Help this clueless newbie on a mission

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Hi, this is my first post on the digital forum.
I want to use a yss901 crosstalk canceller dsp chip from a tv audio board to operate as an external device between my cd player and preamp.
fcserei is guiding me-he has already done it (inserting the chip into a digital amp)-in another thread. See: try ambiophonics with your speakers.
The problem is I know nothing about digital audio and need to have a lot of things explained.
He indicated that I need a spdif receiver before the chip and a transceiver after it. He mentioned the cs8404 or similar.

Why do I need these receivers?
After a google search I understand it extracts some necessary digital information. Will I have to hook some leg from the yss to this receiver chip for syncronization?
Or the receiver circuit will pass these data to the yss along the spdif cable?
Finally, where can I find a suitable receiver/transceiver implementation that I can use? I have found dacs use them but they don´t seem to exist as standalone boards.
Just found this. Could this be it
or could I use this without the smaller chip (a DAC):


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I love cats and I will help. :)

First, you just have that chip or you have the whole implimented board?

Second, do you know it's inputs and outputs? i2s perhaps?

I presume your preamp is a normal analog preamp, not the digital one that recieve spdif. Then you can focus on your CD player. You tap the dac chip's i2s input to your dsp chip input then put your dsp output back to the dac chip. you could design some kind of bypass when you want to compare the sound while your dsp chip is operating or bypassed. (this feature might be included on your dsp chip already pls check)

If you mean digital preamp, then the basic is the same but you have to do it before the preamp dac chip. ;)
I have the full board, not just the chip. It has both analogue and digital inputs and outputs. I don´t know what i2s means?

Fcserei advised me to disconnect the noisy power supplies on the board and use a clean 5v, which I´ll do.
My preamp/amp is the yamaha ax1, with digital inputs, but I wouldn´t dare to tinker inside. My source is a denon 2900 and the idea of tapping into its circuitry scares me without someone´s guidance.
So my idea is to put the crosstalk canceller board in a box with its own power supply. I´ve found a spdif board from twistedpear audio that´s not expensive.
But I could buy an inexpensive cd player and tap into it as you suggest. Would that spare the need for the spdif transceiver? Which option is more foolproof for an inexpert hand?
Here´s the yss´board and the spdif specifications:


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i can see your chip using i2s. for more info about i2s, check out

so your choice now would be:-

- get spdif out from your cd player / convert it to i2s / feed your dsp chip / get i2s out converted back to spdif to feed your digital amp. (please check if your amp also accept i2s but i wouldn't think so)

- start with your new cd player / tap those i2s signal out to feed your amp / tab it back to your dac (with some kind of switch/circuit/) / get analog output to feed your amp.

if i were you, my own choice would be to build a new dac with that dsp chip also in. from those of your two choice it is close to a new dac already. :D
I quite enjoy using the amp´s digital hall effects. So I´d rather keep the yss insertion in the digital domain and avoid converting twice.
Of the two alternatives you described the first seems to suit me better since it remains digital and as a plus I will end up with a external box that I can use with any cd player in the future. ( my denon has already become finicky and will not read certain cd´s).

So, focusing on this route: I see I2s consists of word select, serial clock and serial data. I need spdif receivers that provide those connections both before and after the chip.

I have found a commercially available receiver board from twisted pear audio that I could order if you would confirm it might work.
I have a huge sweet spot for cats.;)
I have already ordered the receiver boards.

Despite the non-standard I2s, the yss901 can adopt four different data formats. I have been advised on the other thread that one of them will likely work. I´ll keep my fingers crossed:)
Here´s the receiver layout. Now I just need to know how to connect the boards.
Before any further detail, the receiver´s spdif goes to the cd player´s digital out and the yss connects to the aif connector?
Re: It's I2S Jim but not as we know it.

Firstly, spdif out from your cd player to spdif in on your reciever board. Next, aif out to your yss chip. ;)

But be careful. this is the hard bit. you have to precisely locate your bck / lrck / sck / data / ground on your yss board. let us know your progress and we will help if you need any. :)
The receivers are working right now.
I am still waiting for the chips to arrive: one in a sony monitor audio board and I also bought ten chips from a retailer in China along with a smd adapter board that will hopefully allow me to make the connections to the chip without a microscope;)

I attach a connection diagram that I figured out based on facserei´s indications on how to attach the chip into a panasonic digital amp.

One of the issues that is bugging me is the chip uses a 2.8224 Mh
crystal and I reckon the twisted pear audio receiver operates on a different frequency. Does that mean this will not work?

Also, do I connect the legs straight to ground or +5v on the DC switches for high or low selection or do I insert a 10k resistor before the switch?

Thanks from the great help so far, I sure need it.


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you sure with your connection diagram? double check if you interface your DSP properly or it will not work at all. this is a very important part of this project. :att'n:

the chip may operates at a different frequency. but as long as you put the bck/lrck/data/gnd right, it will work its timing out don't worry. :)

you have to back check the logic level from the datasheet. but it is likely if the chip consume +5v, the maximum logic level could be up to 5v but anyway please double check. ;)
thanks, archwn.

I am still looking for suitable SMD to DIP adapter boards for the chip and meanwhile gathering information about shift registers, since I´ve been advised I will need one to match the 64fs format in the yamaha to the receiver. Well, the manual does say: delay by one bit.

The news is I do have a sony board with the chip working in analog in/out right now, and the physical barrier has already been removed. Ihave so much space now!

The problem is I have some noticeable background noise which sounds digital to me. Sort of a distant modulated ringing tone.

I removed the chips before and after the yss901 analog in/out, as well as two supply regulator IC´s.
Please check in the attached file where I´m feeding the board with my external 5V supply.

Bypassing IC404 and 412 ( but keeping them on the board) is noisier than tapping before them so these have not been removed. I can´t remove them without destroying them so I would only do so if I was really positive I was not to regret the move.

With these bypassed, or if removed, the same +5V line is fed to both DVDD and AVDD. Would that be sound practice?

What about using two independent power supplies for analog and digital (I would have to lift the AVSS leg and connect one of the grounds there). Would that cure the problem?


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Yes, it is working fine and I´m very happy with it. It does provide as good an effect as a complete physical barrier.

However, getting rid of the crosstalk seems to decrease the sound level by around 10db compared to the untreated signal so I am planning on inserting a level booster after the chip.

Also, the dac inside the chip is somewhat noisy in the analog in/out configuration so there is a slightly audible hiss at normal listening distance from the speakers.

Another peculiar effect is that low bass is significantly diminished to the extent that I had to inject unprocessed signal to the woofers in my active speaker system to hear it.

So it is still an undergoing process and full of hurdles but I´m content and my cats love the way themusic flows out of the dipole. They loathed normal stereo for orquestral music as much as I did.

The SMD to DIP adapter boards I ordered have just arrived from Cambridgeshire in the U.K, so I will be implementing digital in/out soon, which was my final goal all along. I still don´t know wether the shift register delaying the data by one bit goes at the chip´s in or out.:confused:

Hi, I am new to the forum too.
Poldus, I managed to get a Sony U-board too, with schematics, and just like you I am figuring out how to interface the YSS901. Like you I prefer to have a stand alone box. Did you make any progression with the spdif boards and the shift register issue?

Regarding your remarks about missing the low-end:
- looking at the output opamp IC408 (which is'nt that bad), it is used as a HP filter rolling off the bass with 6 dB between 100Hz and 10Hz. See attachment.
- mixing unprocessed bass with the processed dipole signal acoustically may give problems because of the processing time delay.

BTW, I have the Creative (Dimagic) PS2000 and tried it with my main speaker system. It is VERY good exept the 'digital' noises
it makes. As original stand alone dipole this is no problem. In my studio I use them as back stereo dipole together with UNprocessed front speakers. At a just audible level it gives quite a lot of envellopement and depth to the soundfield without to much coloration.
I want to use the YSS901-box in my living room.


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Hi wjkat, one of the receiver boards died on me and I returned it to twistedpearaudio for inspection so the project is on hold right now. I expect to get back to it soon. I´m always busy building more speakers and tweaking my active system.

My expectations are not very high though, what with the format discrepancies between the yss901 and my spdif receiver and the fact that this is all rocket science to me. Even the sony board which I was using with analog in/out is acting up so I´ve removed it from duty. It is funny that I have also been using it as a rear dipole.

If you´re interested I can mail you an unused yss901 chip (I bought ten from China) if you prefer to start from scratch given that the sony board is configured for analogue and it might be tricky to work with for digital.If you are more successful than I, I can always follow your steps, so my gain

Your explanation of the loss in low frequencies makes sense. I can live with the problem though, not a big deal.
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