishi PC CRT!
Can also check my consumer Trinitron (Direct Video > active composite/S-Video adapter) later this week if needed.

[Atohmdiy]

Thank for doing these test. When i saw you post, i decide to order an hd fury X3 as it is suppose to be the reference. After installation, i found the text to look weird. There is a discussion in the shmup forum about it, it seems i am not alone and this dac has some kind of halo effect :
https://shmups.system11.org/viewtopic.p ... 9#p1550549

There is an alternative firmware that could maybe fix it (neo), but i think i will contact hd fury first to see if they have something to say about it.

[The Opponent]

I have a Tendak HDMI to VGA converter I bought in 2019 with a chipset labeled CM6616E. I don't know what the differences are from CM6616S but some cores don't work at all with this DAC. Megadrive, Genesis, TurboGrafx16, Minimig, Groovy, and a lot of arcade cores don't show any picture.