That I am sure
Definitely. Documentation is good.
I hope so. Have not own any before
Not sure what you mean
Well, that's subjective. I have to find out personally
Of course they can be tested. The test points are really convenient though
No use to me. I do not intend to upgrade it. When the next generation chip comes out, I'll just get the new one.
See above
At the discounted price, I totally agree
I hope so. I guess it depends on where you located
Nothing I can think of right now. Will let you know when I have questions.
Thank you!
Regards,
Hi guys
I expect this chip is dumping a broadband of noise so in fact the regulators' noise performance is perhaps somewhat irrelevant. But what about impedance into the gates for the 12V supply? Would a lower impedance (than LM2937/40) benefit dynamics? I plan to find out! I have a very old scope that I don't know how to use (!) but I will dust it off and connect it up to the amp's test points, post what I find, etc. Just bear with me, I have a job, wife, etc, motorcycles, etc. Distractions from my true calling - to break perfectly good bits of kit and call it an upgrade ;-)
BTW, do please stop saying this amplifier is excellent cos Ti made it and it tests so well. Look at the audio coupling caps, 2 pairs of them. 40 cent Panasonic aluminium crap. In the signal path. Like eating a candy bar with the wrapper on. Noooooooooo ! 🙂
I expect this chip is dumping a broadband of noise so in fact the regulators' noise performance is perhaps somewhat irrelevant. But what about impedance into the gates for the 12V supply? Would a lower impedance (than LM2937/40) benefit dynamics? I plan to find out! I have a very old scope that I don't know how to use (!) but I will dust it off and connect it up to the amp's test points, post what I find, etc. Just bear with me, I have a job, wife, etc, motorcycles, etc. Distractions from my true calling - to break perfectly good bits of kit and call it an upgrade ;-)
BTW, do please stop saying this amplifier is excellent cos Ti made it and it tests so well. Look at the audio coupling caps, 2 pairs of them. 40 cent Panasonic aluminium crap. In the signal path. Like eating a candy bar with the wrapper on. Noooooooooo ! 🙂
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I agree with you, I would pull out any ecap in signal path without a second thought. Believing Ti use the optimal "sounding" circuit/parts for their stuff is like believing opamp I/V is the best I/V ever😀
BTW, u can try audio transformer for the +/- input without any coupling caps. I use them in Gmarsh Wiener and Wiener Pro (3250) and it improves the sound quality.
Is your Sigma 11 the old version? It had a problem of the output power trace too thin thus limiting current flow. Did u add a thicker wire from the 0.47R to output?
No idea what version it is but that's a good idea - short fat cable straight off the pass mosfet/resistor into the amp 🙂
The amp has DC on its input pins so do I need to block this DC into the transformer? I assume not ... but it's better to check assumptions...
Hi Lo_Tse, I would encourage you to upgrade it according to the TI app note! The output inductors dominate technical performance. Replacing them with the TI-recommended Wurth inductors should be audibly better.
I have had great success in upgrading from stock inductors on several TI class D amplifiers.
Best regards,
Mike
Listening/comparing on a 4 ohm resistor.
Because none of these EVM's have post filter feedback I do hope you took the 15uH version that distorts more on the 4 ohm resistor but way less on your speakers ?
Because none of these EVM's have post filter feedback I do hope you took the 15uH version that distorts more on the 4 ohm resistor but way less on your speakers ?
There is DC of either + or - input with reference to ground, but if you measure across +/- input, there is no voltage differential as both have the same voltage, thus no DC.
DrMord,
Have you tried using the output inclusive feedback path? If yes what is your opinion of the results? Thanks in advance for any information.
Have you tried using the output inclusive feedback path? If yes what is your opinion of the results? Thanks in advance for any information.
Hi all - I fitted the transformers. I removed the second set of coupling caps and connected the pads to twisted pairs into the transformer secondaries. I managed to invert the phase on one of them but that was easily corrected. The sound is more open and spacious and would be excellent but for a little too much sibilance -it is noticeable but not nasty, and it's a little more than I consider natural. Perhaps my source doesn't like this load? I see there is a low pass 100r and 100pf on the input side - did anyone modify this?
Thanks...
Thanks...
Did an interesting comparison between the 3251 EVM and the 3244 EVM. The 3251 is more sibilant and glassy in the 2-6kHz range. The 3244 is more even and nicer to listen to.
I will continue with the 3244.