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Retro Scaler A1

There is a very special and hard to find converter that will take 24khz and convert it to 31khz output. It is impossible to find and has some very minor frame stutter from what I understand. That is the only one I know of.
 
Not sure if this has been asked before, but @invzim if I split my JAMMA cab's video signal between the retro scaler and the arcade monitor, how much of a load does the retro scaler use? Will it significantly dim the video level on the arcade monitor?

Edit: I went ahead and tested this myself. It does dim the arcade monitor video level, but it's very minimal. You can easily bump up the contrast knob a bit to compensate.
 
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Back in limited stock, this is not a new run but me doing QA/assembly of the remaining ones. With IC shortage, rising production and parts cost this will likely be the last ones.
 
invzim said:
Back in limited stock, this is not a new run but me doing QA/assembly of the remaining ones. With IC shortage, rising production and parts cost this will likely be the last ones.
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If you are officially discontinuing production, would you be willing to open source the design? This is a fantastic device and it would be a shame to see it go the way of the dodo.
 
andynumbers said:
If you are officially discontinuing production, would you be willing to open source the design? This is a fantastic device and it would be a shame to see it go the way of the dodo.
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At the current pace, they should be available for another couple of years. I agree it would be great to have a good line-doubler for arcade board available , that's really the reason the A1 exists in the first place (as the XRGB2 was no longer available/hard to get second hand).
 
andynumbers said:
Not sure if this has been asked before, but @invzim if I split my JAMMA cab's video signal between the retro scaler and the arcade monitor, how much of a load does the retro scaler use? Will it significantly dim the video level on the arcade monitor?

Edit: I went ahead and tested this myself. It does dim the arcade monitor video level, but it's very minimal. You can easily bump up the contrast knob a bit to compensate.
Click to expand...
I do something similar, where I run the output of the A1 video signal simultaneously to a 31khz monitor in my cab and another to a capture device. In my case I use a powered VGA distribution device to handle this and would recommend the same if you're seeing signal degradation. Not a good idea in general to split video passively.

Bonus on my end is my device will also distribute line level audio, which allows me to run that into a headphone amp if I choose to output there instead of my cabinet speakers.
 
@invizm I love the Retro Scaler A1 already, but I have one issue on this setup in that my monitor brightness seems lower than it should be. I have tried all 4 orientations of the `rgb` and `sync` settings in the `[input]` section of `scalera1.ini` and pressing the A button to get the levels to re-adjust.

I'm currently inputting from an AxunWorks JVS / Jamma Control-Box supergun. I have not tried my other superguns (HAS is called out to directly in the documentation, so I will try that).

Is there any way I can increase the brightness coming out of the VGA output?

Edit: Update, I am keeping `rgb=arcade` and `sync=ttl`, and I have figured out I can change the RGB pot on the back of the CBOX to increase the brightness. So I think we're good. I hope the levels won't hurt the Scaler A1 unit.
 
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brandon.arnold said:
@invizm I love the Retro Scaler A1 already, but I have one issue on this setup in that my monitor brightness seems lower than it should be. I have tried all 4 orientations of the `rgb` and `sync` settings in the `[input]` section of `scalera1.ini` and pressing the A button to get the levels to re-adjust.

I'm currently inputting from an AxunWorks JVS / Jamma Control-Box supergun. I have not tried my other superguns (HAS is called out to directly in the documentation, so I will try that).

Is there any way I can increase the brightness coming out of the VGA output?

Edit: Update, I am keeping `rgb=arcade` and `sync=ttl`, and I have figured out I can change the RGB pot on the back of the CBOX to increase the brightness. So I think we're good. I hope the levels won't hurt the Scaler A1 unit.
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I'm not intimate with the AxunWorks stuff, but it likely attenuates the video to be compatible with scart/tv's etc, so rgb=75-ohm is likely the correct setting on the A1.

https://irkenlabs.com/scalera1/rgb-and-sync/
 
invzim said:
I'm not intimate with the AxunWorks stuff, but it likely attenuates the video to be compatible with scart/tv's etc, so rgb=75-ohm is likely the correct setting on the A1.

https://irkenlabs.com/scalera1/rgb-and-sync/
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Hey there, thanks. Like I said, it does the same dark image whether I set rgb to arcade or 75-ohm. But since your documentation said when in doubt to set it to arcade, and since I have now confirmed that I can change the RGB pot on the supergun to get the brightness to come up, I figured I would leave it as arcade. Is that reasonable?
 
Is there a more comprehensive manual for this device ?

Straight RGBS should be straight out without any filtering on RGB and Sync.

I find this sentence strange from the webpage:
Now it has been changed to 0-500 ohm linear adjustment)

Is that RGB or sync or both ?

I use the HAS myself 😀
 
rtw said:
Is there a more comprehensive manual for this device ?

Straight RGBS should be straight out without any filtering on RGB and Sync.

I find this sentence strange from the webpage:
Now it has been changed to 0-500 ohm linear adjustment)

Is that RGB or sync or both ?
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Yep that's a good point but I would be fairly sure it is only RGB. Sync is usually done separately. But I will ask and put a scope on it to verify. I'm glad we looked into this--I should have to begin with.
rtw said:
I use the HAS myself 😀
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I probably prefer this to the HAS but it does require some care!
 
Yup, with lacking documentation a scope is the ultimate solution :)

If it can send RGB unfiltered, rgb=jamma would be the solution (I presume the pot would then have to be at max).
 
@rtw / @invzim confirmed that the POT affects only RGB, which has a range of 0-3.5V, and the sync is TTL (5V) which is unaffected by the POT.

In the video I lower and then raise the pot, showing channels 1-3 (RGB) to be impacted but channel 4 (sync) to stay at 5V. At the end, I zoom in to show Vmax for all signals.

IMG_4468.jpg
RigolDS0.png
 
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Actually @invzim I should also update on what this does with the Retro Scaler A1.

What I think is right is to make my supergun output the same voltage level over HD15/VGA as most other consumer devices. So I have set the supergun potentiometer to output at the 1.4V range (or 700mV for 75 ohm inputs) for RGB pins. And I can confirm that when I plug directly into the monitor, the result is a perfect brightness.

And when I plug it into the Retro Scaler A1, and then into the monitor, the result is quite dark with `rgb=arcade`. But `rgb=75-ohm` looks pretty good (maybe a little dark), so I think that's the right setting for this orientation.
 
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This will get a little technical, but since you ask :)

It depends on your output impedance, which I presume is unknown. A device that re-amplifies and gives the output signal a fixed impedance of 75-ohm makes it simpler (like the HAS, or the tri-sync helper/Jammafier).

The 75-ohm setting is for devices with an output impedance of 75-ohm, and this terminates the signal with 75-ohm. If you measure the signal unterminated at 1.4, the termination in the A1 will bring it down to 0.7V.

The arcade setting has a termination of 1K. Arcade boards have wildly different impedances and there is no standard - but arcade monitors often terminate the signal with 1K. The arcade setting also has a voltage divider in the mix, to bring the levels down to something that will not overload the ADC chip.

If you feed the scaler a 1.4V signal with high impedance - there is no right setting, as the 75-ohm termination will make it dim, and the arcade setting expects a higher voltage.

There is also a component of the A1 that comes into play, which is the analog gain stage. This accepts 0.5 to 1.0V, and will adjust it to make full use of the 10bit ADC. This is adjusted every time sync stabilizes, if something clips, and a few seconds after sync stabilizes. You can also trigger a manual re-adjustment by pressing the middle button on the A1.

In practice, this works pretty well for 75-ohm sources, and raw jamma sources.
 
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