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Multi Boyz Litigator
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I had, at some point, bookmarked a guide on setting up a Q-Sound amp. But I've definitely lost it... Can anyone explain how it's setup, or perhaps pics from a cab that it's already setup in? I know a few guys on here have big blue's.

With both transformer and amp in hand, and a working standard JAMMA cab, where does one go?
 

RealMFnG

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Behold! Snapped from an honest to goodness OG Capcom Big Blue Gen2 Qsound cab. Honestly though, if this ever takes a dive, I am swapping it out for a modernized 12v stereo TDA7297F amp.

qsound.JPG
 

zero238

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Behold! Snapped from an honest to goodness OG Capcom Big Blue Gen2 Qsound cab. Honestly though, if this ever takes a dive, I am swapping it out for a modernized 12v stereo TDA7297F amp.

qsound.JPG
I'll take it off your hands if you do. But am curious on putting stereo sound on the big blues. Hope it doesn't need the step down part for that modern one.
 

RealMFnG

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I am curious too. We'll find out in this weekend or so when I get my second Big Blue (a Gen 1, like yours). MAME guys use the TDA7297F amp all the time. Just need to power it with one of these 12v DC adapters, which is easy enough to do off a power distribution block. I'll use the same DC adapter to power the marquee light with strips of LED's and modernize that too. Reduce heat hitting the marquee preserving it better.

But yeah, back to the topic. Let me know if you need anymore pictures @rewrite.
 

l_oliveira

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You will lose the QSOUND decoder if you remove it. Contrary to what people say there is a sound processing IC (at the pre amplifier stage) which is part of the spatial sound setup.
 

Jdurg

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You will lose the QSOUND decoder if you remove it. Contrary to what people say there is a sound processing IC (at the pre amplifier stage) which is part of the spatial sound setup.
Just curious, but where on the board is that IC? The Q-Sound Amplifier just looks like it's a normal stereo amp. In my cabinet, granted not a big-blue, I simply have a computer speaker amplifier that works great for stereo sound, and with the use of a line output conditioner, I can also connect the normal Jamma audio connection to it and have dual mono for mono games.

When I was putting my cab together, I was thinking about trying to find a Q-Sound amp, but really didn't see a need for it as I saw nothing proprietary or custom on the Q-Sound amp boards out there.
 

l_oliveira

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There's three small chips that can be seen on the picture you posted. The first one is a Mitsumi chip which does the "spatial" decoding of the effect generated at the DSP on the game board. Since the effect requires two channels for encoding the difference and sum of the signal the first chip has to receive both channels at once so they can be processed by some kind of "equalizer" which then apply the effect. At it's output you have then QSOUND signal.
Without that you get standard stereo sound. Then, each channel has another small chip which serves as pre amplifier (two other smaller chips by the middle of the board) and finally the big power amp chips on the heat sinks.

The trick is use the difference and sum of the two stereo channels to give "depth" to the sound effects. On "The Punisher" the sound test menu gives full access to the QSOUND chip registers which control the effects interface, allowing you to play around with the depth and direction of the effects. It's a bit complex but once you understand how it works you can play with it and actually test how it works.
 

zero238

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dammit. I need to find 3 more boards and the step down thing
 

Mitsurugi-w

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Are those chip actually custom? Or are they standard ICs used in a clever way?
 

l_oliveira

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Are those chip actually custom? Or are they standard ICs used in a clever way?
The QSOUND chip is a custom part. I spent some time looking for datasheets. I found some that perform a simulation of the effect on top of a standard signal. For example MM1326.

What is the code for the three small SIP package ICs on the board?
 

RealMFnG

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Are those chip actually custom? Or are they standard ICs used in a clever way?
The QSOUND chip is a custom part. I spent some time looking for datasheets. I found some that perform a simulation of the effect on top of a standard signal. For example MM1326.
What is the code for the three small SIP package ICs on the board?
Actually, I took that photo from my cab. I'll give you all the info you want. I'll take better photos if you want. Just point to me where on that photo you want me to focus on.
 

l_oliveira

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I need photos of the number code on the five chips in the amp, a high res close up photo of each side of the board so I can trace the circuitry and research how it works. :)

Would be awesome if you could provide me with that.
 

RealMFnG

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Alright, it is coming out of the cab this weekend. Will be given a Simple Green wash. Finally followed by a DSLR photoshoot.
 

zero238

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I need photos of the number code on the five chips in the amp, a high res close up photo of each side of the board so I can trace the circuitry and research how it works. :)

Would be awesome if you could provide me with that.
would you like me to donate my board for research? Would like to one day put them on the gen 1 cabs that didn't have q sound.
 

l_oliveira

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For now all I need is the code of the parts on the amp board so I can research further to check if datasheets are available.
 

SmokeMonster

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I just scored a bare Q-Sound amp PCB.

I'm so glad that you guys started this thread to involve people who actually understand how the Q-Sound works.
 
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l_oliveira

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SmokeMonster:

The problem with that is that there are several methods of storing QSOUND encoded data. The method used on CDs or previously recorded media can processed before recording and then any standard stereo sound amplifier can be used.

Qsound can also be encoded also in a way it requires additional circuitry to "activate" so Qsound could bite in some dough from royalties at the hardware (the amplifier chip).

Similar to how Dolby Laboratories were making their money of Compact Cassette players back in the 70s and 80s by adding it's tape enhancement/noise suppression technology on take deck chips. That particularly on early 80s was very common.

Archer/QSOUND inc tried to emulate the Dolby laboratories business model but, well, we know that flopped. lol
 

SmokeMonster

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Thanks Leo, that makes sense.

So I've found some more info on the power requirements. Some sources are saying that there are two versions of the Q-Sound amp, one requiring 12V AC and another 18V AC. Is there a way to know which it requires?

Update: To answer my own question, I found this thread with pictures of the 12V AC and 18V AC Q-Sound PCBs. the 12V AC Q-Sound amps are from the later Impress cabs. I'll re-post the pictures/info from that thread for posterity's sake:

Update #2: AC, not DC!!
As you can see the difference seems to be close to the place where power is connected to, there is a coil in the one on the
. I tested both several times...the one on the left works with 18 volts and the one on the right is the "stock" one in my cab (12V)
Left: 18V AC Standard PCB / Right: Later 12V AC Impress Revision
4347612727_2c1d44d5aa_o.jpg
 
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