Hello all
After a recommendation of Guido Tent i connected a TDA1541 directly on a 1/2 clock signal of 5.6 MHz, by a 74HCT74 flipflop in divide-by-2 mode. The 7220 is removed. I use an XO and sometimes a Kwak 7 via X-in of SAA7210.
The result was: digital noise instead of music, full scale, and far away was some music hearable.
Checked everything, saw a neat squarewave of indeed 1/2 the clock on a scope.
Connected 74/74: 1 and 4 and 14 on +5V, 6(Qnot) to 2(Data) 11.2896 to pin 3 and took 1/2 clock from pin 5.
So what went wrong here?😕
Maybe the timing is a little out of phase and will a 74HC04 inverter after 74HCT74 will do the trick?
Or any other comments?
After a recommendation of Guido Tent i connected a TDA1541 directly on a 1/2 clock signal of 5.6 MHz, by a 74HCT74 flipflop in divide-by-2 mode. The 7220 is removed. I use an XO and sometimes a Kwak 7 via X-in of SAA7210.
The result was: digital noise instead of music, full scale, and far away was some music hearable.
Checked everything, saw a neat squarewave of indeed 1/2 the clock on a scope.
Connected 74/74: 1 and 4 and 14 on +5V, 6(Qnot) to 2(Data) 11.2896 to pin 3 and took 1/2 clock from pin 5.
So what went wrong here?😕
Maybe the timing is a little out of phase and will a 74HC04 inverter after 74HCT74 will do the trick?
Or any other comments?
tubee said:
Hi
I never checked the proposed metod with the 7220 removed, so I can't judge on this.
What 1541 clock connection would you have used without /2 mode ?
best
Guido
Hello Guido
Thanks for reply, i contacted you by mail last week but received no answer.
I now reconnected the 1541A's pin 2 and 4 on the clock signal of the SAA7210, 7220 is removed. So now WS, Data and CLAB from 7210 goes to 1541 via 47ohm resistor.
Clock's used: XO and sometimes a Kwak 7, on X-in of 7210.
Regards:
Thanks for reply, i contacted you by mail last week but received no answer.
I now reconnected the 1541A's pin 2 and 4 on the clock signal of the SAA7210, 7220 is removed. So now WS, Data and CLAB from 7210 goes to 1541 via 47ohm resistor.
Clock's used: XO and sometimes a Kwak 7, on X-in of 7210.
Regards:
tubee said:
Hi Tubee,
Correct, I am somewhat behind in answering mails
Does above config work ? If so, what is the clock freq at pin 2/4 ?
It works, so this player is in Non-os now. At the moment Kwak clock, I/V by 4 transistor scheme of RBroertjes.
I will measure the signal-frequency on pin 2-4 of dac tonight if possible.
regards
I will measure the signal-frequency on pin 2-4 of dac tonight if possible.
regards
Guido you helped me on rails again.🙂 🙂
measured pin 2-4 from TDA: One waveform is about 0.24msec. and looks like a four times slower signal than 11.2896, so would be 2.8224Mhz.
Digged in the serv. manual also: CLAB clock from 7210 to 7220 is 2.8224, CLBD is I2S like 5.6448 MHz.
The Word Select signal does a lot the for the dac, otherwise there should be no music hearable in non-os.
Now we have to connect the 74HCT74 in divide- by-4 mode.
Thanks😎
measured pin 2-4 from TDA: One waveform is about 0.24msec. and looks like a four times slower signal than 11.2896, so would be 2.8224Mhz.
Digged in the serv. manual also: CLAB clock from 7210 to 7220 is 2.8224, CLBD is I2S like 5.6448 MHz.
The Word Select signal does a lot the for the dac, otherwise there should be no music hearable in non-os.
Now we have to connect the 74HCT74 in divide- by-4 mode.
Thanks😎
tubee said:
Hi, Not shure this would be the answer to the solved problem, but here's some calculations:
7210 out is 32 bit's for one (16 bit) sample (16 not used):
(32 +32) * 44.1 * 1000 = 2.8224 MHz
7220 out is 16 bit's for one (16 bit) sample
(16 + 16) * 44.1 * 1000 * 4 = 5.6448 MHz
The DAC can handle these spare bits (e.g. crystal receivers are 24 bits iirc).
As for pin 2 and 4, pin 2 (iirc) is not used with tda1541A (A!) in i2s mode.
GuidoB
GuidoB wrote:
7210 out is 32 bit's for one (16 bit) sample (16 not used):
(32 +32) * 44.1 * 1000 = 2.8224 MHz
7220 out is 16 bit's for one (16 bit) sample
(16 + 16) * 44.1 * 1000 * 4 = 5.6448 MHz
-----------------------------------------------------
Thanks for this simple but clear calculation GuidoB, now for me its clear why there is a only 2 times frequency-difference of clock between 7210 and 7220, would epect with 4 times with OS, but its because 7210 has to handle the 16 subcodebits extra.
Did some thinking of the 74HCT74, divide-by-4 is less easy then.
Better take a 74HC4040, you can choose different dividers also.
But with scope the waveform of 2.8224 MHz from the SAA7210 didn't look bad at all, and i can imagine the SAA7210 doesn't give a lot of pollution as a SAA7220 would on its transmitting clock signal.
Maybe we then have revealed here a little bit more of the quest: why does Non-os sounds better for a lot of people???
7210 out is 32 bit's for one (16 bit) sample (16 not used):
(32 +32) * 44.1 * 1000 = 2.8224 MHz
7220 out is 16 bit's for one (16 bit) sample
(16 + 16) * 44.1 * 1000 * 4 = 5.6448 MHz
-----------------------------------------------------
Thanks for this simple but clear calculation GuidoB, now for me its clear why there is a only 2 times frequency-difference of clock between 7210 and 7220, would epect with 4 times with OS, but its because 7210 has to handle the 16 subcodebits extra.
Did some thinking of the 74HCT74, divide-by-4 is less easy then.
Better take a 74HC4040, you can choose different dividers also.
But with scope the waveform of 2.8224 MHz from the SAA7210 didn't look bad at all, and i can imagine the SAA7210 doesn't give a lot of pollution as a SAA7220 would on its transmitting clock signal.
Maybe we then have revealed here a little bit more of the quest: why does Non-os sounds better for a lot of people???
Just read here its not wise to choose a 74HC4040:
http://www.diyaudio.com/forums/showthread.php?postid=706730#post706730
Anyone an other option for a good divide-by-4 schematic? Meanwhile will search myself also.
Oh and forgot:
http://www.diyaudio.com/forums/showthread.php?postid=706730#post706730
Anyone an other option for a good divide-by-4 schematic? Meanwhile will search myself also.
Oh and forgot:
I use 1541 'A' version but pin 2 is still on CLAB signal as with pin 4.
tubee said:
Yep, iirc was needed. It is pin 4 that is no longer required with the A version. In my dac it's connected to gnd and i do get music.
As for the divider, i'm using a '161 which is the same as '163 but for the reset.
GuidoB
Re: Reclock?
works, but lower jitter can be obtained from direct /2 clocking (remember the jitter levels from the preceeding 7220 are hoorible)
best
Arcamaniac said:
works, but lower jitter can be obtained from direct /2 clocking (remember the jitter levels from the preceeding 7220 are hoorible)
best
Horrible?
You are being kind.
Wretched, more like. Horrendous. Disgusting. Gross. Sickening.
You put tons of functions in one chip........one supply pin.....one ground pin.......and try to use it for an oscillator. And yet some wonder why it has tons of jitter.
Jocko
You are being kind.
Wretched, more like. Horrendous. Disgusting. Gross. Sickening.
You put tons of functions in one chip........one supply pin.....one ground pin.......and try to use it for an oscillator. And yet some wonder why it has tons of jitter.
Jocko
Re: Re: Reclock?
But he wants to remove the SAA7220!
This means that he needs direct /4 clocking........................
Would direct /4 (2 divisions by 2) clocking still be better than reclocking the bitclock from SAA7210 (decoder)?
Guido Tent said:
But he wants to remove the SAA7220!
This means that he needs direct /4 clocking........................
Would direct /4 (2 divisions by 2) clocking still be better than reclocking the bitclock from SAA7210 (decoder)?
Re: Re: Re: Reclock?
Hi
I would be surprised if the SAA7210 is any cleaner....
And then again, a divided clock from an oscillator has lower jitter than a reclocked signal using that same oscillator to clock the flipflop. Bear in mind that reclockers are attenuators......
best
Arcamaniac said:
Hi
I would be surprised if the SAA7210 is any cleaner....
And then again, a divided clock from an oscillator has lower jitter than a reclocked signal using that same oscillator to clock the flipflop. Bear in mind that reclockers are attenuators......
best
I am very pleased with all your reactions!
I think i will go for 74/163, because with implementation of two 74/74 problably add some jitter imo, and thats not wat we want.
Its removed already folks.... and i had some thoughts of the 7220-B but havent tried yet, and problably never will on this player.
Guido, i looked at CL of it on scope (20 Mhz Handykit) not a bad looking squarewave, only the bottom of wave had a little ripple. But that doesn't say anything about the sound.
I think i will go for 74/163, because with implementation of two 74/74 problably add some jitter imo, and thats not wat we want.
Yes Jocko, i know you dislike this chip, and the tda also.
tubee said:
Hi
If you are looking for jitter using a scope, the SAA7210 isn't bad enough......
I never measured the 163 as divider, but a 74 is pretty clean, so are 2..... Make sure to feed them with CLEAN supply.
best
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