Yes, this entire thread is a 'blast from the ancient past', these problems were sorted out decades ago by the introduction of custom made chips.

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PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

No, I haven't built it before but it should work and don't use the LM741, it's rubbish.

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I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez
And http://www.silicontronics.com, same screen name as here.

 

Don't weep. We saw it. I have PGA2310 and PGA2311 samples for a future pre-amp project.

Regards, Mike

 

thanks for reply,
I'll try to build it.

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Publish your web page

 

Hey Speakerguy and all the other helpful heroes of this thread, I do appreciate and look in detail at every response.
So thanks alot and all the best for 2008.


Ive decided digipots are the way to go for me, they are easy for me to get hold of here and look like they could be useful for other projects.




I do have another newbie audio question.
In systems where you can plug in headphones, it will usually shut off the speakers when you plug in the headphones.

How is this acheived?
Using the MCU I can think of many complex ways of detecting the impedance and switching the path of the audio signal.
But I have a feeling there must be a really simple way of doing it that im missing.


Thanks again
John

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The first rule of mstechca club is do not talk about mstechca club.
http://www.electro-tech-online.com/s...induser&u=1245

 

It's simpler than you think. When you push the headphone plug into the jack, it connects the headphone tip and rings on the plug to contacts in there. And in the process of contacting it pushes the speaker contacts apart so they're no longer touching.

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Futz's Microcontrollers & Robotics
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Xicor X9C103 Digitally Controlled Potentiometers (XDCP)
http://www.datasheetcatalog.com/data...1/X9C103.shtml
http://www.attiny.com/x9c103.htm

 

Hi to all the gurus here,
I'm new to this forum. I hv been using TDA8424 Volume chip in my project. I manage to control the level using a pic controller.
However the problem i'm facing are... lots of noise. When the music are paused. Turn the device to a maximum level. The noise level is unacceptable. Beside when i sendind the data to the chip, while it is ramping the vol up or down, I can here some "ramping noise". I dunno how it called. It should be ramp smoothly without any additional noise.
I built this unit using 4 pcs of regulator 7812/7912 for the balance-unbalance input and unbalance-balance output. The ground of this circuit is analog ground and is supply from 1 transformer 909Vac. The other similar transformer 09Vac will supply 5V and 12V from 7805/7812 regulator respectively. The +5V/+12V will supply to the PIC and TDA8424. So here will be a digital ground. I had split the digital and analog ground before they join in certain spot of the board. Is there any problem with the power supply section? I'm quite happy with this chip. The only problem is i wans to get rid of those noise.
Even when i sending the data to increse the bass or treble.... the output will somehow mix with "some unwanted digital sound".
Please help....
Many thanks