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Old 24th July 2010, 02:31 AM   #1
audi0 is offline audi0  Australia
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Default Help!

When it comes to DAC's, I'm a novice! As a introduction to DAC construction I have built a hifiDIY TDA1543 x 8 Extreme DAC but have distorion problems. I am getting realy bad distortion at lower frequencies, for instance female vocals are acceptable but below that distortion sets in.
I have tested the audio output stage separately, and it works fine, so I'm assuming that I have a problem with the conversion (8 x 1543) or receiver (CS8414).
Can anyone suggest what the problem might be, or at least narrow down the search area a bit more!
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Old 24th July 2010, 03:19 AM   #2
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TDA1543 - that is the problem. Multiplied with 8...
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Old 24th July 2010, 03:24 AM   #3
audi0 is offline audi0  Australia
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I was really looking for a constructive answer?
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Old 24th July 2010, 10:47 AM   #4
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I built a 12 x 1543 a few years ago and was completely underwhelmed with its performance, but there was no obvious distortion. Do you have a link or a schematic?
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Old 24th July 2010, 11:08 AM   #5
audi0 is offline audi0  Australia
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Hi Bill,
I would appreciate any constructive input that you can give. I have read many reports about these DAC's, and know their limitations, but as I said in post 1 that I was only really using this as an introduction.
I have some of the schematic, my scanner is refusing to work at the moment so cannot scan the hard copy that I have
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Old 24th July 2010, 12:35 PM   #6
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Should check if each tda1543 is working good alone before it multiple to 8X.
May be one of them is bad.
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Old 25th July 2010, 06:03 AM   #7
audi0 is offline audi0  Australia
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Default Progress

Thanks for the input guy's.
Looking for a possible faulty chip, I removed 4 chips and powered up and discovered no distortion, not sure why? Have I got the wrong resistor values for eight? I have 200R for R8 and 330R for R9 & R10.
I'm running the chips @ 8 volts.
Any ideas?
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Old 25th July 2010, 02:17 PM   #8
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Quote:
Originally Posted by audi0 View Post
Thanks for the input guy's.
Looking for a possible faulty chip, I removed 4 chips and powered up and discovered no distortion, not sure why? Have I got the wrong resistor values for eight? I have 200R for R8 and 330R for R9 & R10.
I'm running the chips @ 8 volts.
Any ideas?
Did you test the other set of 4 to see if any distortion?
If good, then put back 8x tda and check R9,10 should be 2x680 ohm in parallel or equal value.
R8 should be 2x390 ohm in parallel or equal value, or variable resistor to adjust for your best result.

Last edited by fastvideo; 25th July 2010 at 02:27 PM.
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