I'm not Peter but...
Its just an opamp I/V, opamp LPF and opamp output stage. It looks complex because it is built discrete ( HDAM ) and balanced. Compare it to a cdplayer with normal opamps and you'll notice it is almost the same except for the balanced design which doubles everything. In a Denon with balanced outputs there are 3 dual opamps per channel doing the same job ( with more circuitry internally but with much smaller footprint ).
I expected a nicer I/V to be honest.
Its just an opamp I/V, opamp LPF and opamp output stage. It looks complex because it is built discrete ( HDAM ) and balanced. Compare it to a cdplayer with normal opamps and you'll notice it is almost the same except for the balanced design which doubles everything. In a Denon with balanced outputs there are 3 dual opamps per channel doing the same job ( with more circuitry internally but with much smaller footprint ).
I expected a nicer I/V to be honest.
The Left and Right channels are separated, so it's not vanilla IIS but maybe some sony format.
What I don't understand is how they get one chip to output L+ L- (or R+ R-) , especially with the DAC configured for IIS input
You'll also notice that even here, BCK is connected to SCK. And even more: pin 4 is reffered as SCK, on this player designed for a TDA1541A
Maybe some pre-processing is done in the digital filter, to send some tata when WS=0, and the 2's complement of the same data when WS=1
The FF only seem to be some synchronous reclocking or WS and Data, synchronously to BCK.
What I don't understand is how they get one chip to output L+ L- (or R+ R-) , especially with the DAC configured for IIS input
You'll also notice that even here, BCK is connected to SCK. And even more: pin 4 is reffered as SCK, on this player designed for a TDA1541A
Maybe some pre-processing is done in the digital filter, to send some tata when WS=0, and the 2's complement of the same data when WS=1
The FF only seem to be some synchronous reclocking or WS and Data, synchronously to BCK.
jean-paul said:
Ok your message confirms that I was thinking.
Instead of a classical IIS signal like this:
<WS=0> left data bits <WS=1> right data bits [DAC outputs analog values] <WS=0> next left input....
we have this:
-left DAC:
<WS=0> left+ data bits <WS=1> left- data bits [DAC outputs analog values] <WS=0> next left+ input....
right DAC:
<WS=0> right+ data bits <WS=1> right- data bits [DAC outputs analog values] <WS=0> next right+ input....
You need a DSP to do this
Bricolo said:
Guys please: pin 27 is connected to 28. It IS I2S for the TDA. That it gets +left and -left, it is unaware of. It just converts whatever comes in. Sounds very familiar to me
The dig filter must be configured to split i2s and feed +l/-l and +r/-r to the dacs. There is no other way this would work.
Pin 4 is strange. SCK does not exist on A version, so it is no use to put crap onto that pin.
More interesting that this, is that the -5 is made from the -15 and not from a separate supply. It makes sense, if you read the post in the digital section.
gr
Peter Daniel said:I wasn't following that topic lately, that's why I guess
Which thread exactly? Not the one you started a year ago, or so?
It is longer than that and i did not start it. Called 2 TDA1541A in the digital section. Splitting works well.
However, thanks to HtP in the tda1541 info post, i now know that things can be done better around the 1541 (dem reclock, PS, I2S signals etc). So i'm gonna check that out with a new dac with only one 1541 first.
As for this old post: the GAL definitions can be done simpler (mentioned in other posts, seatch for 'GAL' and there is one improvement on the schematics (not tested yet):
pin 1 from the GAL (clock) should be connected to the 11MHz with an inverter to remove the jitter introduced by the '161 on BCK.
Regards,
guido said:
@ the moment I would be more interested in splitting the signal into +r/+r and -r/-r.
2 chips for each channel.
My listening impressions so far:
SAA7220A + TDA1541A:
Strong odd order harmonics and suppressed even orders
Sounds
SAA7220A +TDA1541:
All harmonics distributed evenly, low distortion
Sounds detailed and clean.
SAA7220B + TDA1541(A):
Very good values for K2/K3, but dominating K5
Sounds clinical, narrow and dry.
TDA1541(A) non os:
Medium distortions, but mostly evenly distributed, suppressed K9 & tendential stronger low orders.
Sounds very open & relaxed due to rich harmonics, a little bit watered though.
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