Since your making a new board, perhaps you should include the I/V stage on it as well Ryan. Don’t think many will adopt passive with opt as suggested by John.
Cost is at play here. You were playing with Cen Zen I/V, perhaps you could seek the designer’s blessing to incorporate this into your board ? Yes a new thread is the way to go.
Cheers
Cost is at play here. You were playing with Cen Zen I/V, perhaps you could seek the designer’s blessing to incorporate this into your board ? Yes a new thread is the way to go.
Cheers
I'd like to try the simutanious mode and DEM modified.
But there is no more place to put the decoupling caps on my philip cd's cd473 cd304mk2...
And it's quiet ugly also
I also see the ryan's I2S to Sim converter board(thanks a lot!)
Is it possible to make it pin to pin to the original tda1541?(Like a converter board?)
But there is no more place to put the decoupling caps on my philip cd's cd473 cd304mk2...
And it's quiet ugly also
I also see the ryan's I2S to Sim converter board(thanks a lot!)
Is it possible to make it pin to pin to the original tda1541?(Like a converter board?)
I'd like to try the simutanious mode and DEM modified.
But there is no more place to put the decoupling caps on my philip cd's cd473 cd304mk2...
And it's quiet ugly also
I also see the ryan's I2S to Sim converter board(thanks a lot!)
Is it possible to make it pin to pin to the original tda1541?(Like a converter board?)
Do you mean unsoldering the 1541 from your Cd player, fitting a socket, and then have a daughter pcb which plugs into the socket and has one for the 1541 (pin 27 & 26 connected). plus components for I2S to sim?
This could be quite a good project for someone and if it was compact enough, could be a universal upgrade for commercial 1541 cd players? (some of the I2s to sim components could fit on the under side between the rows of pins for the socket and pins for the cd players dac socket)
There'd be no need to remove the existing dem capacitors. There may even be sonic advantages leaving them in parallel with the 100ufs.
exctly! thanks for your kindly and clearly explainsion!!
Unsoldering the inhernent dem is not a problem actually.
We can also shunt the DEM cap to daughter board's ground.
Then connect the seperated digital and analog ground from daughter board to the TDA1541's digital and analog ground pin.
We can let the decouple pins floating on socket.
It might minimize the effect from org 0.1uF decoupling cap withou removing them.
But I'm concern about the DC for the digtal IC's for the I2S to SIM converter indeed
I left them in. Can't say if it would be better or worse with or without. To my ear it sounds great with both in place. I figured that there are lots of examples where performance is improved when a large cap is paralleled with a smaller better performing cap so why not try it. But I leave that question to the smart engineers that have the science figured out.
Also, the smt caps have the advantage of shorter path to the pin. Even with the 100uF I kept the -ve lead short as possible.
It not a mystery
The 0.1uF is low impedance for the pin
It’s like a well near your house you won’t seek the water from the lake
Although it’s not far away a much bigger
The electronics are lazy as we are.
Quite good analogy. Those lazy electrons can holiday in the 0.1uf caps and the more energetic can relax among friends in the 100uf cans.
On my dual dac pcb I have allowed for both 0.1 and 100uf but if I fit these, the 0.1 will have to be soldered on the underside which is not a problem. (no smt parts, as my hands shake too much and my eyesight is not exactly 20:20 even with reading glasses - its old age!)
Why not?I don’t get it
IS that the Cext on fig11 here?
http://s-audio.systems/public/uploads/Articles/00046328.pdf
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A little story on my progress in TDA1541A DAC building.
I modded two Red Baron PCB to accept 50 Hz DEM mod and used them with Ian Canadas I2S to PCM converter in balanced mode and with passive I/V converter. This immediately bettered my, uptil now , preferred DAC with Ian Canadas FIFO and dual clock with isolator and custom designed I/V converter.
I had to dismantle it again as it was kind of a rats-nest construction and I want to put it in a nice box with remote vol. control etc.
So I had a third red baron pcb and I just got two pcb from ryanj with ecdesigns version of a I2S to Simultaneous converter (worked perfectly first time , thanks ryanj!) and I wanted to make a dac I could use , while building the balanced dac (it also needs to have 4 channels, as I want to make a digital corssover for future subs).
The dac was unmodded (besides 1uF acrylic SMD capacitors for DEM decoupling) and had the original single MOSFET I/V converter. Hmmm good but not great. Then I switched to passive I/V converter and I got a step closer, but not enough. I then modded it with 50Hz DEM and , wow, what a difference! This is a very good mod especially when you run the TDA1541A in simultaneous mode... Spaciousness and perspective is much better and the there is black darkness in the space between and behind instruments, so you can easily hear the recorded rooms response to the instruments..
The output from the passive I/V is too low for my amps , and I did not have a good enough preamp to deal with that, so I desided to try to mod. my TDA1543 I/V converter to work with TDA1541A. It was rather an easy mod and now I had plenty of output to my amps. Comparing the passive I/V to the modded active I/V, @ the levels that the passive could obtain, showed that the active was at least on pair with the passive solution. I had to turn down the digital vol quite a lot for the active I/V and I get lesser resolution that way. When I turn up the vol. the active performs even better.
The active showed me, when the digital vol was turn way down, that there was some noise overlaying the weak signals. Most of it was probably quantization noise, but when I added 100nf smd parallel to the 100 uF DEM capacitors, it was reduced, so I would recommend that.
Both the MOSFET I/V and the modded I/V (also a non-feedback circuit) have way lower distortion figures than the passive solution (FFT analyzer result)....Makes one wonder ...........
Concerning the I/V stage: I like MOSFETS and especially JFets as input devices and prefer them to bipolar, but in the event of an I/V converter bipolar are IMHO much better. They shine when they are used as current operated devices (that is their nature).
I hope this can be used as inspiration for others, but it is only my personal observations and of course subjective..
I modded two Red Baron PCB to accept 50 Hz DEM mod and used them with Ian Canadas I2S to PCM converter in balanced mode and with passive I/V converter. This immediately bettered my, uptil now , preferred DAC with Ian Canadas FIFO and dual clock with isolator and custom designed I/V converter.
I had to dismantle it again as it was kind of a rats-nest construction and I want to put it in a nice box with remote vol. control etc.
So I had a third red baron pcb and I just got two pcb from ryanj with ecdesigns version of a I2S to Simultaneous converter (worked perfectly first time , thanks ryanj!) and I wanted to make a dac I could use , while building the balanced dac (it also needs to have 4 channels, as I want to make a digital corssover for future subs).
The dac was unmodded (besides 1uF acrylic SMD capacitors for DEM decoupling) and had the original single MOSFET I/V converter. Hmmm good but not great. Then I switched to passive I/V converter and I got a step closer, but not enough. I then modded it with 50Hz DEM and , wow, what a difference! This is a very good mod especially when you run the TDA1541A in simultaneous mode... Spaciousness and perspective is much better and the there is black darkness in the space between and behind instruments, so you can easily hear the recorded rooms response to the instruments..
The output from the passive I/V is too low for my amps , and I did not have a good enough preamp to deal with that, so I desided to try to mod. my TDA1543 I/V converter to work with TDA1541A. It was rather an easy mod and now I had plenty of output to my amps. Comparing the passive I/V to the modded active I/V, @ the levels that the passive could obtain, showed that the active was at least on pair with the passive solution. I had to turn down the digital vol quite a lot for the active I/V and I get lesser resolution that way. When I turn up the vol. the active performs even better.
The active showed me, when the digital vol was turn way down, that there was some noise overlaying the weak signals. Most of it was probably quantization noise, but when I added 100nf smd parallel to the 100 uF DEM capacitors, it was reduced, so I would recommend that.
Both the MOSFET I/V and the modded I/V (also a non-feedback circuit) have way lower distortion figures than the passive solution (FFT analyzer result)....Makes one wonder ...........
Concerning the I/V stage: I like MOSFETS and especially JFets as input devices and prefer them to bipolar, but in the event of an I/V converter bipolar are IMHO much better. They shine when they are used as current operated devices (that is their nature).
I hope this can be used as inspiration for others, but it is only my personal observations and of course subjective..
A little story on my progress in TDA1541A DAC building.
I modded two Red Baron PCB to accept 50 Hz DEM mod and used them with Ian Canadas I2S to PCM converter in balanced mode and with passive I/V converter. This immediately bettered my, uptil now , preferred DAC with Ian Canadas FIFO and dual clock with isolator and custom designed I/V converter.
I had to dismantle it again as it was kind of a rats-nest construction and I want to put it in a nice box with remote vol. control etc.
So I had a third red baron pcb and I just got two pcb from ryanj with ecdesigns version of a I2S to Simultaneous converter (worked perfectly first time , thanks ryanj!) and I wanted to make a dac I could use , while building the balanced dac (it also needs to have 4 channels, as I want to make a digital corssover for future subs).
The dac was unmodded (besides 1uF acrylic SMD capacitors for DEM decoupling) and had the original single MOSFET I/V converter. Hmmm good but not great. Then I switched to passive I/V converter and I got a step closer, but not enough. I then modded it with 50Hz DEM and , wow, what a difference! This is a very good mod especially when you run the TDA1541A in simultaneous mode... Spaciousness and perspective is much better and the there is black darkness in the space between and behind instruments, so you can easily hear the recorded rooms response to the instruments..
The output from the passive I/V is too low for my amps , and I did not have a good enough preamp to deal with that, so I desided to try to mod. my TDA1543 I/V converter to work with TDA1541A. It was rather an easy mod and now I had plenty of output to my amps. Comparing the passive I/V to the modded active I/V, @ the levels that the passive could obtain, showed that the active was at least on pair with the passive solution. I had to turn down the digital vol quite a lot for the active I/V and I get lesser resolution that way. When I turn up the vol. the active performs even better.
The active showed me, when the digital vol was turn way down, that there was some noise overlaying the weak signals. Most of it was probably quantization noise, but when I added 100nf smd parallel to the 100 uF DEM capacitors, it was reduced, so I would recommend that.
Both the MOSFET I/V and the modded I/V (also a non-feedback circuit) have way lower distortion figures than the passive solution (FFT analyzer result)....Makes one wonder ...........
Concerning the I/V stage: I like MOSFETS and especially JFets as input devices and prefer them to bipolar, but in the event of an I/V converter bipolar are IMHO much better. They shine when they are used as current operated devices (that is their nature).
I hope this can be used as inspiration for others, but it is only my personal observations and of course subjective..
Thanks for the write up, always interesting to hear from other 1541 users. My own design of dual sim mode 1541 Dac pcbs for use with IanC's I2Sto PCM interface are on their way from Chinas this week.
I designed it for the 50Hz dem capacitors and there is no onboard I/V as I use Sowter's 9545 transformers. I hope to start listening tests next week.
My 1U dac case will also house a dual Ad1865 and a quad AD1820 dac pcb
for comparison. Ultimately one will be for CD replay and one of the others used with a USB to I2S adaptor for Youtube music video listening. (I will need to connect a few gates together to convert I2S into the pcm the AD chips require)