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Old 27th November 2006, 09:00 PM   #1
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Default Full Digital / CrossOver / Multi Amplifier integrated

There are forums and threads for Class D, Cross Over, multi-amplifier, but I thought there are no thread for all combined issue.

I'd like to know anyone playing this way.

At recent, some chips handles digital input and amplification, also Filter for cross over / multi amplifier.

I know TI's TAS5508 and TAS5518, Apogee DDX. Common way of handling is,
(1) Supply I2S PCM signal to chip
(2) Micro Controller handles I2C registers for filter setting, volume control, muting, dB offset for each channels

Attached photo is Apogee DDXi-2161 8way board.
and here is TAS5518 4Way.
http://koon3876.blogspot.com/2006/11...8-channel.html

Keywords
PCM, I2S, SPDIF input to Amplifier
Integrated cross over
Multi Amplifier
BiQuad Filter
Micro Processor, with I2C, C language (for Math)

Resources
http://www.apogeemems.com/ddx/ddx_products.html
http://focus.ti.com/docs/prod/folder...t/tas5518.html
http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
http://www.rabbitsemiconductor.com/products/bl1800/

regards,
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Old 1st December 2006, 06:11 AM   #2
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No one interested?

(you love multi-amplifier) and (you love class-D)
then you will love TAS5518.

TAS5518 can contain cross-over in itself, and can control up to 4 way amplifiers. You only need some micro controller with I2C. PIC, AVR, 8051, MSP430, any can do it.

this piece of code

const unsigned char CH12_Q1[20] = {0x00,0x00,0x13,0x78
,0x00,0x00,0x26,0xEF
,0x00,0x00,0x13,0x78
,0x00,0xF4,0x66,0xEF
,0x0F,0x8B,0x4B,0x33};
:
I2CWrite(TAS5508_ADDRESS, 0x51,CH12_Q1,20);
I2CWrite(TAS5508_ADDRESS, 0x58,CH12_Q1,20);

will set 44.1kHz, 300Hz 24dB/Oct LPF to TAS5518's channel 1 and 2, so it can be woofer driver.
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Old 1st December 2006, 10:51 AM   #3
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Location: Poland
Koon,

Of course everyone is interested. You just haven't asked any specific question and the topic is huge. I have TAS5518 on my list (I even got 1 sample chip - Giovanni thanks for this). But this would be quite a project. Without help of people from this forum, I wouldn't be able to design someting like this. Would you be willing to share e.g. your LCD control (including the code for the microprocessor)?
Any more info on Apogee DDX? Where did you buy it?

PS: I liked the Digikey enclosures on your blog.

Marek
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Old 1st December 2006, 02:43 PM   #4
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Thank you I'm not lonely now

Yes, Topic is too huge! and still I am working around 5518 and DDX. so I wanted to know what people want and how many people around here.

Now C code for TAS5518 amp is > 2700 lines. (still not perfect and bandaids everywhere) so I think it is better to show what is your question and how to solve it, more than just post dirty 2700 lines.

For Crystalfonts Serial LCD,

BYTE Reply[16];
SendCommand(0x18, 0x00, &Reply);
//calc CRC and TX then RX

checks key input with history. (Reply[2] is now / Reply[3] is history)

BYTE Line[16];
strcpy(Line, "aaaaaa ")
SendData(0x07, 0x10, Line, 16);
//calc CRC and TX

displays text at line 1. (for line2, 0x08 instead of 0x07) easy.
making screen string took > 2000 lines by dirty way. I can't recommend my source.

DDXi chips are sent from Asia, but I think

http://gerberelec.com/

has inventory.
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Old 1st December 2006, 03:01 PM   #5
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This is an interesting topic, but somewhat open-ended. I've been persuing something similar using a PC for the xover filters and separate Class-D units (Panasonic Equibit receivers) for the power. However, the 5518 EVM is very very interesting IMHO. As far as I can tell though, it lacks per-channel delay. I'm not sure whether this is a deal-breaker with my intended application until I do some more work - measurement/simulation/prototyping.
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Old 1st December 2006, 03:38 PM   #6
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There was some missunderstanding. I thought that you are refering to RSDA392P Apogee amp but now I see that you refer to Apogee chips. But why not take into account Texas Instruments chips? I have to check the 5518 EVM. On Apogee Web site the DXX chips are listed as Legacy (whatever it means together with the term "New") and it seems that the production was sold to another American company (and it does not look like that they are selling the chips). I would rather prefer to use TI chips.
Concerning the code for microprocessor, I don't was to use it as it is. I would rather like to see the menu structure and how you perform specific tasks.
I you check Brian's thread about TAS5261, you will see that there were some references to your idea. And I'm sure that on this forum 5 to 10 people are interested in this topic but since it is so huge, they are waiting for a "Leader" . I even see a candidate for this position.
Anyway, I'm interested and sooner or later this topic will be on my task list.

Marek
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Old 1st December 2006, 04:28 PM   #7
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This sort of thing is very interesting, and I would love to give it a go, but, I haven't coded since about 1983, and I'm a bit old to learn now!

What we need is an easily available chip set that will get people going, a GB of a suitable board, (or at least gerbers), then software development can be undertaken as a group effort, but without a universal setup as above, everyone will constantly be going their own way, and though individuals might be happy with their own system, they will all be totally different.
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Old 1st December 2006, 06:50 PM   #8
AR1 is offline AR1  United States
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Default EZ Chip

Quote:
Originally posted by pinkmouse
This sort of thing is very interesting, and I would love to give it a go, but, I haven't coded since about 1983, and I'm a bit old to learn now!

What we need is an easily available chip set that will get people going, a GB of a suitable board, (or at least gerbers), then software development can be undertaken as a group effort, but without a universal setup as above, everyone will constantly be going their own way, and though individuals might be happy with their own system, they will all be totally different.

Is thier such a device?
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Old 1st December 2006, 09:09 PM   #9
BWRX is offline BWRX  United States
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Quote:
Originally posted by KOON3876
(you love multi-amplifier) and (you love class-D)
then you will love TAS5518.
I like multi-amp setups and class d The TAS5518 is nice, but I wouldn't say I love it. It would open up options for configurable multi-amp active speaker systems or multi channel audio systems, but what's the point if you're into 2 channel audio which (in my opinion) is really all you need for critical/pleasurable listening anyway?

You can get great results with a quality DAC, active crossover, and actively driven speakers.

Quote:
Originally posted by pinkmouse
...I'm a bit old to learn now!
I never thought I'd hear such blasphemy from you
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Old 1st December 2006, 10:23 PM   #10
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Quote:
Originally posted by dwk123
As far as I can tell though, it lacks per-channel delay.
Yes! TAS5518 has no delay, BiQuad filter is a digital implementation of http://www.linkwitzlab.com/filters.htm .(Linkwitz Riley 24dB/Oct crossover). I loved this design and very natural sound when I made 12 opamp crossover. now it's inside of one chip!

for delay, phase issue, I'm keeping Xilinx XC3S500E FPGA board to build FIR filter future, but almost satisfied now.

Quote:
Originally posted by Markus2006
I thought that you are refering to RSDA392P Apogee amp but now I see that you refer to Apogee chips. But why not take into account Texas Instruments chips?

I would rather like to see the menu structure and how you perform specific tasks.
Hi now I'm contending with both TAS5518 and DDXi-2161. TAS5518 has ascendant now. RSDA302P is just a introducing of Japanese gadget.

.. you want to see my code? please, please do not think I'm writing such a spaghetti also in business.
not completed, I will add Voltage supply controll functions, and will scrap and rebuild for organized code.
(This is for JackRabbit processor)

Quote:
Originally posted by BWRX

but what's the point if you're into 2 channel audio which (in my opinion) is really all you need for critical/pleasurable listening anyway?
Hi imam,
Of course I'm a piece of DIYer and built many speaker network, huge DAC, crossovers and PGA2311 volume, class-A ,chip, or class-D amps etc etc, then now I found speaker have to be multi-way for my satisfaction but components should be as simple as possible, and analog areas should be as few as possible.
So, full digital & integrated Volume control/LPF/HPF is my current interests.
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