Hello
My Mini Muse TDA1543 Dac seems to work fine except its audio output is rather low compared with the radio and cd input to my amp. I have set the sensitivity of the amp, a Quad 34, to max- 100mv but still need almost max gain for a useable output.
It doesnt seem to matter what I drive the muse with, sat receiver, digital output from pc or the cd player optical out, still volume is low.
Any easy way to modify this.
Thanks
thyristor44
My Mini Muse TDA1543 Dac seems to work fine except its audio output is rather low compared with the radio and cd input to my amp. I have set the sensitivity of the amp, a Quad 34, to max- 100mv but still need almost max gain for a useable output.
It doesnt seem to matter what I drive the muse with, sat receiver, digital output from pc or the cd player optical out, still volume is low.
Any easy way to modify this.
Thanks
thyristor44
Can you measure the supply voltage on the DAC chip? As I recall, the output voltage is proportional to the supply voltage and that is one of the reasons people normally run the chip at its max. rating of 8V.
Another option is obviously if there is a gainstage on the output to then change the gain of that, but you probably need a schematic then.
/U.
Another option is obviously if there is a gainstage on the output to then change the gain of that, but you probably need a schematic then.
/U.
Hello Nisbeth
The output comes straight out from the tda1543 loaded to earth by 1k then to the output plug with a 100k restor to earth. So no gainstage.
I will measure the vcc tomorrow.as its a bit late now.
The output comes straight out from the tda1543 loaded to earth by 1k then to the output plug with a 100k restor to earth. So no gainstage.
I will measure the vcc tomorrow.as its a bit late now.
Its Vcc is 5 volts. I have a schematic and its pretty simple. Raising the Vcc to 8 volts would also put it up on the dir9001, probably too much.
Any other ideas.
Any other ideas.
Hmm, not really. I theory it would be possible to power the TDA from 8V and then insert a small 5V regulator to get a suitable voltage for the DIR if the power pin on the DIR is lifted.
However, whether this is possible in practice depends on quite a few things like how the power connections are laid out on the board etc. 🙁
/U.
However, whether this is possible in practice depends on quite a few things like how the power connections are laid out on the board etc. 🙁
/U.
The 1543 has a a current loop output and normally the output is loaded at 180 ohm. See also the Doude Douma 1543 design. A higher load resistance will increase output voltage but there is a max value to take into account. If you want to increse outputsignal you can add a second chip on top (just place it over the existing chip and solder it). Basically you can multiply as much as you want, but then you need extra cooling. One extra did not harm in my case.
You can also add an extra output stage wit a step up transformer or tube stage (Lampizator has a very fine tube stage design with mini tubes, but in that case you shall use tube rectifier and not diodes for power supply.)
You can also add an extra output stage wit a step up transformer or tube stage (Lampizator has a very fine tube stage design with mini tubes, but in that case you shall use tube rectifier and not diodes for power supply.)
Its loaded with 1k as I bought it. I will buy another 1543 and try your idea of adding it in parallel. Thanks for help will be back as soon as ebay delivers.
May be small correction to previous note.
I just found a nice link how to calcualte I/V resistor, the good news is that the example is calculated for the 1543! Check: http://www.diyaudio.com/forums/digi...g-dac-complementing-cd-pro-14.html#post173483
So the 1k is ok and it runs at it max. output voltage swing already. The mentioned 180 Ohm on the Doude Douma site is probably calculated for his 8 pcs 1543 in parallel project. The output current is then 8 times higher but the voltage swing shall be limited.
What mans that my suggested 2 pcs 1543 in parallel shall become 470 Ohm load. Sorry but the output voltage can not be increased by parallelmode, but you will increase sound quality!!!
I just found a nice link how to calcualte I/V resistor, the good news is that the example is calculated for the 1543! Check: http://www.diyaudio.com/forums/digi...g-dac-complementing-cd-pro-14.html#post173483
So the 1k is ok and it runs at it max. output voltage swing already. The mentioned 180 Ohm on the Doude Douma site is probably calculated for his 8 pcs 1543 in parallel project. The output current is then 8 times higher but the voltage swing shall be limited.
What mans that my suggested 2 pcs 1543 in parallel shall become 470 Ohm load. Sorry but the output voltage can not be increased by parallelmode, but you will increase sound quality!!!
Interesting, I can now calculate I/V. It didnt work at all with an extra 1543 in parallel but 1k restor, seemed to oscillate or similar. I may try again with 470 ohm when I get some ic sockets.
Any ideas how to increase gain a bit.
Any ideas how to increase gain a bit.
My still loved TDA1541 (not 1543) has an I/V load resistor of 22 Ohm only and really needs to be amplified. The I/V resistor is followed by a small step-up transformer (1:16) and then a mini-tube amp (famous Lampizator design, visit his website!).
You will need not so much amplification for your 1543 but I can recommend the step-up transformer or the tube amp. The transformer (i.e. Sowter) is very easy to install and if you have to much gain simply lower the load resistor at the DAC. It's even better to lower the load resistor due to output impedance for the next step. Since the step up transformer will increase your output impedance the load at the transformer output shall be as high as possible. A tube amplifier connected to the transformer output with >100kOhm input impedance is very fine. A solid state amp with 10 kOhm will affect the signal.
If you prefer the tube amp (see Lampizator with Russian 6W16 mini tube design) always use tube rectified power supply.
You will need not so much amplification for your 1543 but I can recommend the step-up transformer or the tube amp. The transformer (i.e. Sowter) is very easy to install and if you have to much gain simply lower the load resistor at the DAC. It's even better to lower the load resistor due to output impedance for the next step. Since the step up transformer will increase your output impedance the load at the transformer output shall be as high as possible. A tube amplifier connected to the transformer output with >100kOhm input impedance is very fine. A solid state amp with 10 kOhm will affect the signal.
If you prefer the tube amp (see Lampizator with Russian 6W16 mini tube design) always use tube rectified power supply.
TDA 1543 data sheet says it's voltage output, not current output. So there's no I/V outside chip.
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