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CPS QSound Amp Reverse Engineering

WydD

WydD

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Heyo,

As kind of a follow-up of this thread Capcom Q-Sound amp help? and the interesting research around it.
I decided to make a complete schematics of the CPB-001A QSound Amplifier used on CPS1.5-2-3.

You can explore the schematics here



I don't own one so I did most of the reverse engineering by hand with image references from the web.

Therefore, there are a bunch of resistor or capacitor values that I couldn't figure out for sure. If you guys have this board in your collection and want to contribute, please let me know!
[edit: thanks to nem it's complete now. If you can double-check that would be cool :)]

Also, I know next to nothing in analog electronics so if you're able to figure out exactly how it works that would be rad.


CPS2 Reverse Engineering Project
This work is part of the more global effort of recreating the schematics of the whole CPS2 including all the custom chips.
Project home
 
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I take absolutely zero responsibility for mistakes.

COMPONENTVALUE
C110uF 16V
C210uF 16V
C310nF
C44700uF 25V
C51000uF 25V
C6470uF 16V
C7470uF 16V
C847pF
C947pF
C10150nF
C11150nF
C12150nF
C13150nF
C1468nF
C1568nF
C16560nF
C17560nF
C182.2uF 50V
C192.2uF 50V
C20470uF 16V
C21470uF 16V
C2210uF 16V
C2310uF 16V
C24100pF
C25100pF
C2647uF 16V
C2747uF 16V
C2847uF 16V
C2947uF 16V
C3047uF 25V
C3147uF 25V
C32470uF 25V
C33470uF 25V
C34220uF 16V
C35220uF 16V
C36220uF 16V
C37220uF 16V
C38100nF
C39100nF
C40100nF
C41100nF
C4247uF 16V
C4347uF 16V
C44220nF
C45220nF
C46220nF
C47220nF
C4868nF
C4968nF
D1D3SBA20
D27.5V (?) zener
D37.5V (?) zener
IC1C4570HA
IC2C4570HA
IC3C4570HA
IC4uPC2500H
IC5uPC2500H
Q1C2240
Q2C2240
R101000 ohm
R111000 ohm
R122700 ohm
R132700 ohm
R1415k ohm
R1515k ohm
R1615k ohm
R1715k ohm
R182200 ohm
R192200 ohm
R202700 ohm
R212700 ohm
R222200 ohm
R232200 ohm
R242200 ohm
R252200 ohm
R262200 ohm
R272200 ohm
R283300 ohm
R293300 ohm
R312k ohm
R30100 ohm
R31100 ohm
R323900 ohm
R333900 ohm
R34220 ohm
R35220 ohm
R36100k ohm
R37100k ohm
R3822 ohm
R3922 ohm
R412k ohm
R4022 ohm
R4122 ohm
R421000 ohm
R431000 ohm
R441000 ohm
R451000 ohm
R461 ohm
R471 ohm
R481 ohm
R491 ohm
R522 ohm
R500.1 ohm
R510.1 ohm
R524700 ohm
R534700 ohm
R544700 ohm
R554700 ohm
R564700 ohm
R574700 ohm
R58100k ohm
R59100k ohm
R61500 ohm
R60100k ohm
R61100k ohm
R624700 ohm
R634700 ohm
R646800 ohm
R656800 ohm
R666800 ohm
R676800 ohm
R686800 ohm
R696800 ohm
R71500 ohm
R703300 ohm
R856k ohm
R956k ohm
 
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Oh yeah! Thank you so much. <3

Small correction though. When you say 104nF for C40 for instance, it's actually 100nF. The way it's noted on the component is "104" which means "10 with 4 zeros pF" meaning 100nF. See here
I'm assuming this is the case for C10-C13, C16-C17, C38-C41.

I'll start fixing this right away.

EDIT: Values have been updated, thank you again.
 
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WydD said:
Small correction though. When you say 104nF for C40 for instance, it's actually 100nF. The way it's noted on the component is "104" which means "10 with 4 zeros pF" meaning 100nF. See here
I'm assuming this is the case for C10-C13, C16-C17, C38-C41.
Click to expand...
Oh right :whistling:

I'll fix them in the list too.
 
Thanks for your effort @WydD.

Now the question is if this is only a stereo amp or it really takes a role in the Q-sound effects.
 
Nebula said:
Now the question is if this is only a stereo amp or it really takes a role in the Q-sound effects.
Click to expand...
It's amazing that in 2020 we still don't have a definitive answer to this. Thanks for tackling it WydD, curious to see if anything becomes more clear. Seen a lot of arguments about QSound and honestly have no clue which side is right.
 
I just don't understand Q-sound period...
I mean I know its a special type of stereo separation that provides a 3D effect dependent on the physical position (fixed/static) of the end user.

But... I also thought what make it "special" was its ability to be transmitted/amplified/projected via normal stereo equipment.

So why do we need a specialized amp period if this is the case?
 
Aurich said:
Seen a lot of arguments about QSound and honestly have no clue which side is right.
Click to expand...
Me too, and I'm curious about that.

@WydD just to full document it, there is also another slightly different version of the CPB-001A (yes, same reference...) that is powered directly using 12V DC and because of that, the diode bridge rectifier is replaced by a coil. Some other components may also change in the power-in section.
That version is used in the Capcom Impress candy cab.
Maybe any Impress owners here could see the differences or take directly a good quality picture in order to figure out those differences and properly document them.
 
Yes I saw those. At first I wondered if it was an official alteration or just a mod done :P
I'll add a note to the schematics.
 
Agreed, the only one weird thing that I don't understand: there is a feedback loop using the 0.1 ohm resistor. I'm not sure how it impacts the rest.
 
Q sound adopted by Capcom is a technology to obtain three-dimensional sound in a normal stereo environment.

What is installed in the Capcom cabinet is YAMAHA AST SYSTEM audio, which is not dedicated to Q sound and does not have a function to decode three-dimensional sound.
I will omit the details of AST, but in short, it is audio that is strong in the bass range.
AST is sometimes referred to as YST.
Q sound is given from the stereo output terminal of the CPS2 board, and all you need to watch it is a general stereo speaker.

Note that this AST amplifier works as a set with a dedicated AST speaker, and since the drive system is different, there is a risk of failure if it is connected to a normal speaker. Be careful if you get only the board.

In Japan, a product called the Q sound amplifier has been released by other companies, but this is an effector that makes a normal stereo sound source a pseudo-three-dimensional sound.
If you connect this to a CPS2 board, you will add another step effect to the Q sound output, which is a mistake.
Inside this product is the QXpander, a device that receives unencoded signals.

The false information that Capcom's Q sound requires a dedicated device has been widely disseminated, but I hope that the correct information will spread.
 
UYO said:
In Japan, a product called the Q sound amplifier has been released by other companies, but this is an effector that makes a normal stereo sound source a pseudo-three-dimensional sound.
If you connect this to a CPS2 board, you will add another step effect to the Q sound output, which is a mistake.
Click to expand...
That was my thought also.
UYO said:
What is installed in the Capcom cabinet is YAMAHA AST SYSTEM audio, which is not dedicated to Q sound and does not have a function to decode three-dimensional sound.

Q sound is given from the stereo output terminal of the CPS2 board, and all you need to watch it is a general stereo speaker.
Click to expand...
This is very good info. Thanks.
 
UYO said:
Q sound adopted by Capcom is a technology to obtain three-dimensional sound in a normal stereo environment.

What is installed in the Capcom cabinet is YAMAHA AST SYSTEM audio, which is not dedicated to Q sound and does not have a function to decode three-dimensional sound.
I will omit the details of AST, but in short, it is audio that is strong in the bass range.
AST is sometimes referred to as YST.
Q sound is given from the stereo output terminal of the CPS2 board, and all you need to watch it is a general stereo speaker.

Note that this AST amplifier works as a set with a dedicated AST speaker, and since the drive system is different, there is a risk of failure if it is connected to a normal speaker. Be careful if you get only the board.

In Japan, a product called the Q sound amplifier has been released by other companies, but this is an effector that makes a normal stereo sound source a pseudo-three-dimensional sound.
If you connect this to a CPS2 board, you will add another step effect to the Q sound output, which is a mistake.
Inside this product is the QXpander, a device that receives unencoded signals.

The false information that Capcom's Q sound requires a dedicated device has been widely disseminated, but I hope that the correct information will spread.
Click to expand...
Years later, but thank you for this detailed reply. I think a huge problem with the spread of misinformation is that most people don't own stereo equipment worth a damn to tell the difference between anything. My dad is an old-school audiophile that gifted me a lot, so I realize I'm a bit spoiled, but I promise you guys those dinky speakers in your cabs being powered by tiny amplifiers aren't doing you in any sonic favors; they weren't exactly designed for good sound quality. Before moving to Japan I switched between a stereo my dad built and a 1960s Fisher 500B; both setups used 80s EPI speakers. The sound on CPS2 in particular was awesome and had a noticeable difference in the soundscape compared to other boards. If your boards have RCA ports then output them to a real stereo (doesn't have to be ridiculous as mine) and enjoy the results :thumbsup:

Edit: 5-7 year old pics of previous setups of mine back in the States.
 

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jassin000 said:
But... I also thought what make it "special" was its ability to be transmitted/amplified/projected via normal stereo equipment.

So why do we need a specialized amp period if this is the case?
Click to expand...
I feel this is a part people gloss over a lot. Just look at the long list of CONSOLE ONLY games that use Q-Sound. There certainly wasn't any special amplifier released to enjoy Sonic CD or Terminator in "true Q-Sound". Do you guys not remember the massive stereos your friend's dads owned back in the late 80s and early 90s??? That's how you hear the difference lol.
 
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