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Old 27th April 2011, 04:15 PM   #21
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I think I'm going to start working on making a new audio amp sometime next week, have you found anything new?
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Old 22nd May 2011, 04:58 AM   #22
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I do final test on EVMs with TAS5518 or TAS5508, but don't know much outside
test procedure. I'll be watching this thread to see if I can learn anything useful.
I had a beast of a time just figuring how to map inputs to outputs with the GUI.
I'm no TI engineer, nor do I work for TI, just a tech at a contract manufacturer.

This chip is usually followed up by one to three big power devices with heatsink,
I was under the impression 5518 was just a driver, not an amp used by itself.
Am I wrong, can it drive an output by itself? Your thread seems to imply...

Last edited by kenpeter; 22nd May 2011 at 05:01 AM.
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Old 22nd May 2011, 05:08 AM   #23
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Quote:
Originally Posted by legomanww View Post
Yes, a digital crossover would definitely have a better phase response and have a very sharp cutoff at exactly the frequency you want... Could tweak it for each speaker too, that would be neat. I've recently started to get into some digital filtering and it is pretty cool stuff, very powerful...
I think TAS3308 might do that? I'm not at work, I can't say for sure thats the
EVM I'm thinking of. Put into the ribbon cable between INPUT USB and one of
the big amps with TAS5518 and 5 or more output channels...

I know the engineer of that EVM, I could ask Monday or Tuesday...

Last edited by kenpeter; 22nd May 2011 at 05:12 AM.
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Old 22nd May 2011, 06:42 AM   #24
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5518 cannot drive high output power by itself. It just generates pwm signals. Some of them are designated for driving line level stuff, or headphones (like the 3308), and you could probably use the rest of them to drive low level audio too (headphones possibly). But for main audio signals, they need to be amplified (also like the 3308, I think).

The 5518 can also do some filtering, so you can make a crossover within the 5518.

It looks like the 3308 can do some more advanced processing, for some fancy effect (but it might just be that it can handle larger filters or that the filters are predesigned and easy to implement using the GUI, where with the 5518 you have to compute the filter coefficients yourself)

The 3308 COULD be connected to the 5518 (the 3308 EVM does output some I2S signals), however it would be a little redundant. The 5518 would then run it through all its processing and generate PWM signals. The 3308 outputs PWM signals that could be fed to the same output stages that the 5518 feeds.

They keep coming out with new processors, I'll have to take another look at them all and see what's new... I haven't checked them out in a while. The 3308 looks neat, and I haven't seen the GUI before...
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Old 22nd May 2011, 09:14 AM   #25
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3308 also can't drive headphones, in can oly generate pwm signals, and from there you can get analog signals to... but can't drive any headphones
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Old 22nd May 2011, 03:56 PM   #26
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Ah, yes I see now. They have PWM outputs labeled as Headphone, but you still have to buffer/amplify it.
I never really looked at that part closely, since I wasn't interested in using headphones...
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Old 23rd May 2011, 05:17 AM   #27
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indeed, there is amp just for that on board, and it yes, it uses one of the pwm ch. to get analog for this amp
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Old 11th July 2011, 08:33 PM   #28
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Question A hint and a question

I've quickly read this thread and I have a tip and a question for you all looking for direct digital amplification:
the tip is that this amplifier -you can read about it in this thread- has a second PWM input, and sounds very good, specially for the price. It's a DDX based (so like Apogee).
The question is: have you some news about some TAS5518 kit? (I don't... all what I've found is this thread!) Would be possible through some forum mechanism to get a stock of pre-assembled boards? What I [and others] need is a board that manages I2C-S/PDIF signal and modulates it in PWM, in order to feed that or other amplifiers....I think this board could be very cheap...

Can you help me in some way?
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Old 11th July 2011, 09:57 PM   #29
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You just want a board that uses the TAS5518 with SPDIF inputs to produce PWM outputs?
How many SPDIF? Optical? Coaxial? Just pins? No I2S?

The I2C is used for configuration of the TAS5518, do you really want I2C, or would an isolated USB or isolated RS232 connection be more useful?

I'd be happy to design such a board, it's very simple, if you can help with determining the requirements.
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Old 12th July 2011, 09:57 AM   #30
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Oh! Thank you legomanww!
What I need is an 8 channel PWM modulator. I try to explain me better: I need this board to connect a digital source such as a Creative Soundblaster (now is Audigy 2zs, in feature could be this or something better, also non Creative -as an example Xonar). A2ZS has 4 stereo S/PDIF outputs, X-Fi has optical out...finally could be useful a multi-interface(S/PDIF, I2S, optical...because I really don't know what I will use; at least main interfaces) with USB to control the chip (when I wrote I2C I was meaning I2S...ghgh).
The output I need is PWM to feed 4 stereo T4 DDX amplifiers.
Tell me if I'm clear enough...
as you can see I'm not expert of digital interfaces, so if you can read audio cards specifications I've linked, you can understand which kind of interfaces could be most useful....

Thank you very much legoman!
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