RGB bypass borti or Voultar

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brunofree
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RGB bypass borti or Voultar

Post by brunofree »

hello guys, is there any difference in RGB bypass of borti4938 and voultar? Which do you recommend? I could not find the resistor and capacitor values ​​on the borti page, could anyone help me? https://github.com/borti4938/SNES-AddOn ... B%20Bypass
nmalinoski
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Re: RGB bypass borti or Voultar

Post by nmalinoski »

Personally, I'd just use Voultar's board, regardless of differences, because it can be purchased preassembled.
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unmaker
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Re: RGB bypass borti or Voultar

Post by unmaker »

This is the BOM for borti's boards. He has three types

https://github.com/borti4938/SNES-AddOn ... ypass.xlsx

I've compared both and they were EXACTLY the same in terms of video output. In the BOM borti recommends 1.2kohm brightness attenuation resistors for the SNES Jr., as they were a common choice at the time, but Voultar uses 1.4kohm on his. I went with 1.4kohm as Voultar has spent more time fine tuning his.
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Syntax
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Re: RGB bypass borti or Voultar

Post by Syntax »

unmaker wrote:
I've compared both and they were EXACTLY the same in terms of video output. In the BOM borti recommends 1.2kohm brightness attenuation resistors for the SNES Jr., as they were a common choice at the time, but Voultar uses 1.4kohm on his. I went with 1.4kohm as Voultar has spent more time fine tuning his.

Or with the jnr you can just change the value of R3 (Right next to C11 ghost fix cap) and omit those 3 resistors. More uniform approach.
kel
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Re: RGB bypass borti or Voultar

Post by kel »

unmaker wrote:This is the BOM for borti's boards. He has three types

https://github.com/borti4938/SNES-AddOn ... ypass.xlsx

I've compared both and they were EXACTLY the same in terms of video output. In the BOM borti recommends 1.2kohm brightness attenuation resistors for the SNES Jr., as they were a common choice at the time, but Voultar uses 1.4kohm on his. I went with 1.4kohm as Voultar has spent more time fine tuning his.
From my experience the value is different per console. 1.2kohm was the value calculated for the first console to be measured regarding the brightness issue by Ultron on the Assemblergames forum and was IMHO specific to that console as I personally have not found a console that quite matched that value yet and some were no where near.

If you don't have an oscilloscope to check for yourself then you are better off leaving the attenuation resistors as you could end up making things worse. borti's board has the option for this and so does voultar's in the sense that you can easily remove them but either way both borti's and voultar's designs will work just as well as each other.
rama
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Re: RGB bypass borti or Voultar

Post by rama »

The attenuation value also isn't super critical, as long as it's there. You want to reduce the brightness a bit. For anything more exact, you will need a scope.
Oh and I agree, using R3 is better (unless you already have a multi mod board covering it, which happens to me all the time :p).
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Syntax
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Re: RGB bypass borti or Voultar

Post by Syntax »

The value of R3 can still vary but not as much as the 3 resistor approach.

I've been using the same value for all Jr mods I do with no worries.
brunofree
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Re: RGB bypass borti or Voultar

Post by brunofree »

unmaker wrote:This is the BOM for borti's boards. He has three types

https://github.com/borti4938/SNES-AddOn ... ypass.xlsx

I've compared both and they were EXACTLY the same in terms of video output. In the BOM borti recommends 1.2kohm brightness attenuation resistors for the SNES Jr., as they were a common choice at the time, but Voultar uses 1.4kohm on his. I went with 1.4kohm as Voultar has spent more time fine tuning his.

Thank you very much, it helped me a lot. I created a schematic to facilitate the visualization of the circuit, but some doubts appeared.
- Borti gives the option to short circuit J2 or add the capacitor C43, what is the best option?
- Should I short circuit J1?
Image
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unmaker
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Re: RGB bypass borti or Voultar

Post by unmaker »

brunofree wrote:
unmaker wrote:This is the BOM for borti's boards. He has three types

https://github.com/borti4938/SNES-AddOn ... ypass.xlsx

I've compared both and they were EXACTLY the same in terms of video output. In the BOM borti recommends 1.2kohm brightness attenuation resistors for the SNES Jr., as they were a common choice at the time, but Voultar uses 1.4kohm on his. I went with 1.4kohm as Voultar has spent more time fine tuning his.

Thank you very much, it helped me a lot. I created a schematic to facilitate the visualization of the circuit, but some doubts appeared.
- Borti gives the option to short circuit J2 or add the capacitor C43, what is the best option?
- Should I short circuit J1?
Image
For J2, it depends if you want TTL or attenuated 75 ohm CSYNC. For TTL CSYNC you short the jumper, for 75 ohm CSYNC you will use either a 330 or 220 uF capacitor. The necessary components for TTL or 75 ohm CSYNC are specified in the BOM under "/CSYNC branch". Make sure you don't mix up the components. For example, R41 = 4.99kOhm for TTL but R41 = 9.53kOhm for 75 ohm CSYNC.

J1 can be used to bypass the low pass filter. Short J1 = LPF bypass, leave J1 open = LPF not bypassed. Borti talks about this further in his github page:

https://github.com/borti4938/SNES-AddOn ... B%20Bypass
brunofree
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Re: RGB bypass borti or Voultar

Post by brunofree »

unmaker wrote:
brunofree wrote:
unmaker wrote:This is the BOM for borti's boards. He has three types

https://github.com/borti4938/SNES-AddOn ... ypass.xlsx

I've compared both and they were EXACTLY the same in terms of video output. In the BOM borti recommends 1.2kohm brightness attenuation resistors for the SNES Jr., as they were a common choice at the time, but Voultar uses 1.4kohm on his. I went with 1.4kohm as Voultar has spent more time fine tuning his.

Thank you very much, it helped me a lot. I created a schematic to facilitate the visualization of the circuit, but some doubts appeared.
- Borti gives the option to short circuit J2 or add the capacitor C43, what is the best option?
- Should I short circuit J1?
Image
For J2, it depends if you want TTL or attenuated 75 ohm CSYNC. For TTL CSYNC you short the jumper, for 75 ohm CSYNC you will use either a 330 or 220 uF capacitor. The necessary components for TTL or 75 ohm CSYNC are specified in the BOM under "/CSYNC branch". Make sure you don't mix up the components. For example, R41 = 4.99kOhm for TTL but R41 = 9.53kOhm for 75 ohm CSYNC.

J1 can be used to bypass the low pass filter. Short J1 = LPF bypass, leave J1 open = LPF not bypassed. Borti talks about this further in his github page:

https://github.com/borti4938/SNES-AddOn ... B%20Bypass

Thank you very much for the information, I'm going to study this circuit. Thanks also to all who participated in this topic
brunofree
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Re: RGB bypass borti or Voultar

Post by brunofree »

unmaker wrote:
brunofree wrote:
unmaker wrote:This is the BOM for borti's boards. He has three types

https://github.com/borti4938/SNES-AddOn ... ypass.xlsx

I've compared both and they were EXACTLY the same in terms of video output. In the BOM borti recommends 1.2kohm brightness attenuation resistors for the SNES Jr., as they were a common choice at the time, but Voultar uses 1.4kohm on his. I went with 1.4kohm as Voultar has spent more time fine tuning his.

Thank you very much, it helped me a lot. I created a schematic to facilitate the visualization of the circuit, but some doubts appeared.
- Borti gives the option to short circuit J2 or add the capacitor C43, what is the best option?
- Should I short circuit J1?
For J2, it depends if you want TTL or attenuated 75 ohm CSYNC. For TTL CSYNC you short the jumper, for 75 ohm CSYNC you will use either a 330 or 220 uF capacitor. The necessary components for TTL or 75 ohm CSYNC are specified in the BOM under "/CSYNC branch". Make sure you don't mix up the components. For example, R41 = 4.99kOhm for TTL but R41 = 9.53kOhm for 75 ohm CSYNC.

J1 can be used to bypass the low pass filter. Short J1 = LPF bypass, leave J1 open = LPF not bypassed. Borti talks about this further in his github page:

https://github.com/borti4938/SNES-AddOn ... B%20Bypass

Image


I redesigned some parts of the circuit that were missing. Could you give me some suggestion if something in the circuit designed is not good? Which is better TTL or 75ohm / CSync? All C * 4 are 47pf?
is there any difference between NTSC and PAL besides resistors R13, R23, R33? Sorry for the inexperience, thank you
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unmaker
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Re: RGB bypass borti or Voultar

Post by unmaker »

What sort of SNES console will you be installing this into and what is your setup like?
brunofree
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Re: RGB bypass borti or Voultar

Post by brunofree »

unmaker wrote:What sort of SNES console will you be installing this into and what is your setup like?
would be in SNES mini, 1chip03, I would use a RGB transcoder for component, use on a led tv, but sometimes I use in crt, I think in the future buy an OSSC or framemeister
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unmaker
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Re: RGB bypass borti or Voultar

Post by unmaker »

Here are some examples of installs in NTSC consoles, the first is a 1chip-03 and the second is a snes mini:

https://imgur.com/a/txdE0x7

There is a mistake in the first. The three resistors R15,R16, R17 should be removed. You only need 1 C*4 cap because the decoupling cap C46 is missing from the console. The other three, C44, C45, C47, are present. This will also give you csync since the csync circuitry is missing from 1chip-03 consoles.

For the snes mini, you will want all 4 C*4 caps since there aren't any decoupling caps on the console end. Both installs used the TTL csync circuitry. If you do so also, make sure you get a scart cable with a resistor on the csync line for attenuated 75 ohm csync. You will want attenuated csync if you will be using a framemeister or ossc.
brunofree
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Re: RGB bypass borti or Voultar

Post by brunofree »

unmaker wrote:Here are some examples of installs in NTSC consoles, the first is a 1chip-03 and the second is a snes mini:

https://imgur.com/a/txdE0x7

There is a mistake in the first. The three resistors R15,R16, R17 should be removed. You only need 1 C*4 cap because the decoupling cap C46 is missing from the console. The other three, C44, C45, C47, are present. This will also give you csync since the csync circuitry is missing from 1chip-03 consoles.

For the snes mini, you will want all 4 C*4 caps since there aren't any decoupling caps on the console end. Both installs used the TTL csync circuitry. If you do so also, make sure you get a scart cable with a resistor on the csync line for attenuated 75 ohm csync. You will want attenuated csync if you will be using a framemeister or ossc.
Image


Thank you very much. I upgraded the schematic, I did not know the cables were coming with a resistor in the Csync line. So TTL uses when the cable has this resistor and 75 ohms csync when the cable has not, is that correct? I appreciate your help
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Syntax
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Re: RGB bypass borti or Voultar

Post by Syntax »

If the cable has the resistor and the TV has a 75r termination then the sync output will be low level around 300-600mvpp.

With no resistor or no 75r termination(either on missing) the sync is 2.5 to 5vpp TTL
romulocff
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Re: RGB bypass borti or Voultar

Post by romulocff »

Syntax wrote:If the cable has the resistor and the TV has a 75r termination then the sync output will be low level around 300-600mvpp.

With no resistor or no 75r termination(either on missing) the sync is 2.5 to 5vpp TTL
Good morning Syntax, Is it possible to modify some components for more commercial values? for example 5.1MOhm, 0.082uF, 4.99kOhm, are not easy to find values, I will not use SMD at the moment, is there any approximation that I can make for these components? or would you have to make associations?
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Syntax
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Re: RGB bypass borti or Voultar

Post by Syntax »

0.1uf , 5k, id probably keep the 5.1Meg one as it is.
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