Hello Christian
Thnx for the quick reply....
It plays, but somethings wrong - the volume is somewhat lower than before, and lover than the analog stage in my sony cdplayer - and theres not much ambiance - the high end lacks detail, and there may be some feeling of distortion og "gruntness" in the sound. Very punchy bottom btw.
Its replacing the built in analog stage in my dac based on a AD1865 chip.
Any ideas ?
Cheers !
Hans
Thnx for the quick reply....
It plays, but somethings wrong - the volume is somewhat lower than before, and lover than the analog stage in my sony cdplayer - and theres not much ambiance - the high end lacks detail, and there may be some feeling of distortion og "gruntness" in the sound. Very punchy bottom btw.
Its replacing the built in analog stage in my dac based on a AD1865 chip.
Any ideas ?
Cheers !
Hans
Ok, is it possible to redesign the d1 for lover current input ??
My friend, who build the dac, have used a I/V stage similar to the D1, a 610 FET but without the cascoding fet, and higher voltage (around 150 volt i recall) - this was in his word very much better than the build in analog stage - having the speed and detail of some of the good 6sn7 tube output stages he had tried.
Thnx
Hans
My friend, who build the dac, have used a I/V stage similar to the D1, a 610 FET but without the cascoding fet, and higher voltage (around 150 volt i recall) - this was in his word very much better than the build in analog stage - having the speed and detail of some of the good 6sn7 tube output stages he had tried.
Thnx
Hans
Ok, I cheked the datasheets - the pcm63 that the D1 uses has an output of +/- 2 mA - giving 4 mA - the ad1865 gives half that, +/-1mA as you said Christian - can I solve this by piggybacking another ad1865 on top of the one Im using, so it will give +/-2 mA - or could I change something in the "stock" version of the D1 i have build so it will run on 2 mA ?
Last possibility, is to use a 300 ohm resistor in series with Iout and then use a ordinary gainstage of 20-26dB - BoSoZ, or mabye make a circuit with a zvp3310, or a jfet, or..........??
Cheers !
Hans
Last possibility, is to use a 300 ohm resistor in series with Iout and then use a ordinary gainstage of 20-26dB - BoSoZ, or mabye make a circuit with a zvp3310, or a jfet, or..........??
Cheers !
Hans
I guess you could get the required gain by piggybacking the ad1865, but I don't know if that is the best option.
I will try to do some simulations soon, because I plan to use ad1955 which outputs +/- 4mA.
You might be able to change the 1.5k and 3.3k resistor to give you a different gain or perhaps you could just piggyback the irf610 with another. At least that is some of the things I guess could change the gain.
I will try to do some simulations soon, because I plan to use ad1955 which outputs +/- 4mA.
You might be able to change the 1.5k and 3.3k resistor to give you a different gain or perhaps you could just piggyback the irf610 with another. At least that is some of the things I guess could change the gain.
Thnx for the sim. Christian
No, cold mosfets are like wet close - you can use it, but.....it feels terrible ;-)
Mabye I could overcome the problem by running it of af 60-0-60 volt supply, doubling the voltage, and then get the same current flow in the fet and restore the heat....?
BTW - my friend ran the D1 of an 1792 with +/- 4 mA output - so that why it sounded so well for hum i guess......
Cheers !
Hans
No, cold mosfets are like wet close - you can use it, but.....it feels terrible ;-)
Mabye I could overcome the problem by running it of af 60-0-60 volt supply, doubling the voltage, and then get the same current flow in the fet and restore the heat....?
BTW - my friend ran the D1 of an 1792 with +/- 4 mA output - so that why it sounded so well for hum i guess......
Cheers !
Hans
I just tried R3 @ 3K and leaving R2 @ 3.3K - now I have the gain, and much more detail and air, but still some sort of "gentle" distortion, especially on transients..... Is it important that R2 is also doubled compared to the original schematic ?
I have also tried to tap the current output direct to the phone sockets, but with a good 300 ohm resistor in parallel - giving me 0,3 volts, and then letting my BLS do the rest with its 20dB of gain - this was also lacking some (serious) detail.....but with good dynamics.
Cheers !
Hans
I have also tried to tap the current output direct to the phone sockets, but with a good 300 ohm resistor in parallel - giving me 0,3 volts, and then letting my BLS do the rest with its 20dB of gain - this was also lacking some (serious) detail.....but with good dynamics.
Cheers !
Hans
cviller said:
You were so rigth !!!
Two 3.3K's went in series with the existing ones, and the distortion on transients went out, and along came a large soundstage, and a bass attack that is the best I have ever heard in my system.....
It still has a very sligth (this is in the real small scale department !!) hardness to the sound in the middle and treble, but this could also be due to the lack of burn in time of the circuits, I have tried that before with good caps, they sometimes takes months to sound their best.
But, I think I will start the new year with ordering the parts for a PSU for the BLS - 60-0-60 volts, so I can bring the heat back in the mosfets...
Thnx for the help Cviller - you are the man of the day - the last in 2006 ! Now we can enjoy nice music during the party tonight...
Happy new year to all in here !!
Cheers !
Hans
I'm glad to hear it was a success! 
You might need to adjust other things if you turn up the rails... perhaps it will be easier to give the other 610 (Q3 in my schematic) the full +/- 30 V range - right now it is connected from +30 to ground through a 1.5k resistor. And Q3 is the one responsible for the clipping when the drain of Q4 goes below ~4 V it shuts off.
You might need to adjust other things if you turn up the rails... perhaps it will be easier to give the other 610 (Q3 in my schematic) the full +/- 30 V range - right now it is connected from +30 to ground through a 1.5k resistor. And Q3 is the one responsible for the clipping when the drain of Q4 goes below ~4 V it shuts off.
Yes, it's the output. But to my knowledge, tda1543 has been made in many different versions - so the output current might differ...
http://www.alldatasheet.com/datasheet-pdf/pdf/19214/PHILIPS/TDA1543.html
http://www.alldatasheet.com/datasheet-pdf/pdf/19214/PHILIPS/TDA1543.html
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