hi stefanobilliani,
I had a small question, do U think the Xo was enough. if yes,I will use xo only. can less some money.
I test the dac full time running in 48 hours & the temperature inside the chassis if not higher than 45 drgree. The xo will stable. If higher, U ca hear the sound had little change. I suppose the dac will 24 hours turn on.
thx
thomas
I had a small question, do U think the Xo was enough. if yes,I will use xo only. can less some money.
I test the dac full time running in 48 hours & the temperature inside the chassis if not higher than 45 drgree. The xo will stable. If higher, U ca hear the sound had little change. I suppose the dac will 24 hours turn on.
thx
thomas
As I posted above I do not know the difference between Xo and VCXO.
What I know is that the Tent Xo is the only things I see with real good low jitter.
It is like you get used to hear with plenty of jitter , at the same time you get used to listen with low jitter. After quite a while it is easy to recognize what is low jitter. For example for my taste the CS8412 *alone* is not acceptable without a good jitter strategy.
In your dac Xo works pretty good inserting a feerite bead , a cap and 2 resistors. No problem for the load since all it has to do is driving the ripple counter wich has a buffer inside , and the 7220 . In all 2 input gates.
I know the good Xo has a considerable cost over the entire dac . And I do not have complaints on that.
By my point of view , the I/V stage with resistors do not make justice for the TDA1541A . The noise is considerably higher that way .So if Pass doesnt want you to put his design into your dac , you can still try something with bjt (cascode) jfet , or simply use the op amp as I/V converter as shown in the datasheet . With a buffer .
So with respect to the current version you do not have to add almost anything ... just fiew resistors .
The dissipation for the regulator that serves saa7220 is not a big issue , I solved elegantly just using an adeguate heat sink. If the temperature is within 50°C I do not see a reason to worry.
The groud loop is important ... must say that the Ver3 itself is not quiet at all !!! Looking at the PCB I noticed some strange things (lol) in the way it has been designed .
What I know is that the Tent Xo is the only things I see with real good low jitter.
It is like you get used to hear with plenty of jitter , at the same time you get used to listen with low jitter. After quite a while it is easy to recognize what is low jitter. For example for my taste the CS8412 *alone* is not acceptable without a good jitter strategy.
In your dac Xo works pretty good inserting a feerite bead , a cap and 2 resistors. No problem for the load since all it has to do is driving the ripple counter wich has a buffer inside , and the 7220 . In all 2 input gates.
I know the good Xo has a considerable cost over the entire dac . And I do not have complaints on that.
By my point of view , the I/V stage with resistors do not make justice for the TDA1541A . The noise is considerably higher that way .So if Pass doesnt want you to put his design into your dac , you can still try something with bjt (cascode) jfet , or simply use the op amp as I/V converter as shown in the datasheet . With a buffer .
So with respect to the current version you do not have to add almost anything ... just fiew resistors .
The dissipation for the regulator that serves saa7220 is not a big issue , I solved elegantly just using an adeguate heat sink. If the temperature is within 50°C I do not see a reason to worry.
The groud loop is important ... must say that the Ver3 itself is not quiet at all !!! Looking at the PCB I noticed some strange things (lol) in the way it has been designed .
hi stefanobilliani,
very thanks for your quick feedback.
yes, I re-layout power supply already.
looks the noise from mthe power supply will lower.
secondly was the noise from the 7220. I will try your method to test for it. if really lower I will update for the dac.
Non-profit version I use 7805 for 7220.now I use 317,337 for it will lower the temp. Not need to worry for it.
I will keep contact to NSK that I need low jitter XO hope the price will reasonable. Xo will cheaper than the VCXO. looks in this area not need VCXO, XO was enough, mainly will low jitter.
I will do for this.
thx
thomas
very thanks for your quick feedback.
yes, I re-layout power supply already.
looks the noise from mthe power supply will lower.
secondly was the noise from the 7220. I will try your method to test for it. if really lower I will update for the dac.
Non-profit version I use 7805 for 7220.now I use 317,337 for it will lower the temp. Not need to worry for it.
I will keep contact to NSK that I need low jitter XO hope the price will reasonable. Xo will cheaper than the VCXO. looks in this area not need VCXO, XO was enough, mainly will low jitter.
I will do for this.
thx
thomas
hi all,
this is the new power supply jmep image of the PCB.
improve stefanobilliani advise,
the ground loop was improve more, relayout all the ground area in the [power supply area. I use 96db speaker full range & 94 db ( TAD speaker) & test low noise. The original also no problem in normal speaker. Only high efficiency will little noise.
1. New layout of the power supply.
2. increase the capacitance of the caps before the diode from 3300uf >>>>4300uf+0.1ufMKP ( 3300+1000+0.1MKP). or if diyers still like to increase more. (3300+2200+0.1ufMKP)
I was so sorry that if I use too large capacitors te sound will little lower. or I will advise paralell two 470uf on the 3300uf & 1000uf caps. ( use BC philips & test good)
I use ,my friend with 2X15inch woofer & horn(2'throats to test)& alnico tweeter for more dynamic sound & noise, over 97db.
If the capacitor was too large, the sound will little slow. So if U heard classis & more dynamic music will not so good.
3. All the isolated power transformers was mould into the pcb. approx no cable seen into the dac.
thx
thomas
this is the new power supply jmep image of the PCB.
improve stefanobilliani advise,
the ground loop was improve more, relayout all the ground area in the [power supply area. I use 96db speaker full range & 94 db ( TAD speaker) & test low noise. The original also no problem in normal speaker. Only high efficiency will little noise.
1. New layout of the power supply.
2. increase the capacitance of the caps before the diode from 3300uf >>>>4300uf+0.1ufMKP ( 3300+1000+0.1MKP). or if diyers still like to increase more. (3300+2200+0.1ufMKP)
I was so sorry that if I use too large capacitors te sound will little lower. or I will advise paralell two 470uf on the 3300uf & 1000uf caps. ( use BC philips & test good)
I use ,my friend with 2X15inch woofer & horn(2'throats to test)& alnico tweeter for more dynamic sound & noise, over 97db.
If the capacitor was too large, the sound will little slow. So if U heard classis & more dynamic music will not so good.
3. All the isolated power transformers was mould into the pcb. approx no cable seen into the dac.
thx
thomas
Attachments
Hi stefanobilliani
Thank you for pointing me the JP6 on the dac board. I had overlooked it.
I also appreciated your report on the Nelson Pass D1 i/v converter.
I had one of these, doing nothing in the basement, waiting for the right opportunity. That was the good time to dig it out and install it on the dac. The model I have is from Promethius.
First, let me confirm you and Thomas that it works better this way. There is still noise at hight level, but very little, it is a great improvement.
Sonicaly this dac is performing very well now and it is the little "extra" I needed to compete with the high end equipment I have a chance to compare with.
It is a blessing for me to have access to such very expensive equipment to make my tests. It is a unique laboratory for a DIYer to know exactly where we are. I will continue reporting to you all, so we know we are heading in the right dirrection.
Stefanobilliani, I am happy you have found and corrected the noise source. Important also, is your contribution to isolate ground loops.
I will read your posts again and see what I can do.
I know Thomas is working on it too, so I may wait for him to come out with his solution.
I would like to say a word about the D1 i/v. I have also seen your version with the 2SK170 in an other thread and I found very good ideas there.
I noticed a slow dc drift at the input. Not very much, a few milivolts and it does not seem to bother the TDA1541A at all. However I do not like that and I beleive a dc servo would be a nice addition to keep the zero rock solid.
Have you considered that?
Thank you again for your important contribution to upgrade this project.
Jean-Charles
Thank you for pointing me the JP6 on the dac board. I had overlooked it.
I also appreciated your report on the Nelson Pass D1 i/v converter.
I had one of these, doing nothing in the basement, waiting for the right opportunity. That was the good time to dig it out and install it on the dac. The model I have is from Promethius.
First, let me confirm you and Thomas that it works better this way. There is still noise at hight level, but very little, it is a great improvement.
Sonicaly this dac is performing very well now and it is the little "extra" I needed to compete with the high end equipment I have a chance to compare with.
It is a blessing for me to have access to such very expensive equipment to make my tests. It is a unique laboratory for a DIYer to know exactly where we are. I will continue reporting to you all, so we know we are heading in the right dirrection.
Stefanobilliani, I am happy you have found and corrected the noise source. Important also, is your contribution to isolate ground loops.
I will read your posts again and see what I can do.
I know Thomas is working on it too, so I may wait for him to come out with his solution.
I would like to say a word about the D1 i/v. I have also seen your version with the 2SK170 in an other thread and I found very good ideas there.
I noticed a slow dc drift at the input. Not very much, a few milivolts and it does not seem to bother the TDA1541A at all. However I do not like that and I beleive a dc servo would be a nice addition to keep the zero rock solid.
Have you considered that?
Thank you again for your important contribution to upgrade this project.
Jean-Charles
Thomas,
In your quest to reduce noise and improve power supply, I would like to inform you that Walt Jung has made important researches on regulators. He found that the 78XX, 79XX, three terminal regulators are not adequate for audio work.
You are right in using the adjustable type LM317, LM337. According to Jung they are better, but may be, you would like to read the interesting articles he contributed to the audio community.
You will find it here: http://waltjung.org/Regs.html
I beleive John should be informed of that since he uses a lot of them in his design.
In the years after these publications, I have seen all the high end audio builders introduce, in a way or an other, Walt's principles in their power supply designs.
I hope it will interest you.
Jean-Charles
In your quest to reduce noise and improve power supply, I would like to inform you that Walt Jung has made important researches on regulators. He found that the 78XX, 79XX, three terminal regulators are not adequate for audio work.
You are right in using the adjustable type LM317, LM337. According to Jung they are better, but may be, you would like to read the interesting articles he contributed to the audio community.
You will find it here: http://waltjung.org/Regs.html
I beleive John should be informed of that since he uses a lot of them in his design.
In the years after these publications, I have seen all the high end audio builders introduce, in a way or an other, Walt's principles in their power supply designs.
I hope it will interest you.
Jean-Charles
Hi Thomas!
Based on my listening experience, I found out that a single op amps always sounds better than the dual op amp version. Mosst of the high end designs uses single op amp. Better implementations. No doubt the cost will be sllightly higher. Why don't u design the ultimate based on the single op amps.
Cheers!
Eddy.
Based on my listening experience, I found out that a single op amps always sounds better than the dual op amp version. Mosst of the high end designs uses single op amp. Better implementations. No doubt the cost will be sllightly higher. Why don't u design the ultimate based on the single op amps.
Cheers!
Eddy.
hi flyboi,
your comment I did already.
But in the LPF loks less effect than the bufffer. so I still choose the double op-amp, but outpt will be same use single o-amp.
hi jeans & stefanobilliani,
all your comment for improve did already.
Full balance sample a was tesing this several place.
detail will post later.
this several days I try the full balance in several audio setup all were over 96DB to test the dynamic & noise, this is dead silent, clos to the speaker several inch & still cannot hear any noise.
I private use headphone to test too.
thx
thomas
your comment I did already.
But in the LPF loks less effect than the bufffer. so I still choose the double op-amp, but outpt will be same use single o-amp.
hi jeans & stefanobilliani,
all your comment for improve did already.
Full balance sample a was tesing this several place.
detail will post later.
this several days I try the full balance in several audio setup all were over 96DB to test the dynamic & noise, this is dead silent, clos to the speaker several inch & still cannot hear any noise.
I private use headphone to test too.
thx
thomas
PC CD-Rom and ver.3 DAC
Hi, just to post my findings:
I like the DAC very well, it works equally good with a CD-Transport as it does with the optical out from my PC.
Never did Audio from my Computer sound better...
But I had the same problem as Kip, harsh sounding TTL.
Now I finally got to connect another drive, and I found something.
The first I used is a Phillips DVD-writer. The new one is an ASUS DVD.
Now both work, but I noticed that only with the ASUS the red light indicating data or connect (?) comes on.
I think that with the ASUS the sound quality is as excellent as with a standard CD-Player used as Transport.
Kip, unless you have already sold your CD-Controller, can you see if the red light comes on for you and/or can you test with a different drive?
I will try to hook up still another drive and try to do a comparison.
Please do not hold your breath, it will probably only happen in two to three weeks time.
And I will try to build a little circuit that brings TTL level down to "standard" levels and post my experience with that as well.
Regards
Michael
Hi, just to post my findings:
I like the DAC very well, it works equally good with a CD-Transport as it does with the optical out from my PC.
Never did Audio from my Computer sound better...
But I had the same problem as Kip, harsh sounding TTL.
Now I finally got to connect another drive, and I found something.
The first I used is a Phillips DVD-writer. The new one is an ASUS DVD.
Now both work, but I noticed that only with the ASUS the red light indicating data or connect (?) comes on.
I think that with the ASUS the sound quality is as excellent as with a standard CD-Player used as Transport.
Kip, unless you have already sold your CD-Controller, can you see if the red light comes on for you and/or can you test with a different drive?
I will try to hook up still another drive and try to do a comparison.
Please do not hold your breath, it will probably only happen in two to three weeks time.
And I will try to build a little circuit that brings TTL level down to "standard" levels and post my experience with that as well.
Regards
Michael
The red led comes on for the TTL input when I connect the digital output from the ASUS cd-rom drive. There is distortion on loud parts of the music and lyric. I thought that the cd-rom could be overdriving the input of the dac, but don't know how to test it. I have two other drives, but neither work with the controller. I tried a IDE thin laptop drive and didn't get any communication, then an old Creative Labs 4x drive and couldn't use all functions of the controller and then the controller would lock up. Neither drive has a digital out.
Hi all,
I bought an ASUS E616A2 DVD Rom, it works well with the CD Control kit, connected in TTL mode with the DAC.
But as many here, I hear sometimes harsh sound.
What i notice is that it occurs when the CD is slightly striped, The TTL led slightly blinking as if the drive are loosing signal.
So i Think this ASUS drive has problem reading used CDs ,
. Those same CD works well on my PC ( LG drive)
I will try later with my LG drive connected to the DAC, will report back.
Is the anyone who has feeback with PLEXTOR DVD Drive ?
Otherwise when CD is Ok, the ASUS drive does well its job. Better than my old Pionner DV-646A as optical drive (it's not a reference I know ) even though the ASUS drive are powered by a noname PC PSU of 200W
I bought an ASUS E616A2 DVD Rom, it works well with the CD Control kit, connected in TTL mode with the DAC.
But as many here, I hear sometimes harsh sound.
What i notice is that it occurs when the CD is slightly striped, The TTL led slightly blinking as if the drive are loosing signal.
So i Think this ASUS drive has problem reading used CDs ,
. Those same CD works well on my PC ( LG drive)I will try later with my LG drive connected to the DAC, will report back.
Is the anyone who has feeback with PLEXTOR DVD Drive ?
Otherwise when CD is Ok, the ASUS drive does well its job. Better than my old Pionner DV-646A as optical drive (it's not a reference I know
) even though the ASUS drive are powered by a noname PC PSU of 200WMy ASUS CD-S520/A5 cd-rom drive did not make the TTL input on the dac flicker. It stayed fully lit, but caused distortion. A slight crackle on some vocals and loud passages like the dac's input was being overdriven. I am now considering the purchase of a California Audio Labs CL-2500 DVD for use as a transport. I want to upgrade the output of the dac and still need to know where all the caps go that I bought with the dac.
Hi,
The green caps (rubbycon) are those near the TDA1541A, the oscon (x4) are the coupling caps on the edge of the PCB ( same line as output)... There is many picture on group buy post.
i tried plextor 130A, a noname DVD-ROM and a NEC DVD-Writer.
They all work with the control kit. They all read my striped CD ... but are slightly less good to my opinion than the ASUS DVD Rom (that i gave back to the store ). The ASUS has more improved stereo soundstage ( especially in depth), it sounds more detailed ( these are memory comparison)... But work fine only with new or just sligthly striped CDs... (the one I bought of course). So i Will see later which one i will definitively use ( or tweak)
The green caps (rubbycon) are those near the TDA1541A, the oscon (x4) are the coupling caps on the edge of the PCB ( same line as output)... There is many picture on group buy post.
i tried plextor 130A, a noname DVD-ROM and a NEC DVD-Writer.
They all work with the control kit. They all read my striped CD ... but are slightly less good to my opinion
than the ASUS DVD Rom (that i gave back to the store ). The ASUS has more improved stereo soundstage ( especially in depth), it sounds more detailed ( these are memory comparison)... But work fine only with new or just sligthly striped CDs... (the one I bought of course). So i Will see later which one i will definitively use ( or tweak)- Status
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