Receiver loop filter and OP analog filter.
Very interresting erin. I have seen some comments and similar values as you recommend. I have also read the Crystal Application note 159, but those values comply only for the later chips from Crystal, such as CS8415A, CD8420 and CS8427. The CS8412 Datasheet doesn't say anything other then the values you say we should change if we run NOS.
Can you elaborate more ? Have you also measured something?
I think you have to measure together with listening to not get lost in the labyrinth of mods.
I have the same kit and did those PLL filter changes but I'm not sure it did anything to the sound.
Hmm... I will try his. Your other posts seems OK so I will definately try it.
Yes, this DAC is really good and fun to try different mods on. I like it NOS and no recklocking. Ripping the clock and divider counter out all togeter. It's absolutely dead silent between tracks and then the music hit you....
It's that good I now can hear difference between different high quality OP's. Before I never thought that was possible.
Very interresting erin. I have seen some comments and similar values as you recommend. I have also read the Crystal Application note 159, but those values comply only for the later chips from Crystal, such as CS8415A, CD8420 and CS8427. The CS8412 Datasheet doesn't say anything other then the values you say we should change if we run NOS.
Can you elaborate more ? Have you also measured something?
I think you have to measure together with listening to not get lost in the labyrinth of mods.
I have the same kit and did those PLL filter changes but I'm not sure it did anything to the sound.
Have you tried it using OS? I thought the analog filters was even more important running NOS. Offcourse you need a good amplifier after, to take care of the rubbish.
Hmm... I will try his. Your other posts seems OK so I will definately try it.
I can't here any difference at all with or without the WIMA 10uF (bypassed alltogether). I think maybe a "favourite coupling cap" may be the coloration here ....
Yes, this DAC is really good and fun to try different mods on. I like it NOS and no recklocking. Ripping the clock and divider counter out all togeter. It's absolutely dead silent between tracks and then the music hit you....
It's that good I now can hear difference between different high quality OP's. Before I never thought that was possible.
Very interresting erin. I have seen some comments and similar values as you recommend. I have also read the Crystal Application note 159, but those values comply only for the later chips from Crystal, such as CS8415A, CD8420 and CS8427. The CS8412 Datasheet doesn't say anything other then the values you say we should change if we run NOS.
Can you elaborate more ? Have you also measured something?
I think you have to measure together with listening to not get lost in the labyrinth of mods.
I have the same kit and did those PLL filter changes but I'm not sure it did anything to the sound.
Have you tried it using OS? I thought the analog filters was even more important running NOS. Offcourse you need a good amplifier after, to take care of the rubbish.
Hmm... I will try his. Your other posts seems OK so I will definately try it.
I can't here any difference at all with or without the WIMA 10uF (bypassed alltogether). I think maybe a "favourite coupling cap" may be the coloration here ....
Yes, this DAC is really good and fun to try different mods on. I like it NOS and no recklocking. Ripping the clock and divider counter out all togeter. It's absolutely dead silent between tracks and then the music hit you....
It's that good I now can hear difference between different high quality OP's. Before I never thought that was possible.
The PLL C and R values I suggested, I read in another forum and, tried them for myself, and noticed a large sonic improvement. I have built two of these kits one for myself and another for a friend. they are both identical but i used a different brand of capacitor in the PLL circuit of one of the kits and actually they ended up sounding a little different from each other, so perhaps the brand of cap makes a difference, i certanly could notice a sonic difference.
I have not tried this kit with OS because i have heard and owned many philips / marantz players with the SAA7220 oversampling filter and i do not like the sound that this particular IC produces. ( i do not dislike all oversampling - just the SAA7220. Perhaps its just the players that i have heard)
Whether or not you can hear a difference in the sound of coupling capacitors depends upon the resolution of your system / the input impedance of your amp/s and the bandwidth of your amps, cable capacitance, and probably other factors i have not mentioned. In my friends system I changed the caps from Nichicon Muse to metalised polypropelene (my new favourite) - which in my system the change was very noticable, but in my friends system the change was hardly noticable at all, his system is very good. So I think there are many factors involved.
The output filtering i have changed my mind about. I think now that the filter should be left in. In the kit the C and R in the low pass filter is set to about 44Khz. and is a gentle 3dB per octave filter. I actually reinstalled the output filter caps and actually paralled these caps with a small ? pF caps (cant remember exact value) but this sets the low pass filter -3dB point to about 40Khz and in my system this sounds a bit better. this means that the frequency response should be flat to 20Khz before being gently attenuated. After about a year of listening and going back and forth listening to different sources in my system, i decided that with no LPF, i could hear aliasing at some frequencies. In my friends system, using the kit i made with no LPF, I cant hear the aliasing. So i think again that whether or not you will hear aliasing, is dependant upon the associated equipment that is used.
If you really want to make a giant improvement to the sound get another TDA1541 solder a 470pF cap on to the DEM reclocking pins (16 and 17 - from memory) and then solder (piggyback) the new TDA1541 on top of the one allready installed (only dont connect the DEM reclocking pins of the two ICs together) - put a small aluminium heatsink between the IC's and you will hear bass and slam and attack like never before. WHOA!!!! PHWOOOOR!!!:
If there is a DAC bettter than this kit I'd like to hear it!
This Kit has just stomped on any other source that ive put it up against!
glad you are enjoying the kit!
Thanks for valuable insights
Hi erin
It's strong to confess that you changed your mind.
As someone said in another thread, "people are often doing other things at home then what they write in this forum" or someting along that line
I am of the opinion that, at least, a first order filtering is needed.
For my latest lab sessions I use a very high bandwith Class A Headphone amp, homemade from a recipe of Nico Ras on this forum (see my homepage for schematic and layout). Pretty low input impedance, 3.9k // 100pF after input cap. We do not want radio interference Together with a pair of Sennheizer HD650 that is the best I can come up with for little money.
Your suggestion of pairing the TDA's piggyback seems like a very delightful mod to do. Are you sure that one chip can live without the DEM clock? There have been discussions on syncing the clocks all over this forum trough the years. And also, the piggyback chip have to use the same decoupling caps as the other one ?
Hi erin
It's strong to confess that you changed your mind.
As someone said in another thread, "people are often doing other things at home then what they write in this forum" or someting along that line
I am of the opinion that, at least, a first order filtering is needed.
For my latest lab sessions I use a very high bandwith Class A Headphone amp, homemade from a recipe of Nico Ras on this forum (see my homepage for schematic and layout). Pretty low input impedance, 3.9k // 100pF after input cap. We do not want radio interference
Together with a pair of Sennheizer HD650 that is the best I can come up with for little money.Your suggestion of pairing the TDA's piggyback seems like a very delightful mod to do. Are you sure that one chip can live without the DEM clock? There have been discussions on syncing the clocks all over this forum trough the years. And also, the piggyback chip have to use the same decoupling caps as the other one ?
Hi,
I was not clear with my instructions.
Both TDA1541 must have the DEM clock capacitor attached, however, when piggybacking, solder each pin of one DAC to the other DAC, except for pins 16 & 17 of the top DAC which should not be soldered to the bottom DAC, but rather have its own capacitor soldered to pins 16 & 17. You leave the 470pF cap soldered on to the PCB and the top DAC gets its own capacitor.
Yes, both ICs share the decoupling capacitors.
I use 2uF on the two MSB and 220nF on all the rest.
If you are still not clear i can post a photo if you want. But not tonight as I dont have a camera here right now.
I put a flat piece of 3mm x 10mm x 150mm aluminium between each IC which protrudes out of each end of the DAC,and some thermal transfer compound on top and bottom of the aluminium, this acts as a heat sink and keeps the ICs cool, without the heatsink they might get too hot after a while.
If you just piggyback TDA1541s without giving each IC its own capacitor, you will hear some distortion, however if you want to get the general idea of the sound you will get with piggybacking, you can just stack one IC on top of the other without soldering and you will hear that it is a much more powerfull sound.
you will get a higher level output with stacking as the output current is doubled. This is not a problem in this circuit as the op amps can handle 4V p-p. If you dont like this level you could change the resistors around the op amps to reduce the gain. But I left mine the same.
I was not clear with my instructions.
Both TDA1541 must have the DEM clock capacitor attached, however, when piggybacking, solder each pin of one DAC to the other DAC, except for pins 16 & 17 of the top DAC which should not be soldered to the bottom DAC, but rather have its own capacitor soldered to pins 16 & 17. You leave the 470pF cap soldered on to the PCB and the top DAC gets its own capacitor.
Yes, both ICs share the decoupling capacitors.
I use 2uF on the two MSB and 220nF on all the rest.
If you are still not clear i can post a photo if you want. But not tonight as I dont have a camera here right now.
I put a flat piece of 3mm x 10mm x 150mm aluminium between each IC which protrudes out of each end of the DAC,and some thermal transfer compound on top and bottom of the aluminium, this acts as a heat sink and keeps the ICs cool, without the heatsink they might get too hot after a while.
If you just piggyback TDA1541s without giving each IC its own capacitor, you will hear some distortion, however if you want to get the general idea of the sound you will get with piggybacking, you can just stack one IC on top of the other without soldering and you will hear that it is a much more powerfull sound.
you will get a higher level output with stacking as the output current is doubled. This is not a problem in this circuit as the op amps can handle 4V p-p. If you dont like this level you could change the resistors around the op amps to reduce the gain. But I left mine the same.
As clear as it can be
It's clear now erin.
The higer output is a bonus. Then I can even lower my I/V resistor in my latest approach.
Maybe I then can omit the thoughts of injecting some current with a CCS to get 0 volt over the I/V resistor.
It's clear now erin.
The higer output is a bonus. Then I can even lower my I/V resistor in my latest approach.
Maybe I then can omit the thoughts of injecting some current with a CCS to get 0 volt over the I/V resistor.
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