TDA 1543 I/V stage education needed!!

Chris · 12th January 2004, 05:14 PM

Help please...

Some time ago I purchased Scott Nixons dac kit (2.5 v) pcb board, cs8412 and some TDA1543 dacs.
I have not started to build yet, since I have been working on a phono pre lately.(And things take time

). Now the riia is done and I`m satisfied (for a while). Well enough blah blah....

As far I understand the non os dac with a passive I/V gives an inverted audio signal. Doing this would make the dac very difficult to use considering my other sources.
Does using an op amp for active I/V degrade the sound in a big way??
How about the circuit that Kuei Yang Wang designed with opa660, does that one give a noninverted audio signal?

Hope you understand my problem?

Elso Kwak · 12th January 2004, 07:46 PM

Hi Chris,
If you search the archive you will find many followers of different believes:
Passive IV conversion, various schemes by Rudolf Broertjes and Thijs, and Jocko using a common base amplifier (input going to the emitter ), Opamp IV with virtual ground at the non-inverting input, me and Chris Owen of Ack Dack, and so on and so on.
I don't remember a working solution with the OPA660 and the TDA1543.
One of the least important issues is if the DAC inverts phase or not. I can't hear that, but others will vigorously disagree.

I can't hear the effect of the Grunge Buster CD mat, green or black pens, green, red or blue lights shining light on the CD, Bedini Ultra Clarifier, dampening of the case of the player, placing stripes of paper on the CD or placing square pieces of paper on my loudspeaker, knocking the energy out of my speakers with my bare fists, demagnetisizing my system with a XLO CD (the noises frighten my neighbours), placing pyramids at strategic locations in my room, placing the speaker cables on large pieces of porcelain to "isolate" them, hanging Dr. Boner's "polycylindrical surfaces" at the ceiling, placing the Magic Brick on top of equipment or on the transformer, Jon Risch's famous sandbag trick: placing a bag of canary sand over the crystal of the CD Player, dampening said crystal with chewing gum, poster buddy or blue tack, multileadcoils in a loudspeaker crossover, rounding off corners on PCB's, "burn in effects", varous sharp cones supporting my equipment and damaging my furniture, etc. etc.

sparkle · 12th January 2004, 08:20 PM

I agree with that one

Also how could You tell the original recording fase (inverted or not). I think none of us don't know the real fase of the recorded signal. (only maybe a few of us that have Van den Hul's fase meter's or how U call that devices)
Also is Your amp inverted or not.
My opinion don't worry about it very much. I have dac that inverts fase and it works just fine. I am still working on it but it is good.

happy diy-ing
daniel

Elso Kwak · 12th January 2004, 09:27 PM

Quote:

Originally posted by sparkle
I agree with that one
daniel

Daniel, you agree on what?

sparkle · 12th January 2004, 09:53 PM

I agree with You
daniel

"One of the least important issues is if the DAC inverts phase or not. I can't hear that, but others will vigorously disagree"

Pedja · 12th January 2004, 10:15 PM

Quote:

Originally posted by Chris
How about the circuit that Kuei Yang Wang designed with opa660, does that one give a noninverted audio signal?

Yes, it inverts the phase. But it is not directly applicable for the TDA1543.

Pedja

Peter Daniel · 12th January 2004, 10:16 PM

I can easily hear the difference if I reverse speaker cables polarity.

This could actually be a solution to your question. If you have sources which reverse phase and which not, you might put a swith at amp' output, providing normal polarity, reversed polarity and speakers off. I wouldn't mind having such a switch on my amp

Chris · 12th January 2004, 10:30 PM

How about this active I/V stage?

jean-paul · 12th January 2004, 10:32 PM

Quote:

Originally posted by Chris
dfsgdfgfdnhf
,.b.bjk.

That was what I wanted to tell them too.

I tried your solution but I discovered it is not active and my DAC sounded weird with it connected to it as I/V converter

edit: Mmm, you edit your posts faster than my eyes can move; I swear I saw a turntable pickup just a minute ago.

Chris · 12th January 2004, 10:35 PM

Quote:

Originally posted by jean-paul

That was what I wanted to tell them too.

Sorry about that!!! some problems attaching an image

12th January 2004, 05:14 PM	#1
Chris diyAudio Member Join Date: Sep 2001 Location: NORWAY	TDA 1543 I/V stage education needed!! Help please... Some time ago I purchased Scott Nixons dac kit (2.5 v) pcb board, cs8412 and some TDA1543 dacs. I have not started to build yet, since I have been working on a phono pre lately.(And things take time ). Now the riia is done and I`m satisfied (for a while). Well enough blah blah.... As far I understand the non os dac with a passive I/V gives an inverted audio signal. Doing this would make the dac very difficult to use considering my other sources. Does using an op amp for active I/V degrade the sound in a big way?? How about the circuit that Kuei Yang Wang designed with opa660, does that one give a noninverted audio signal? Hope you understand my problem?

12th January 2004, 07:46 PM	#2
Elso Kwak Banned Join Date: Dec 2001 Location: Zamboanga, City of Flowers, Mindanao	TDA1543 IV Stage Hi Chris, If you search the archive you will find many followers of different believes: Passive IV conversion, various schemes by Rudolf Broertjes and Thijs, and Jocko using a common base amplifier (input going to the emitter ), Opamp IV with virtual ground at the non-inverting input, me and Chris Owen of Ack Dack, and so on and so on. I don't remember a working solution with the OPA660 and the TDA1543. One of the least important issues is if the DAC inverts phase or not. I can't hear that, but others will vigorously disagree. I can't hear the effect of the Grunge Buster CD mat, green or black pens, green, red or blue lights shining light on the CD, Bedini Ultra Clarifier, dampening of the case of the player, placing stripes of paper on the CD or placing square pieces of paper on my loudspeaker, knocking the energy out of my speakers with my bare fists, demagnetisizing my system with a XLO CD (the noises frighten my neighbours), placing pyramids at strategic locations in my room, placing the speaker cables on large pieces of porcelain to "isolate" them, hanging Dr. Boner's "polycylindrical surfaces" at the ceiling, placing the Magic Brick on top of equipment or on the transformer, Jon Risch's famous sandbag trick: placing a bag of canary sand over the crystal of the CD Player, dampening said crystal with chewing gum, poster buddy or blue tack, multileadcoils in a loudspeaker crossover, rounding off corners on PCB's, "burn in effects", varous sharp cones supporting my equipment and damaging my furniture, etc. etc.

12th January 2004, 10:16 PM	#7
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	I can easily hear the difference if I reverse speaker cables polarity. This could actually be a solution to your question. If you have sources which reverse phase and which not, you might put a swith at amp' output, providing normal polarity, reversed polarity and speakers off. I wouldn't mind having such a switch on my amp __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

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12th January 2004, 08:20 PM	#3
sparkle diyAudio Member Join Date: Oct 2003 Location: middle of nowhere...	I agree with that one Also how could You tell the original recording fase (inverted or not). I think none of us don't know the real fase of the recorded signal. (only maybe a few of us that have Van den Hul's fase meter's or how U call that devices) Also is Your amp inverted or not. My opinion don't worry about it very much. I have dac that inverts fase and it works just fine. I am still working on it but it is good. happy diy-ing daniel

12th January 2004, 09:53 PM	#5
sparkle diyAudio Member Join Date: Oct 2003 Location: middle of nowhere...	I agree with You daniel "One of the least important issues is if the DAC inverts phase or not. I can't hear that, but others will vigorously disagree"

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