This is what RS comes up with for 'S1D'.
Rectifier Diodes & Schottky Diodes RS Components
Edit.....that didnt work it hasn't filtered the results.
I think that is a Vishay logo on your diodes
Rectifier Diodes & Schottky Diodes RS Components
Edit.....that didnt work it hasn't filtered the results.
I think that is a Vishay logo on your diodes
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Hi, thanks for the reply.
At the moment I have only changed all the electrolytic capacitors with others of higher quality.
I increased some of them .. c414-415-426-431-435 from 10uF to 22uf, c8-10-26 from 10uF to 100uF.
C103 from 100uF electrolytic to 100uF tantalum (the only one I put in tantalum).
The capacitors on the output (470uF bypassed by 0.1uF) ... I removed them and put a jumper.
I have always changed the 8 non-polarized capacitors with non-polarized ones ... same value but better quality.
Now I would like to devote myself to the diodes (but I'm not sure that it serves anything) .... oscillator ... and voltage regulators...and of course ... the opamps.
I think I keep them last.
I'm thinking about whether to use opamp or discrete modules.
I have already built a serious power supply (I attach photo).
Speaking of diodes:
The 4 diodes (d400-401-402-403) of my previous photo are part of a voltage doubler. Are we sure that changing them for schottky (or SIC) there is a benefit?
I wonder why they are part of a voltage doubler and not a normal diode bridge.
The other diodes that I see are for the protection of the regulators and I suppose that there is nothing good in changing them...
.. there would be no improvement .. What do you think?
D405 is the diode that is before the dc-dc converter..maybe it could be the only one that makes sense to change. What do you think?
.....but also for this diode I think that there would be no improvement because it is before a dc-dc converter.
There are 9 diodes in total, am I right?
I should have named them all.
Has anyone changed the diodes? Which ones and with what?
In addition I wanted to ask if it is "official" that there are benefits to put a 10uF tantalum in parallel to the C419 (but the electrolytic remains? >>> Probably stupid question!). Thanks again and sorry if I ask many questions!
Sorry for my bad english!
I put some photos of my dac:
At the moment I have only changed all the electrolytic capacitors with others of higher quality.
I increased some of them .. c414-415-426-431-435 from 10uF to 22uf, c8-10-26 from 10uF to 100uF.
C103 from 100uF electrolytic to 100uF tantalum (the only one I put in tantalum).
The capacitors on the output (470uF bypassed by 0.1uF) ... I removed them and put a jumper.
I have always changed the 8 non-polarized capacitors with non-polarized ones ... same value but better quality.
Now I would like to devote myself to the diodes (but I'm not sure that it serves anything) .... oscillator ... and voltage regulators...and of course ... the opamps.
I think I keep them last.
I'm thinking about whether to use opamp or discrete modules.
I have already built a serious power supply (I attach photo).
Speaking of diodes:
The 4 diodes (d400-401-402-403) of my previous photo are part of a voltage doubler. Are we sure that changing them for schottky (or SIC) there is a benefit?
I wonder why they are part of a voltage doubler and not a normal diode bridge.
The other diodes that I see are for the protection of the regulators and I suppose that there is nothing good in changing them...
.. there would be no improvement .. What do you think?
D405 is the diode that is before the dc-dc converter..maybe it could be the only one that makes sense to change. What do you think?
.....but also for this diode I think that there would be no improvement because it is before a dc-dc converter.
There are 9 diodes in total, am I right?
I should have named them all.
Has anyone changed the diodes? Which ones and with what?
In addition I wanted to ask if it is "official" that there are benefits to put a 10uF tantalum in parallel to the C419 (but the electrolytic remains? >>> Probably stupid question!). Thanks again and sorry if I ask many questions!
Sorry for my bad english!
I put some photos of my dac:
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I checked the link to aliexpress. That seller only has the + 5v and the + 15v.
Would a -15v also be needed? I mean ... the most important are these three ... to change?
Are we sure that as a current seal and dissipation will not be damaged?
It should be remembered that +/- 15v come from the voltage doubler ... therefore input at 78/7915 can also be 25v ... and beyond.
... the same for the 7805 ... which has 10 volts more than the output.
I have not measured. ..and I don't know the load absorption.
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Hi Taso
The seller has the negative regulator...they are listed as S79. The maximum input voltage for the Ti chips on these regs appears to be 36V, but please check. I think you know more about these things than I do.!
There is also an important 3term reg in the dacmagic at 3v3 for the clock I believe but this is an LM1117t which I think is not pin compatible.
I have read all this thread more than once and the last time just recently. I dont think many people spent much time changing the diodes.
The biggest gains seem to come from bypassing output caps...recap various rails and decoupling, and cleaner power supplies.
The majority used the Dexa regs which I believe are a discrete voltage regulator on a 3pin 78xx/79xx compatible TO220 package. They are quite expensive and that is why I am considering trying the ones I linked to on Aliexpress.
The seller has the negative regulator...they are listed as S79. The maximum input voltage for the Ti chips on these regs appears to be 36V, but please check. I think you know more about these things than I do.!
There is also an important 3term reg in the dacmagic at 3v3 for the clock I believe but this is an LM1117t which I think is not pin compatible.
I have read all this thread more than once and the last time just recently. I dont think many people spent much time changing the diodes.
The biggest gains seem to come from bypassing output caps...recap various rails and decoupling, and cleaner power supplies.
The majority used the Dexa regs which I believe are a discrete voltage regulator on a 3pin 78xx/79xx compatible TO220 package. They are quite expensive and that is why I am considering trying the ones I linked to on Aliexpress.
If I remember correctly, current through 7805 is 30 or 40 mA. Anyway, it is bellow 100 mA and voltage drop over regulator is 10V.
Current through 7815/7915 is a little bit less than 100 mA with original opamps.
Sorry, I don't remember exact numbers anymore.
Diodes were 10MQ100NPBF. i think they are obsolete now.
Current through 7815/7915 is a little bit less than 100 mA with original opamps.
Sorry, I don't remember exact numbers anymore.
Diodes were 10MQ100NPBF. i think they are obsolete now.
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I'm really tempted to change the 78/7915 and 7805 to get started.
I would be tempted to buy these..with LT3045: LT3045-78XX Ultra Low Noise LDO Voltage Regulator.
I hope..I think I understand that the LT3045 is better than the TPS7A4700. Reading the various tests well on the site Superpower Super Regulator by Belleson it seems to me that there is confirmation that the LT3045 is an excellent choice .... and cheap compared to Belleson and all the others.
What do you think about this choice? For 20/25 USD/Euro for each piece..is it the best choice? The improvements will be audible or is it worth the upgrade? Later I would like to change the crystal and its PSU.
The pcb with LT3045 have input at maximum 20v.
I have a special external power supply (see photo) .... I'm wondering if it is better to reduce the main output voltage from 12/13vdc ... to about 10.5vdc (with an armored resistance of 20/30w internally at power supply) ++++ reduce it further by changing the R400/401 ..... or perhaps it is better to reduce it only by working on R400/401 and leaving the main power output at about 12/13vdc.
What is the best solution?
I'm thinking that perhaps it is better to reduce the main output voltage a bit ... to make the R400/401 heat less and 2w resistance can be mounted.
Bigger resistances may not fit into the dacmagic.
What do you think?
Finally .... what is the ideal imput voltage for an LT3045 with 15vdc output?
Thanks! and sorry for my bad english
PS:
In here (see below) there are no space problems to put a 30/40w armored resistor to reduce the main output ... from 12/13vdc (maybe even 13.5vdc..I don't remember) ..... to ... I guess but I have no idea....about 10/10,5vdc.
Is there any problem for the dc-dc converter if it is powered at 10/10.5vdc?
.
I would be tempted to buy these..with LT3045: LT3045-78XX Ultra Low Noise LDO Voltage Regulator.
I hope..I think I understand that the LT3045 is better than the TPS7A4700. Reading the various tests well on the site Superpower Super Regulator by Belleson it seems to me that there is confirmation that the LT3045 is an excellent choice .... and cheap compared to Belleson and all the others.
What do you think about this choice? For 20/25 USD/Euro for each piece..is it the best choice? The improvements will be audible or is it worth the upgrade? Later I would like to change the crystal and its PSU.
The pcb with LT3045 have input at maximum 20v.
I have a special external power supply (see photo) .... I'm wondering if it is better to reduce the main output voltage from 12/13vdc ... to about 10.5vdc (with an armored resistance of 20/30w internally at power supply) ++++ reduce it further by changing the R400/401 ..... or perhaps it is better to reduce it only by working on R400/401 and leaving the main power output at about 12/13vdc.
What is the best solution?
I'm thinking that perhaps it is better to reduce the main output voltage a bit ... to make the R400/401 heat less and 2w resistance can be mounted.
Bigger resistances may not fit into the dacmagic.
What do you think?
Finally .... what is the ideal imput voltage for an LT3045 with 15vdc output?
Thanks! and sorry for my bad english
PS:
In here (see below) there are no space problems to put a 30/40w armored resistor to reduce the main output ... from 12/13vdc (maybe even 13.5vdc..I don't remember) ..... to ... I guess but I have no idea....about 10/10,5vdc.
Is there any problem for the dc-dc converter if it is powered at 10/10.5vdc?
.
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Hey old thread guys. Today I swapped out the 7805/7812/7912 regs for some tps7a4701 from Aliexpress
￡7.92 30%OFF | Lusya SUQIYA-Sigma78 Series LDO Low Noise Step-Down Linear Regulated Power Supply Module T0703
Lusya SUQIYA Sigma78 Series LDO Low Noise Step Down Linear Regulated Power Supply Module T0703|Amplifier| - AliExpress
Bit of a chore but you know how these 'simple ' jobs go! Damaged one track from one of the 3 term regs but was an easy fix.
Also added 0.1uf Wima across C95,96.
Well the main thing is it still works.......but......wow I'm oretty sure it has really added some weight and clarity to the LF. The regs aligned nicely with the heatsink so it was easy in thay respect. It raises the Hs off the PCB but it does not foul the chassis.
A worthy mod if you ask me and with a few hours it may well be better still.
￡7.92 30%OFF | Lusya SUQIYA-Sigma78 Series LDO Low Noise Step-Down Linear Regulated Power Supply Module T0703
Lusya SUQIYA Sigma78 Series LDO Low Noise Step Down Linear Regulated Power Supply Module T0703|Amplifier| - AliExpress
Bit of a chore but you know how these 'simple ' jobs go! Damaged one track from one of the 3 term regs but was an easy fix.
Also added 0.1uf Wima across C95,96.
Well the main thing is it still works.......but......wow I'm oretty sure it has really added some weight and clarity to the LF. The regs aligned nicely with the heatsink so it was easy in thay respect. It raises the Hs off the PCB but it does not foul the chassis.
A worthy mod if you ask me and with a few hours it may well be better still.
Listened some more this evening. Spotify> Google chromecast audio> Dacmagic> Salas DCG3 > 3e Audio tpa3255.
There were times before the reg mods...quite often actually...where what i heard thru Spotify was less than brilliant but I am fairly certain that the change of those voltage regs has made a.big step up in SQ...more weight in the bass....and I think clearer tops .
One benefit as a side effect is also lower temperatures....the case used to feel.pretty warm to the touch but it was entirely cool this evening.
There were times before the reg mods...quite often actually...where what i heard thru Spotify was less than brilliant but I am fairly certain that the change of those voltage regs has made a.big step up in SQ...more weight in the bass....and I think clearer tops .
One benefit as a side effect is also lower temperatures....the case used to feel.pretty warm to the touch but it was entirely cool this evening.
Hi, I too would like to upgrade the regulators and the oscillator shortly.
I would also like to eliminate the dc-dc converter that powers the oscillator.
At the moment I have upgraded all capacitors and created a serious external power supply.
Do you plan to do other mods? Oscillator? ..and relative power?
Thanks!
I would also like to eliminate the dc-dc converter that powers the oscillator.
At the moment I have upgraded all capacitors and created a serious external power supply.
Do you plan to do other mods? Oscillator? ..and relative power?
Thanks!
Hi Taso. I dont know how far I shall take the modifications to this Dac. I also have an Ian Canada dac stack to play with.
The potato thing interests me although the soldering would test me.
I woukd like to maybe add additional power rail filtering to the clock....or maybe a new clock.
U407 would be a good reg to swap if that powers the clock.?
The potato thing interests me although the soldering would test me.
I woukd like to maybe add additional power rail filtering to the clock....or maybe a new clock.
U407 would be a good reg to swap if that powers the clock.?
The oscillator is powered by the U12 DC-DC converter (+ 5_DIG).
The best solution is to replace the converter with a linear and ultra-quiet power supply. The problem is the voltage drop and dissipation.
At the input of the converter DC-DC there is a discretely higher voltage than the 5v output ... and therefore there is to fight with the dissipation.
Maybe you can lower the voltage with resistors a bit before going into the linear power supply? .......... I do not know!
I think the best solution is a small independent power supply-pcb which should be connected as in and out instead of the converter.
The DC-DC converter should be "deactivated".
Then yes… it would be good to change the U407 (LM117T 3.3v) with something more "quiet and clean".
I think that intervening on the oscillator and its power supply (above all) is a nice positive change.
On the market there are already pcb with power supply and oscillator. Single small pcb. Or you can change the oscillator and leave it on the dacmagic pcb .. and the power supply pcb .. apart.
Super oscillator with power supply:
HPRC - 331_SE molto basso jitter audio Orologio con Ultra Basso Rumore Regolamento CIRCUITO | eBay
HPRC - 331: alta precisione e bassa distorsione audio Orologio con circuito ultra bassa rumorosita | eBay
ULPNC: - 172dBc ultra basso rumore di fase & alta precisione & ultra basso rumore del circuito | eBay
The best solution is to replace the converter with a linear and ultra-quiet power supply. The problem is the voltage drop and dissipation.
At the input of the converter DC-DC there is a discretely higher voltage than the 5v output ... and therefore there is to fight with the dissipation.
Maybe you can lower the voltage with resistors a bit before going into the linear power supply? .......... I do not know!
I think the best solution is a small independent power supply-pcb which should be connected as in and out instead of the converter.
The DC-DC converter should be "deactivated".
Then yes… it would be good to change the U407 (LM117T 3.3v) with something more "quiet and clean".
I think that intervening on the oscillator and its power supply (above all) is a nice positive change.
On the market there are already pcb with power supply and oscillator. Single small pcb. Or you can change the oscillator and leave it on the dacmagic pcb .. and the power supply pcb .. apart.
Super oscillator with power supply:
HPRC - 331_SE molto basso jitter audio Orologio con Ultra Basso Rumore Regolamento CIRCUITO | eBay
HPRC - 331: alta precisione e bassa distorsione audio Orologio con circuito ultra bassa rumorosita | eBay
ULPNC: - 172dBc ultra basso rumore di fase & alta precisione & ultra basso rumore del circuito | eBay
TasoTaso,
Regarding the clock oscillator boards you linked to, IMO none of them is ideal for high performance audio. They are advertising jitter and phase noise numbers at offset frequencies that are pretty meaningless for use in DACs. What matters more and what is harder to get from a clock is very low phase noise at 10Hz or even at 1Hz offset from the carrier. The clocks in the ads don't show performance numbers at the relevant offsets, which is probably a clue that the numbers are would not look very good.
Regarding the clock oscillator boards you linked to, IMO none of them is ideal for high performance audio. They are advertising jitter and phase noise numbers at offset frequencies that are pretty meaningless for use in DACs. What matters more and what is harder to get from a clock is very low phase noise at 10Hz or even at 1Hz offset from the carrier. The clocks in the ads don't show performance numbers at the relevant offsets, which is probably a clue that the numbers are would not look very good.
Hi, I have installed a voltage stabilizer in the house.
Now the voltage fluctuates between 229vac and 231vac.
I opened the power supply of the DacMagic and, through two resistors in parallel for a total of 2.13k 20w (3.9k + 4.7k), I calibrated a power supply voltage of the dac of about 11.15vdc.
Now I have these tensions in regulator imput:
Input 7815 = 20.4vdc (before, without resistor = 26.4vdc)
Input 7915 = 19.4vdc (before, without resistor = 25.4vdc)
Input DC-DC Converter = 10.1vdc
and this tension on regulator output:
Output 7815 =14.92vdc
Output 7915 = 14.95vdc
Output DC-DC Converter = 5.00vdc
Do you think everything is ok?
Can the two resistors be a problem for the final "audio quality"?
Are ceramic resistors good as shown in the picture?
Or is there some kind of more suitable resistance?
The resistances are slightly warm, I guess 35 ° celsius.
Now the dac is really much cooler!
..and now, one question:
Considering approximately 10vdc input to the DC-DC Converter it would not be possible to replace it with a quality 7805 .. similar to the Dexa? How much absorption do we have on the DC-DC Converter?
Other question:
What are those 2 "free" connectors on the pcb for?
Why on the pcb I have an R5 but I can't find it in the schematic?
Many thanks!
Now the voltage fluctuates between 229vac and 231vac.
I opened the power supply of the DacMagic and, through two resistors in parallel for a total of 2.13k 20w (3.9k + 4.7k), I calibrated a power supply voltage of the dac of about 11.15vdc.
Now I have these tensions in regulator imput:
Input 7815 = 20.4vdc (before, without resistor = 26.4vdc)
Input 7915 = 19.4vdc (before, without resistor = 25.4vdc)
Input DC-DC Converter = 10.1vdc
and this tension on regulator output:
Output 7815 =14.92vdc
Output 7915 = 14.95vdc
Output DC-DC Converter = 5.00vdc
Do you think everything is ok?
Can the two resistors be a problem for the final "audio quality"?
Are ceramic resistors good as shown in the picture?
Or is there some kind of more suitable resistance?
The resistances are slightly warm, I guess 35 ° celsius.
Now the dac is really much cooler!
..and now, one question:
Considering approximately 10vdc input to the DC-DC Converter it would not be possible to replace it with a quality 7805 .. similar to the Dexa? How much absorption do we have on the DC-DC Converter?
Other question:
What are those 2 "free" connectors on the pcb for?
Why on the pcb I have an R5 but I can't find it in the schematic?
Many thanks!
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